Mục tiêu: So sánh đặc đặc điểm lâm sàng, cắt lớp vi tính lồng ngực và hình ảnh tổn thương quan sá... more Mục tiêu: So sánh đặc đặc điểm lâm sàng, cắt lớp vi tính lồng ngực và hình ảnh tổn thương quan sát được trong PTNS ở bệnh nhân u lao với ung thư phổi nguyên phát. Đối tượng và phương pháp: Nghiên cứu tiến cứu, mô tả bệnh nhân có tổn thương dạng u đơn độc ở ngoại vi phổi được Phẫu thuật nội soi chẩn đoán và điều trị tại Khoa Ngoại lồng ngực - Bệnh viện Phạm Ngọc Thạch, thời gian từ 11/2011 đến 7/2014. Kết quả: Có 147 bệnh nhân, trong đó 47 trường hợp u lao và 100 BN UTP. Bệnh nhân u lao có tuổi trung bình thấp hơn (49,7±11,2 so với 60,0±10,4), tiền sử mắc bệnh lao phổi nhiều hơn (4,1% so với 1,4%), triệu chứng ho ra máu chiếm tỷ lệ thấp hơn (2,0% so với 13,6%). Trên phim CLVT lồng ngực, u lao phổi chiếm tỷ lệ cao hơn khi kích thước u ≤ 2,0cm, u có bờ rõ nhẵn; khi kích thước u > 3,0cm, bờ khối u có múi, đa cung hay tua gai khả năng cao là UTP. Quan sát hình ảnh tổn thương đại thể trong PTNS cho thấy, khi có dấu hiệu dầy dính màng phổi tại vị trí u, khả năng cao là u lao, khi có dấu...
River deltas globally are highly exposed and vulnerable to natural hazards and are often over-exp... more River deltas globally are highly exposed and vulnerable to natural hazards and are often over-exploited landforms. The Global Delta Risk Index (GDRI) was developed to assess multi-hazard risk in river deltas and support decision-making in risk reduction interventions in delta regions. Disasters have significant impacts on the progress towards the Sustainable Development Goals (SDGs). However, despite the strong interlinkage between disaster risk reduction and sustainable development, global frameworks are still developed in isolation and actions to address them are delegated to different institutions. Greater alignment between frameworks would both simplify monitoring progress towards disaster risk reduction and sustainable development and increase capacity to address data gaps in relation to indicator-based assessments for both processes. This research aims at aligning the GDRI indicators with the SDGs and the Sendai Framework for Disaster and Risk Reduction (SFDRR). While the GDRI...
There has been substantial commentary on the role of cyberattacks carried by low-level cybercrime... more There has been substantial commentary on the role of cyberattacks carried by low-level cybercrime actors in the Russia-Ukraine conflict. We analyse 358k web defacement attacks, 1.7M reflected DDoS attacks, 1 764 Hack Forums posts mentioning the two countries, and 441 announcements (with 58k replies) of a volunteer hacking group for two months before and four months after the invasion. We find the conflict briefly but notably caught the attention of low-level cybercrime actors, with significant increases in online discussion and both types of attack targeting Russia and Ukraine. However, there was little evidence of high-profile actions; the role of these players in the ongoing hybrid warfare is minor, and they should be separated from persistent and motivated 'hacktivists' in statesponsored operations. Their involvement in the conflict appears to have been short-lived and fleeting, with a clear loss of interest in discussing the situation and carrying out both defacement and DDoS attacks against either Russia or Ukraine after a few weeks. CCS CONCEPTS • Social and professional topics → Computer crime; • Applied computing → Cyberwarfare; • Security and privacy → Social aspects of security and privacy; • Mathematics of computing → Time series analysis; • Networks → Denial-of-service attacks.
Towards the growing trends in lightweight, flexible, and optical advantages, thin glasses become ... more Towards the growing trends in lightweight, flexible, and optical advantages, thin glasses become key components in numerous applications such as consumer electronics like foldable smartphones, or automotive interiors. Nonisothermal glass molding promises a viable technology for the cost-efficient production of precision glass components. In the existing production, the quality of the glass products can only be accessed at the end of the hot forming process. Due to high rates of product failures often appeared in the precision glass molding processes, the current quality control of the produced optical products suffers low process efficiency. This work introduces an enabling approach for monitoring the product quality in real-time using thermography and machine learning. Specifically, the acquisition of the temperature fields of the glass components during the hot forming stage enabled by an infrared thermographic camera allows machine learning to predict the final shape of the molde...
The influence of La, Ce elements and thermal-mechanical treatment on microstructure and mechanica... more The influence of La, Ce elements and thermal-mechanical treatment on microstructure and mechanical properties of Al-Zn-Mg-Cu alloy are presented in this study. According to the results, when the alloy was added to the La, Ce elements, after casting, the grain size of samples was around 40-50µm compared to that of without about 65µm; and then these impurity samples attained 30µm after homogeneous mixture the grain sizes. After the cold deformation process, the distance between plates is 10µm. This homogenization process contributes to increasing the ductility of the studied alloy. In addition, the EDS lines study shows that after the combination of the deformation and heat treatment, the uniformation of elements mainly focuses on the boundary and in the grain. After recrystallization annealing, the grain size is around 10 µm with the modification sample. Further, as a result of ability deformation from the tensile test, these results demonstrate that the tensile test obtained 140 % w...
