Professionalism is a central part of medical practice, and medical organisations worldwide have m... more Professionalism is a central part of medical practice, and medical organisations worldwide have mandated training on this topic for future medical doctors. In China, national guidelines were developed to make explicit expectations that were once implicit. Medical education reform over the past decade has emphasised topics such as medical humanities, life-long learning, and patient-centered learning in an effort to increase the professionalism of future physicians. Although the importance of teaching professionalism has been well recognised, few studies have evaluated its implementation at Chinese medical schools. We recruited medical students from three medical schools deemed to be representative of different regions in China (Tongji University School of Medicine, Shanghai (national); Nanjing Medical University, Jiangsu (provincial); Qiqihar Medical University, Heilongjiang (local)). We used the Jefferson Scale of Physician Empathy- Student Version (JSPES), Chinese version of the Ge...
Over the past decade, China's systems of medical education and health care have undergone unp... more Over the past decade, China's systems of medical education and health care have undergone unprecedented reform. Despite these reforms, a trend of declining interest among medical graduates in pursuing careers in clinical practice has persisted. The aim of this analysis is to examine physician workforce production and attrition rates and use current trends to predict whether an adequate and equitable supply of physicians will exist in the future. We analysed data about Chinese medical graduates and physicians in clinical practice between 2005 and 2015 using the Chinese National Health and Family Planning Commission reports and yearbooks published by the government of China and the Peking Union Medical College. These sources covered all of China (31 provinces; Hong-Kong and Macao were not included). The international review board of National Yang-Ming University approved this study. From the beginning of 2005 to the end of 2014, China produced 4 314 791 5-year clinical medical gra...
Recent material research about the thermoelectric has been reviewed. Recent development and appli... more Recent material research about the thermoelectric has been reviewed. Recent development and application in thermoelectric generator (TEG) has been reviewed. Recent development and application in thermoelectric cooler (TEC) has been reviewed.
ABSTRACT Keywords: MPCM slurry PV/T module Efficiency Flow resistance Laminar flow Turbulent flow... more ABSTRACT Keywords: MPCM slurry PV/T module Efficiency Flow resistance Laminar flow Turbulent flow a b s t r a c t Aim of the paper is to present a theoretical investigation into the energy performance of a novel PV/T module that employs the MPCM (Micro-encapsulated Phase Change Material) slurry as the working fluid. This involved (1) development of a dedicated mathematical model and computer program; (2) validation of the model by using the published data; (3) prediction of the energy performance of the MPCM (Microencapsulated Phase Change Material) slurry based PV/T module; and (4) investigation of the impacts of the slurry flow state, concentration ratio, Reynolds number and slurry serpentine size onto the energy performance of the PV/T module. It was found that the established model, based on the Hottel eWhillier assumption, is able to predict the energy performance of the MPCM slurry based PV/T system at a very good accuracy, with 0.3e0.4% difference compared to a validated model. Analyses of the simulation results indicated that laminar flow is not a favorite flow state in terms of the energy efficiency of the PV/T module. Instead, turbulent flow is a desired flow state that has potential to enhance the energy performance of PV/T module. Under the turbulent flow condition, increasing the slurry concentration ratio led to the reduced PV cells' temperature and increased thermal, electrical and overall efficiency of the PV/T module, as well as increased flow resistance. As a result, the net efficiency of the PV/T module reached the peak level at the concentration ratio of 5% at a specified Reynolds number of 3,350. Remaining all other parameters fixed, increasing the diameter of the serpentine piping led to the increased slurry mass flow rate, decreased PV cells' temperature and consequently, increased thermal, electrical, overall and net efficiencies of the PV/T module. In overall, the MPCM slurry based PV/T module is a new, highly efficient solar thermal and power configuration, which has potential to help reduce fossil fuel consumption and carbon emission to the environment.