Lecture notes in networks and systems, Nov 9, 2020
In this work, we study a new image annotation task named Extractive Tags Summarization (ETS). The... more In this work, we study a new image annotation task named Extractive Tags Summarization (ETS). The goal is to extract important tags from the context lying in an image and its corresponding tags. We adjust some state-of-the-art deep learning models to utilize both visual and textual information. Our proposed solution consists of different widely used blocks like convolutional and self-attention layers, together with a novel idea of combining auxiliary loss functions and the gating mechanism to glue and elevate these fundamental components and form a unified architecture. Besides, we introduce a loss function that aims to reduce the imbalance of the training data and a simple but effective data augmentation technique dedicated to alleviates the effect of outliers on the final results. Last but not least, we explore an unsupervised pre-training strategy to further boost the performance of the model by making use of the abundant amount of available unlabeled data. Our model shows the good results as 90% F 1 score on the public NUS-WIDE benchmark, and 50% F 1 score on a noisy largescale real-world private dataset. Source code for reproducing the experiments is publicly available at: https: // github. com/ pixta-dev/ labteam
Dichromate anions were intercalated between two consecutive hydroxide layers of [Mg0.6Al0.4(OH)2]... more Dichromate anions were intercalated between two consecutive hydroxide layers of [Mg0.6Al0.4(OH)2]0.40+ via co-precipitation at different pH conditions. The physico-chemical properties of the obtained solids were examined by physical methods such as X-ray diffraction (XRD), Infrared (IR), Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET) and Energy-Dispersive Spectroscopy (EDS). The experimental results indicated that the amount of dichromate anions in the catalysts varies with the pH media. Also, the morphology, structure and chemical composition of the materials depends strongly on the preparation conditions. The Mg-Al-Cr2O7 hydrotalcite-like compounds are used as heterogeneous catalysts for the styrene oxidation with H2O2 at mild conditions. The styrene conversion is about 20-50% while styrene selectivity remains rather high.
CoOx/magenium silicate catalysts are obtained though precipitation and calcination method. The pr... more CoOx/magenium silicate catalysts are obtained though precipitation and calcination method. The prepared solids were analyzed by XRD, BET, EDS... Cobalt(II) ions supported-magnesium silicate catalysts expressed as effective catalysts for selective oxidation of benzyl alcohol using tert-butyl hydroperoxide as an oxidizing agent. The experimental results showed very high selectivity to the benzaldehyde product at benzyl alcohol conversion of 18-25%.
Corals-like molybdenum disulfide (MoS2) have been successfully synthesized via the hydrothermal m... more Corals-like molybdenum disulfide (MoS2) have been successfully synthesized via the hydrothermal method. The as-prepared MoS2 material with a high surface area of 83.9 m2.g-1 was used for the removal of tartrazine from an aqueous solution. The effects of parameters including contact time, MoS2 dosage, and solution pH on adsorption capacity were studied. The optimal dosage of MoS2 for removing tartrazine was 0.08 g and the removal efficiency of tartrazine reached 81.5 % for 100 min of adsorption. The adsorption kinetics studies were carried out using pseudo-first-order, pseudo-second-order, and intra-particle diffusion models. The results showed that the pseudo-second-kinetic model better described the adsorption kinetics of tartrazine on MoS2 and film diffusion was the rate-limiting step. In addition, the adsorption capacity of MoS2 was also performed with various organic dyes such as nile blue, janus green B, and congo red.
Received: 05/4/2020 Accepted: 30/6/2020 ZnO, C3N4 and ZnO/g-C3N4 composite were prepared for degr... more Received: 05/4/2020 Accepted: 30/6/2020 ZnO, C3N4 and ZnO/g-C3N4 composite were prepared for degradation of methylene blue (MB) under visible light irradiation. The obtained samples were characterized by N2 adsorption/desorption isotherm and Ultraviolet– Visible Diffuse Reflectance Spectroscopy (UV-vis DRS). The results showed that the ZnO/g-C3N4 composite had a lower surface area and pore volume than ZnO and g-C3N4. The bandgap energy of ZnO/g-C3N4 composite was 3.20 eV showing a slight decrease with that of pure ZnO (3.21 eV). The degradation of MB on g-C3N4 was higher than those of ZnO and ZnO/g-C3N4 composite in initial 40 min, but its degradation reaction rate was lower than those of ZnO and ZnO/g-C3N4 composite in 90 min. As the result, the ZnO/g-C3N4 composite exhibited the highest degradation efficiency (93.2 %) among the prepared samples. In addition, the effect of molar ratio of ZnO:g-C3N4 on photocatalytic activity and photocatalytic mechanism under visible light was inve...
Zinc oxide (ZnO) has been shown as a potential photocatalyst under ultraviolet (UV) light but its... more Zinc oxide (ZnO) has been shown as a potential photocatalyst under ultraviolet (UV) light but its catalytic activity has a limitation under visible (Vis) light due to the wide bandgap energy and the rapid recombination of electrons and holes. Thus, hierarchical structure Au/ZnO composites were fabricated by the hydrothermal method and chemical reduction method for enhanced photocatalytic performance under visible light. As-prepared composites were characterized by UV-vis diffuse reflectance spectra (DR/UV-Vis), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and electron paramagnetic resonance (EPR). The Au/ZnO-5 composite showed the highest adsorption among as-prepared samples in the range of 250-550 nm, having bandgap energy of 0.13 eV. Au nanoparticles of about 3-5 nm were well dispersed on hierarchical flower ZnO with ...
In this study, the physical properties of ZnO were facile controlled by the synthesis method with... more In this study, the physical properties of ZnO were facile controlled by the synthesis method with the addition of capping and precipitation agents. As-prepared ZnO samples had different morphologies such as carnation flower-like ZnO (CF-ZnO), rose-flower-like ZnO (RF-ZnO), rod-like ZnO (R-ZnO), and nanoparticle ZnO (N-ZnO) and were characterized by SEM, XRD, N2 adsorption/desorption isotherms, FT-IR, and DR/UV-vis. All samples had a crystallite structure of hexagonal wurtzite type. The CF-ZnO and RF-ZnO samples had the hierarchical structure like a carnation flower and a beautiful rose, respectively. R-ZnO was composed of many hexagonal rods and few spherical particles, while N-ZnO microstructures were made up of nanoparticles with approximately 20–30 nm, exhibiting the largest surface area, pore volume, and pore width among as-prepared samples, and their crystal size and bandgap energy were 17.8 nm and 3.207 eV, respectively. The catalytic performances of ZnO samples were evaluated...
Transportation Research Part F: Traffic Psychology and Behaviour, 2020
Mobile phone use while riding is one of the five most common risky behaviors of motorcycle riders... more Mobile phone use while riding is one of the five most common risky behaviors of motorcycle riders in Vietnam. This study investigated motorcyclist's mobile phone use while riding intention and behavior based on the extended Theory of Planned Behavior (TPB) framework. Based on this framework, attitude, subjective norm, perceived behavioral control, habits, and health motivation underlying the rider's mobile phone use while riding intentions and behavior were included in a questionnaire and captured by direct and indirect measurements. Small-displacement motorcycle riders (N = 291) completed the extended TPB based questionnaire. An exploratory factor analysis technique identified the selected factors (e.g., attitude, habit, etc.). Moreover, Structural Equation Modeling results showed moderate to good fits to the observed data. Therefore, the results supported the utilization of extended TPB framework in identifying factors of mobile phone use while riding intention and behavior. Specifically, negative attitude, perceived behavioral control, and mobile phone use while riding habit related to the intention to use a mobile phone while riding of small-displacement motorcyclists. Meanwhile, habit and behavioral intention related to the behavior to use a mobile phone while riding of small-displacement motorcycle riders. Especially, the correlation between behavioral intention and self-reported behavior was very strong. This finding embraced previous research indicating that intention was a major motivational component of behavior. Based on the results, safety intervention implications for small-displacement motorcycle riders were discussed.
Recently, Malware Analysis has been received much attention not only in industry but also in the ... more Recently, Malware Analysis has been received much attention not only in industry but also in the academic community. Modern malware frequently applies obfuscation techniques (e.g., indirect jump, overlapping instruction) to conceal its behaviors and protect itself against antivirus software, which regularly uses lightweight detection methods like bitbased fingerprints. Since famous commercial disassemblers such as IDA Pro and Capstone are easily fooled by these obfuscations, analyzing and detecting the obfuscated malware are not straightforward. For dealing with these problems, some malware analysis approaches based on Control Flow Graph (CFG) have been proposed (e.g., VxClass at Google). To effectively reconstruct the CFG, a technique called Dynamic Symbolic Execution (DSE) (known as concolic testing) has been widely applied. It is the combination of symbolic execution and testing to automatically explore all feasible program execution paths and determine the destination of obfuscation code like indirect jumps (by using a binary emulator). In DSE, the feasibility of a path constraint is checked by testing with a satisfiable instance using a Theorem Prover. Currently, we have developed BE-PUM (Binary Emulation for PUshdown Model), a binary analyzer concentrating on malware for Intel x86 architecture. Learning from its experiences, BE-PUM can be extended to other platforms. By considering IoT Malware, ARM is our first target.
Zinc oxide (ZnO) has been known as an excellent photocatalyst for the degradation of a variety of... more Zinc oxide (ZnO) has been known as an excellent photocatalyst for the degradation of a variety of organic pollutants under UV irradiation. This work describes a synthesis of ZnO nanoparticles via a facile precipitation method, and Ag was doped into Ag/ZnO nanocomposite to improve the photocatalytic degradation of BPA under visible light irradiation. The obtained ZnO nanoparticles were 20 nm in size and had a relatively high surface area and pore volume, 26.2 m2/g and 0.48 cm3/g, respectively. The deposition of Ag led to a decrease in the surface area, pore volume, and band gap energy ( E g ) of ZnO nanoparticles. However, the photocatalytic activity of Ag/ZnO composite in the case increased. The performance of ZnO was compared with Ag/ZnO composites at the different molar ratios, and the kinetic reaction of BPA in these catalysts was investigated by the first-order kinetic model. The sample of Ag/ZnO-10 composite had the highest catalytic activity and showed the degradation efficien...