An amorphous Fe-N alloy is prepared by ball milling a mixture of Fe and hexagonal boron nitride. ... more An amorphous Fe-N alloy is prepared by ball milling a mixture of Fe and hexagonal boron nitride. Its crystallization processes were studied upon mechanical milling and annealing under normal and high pressure. The crystallization product of the amorphous Fe-N alloy induced by mechanical milling and annealing at temperatures between 690 and 800 K under pressures of 3-4 GPa is the´-Fe N phase, x while the thermal crystallization product under normal pressure is g9-Fe N. The difference in crystallization product between mechanical 4 crystallization and thermal crystallization is attributed to the effects of local pressure and local temperature produced by ball collisions on crystallization of amorphous Fe-N alloy.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi Chinese Journal of Cellular and Molecular Immunology, 2012
Quercetin affects the expressions of leptin and its receptor in human gastric cancer MGC-803 cell... more Quercetin affects the expressions of leptin and its receptor in human gastric cancer MGC-803 cells and JAK-STAT pathway. The cultured MGC-803 cells were divided into three groups: the cultured cells without quercetin, and Quercetin group: the cultured cells with quercetin(40 μmol/L), and AG490group: the cultured cells with AG490(40 μmol/L)The expressions of Leptin, Leptin receptor and P-STAT3 were detected in protein level by immunocytochemical and Western bloting method respectively. The expressions of Leptin, Leptin receptor were detected in mRNA level by RT-PCR method. MGC-803 cell cycle was arrest by flow cytometry (FCM); MGC-803 cell apoptosis ratio by apoptotic marker An-necxinV. The protein expression of Leptin, Leptin receptor, P-STAT3 and the the mRNA expression of Leptin and Leptin receptor were significantly increased (P<0.05), compared with the control group.There was the rectilinear correlation relationship not only between Leptin and P-STAT3 protein(r=0.741, P<0.05) but also between Leptin receptor and P-STAT3 protein(r=0.693, P<0.05). FCM analysis showed that quercetin arrested MGC-803 cells at the G2/M phase, The ratio of apoptotic and necrosic cells increased with added quercetin concentration. Quercetin could inhibit the Proliferation of MGC-803 cells. It is probably relevant to the down-regulation the expressions of Leptin and Leptin receptor protein, Leptin mRNA and Leptin receptor mRNA by JAK-STAT pathway.
Among the high-Tc superconductors, HgBa2CuO4+δ (Hg1201) is one of the most desirable systems for ... more Among the high-Tc superconductors, HgBa2CuO4+δ (Hg1201) is one of the most desirable systems for experimental study due to its relatively simple structure and high Tc. For quantitative experimental work, it is necessary to grow sizable, high-quality crystals, and to obtain fine oxygen/doping control. Here we report on our most recent improvements in the growth and characterization of Hg1201, leading to further improved sample quality. Our new results include charge transport, magnetic susceptibility, and x-ray photoelectron spectroscopy (XPS) measurements.
The compound HgBa$_2$CuO$_{4+\Delta}$ (Hg1201) exhibits a simple tetragonal crystal structure and... more The compound HgBa$_2$CuO$_{4+\Delta}$ (Hg1201) exhibits a simple tetragonal crystal structure and the highest superconducting transition temperature (T$_c$) among all single Cu-O layer cuprates, with T$_c$ = 97 K (onset) at optimal doping. Due to a lack of sizable single crystals, experimental work on this very attractive system has been significantly limited. Thanks to a recent breakthrough in crystal growth, such crystals have now become available. Here, we demonstrate that it is possible to identify suitable heat treatment conditions to systematically and uniformly tune the hole concentration of Hg1201 crystals over a wide range, from very underdoped (T$_c$ = 47 K, hole concentration p ~ 0.08) to overdoped (T$_c$ = 64 K, p ~ 0.22). We then present quantitative magnetic susceptibility and DC charge transport results that reveal the very high-quality nature of the studied crystals. Using XPS on cleaved samples, we furthermore demonstrate that it is possible to obtain large surfaces of good quality. These characterization measurements demonstrate that Hg1201 should be viewed as a model high-temperature superconductor, and they provide the foundation for extensive future experimental work.