The pyridinedicarboxylate-Tb(III) complexes, TbPDC and Tb(PDC)3, as luminescent probes for ATP mo... more The pyridinedicarboxylate-Tb(III) complexes, TbPDC and Tb(PDC)3, as luminescent probes for ATP monitoring have been conveniently prepared and characterized by FT-IR, 1H-NMR, ESI-MS, UV-Vis, excitation, and emission spectroscopy. Interestingly, these two Tb(III) complexes were quenched by ATP by a similar mechanism via π-π stacking interaction between the chelating ligand and adenine moiety. The ability of luminescent probes applied for the determination of ATP in aqueous solution has been investigated. The dynamic ranges for the quantification of ATP are within 10−90 μM and 10−100 μM with detection limits of 7.62 and 11.20 μM for TbPDC and Tb(PDC)3, respectively. The results demonstrated that these luminescent probes would be a potential candidate assay for ATP monitoring in hygiene assessment.
Magnetically responsive ultrafiltration membranes were prepared by grafting poly(2-hydroxyethyl m... more Magnetically responsive ultrafiltration membranes were prepared by grafting poly(2-hydroxyethyl methacrylate) chains from the outer surface of 100-kDa regenerated cellulose ultrafiltration membranes. Surface-initiated atom transfer radical polymerization was used to graft the polymer chains. Grafting from the internal pore surface was suppressed by using glycerol as a pore-filling solvent during initiator immobilization at varied densities. Glycerol suppresses the initiator attachment to the pore surface. Polymerization times of up to four hours were investigated. Superparamagnetic nanoparticles were covalently attached to the chain end. Membrane performance was determined using bovine serum albumin and dextran as model solutes. Increasing the grafted polymer chain density and length led to a decrease in the permeate flux and an increase in the apparent rejection coefficient. In an oscillating magnetic field, movement of the grafted polymer chains led to a decrease in the permeate f...
This paper presents an application of the Radial Basis Function – Based Finite Difference Method ... more This paper presents an application of the Radial Basis Function – Based Finite Difference Method (RBF-FD) to solving the electrical transient problems defined by the time-dependent ordinary differential equations. In this method, the finite difference approximations of first- and second-order derivatives in time domain are formalated the same as those in space domain based on the MQ (Multiquadrics) function presented in [1]. The MQ RBF-FD method are for the sake of evaluating the accuracy, effectiveness and applicability used to compute the transient voltages on the benchmark circuit and 220 kV three-phase transmission line of Viet Nam. Our numerical results are compared with those obtained by the analytical method, the traditional FD method and ATP/EMTP software. The compared results have been shown that the MQ RBF-FD method has accuracy that is higher than ones of the traditional numerical methods, especially with the optimal shape parameter.
Objective: This study aims to determine the trace cadmium in water and fish species from estuarie... more Objective: This study aims to determine the trace cadmium in water and fish species from estuaries in Tien Hai, Thai Binh province, Vietnam by graphite furnace atomic absorption spectrometry (GF-AAS). Methodology: The optimal conditions has been investigated by studying the effects of analysis parameters such as spectral line, current of cathode lamp, slit width, furnace temperature, acid concentration and subtracted solution on absorbance. The validation method was evaluated by linear range, accuracy, repeatability, limit of detection (LOD), limit of quantitation (LOQ), recovery (Re), and determination of trace cadmium in water and fish species. Findings: The results showed that the spectral line of 228.3 nm, current of cathode lamp of 4 mA, slit width of 0.5 nm, furnace temperature of 1800 • C, HNO 3 concentration of 1%, CH 3 COONH 4 concentration of 1% were optimal conditions for determination of cadmium. At these conditions, the analytical procedure exhibited the high accuracy and repeatability. The linear range of cadmium was 0-4 ppb. The LOD and LOQ values were 0.0058 and 0.019 ppb, respectively. Application/Improvements: Determination of the trace cadmium in the water and fish samples was done by the development of analytical procedure. It was applied to determine the water and fish species from Ba Lat and Lan estuaries in Tien Hai,
Nonisothermal Glass Molding (NGM) has become a viable replicative manufacturing technology for th... more Nonisothermal Glass Molding (NGM) has become a viable replicative manufacturing technology for the cost-efficient production of complex precision optical components made of glass. During the pressing stage in NGM, glass materials undergo a huge temperature change in the glass transition range. In this range, glass exhibits thermo-viscoelastic responses, and the temperature drop through the glass transition leads glass structure to depart from an equilibrium to a nonequilibrium state. Thermo-viscoelastic properties of the nonequilibrium glass material greatly depend on temperature and thermal history. This paper presents a phenomenological constitutive model developed for modeling the thermoviscoelastic responses of nonequilibrium glass. We propose a direct incorporation of the temperature-and thermal history effects into each parameter of the phenomenological model. This novelty allows the model to describe the nonequilibrium phenomena and to study temperaturedependent viscoelasticity of glass without assuming thermo-rheologically simple characteristics. Furthermore, the phenomenological model enables the coupling of structural-and stress relaxation phenomena. The model validation conducted for creep experiments demonstrates an enhancement in numerical predictions of the nonequilibrium material behaviors of glass over wide ranges of temperature and thermal history.
Mục tiêu: So sánh đặc đặc điểm lâm sàng, cắt lớp vi tính lồng ngực và hình ảnh tổn thương quan sá... more Mục tiêu: So sánh đặc đặc điểm lâm sàng, cắt lớp vi tính lồng ngực và hình ảnh tổn thương quan sát được trong PTNS ở bệnh nhân u lao với ung thư phổi nguyên phát. Đối tượng và phương pháp: Nghiên cứu tiến cứu, mô tả bệnh nhân có tổn thương dạng u đơn độc ở ngoại vi phổi được Phẫu thuật nội soi chẩn đoán và điều trị tại Khoa Ngoại lồng ngực - Bệnh viện Phạm Ngọc Thạch, thời gian từ 11/2011 đến 7/2014. Kết quả: Có 147 bệnh nhân, trong đó 47 trường hợp u lao và 100 BN UTP. Bệnh nhân u lao có tuổi trung bình thấp hơn (49,7±11,2 so với 60,0±10,4), tiền sử mắc bệnh lao phổi nhiều hơn (4,1% so với 1,4%), triệu chứng ho ra máu chiếm tỷ lệ thấp hơn (2,0% so với 13,6%). Trên phim CLVT lồng ngực, u lao phổi chiếm tỷ lệ cao hơn khi kích thước u ≤ 2,0cm, u có bờ rõ nhẵn; khi kích thước u > 3,0cm, bờ khối u có múi, đa cung hay tua gai khả năng cao là UTP. Quan sát hình ảnh tổn thương đại thể trong PTNS cho thấy, khi có dấu hiệu dầy dính màng phổi tại vị trí u, khả năng cao là u lao, khi có dấu...
River deltas globally are highly exposed and vulnerable to natural hazards and are often over-exp... more River deltas globally are highly exposed and vulnerable to natural hazards and are often over-exploited landforms. The Global Delta Risk Index (GDRI) was developed to assess multi-hazard risk in river deltas and support decision-making in risk reduction interventions in delta regions. Disasters have significant impacts on the progress towards the Sustainable Development Goals (SDGs). However, despite the strong interlinkage between disaster risk reduction and sustainable development, global frameworks are still developed in isolation and actions to address them are delegated to different institutions. Greater alignment between frameworks would both simplify monitoring progress towards disaster risk reduction and sustainable development and increase capacity to address data gaps in relation to indicator-based assessments for both processes. This research aims at aligning the GDRI indicators with the SDGs and the Sendai Framework for Disaster and Risk Reduction (SFDRR). While the GDRI...
There has been substantial commentary on the role of cyberattacks carried by low-level cybercrime... more There has been substantial commentary on the role of cyberattacks carried by low-level cybercrime actors in the Russia-Ukraine conflict. We analyse 358k web defacement attacks, 1.7M reflected DDoS attacks, 1 764 Hack Forums posts mentioning the two countries, and 441 announcements (with 58k replies) of a volunteer hacking group for two months before and four months after the invasion. We find the conflict briefly but notably caught the attention of low-level cybercrime actors, with significant increases in online discussion and both types of attack targeting Russia and Ukraine. However, there was little evidence of high-profile actions; the role of these players in the ongoing hybrid warfare is minor, and they should be separated from persistent and motivated 'hacktivists' in statesponsored operations. Their involvement in the conflict appears to have been short-lived and fleeting, with a clear loss of interest in discussing the situation and carrying out both defacement and DDoS attacks against either Russia or Ukraine after a few weeks. CCS CONCEPTS • Social and professional topics → Computer crime; • Applied computing → Cyberwarfare; • Security and privacy → Social aspects of security and privacy; • Mathematics of computing → Time series analysis; • Networks → Denial-of-service attacks.
Towards the growing trends in lightweight, flexible, and optical advantages, thin glasses become ... more Towards the growing trends in lightweight, flexible, and optical advantages, thin glasses become key components in numerous applications such as consumer electronics like foldable smartphones, or automotive interiors. Nonisothermal glass molding promises a viable technology for the cost-efficient production of precision glass components. In the existing production, the quality of the glass products can only be accessed at the end of the hot forming process. Due to high rates of product failures often appeared in the precision glass molding processes, the current quality control of the produced optical products suffers low process efficiency. This work introduces an enabling approach for monitoring the product quality in real-time using thermography and machine learning. Specifically, the acquisition of the temperature fields of the glass components during the hot forming stage enabled by an infrared thermographic camera allows machine learning to predict the final shape of the molde...
The influence of La, Ce elements and thermal-mechanical treatment on microstructure and mechanica... more The influence of La, Ce elements and thermal-mechanical treatment on microstructure and mechanical properties of Al-Zn-Mg-Cu alloy are presented in this study. According to the results, when the alloy was added to the La, Ce elements, after casting, the grain size of samples was around 40-50µm compared to that of without about 65µm; and then these impurity samples attained 30µm after homogeneous mixture the grain sizes. After the cold deformation process, the distance between plates is 10µm. This homogenization process contributes to increasing the ductility of the studied alloy. In addition, the EDS lines study shows that after the combination of the deformation and heat treatment, the uniformation of elements mainly focuses on the boundary and in the grain. After recrystallization annealing, the grain size is around 10 µm with the modification sample. Further, as a result of ability deformation from the tensile test, these results demonstrate that the tensile test obtained 140 % w...