The investigation of the physical properties of high-TC superconductors (HTSCs) is complicated by... more The investigation of the physical properties of high-TC superconductors (HTSCs) is complicated by several materials-related obstacles. In order to obtain reliable experimental results, homogeneous single crystals are needed, which are difficult to obtain due to chemical and/or electronic disorder. HgBa2CuO4+δ (Hg1201) is a particularly interesting HTSC, since it possesses the highest superconducting transition temperature (TC=97 K) among single Cu-O layer compounds, a simple crystal structure, and the property to confine disorder relatively far a way from the superconducting pivotal Cu-O layers. Recently, we reported a new recipe for the growth of unprecedentedly large, gram-sized monocrystals of Hg1201 [1]. Here, we demonstrate that it is possible to select samples of the highest quality, with very few vortex pinning centers, and to dope them uniformly over a wide range of hole concentration. Furthermore, we show that those crystals can be cleaved and contacted with high-quality electrical contacts. These results make Hg1201 a particularly interesting model system for extensive experimental investigation. [1] X. Zhao et al., Adv. Mater. 18, 3243 (2006)
The International journal of social psychiatry, Jan 14, 2016
In China, since the rural labor, leaving their children in the hometown to other caregivers is a ... more In China, since the rural labor, leaving their children in the hometown to other caregivers is a trend that has been increasing, and the impact of parental absence on the well-being of left-behind children is increasingly drawing attention in the Chinese society. However, there is a lack of study on the potential impacts of being left behind on later psychosocial outcomes in adolescence and associated protective factors. This study was conducted on a large sample of Chinese college students to test the moderating effect of resilience between left-behind experience and mental health problems. The Connor-Davidson Resilience Scale and Symptom Checklist as well as a self-reported questionnaire about left-behind experience designed by the authors were adopted for a survey with 2,968 Chinese college students as respondents. Totally, 1,063 students (35.8%) had 1 year or more left-behind experience. Compared to those who had no left-behind experience, the students who had left-behind experi...
Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi Chinese Journal of Parasitology Parasitic Diseases, Apr 1, 2013
To compare the laboratory tests of the imported Plasmodium ovale infection and analyse the geneti... more To compare the laboratory tests of the imported Plasmodium ovale infection and analyse the genetic character. After Giemsa staining and microscopy, CareStart rapid detection and nested PCR were used to detect two cases with P. ovale infection returning from Congo (Brazzaville) in Henan Province. Sequencing was performed after PCR amplification using the 18S rRNA genus-specific primers. Their genetic characteristics were analyzed and the sequence homology analysis was performed in the NCBI. The two cases were confirmed as P. ovale infection by morphological examination microscopically. Amplified bands were produced by 18S rRNA nested PCR, which was the same with P. ovale in size, whereas the results of CareStart rapid detection test were all negative. A sequence of 906 bp in length was obtained by sequencing their 18S rRNA genes in which GC accounted for 35.4%, and the sequence showed 99% homology to the corresponding part of the known P. ovale 18S rRNA gene (GenBank accession No. AB182492). Both the nested PCR and microscopy confirm the infection of P. ovale. A negative result of CareStart rapid detection can not ruled out the Plasmodium infection.
Cu2O truncated octahedral crystals exposing the active basal (110) facets are synthesized from a ... more Cu2O truncated octahedral crystals exposing the active basal (110) facets are synthesized from a mixture of CuO and Cu using NaOH/KOH (1:1) as a flux (autoclave, 0.2 GPa, 300-600°C, 6 h). The samples are characterized by powder XRD, SEM, and XPS. Cu2O crystallizes in the cubic space group Pn3m with Z = 2 (single crystal XRD). The synthesis method is an effective, novel, and green way for large scale production of Cu2O in the chemical industry. -(LI, B.; WANG, X.; XIA, D.; CHU, Q.; LIU*, X.; LU, F.; ZHAO, X.; J. Solid State Chem. 184 (2011) 8, 2097-2102, http://dx.doi.org/10.
Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi Chinese Journal of Parasitology Parasitic Diseases, Dec 1, 2013
Thirty-seven blood samples from Plasmodium vivax-infected patients were collected in Henan Provin... more Thirty-seven blood samples from Plasmodium vivax-infected patients were collected in Henan Province in 2011. The gene for circumsporozoite protein (PvCSP) was amplified by nested PCR. According to the epidemiological data, among the 37 Plasmodium vivax malaria cases, 26 were indigenous cases and 11 were imported cases. A fragment of 750 bp was obtained in the 37 blood samples. The 750 bp PCR product was digested with restriction endonuclease Alu-I and Mva-I, and genetic polymorphism was investigated with PCR-RFLP. PCR-RFLP analysis of PvCSP revealed that the parasites were PV-I type (97.3%, 36/37) and PV-II type (2.7%, 1/37). 26 samples from indigenous cases were exclusively PV-I type with PV-I-b type (57.7%, 15/26) and PV-I-a type (42.3%, 11/26). Among 11 samples from imported cases, PV-I-a type accounted for 90.9% (10/11), and 1 PV-II type accounted for 9.1% (1/11), no PV-I-b type were detected.