Lecture notes in networks and systems, Nov 9, 2020
In this work, we study a new image annotation task named Extractive Tags Summarization (ETS). The... more In this work, we study a new image annotation task named Extractive Tags Summarization (ETS). The goal is to extract important tags from the context lying in an image and its corresponding tags. We adjust some state-of-the-art deep learning models to utilize both visual and textual information. Our proposed solution consists of different widely used blocks like convolutional and self-attention layers, together with a novel idea of combining auxiliary loss functions and the gating mechanism to glue and elevate these fundamental components and form a unified architecture. Besides, we introduce a loss function that aims to reduce the imbalance of the training data and a simple but effective data augmentation technique dedicated to alleviates the effect of outliers on the final results. Last but not least, we explore an unsupervised pre-training strategy to further boost the performance of the model by making use of the abundant amount of available unlabeled data. Our model shows the good results as 90% F 1 score on the public NUS-WIDE benchmark, and 50% F 1 score on a noisy largescale real-world private dataset. Source code for reproducing the experiments is publicly available at: https: // github. com/ pixta-dev/ labteam
Dichromate anions were intercalated between two consecutive hydroxide layers of [Mg0.6Al0.4(OH)2]... more Dichromate anions were intercalated between two consecutive hydroxide layers of [Mg0.6Al0.4(OH)2]0.40+ via co-precipitation at different pH conditions. The physico-chemical properties of the obtained solids were examined by physical methods such as X-ray diffraction (XRD), Infrared (IR), Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET) and Energy-Dispersive Spectroscopy (EDS). The experimental results indicated that the amount of dichromate anions in the catalysts varies with the pH media. Also, the morphology, structure and chemical composition of the materials depends strongly on the preparation conditions. The Mg-Al-Cr2O7 hydrotalcite-like compounds are used as heterogeneous catalysts for the styrene oxidation with H2O2 at mild conditions. The styrene conversion is about 20-50% while styrene selectivity remains rather high.
CoOx/magenium silicate catalysts are obtained though precipitation and calcination method. The pr... more CoOx/magenium silicate catalysts are obtained though precipitation and calcination method. The prepared solids were analyzed by XRD, BET, EDS... Cobalt(II) ions supported-magnesium silicate catalysts expressed as effective catalysts for selective oxidation of benzyl alcohol using tert-butyl hydroperoxide as an oxidizing agent. The experimental results showed very high selectivity to the benzaldehyde product at benzyl alcohol conversion of 18-25%.
Corals-like molybdenum disulfide (MoS2) have been successfully synthesized via the hydrothermal m... more Corals-like molybdenum disulfide (MoS2) have been successfully synthesized via the hydrothermal method. The as-prepared MoS2 material with a high surface area of 83.9 m2.g-1 was used for the removal of tartrazine from an aqueous solution. The effects of parameters including contact time, MoS2 dosage, and solution pH on adsorption capacity were studied. The optimal dosage of MoS2 for removing tartrazine was 0.08 g and the removal efficiency of tartrazine reached 81.5 % for 100 min of adsorption. The adsorption kinetics studies were carried out using pseudo-first-order, pseudo-second-order, and intra-particle diffusion models. The results showed that the pseudo-second-kinetic model better described the adsorption kinetics of tartrazine on MoS2 and film diffusion was the rate-limiting step. In addition, the adsorption capacity of MoS2 was also performed with various organic dyes such as nile blue, janus green B, and congo red.
Received: 05/4/2020 Accepted: 30/6/2020 ZnO, C3N4 and ZnO/g-C3N4 composite were prepared for degr... more Received: 05/4/2020 Accepted: 30/6/2020 ZnO, C3N4 and ZnO/g-C3N4 composite were prepared for degradation of methylene blue (MB) under visible light irradiation. The obtained samples were characterized by N2 adsorption/desorption isotherm and Ultraviolet– Visible Diffuse Reflectance Spectroscopy (UV-vis DRS). The results showed that the ZnO/g-C3N4 composite had a lower surface area and pore volume than ZnO and g-C3N4. The bandgap energy of ZnO/g-C3N4 composite was 3.20 eV showing a slight decrease with that of pure ZnO (3.21 eV). The degradation of MB on g-C3N4 was higher than those of ZnO and ZnO/g-C3N4 composite in initial 40 min, but its degradation reaction rate was lower than those of ZnO and ZnO/g-C3N4 composite in 90 min. As the result, the ZnO/g-C3N4 composite exhibited the highest degradation efficiency (93.2 %) among the prepared samples. In addition, the effect of molar ratio of ZnO:g-C3N4 on photocatalytic activity and photocatalytic mechanism under visible light was inve...
Zinc oxide (ZnO) has been shown as a potential photocatalyst under ultraviolet (UV) light but its... more Zinc oxide (ZnO) has been shown as a potential photocatalyst under ultraviolet (UV) light but its catalytic activity has a limitation under visible (Vis) light due to the wide bandgap energy and the rapid recombination of electrons and holes. Thus, hierarchical structure Au/ZnO composites were fabricated by the hydrothermal method and chemical reduction method for enhanced photocatalytic performance under visible light. As-prepared composites were characterized by UV-vis diffuse reflectance spectra (DR/UV-Vis), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and electron paramagnetic resonance (EPR). The Au/ZnO-5 composite showed the highest adsorption among as-prepared samples in the range of 250-550 nm, having bandgap energy of 0.13 eV. Au nanoparticles of about 3-5 nm were well dispersed on hierarchical flower ZnO with ...
In this study, the physical properties of ZnO were facile controlled by the synthesis method with... more In this study, the physical properties of ZnO were facile controlled by the synthesis method with the addition of capping and precipitation agents. As-prepared ZnO samples had different morphologies such as carnation flower-like ZnO (CF-ZnO), rose-flower-like ZnO (RF-ZnO), rod-like ZnO (R-ZnO), and nanoparticle ZnO (N-ZnO) and were characterized by SEM, XRD, N2 adsorption/desorption isotherms, FT-IR, and DR/UV-vis. All samples had a crystallite structure of hexagonal wurtzite type. The CF-ZnO and RF-ZnO samples had the hierarchical structure like a carnation flower and a beautiful rose, respectively. R-ZnO was composed of many hexagonal rods and few spherical particles, while N-ZnO microstructures were made up of nanoparticles with approximately 20–30 nm, exhibiting the largest surface area, pore volume, and pore width among as-prepared samples, and their crystal size and bandgap energy were 17.8 nm and 3.207 eV, respectively. The catalytic performances of ZnO samples were evaluated...
Transportation Research Part F: Traffic Psychology and Behaviour, 2020
Mobile phone use while riding is one of the five most common risky behaviors of motorcycle riders... more Mobile phone use while riding is one of the five most common risky behaviors of motorcycle riders in Vietnam. This study investigated motorcyclist's mobile phone use while riding intention and behavior based on the extended Theory of Planned Behavior (TPB) framework. Based on this framework, attitude, subjective norm, perceived behavioral control, habits, and health motivation underlying the rider's mobile phone use while riding intentions and behavior were included in a questionnaire and captured by direct and indirect measurements. Small-displacement motorcycle riders (N = 291) completed the extended TPB based questionnaire. An exploratory factor analysis technique identified the selected factors (e.g., attitude, habit, etc.). Moreover, Structural Equation Modeling results showed moderate to good fits to the observed data. Therefore, the results supported the utilization of extended TPB framework in identifying factors of mobile phone use while riding intention and behavior. Specifically, negative attitude, perceived behavioral control, and mobile phone use while riding habit related to the intention to use a mobile phone while riding of small-displacement motorcyclists. Meanwhile, habit and behavioral intention related to the behavior to use a mobile phone while riding of small-displacement motorcycle riders. Especially, the correlation between behavioral intention and self-reported behavior was very strong. This finding embraced previous research indicating that intention was a major motivational component of behavior. Based on the results, safety intervention implications for small-displacement motorcycle riders were discussed.
Recently, Malware Analysis has been received much attention not only in industry but also in the ... more Recently, Malware Analysis has been received much attention not only in industry but also in the academic community. Modern malware frequently applies obfuscation techniques (e.g., indirect jump, overlapping instruction) to conceal its behaviors and protect itself against antivirus software, which regularly uses lightweight detection methods like bitbased fingerprints. Since famous commercial disassemblers such as IDA Pro and Capstone are easily fooled by these obfuscations, analyzing and detecting the obfuscated malware are not straightforward. For dealing with these problems, some malware analysis approaches based on Control Flow Graph (CFG) have been proposed (e.g., VxClass at Google). To effectively reconstruct the CFG, a technique called Dynamic Symbolic Execution (DSE) (known as concolic testing) has been widely applied. It is the combination of symbolic execution and testing to automatically explore all feasible program execution paths and determine the destination of obfuscation code like indirect jumps (by using a binary emulator). In DSE, the feasibility of a path constraint is checked by testing with a satisfiable instance using a Theorem Prover. Currently, we have developed BE-PUM (Binary Emulation for PUshdown Model), a binary analyzer concentrating on malware for Intel x86 architecture. Learning from its experiences, BE-PUM can be extended to other platforms. By considering IoT Malware, ARM is our first target.
Zinc oxide (ZnO) has been known as an excellent photocatalyst for the degradation of a variety of... more Zinc oxide (ZnO) has been known as an excellent photocatalyst for the degradation of a variety of organic pollutants under UV irradiation. This work describes a synthesis of ZnO nanoparticles via a facile precipitation method, and Ag was doped into Ag/ZnO nanocomposite to improve the photocatalytic degradation of BPA under visible light irradiation. The obtained ZnO nanoparticles were 20 nm in size and had a relatively high surface area and pore volume, 26.2 m2/g and 0.48 cm3/g, respectively. The deposition of Ag led to a decrease in the surface area, pore volume, and band gap energy ( E g ) of ZnO nanoparticles. However, the photocatalytic activity of Ag/ZnO composite in the case increased. The performance of ZnO was compared with Ag/ZnO composites at the different molar ratios, and the kinetic reaction of BPA in these catalysts was investigated by the first-order kinetic model. The sample of Ag/ZnO-10 composite had the highest catalytic activity and showed the degradation efficien...