63 Cu and 199 Hg NMR shifts for an optimally and underdoped HgBa2CuO 4+δ single crystal are repor... more 63 Cu and 199 Hg NMR shifts for an optimally and underdoped HgBa2CuO 4+δ single crystal are reported, and the temperature dependence dictates a two-component description of the uniform spin susceptibility. The first component, associated with the pseudogap phenomenon in the NMR shifts, decreases already at room temperature and continues to drop as the temperature is lowered, without a drastic change at the transition temperature into the superconducting state. The second component is temperature independent above the superconducting transition temperature and vanishes rapidly below it. It increases with doping and is a substantial part of the total spin susceptibility measured at both nuclei.
With widespread deployment of the urban natural gas industry, the energy security is now becoming... more With widespread deployment of the urban natural gas industry, the energy security is now becoming one of the priorities in practice. Gas leakage may occur from the pipeline during the collection and transportation process. This article therefore presented a theoretical study on the urban natural gas pipeline leakage in order to provide the basic theory of the rescue policy making in emergent occasions. The investigation was undertaken through the fundamental analysis based on derivation of gas leakage models. The gas leakage model was applied to analyze the pressure, temperature and flow rate of gas leakage over time under both the steady-state and dynamic conditions. Two main impacting factors, pressure and hole size, were subsequently discussed. It is concluded that for the steady leakage the flow rate increases with the increase of pipeline pressure and hole size. And the distribution of pressure, temperature, density and velocity were calculated along the pipeline. For the unsteady leakage, the time of leakage is very short under different initial pressure and hole size, and the total leakage and average leakage rates were analyzed.
Journal of the Chemical Society, Chemical Communications, 1992
The irreversible direct transformation of ZSM-5 zeolite to ZSM-11 zeolite under high pressure is ... more The irreversible direct transformation of ZSM-5 zeolite to ZSM-11 zeolite under high pressure is observed and characterized by means of X-ray powder diffraction, thermogravimetric analysis and differential thermal analysis.
Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi Chinese Journal of Parasitology Parasitic Diseases, Dec 30, 2010
Imported falciparum malaria data of Henan Province in 2005-2009 were collected and statistically ... more Imported falciparum malaria data of Henan Province in 2005-2009 were collected and statistically analyzed by using Microsoft Office Excel 2003. A total of 84 imported falciparum malaria cases with one death were reported during 2005-2009. The ratio of males to females was 20 : 1(80/4). The average age was (34 +/- 11) years old. Seventy-five patients returned from Africa, occupying 89.3%. The number of annual cases reported in 2008 (24 cases) and 2009 (32 cases) was higher than that in 2005-2007(9-10 cases). The top three high-risk populations were farmers (34 cases), workers (17 cases) and the cadre (13 cases), accounted for 76.2% of all cases. The cases were reported every month, of which 37 cases (44.0%) were reported in June and July. All cases had a history of prior residence in falciparum malaria endemic area, and the initial symptom was fever. The average interval from symptom appearing to diagnosis was (5.9 +/- 8.6) d, only 21.4% (18/84) of the patients was diagnosed within 24h. There were 72 laboratory-confirmed cases (85.7%). Seventeen cases (22.1%) were reported by county level medical treatment units. A total of 83 cases recovered with the treatment of artemisinin-based combination drugs. One case died with serious cerebral malaria. Effective measures should be carried to control the increasing trend of imported falciparum malaria.