The pyridinedicarboxylate-Tb(III) complexes, TbPDC and Tb(PDC)3, as luminescent probes for ATP mo... more The pyridinedicarboxylate-Tb(III) complexes, TbPDC and Tb(PDC)3, as luminescent probes for ATP monitoring have been conveniently prepared and characterized by FT-IR, 1H-NMR, ESI-MS, UV-Vis, excitation, and emission spectroscopy. Interestingly, these two Tb(III) complexes were quenched by ATP by a similar mechanism via π-π stacking interaction between the chelating ligand and adenine moiety. The ability of luminescent probes applied for the determination of ATP in aqueous solution has been investigated. The dynamic ranges for the quantification of ATP are within 10−90 μM and 10−100 μM with detection limits of 7.62 and 11.20 μM for TbPDC and Tb(PDC)3, respectively. The results demonstrated that these luminescent probes would be a potential candidate assay for ATP monitoring in hygiene assessment.
Magnetically responsive ultrafiltration membranes were prepared by grafting poly(2-hydroxyethyl m... more Magnetically responsive ultrafiltration membranes were prepared by grafting poly(2-hydroxyethyl methacrylate) chains from the outer surface of 100-kDa regenerated cellulose ultrafiltration membranes. Surface-initiated atom transfer radical polymerization was used to graft the polymer chains. Grafting from the internal pore surface was suppressed by using glycerol as a pore-filling solvent during initiator immobilization at varied densities. Glycerol suppresses the initiator attachment to the pore surface. Polymerization times of up to four hours were investigated. Superparamagnetic nanoparticles were covalently attached to the chain end. Membrane performance was determined using bovine serum albumin and dextran as model solutes. Increasing the grafted polymer chain density and length led to a decrease in the permeate flux and an increase in the apparent rejection coefficient. In an oscillating magnetic field, movement of the grafted polymer chains led to a decrease in the permeate f...
This paper presents an application of the Radial Basis Function – Based Finite Difference Method ... more This paper presents an application of the Radial Basis Function – Based Finite Difference Method (RBF-FD) to solving the electrical transient problems defined by the time-dependent ordinary differential equations. In this method, the finite difference approximations of first- and second-order derivatives in time domain are formalated the same as those in space domain based on the MQ (Multiquadrics) function presented in [1]. The MQ RBF-FD method are for the sake of evaluating the accuracy, effectiveness and applicability used to compute the transient voltages on the benchmark circuit and 220 kV three-phase transmission line of Viet Nam. Our numerical results are compared with those obtained by the analytical method, the traditional FD method and ATP/EMTP software. The compared results have been shown that the MQ RBF-FD method has accuracy that is higher than ones of the traditional numerical methods, especially with the optimal shape parameter.
Objective: This study aims to determine the trace cadmium in water and fish species from estuarie... more Objective: This study aims to determine the trace cadmium in water and fish species from estuaries in Tien Hai, Thai Binh province, Vietnam by graphite furnace atomic absorption spectrometry (GF-AAS). Methodology: The optimal conditions has been investigated by studying the effects of analysis parameters such as spectral line, current of cathode lamp, slit width, furnace temperature, acid concentration and subtracted solution on absorbance. The validation method was evaluated by linear range, accuracy, repeatability, limit of detection (LOD), limit of quantitation (LOQ), recovery (Re), and determination of trace cadmium in water and fish species. Findings: The results showed that the spectral line of 228.3 nm, current of cathode lamp of 4 mA, slit width of 0.5 nm, furnace temperature of 1800 • C, HNO 3 concentration of 1%, CH 3 COONH 4 concentration of 1% were optimal conditions for determination of cadmium. At these conditions, the analytical procedure exhibited the high accuracy and repeatability. The linear range of cadmium was 0-4 ppb. The LOD and LOQ values were 0.0058 and 0.019 ppb, respectively. Application/Improvements: Determination of the trace cadmium in the water and fish samples was done by the development of analytical procedure. It was applied to determine the water and fish species from Ba Lat and Lan estuaries in Tien Hai,
Nonisothermal Glass Molding (NGM) has become a viable replicative manufacturing technology for th... more Nonisothermal Glass Molding (NGM) has become a viable replicative manufacturing technology for the cost-efficient production of complex precision optical components made of glass. During the pressing stage in NGM, glass materials undergo a huge temperature change in the glass transition range. In this range, glass exhibits thermo-viscoelastic responses, and the temperature drop through the glass transition leads glass structure to depart from an equilibrium to a nonequilibrium state. Thermo-viscoelastic properties of the nonequilibrium glass material greatly depend on temperature and thermal history. This paper presents a phenomenological constitutive model developed for modeling the thermoviscoelastic responses of nonequilibrium glass. We propose a direct incorporation of the temperature-and thermal history effects into each parameter of the phenomenological model. This novelty allows the model to describe the nonequilibrium phenomena and to study temperaturedependent viscoelasticity of glass without assuming thermo-rheologically simple characteristics. Furthermore, the phenomenological model enables the coupling of structural-and stress relaxation phenomena. The model validation conducted for creep experiments demonstrates an enhancement in numerical predictions of the nonequilibrium material behaviors of glass over wide ranges of temperature and thermal history.
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