We report on the temperature dependence of $^{63}$Cu and $^{199}$Hg NMR magnetic shifts and linew... more We report on the temperature dependence of $^{63}$Cu and $^{199}$Hg NMR magnetic shifts and linewidths for an optimally doped and an underdoped HgBa$_{2}$CuO$_{4+\delta}$ single crystal, as well as the quadrupole splitting and its distribution for $^{63}$Cu. From the $^{63}$Cu and $^{199}$Hg \textit{magnetic shifts} we have recently concluded on the existence of two spin components with different temperature dependencies [J. Haase, D. Rybicki, C. P. Slichter, M. Greven, G. Yu, Y. Li, and X. Zhao, Phys. Rev. B 85, 104517 (2012)]. Here we give a comprehensive account of all data and focus on the linewidths and quadrupole splittings. While the $^{63}$Cu quadrupole coupling and its distribution are by and large temperature independent, we identify three regions in temperature for which the magnetic widths differ significantly: at the lowest temperatures the magnetic linewidths are dominated by the rigid fluxoid lattice that seems to have disappeared above about 60 K. In the intermediate temperature region, starting above 60 K, the magnetic linewidth is dominated by the spatial distribution of the magnetic shift due to the pseudogap spin component, and grows linearly with the total shift up to about \textit{$\sim$}170-230 K, depending on sample and nucleus. Above this temperature the third region begins with an sudden narrowing where the second, Fermi-liquid-like spin component becomes homogeneous. We show that all linewidths, quadrupolar as well as magnetic, above the fluxoid dominated region can be understood with a simple model that assumes a coherent charge density variation with concomitant variations of the two spin components. In addition, we find a temperature independent spin based broadening in both samples that is incoherent with the other broadening for the underdoped crystal, but becomes coherent for the optimally doped crystal.
Professionalism is a central part of medical practice, and medical organisations worldwide have m... more Professionalism is a central part of medical practice, and medical organisations worldwide have mandated training on this topic for future medical doctors. In China, national guidelines were developed to make explicit expectations that were once implicit. Medical education reform over the past decade has emphasised topics such as medical humanities, life-long learning, and patient-centered learning in an effort to increase the professionalism of future physicians. Although the importance of teaching professionalism has been well recognised, few studies have evaluated its implementation at Chinese medical schools. We recruited medical students from three medical schools deemed to be representative of different regions in China (Tongji University School of Medicine, Shanghai (national); Nanjing Medical University, Jiangsu (provincial); Qiqihar Medical University, Heilongjiang (local)). We used the Jefferson Scale of Physician Empathy- Student Version (JSPES), Chinese version of the Ge...
Over the past decade, China's systems of medical education and health care have undergone unp... more Over the past decade, China's systems of medical education and health care have undergone unprecedented reform. Despite these reforms, a trend of declining interest among medical graduates in pursuing careers in clinical practice has persisted. The aim of this analysis is to examine physician workforce production and attrition rates and use current trends to predict whether an adequate and equitable supply of physicians will exist in the future. We analysed data about Chinese medical graduates and physicians in clinical practice between 2005 and 2015 using the Chinese National Health and Family Planning Commission reports and yearbooks published by the government of China and the Peking Union Medical College. These sources covered all of China (31 provinces; Hong-Kong and Macao were not included). The international review board of National Yang-Ming University approved this study. From the beginning of 2005 to the end of 2014, China produced 4 314 791 5-year clinical medical gra...
Recent material research about the thermoelectric has been reviewed. Recent development and appli... more Recent material research about the thermoelectric has been reviewed. Recent development and application in thermoelectric generator (TEG) has been reviewed. Recent development and application in thermoelectric cooler (TEC) has been reviewed.
ABSTRACT Keywords: MPCM slurry PV/T module Efficiency Flow resistance Laminar flow Turbulent flow... more ABSTRACT Keywords: MPCM slurry PV/T module Efficiency Flow resistance Laminar flow Turbulent flow a b s t r a c t Aim of the paper is to present a theoretical investigation into the energy performance of a novel PV/T module that employs the MPCM (Micro-encapsulated Phase Change Material) slurry as the working fluid. This involved (1) development of a dedicated mathematical model and computer program; (2) validation of the model by using the published data; (3) prediction of the energy performance of the MPCM (Microencapsulated Phase Change Material) slurry based PV/T module; and (4) investigation of the impacts of the slurry flow state, concentration ratio, Reynolds number and slurry serpentine size onto the energy performance of the PV/T module. It was found that the established model, based on the Hottel eWhillier assumption, is able to predict the energy performance of the MPCM slurry based PV/T system at a very good accuracy, with 0.3e0.4% difference compared to a validated model. Analyses of the simulation results indicated that laminar flow is not a favorite flow state in terms of the energy efficiency of the PV/T module. Instead, turbulent flow is a desired flow state that has potential to enhance the energy performance of PV/T module. Under the turbulent flow condition, increasing the slurry concentration ratio led to the reduced PV cells' temperature and increased thermal, electrical and overall efficiency of the PV/T module, as well as increased flow resistance. As a result, the net efficiency of the PV/T module reached the peak level at the concentration ratio of 5% at a specified Reynolds number of 3,350. Remaining all other parameters fixed, increasing the diameter of the serpentine piping led to the increased slurry mass flow rate, decreased PV cells' temperature and consequently, increased thermal, electrical, overall and net efficiencies of the PV/T module. In overall, the MPCM slurry based PV/T module is a new, highly efficient solar thermal and power configuration, which has potential to help reduce fossil fuel consumption and carbon emission to the environment.
An amorphous Fe-N alloy is prepared by ball milling a mixture of Fe and hexagonal boron nitride. ... more An amorphous Fe-N alloy is prepared by ball milling a mixture of Fe and hexagonal boron nitride. Its crystallization processes were studied upon mechanical milling and annealing under normal and high pressure. The crystallization product of the amorphous Fe-N alloy induced by mechanical milling and annealing at temperatures between 690 and 800 K under pressures of 3-4 GPa is the´-Fe N phase, x while the thermal crystallization product under normal pressure is g9-Fe N. The difference in crystallization product between mechanical 4 crystallization and thermal crystallization is attributed to the effects of local pressure and local temperature produced by ball collisions on crystallization of amorphous Fe-N alloy.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi Chinese Journal of Cellular and Molecular Immunology, 2012
Quercetin affects the expressions of leptin and its receptor in human gastric cancer MGC-803 cell... more Quercetin affects the expressions of leptin and its receptor in human gastric cancer MGC-803 cells and JAK-STAT pathway. The cultured MGC-803 cells were divided into three groups: the cultured cells without quercetin, and Quercetin group: the cultured cells with quercetin(40 μmol/L), and AG490group: the cultured cells with AG490(40 μmol/L)The expressions of Leptin, Leptin receptor and P-STAT3 were detected in protein level by immunocytochemical and Western bloting method respectively. The expressions of Leptin, Leptin receptor were detected in mRNA level by RT-PCR method. MGC-803 cell cycle was arrest by flow cytometry (FCM); MGC-803 cell apoptosis ratio by apoptotic marker An-necxinV. The protein expression of Leptin, Leptin receptor, P-STAT3 and the the mRNA expression of Leptin and Leptin receptor were significantly increased (P<0.05), compared with the control group.There was the rectilinear correlation relationship not only between Leptin and P-STAT3 protein(r=0.741, P<0.05) but also between Leptin receptor and P-STAT3 protein(r=0.693, P<0.05). FCM analysis showed that quercetin arrested MGC-803 cells at the G2/M phase, The ratio of apoptotic and necrosic cells increased with added quercetin concentration. Quercetin could inhibit the Proliferation of MGC-803 cells. It is probably relevant to the down-regulation the expressions of Leptin and Leptin receptor protein, Leptin mRNA and Leptin receptor mRNA by JAK-STAT pathway.
Among the high-Tc superconductors, HgBa2CuO4+δ (Hg1201) is one of the most desirable systems for ... more Among the high-Tc superconductors, HgBa2CuO4+δ (Hg1201) is one of the most desirable systems for experimental study due to its relatively simple structure and high Tc. For quantitative experimental work, it is necessary to grow sizable, high-quality crystals, and to obtain fine oxygen/doping control. Here we report on our most recent improvements in the growth and characterization of Hg1201, leading to further improved sample quality. Our new results include charge transport, magnetic susceptibility, and x-ray photoelectron spectroscopy (XPS) measurements.
The compound HgBa$_2$CuO$_{4+\Delta}$ (Hg1201) exhibits a simple tetragonal crystal structure and... more The compound HgBa$_2$CuO$_{4+\Delta}$ (Hg1201) exhibits a simple tetragonal crystal structure and the highest superconducting transition temperature (T$_c$) among all single Cu-O layer cuprates, with T$_c$ = 97 K (onset) at optimal doping. Due to a lack of sizable single crystals, experimental work on this very attractive system has been significantly limited. Thanks to a recent breakthrough in crystal growth, such crystals have now become available. Here, we demonstrate that it is possible to identify suitable heat treatment conditions to systematically and uniformly tune the hole concentration of Hg1201 crystals over a wide range, from very underdoped (T$_c$ = 47 K, hole concentration p ~ 0.08) to overdoped (T$_c$ = 64 K, p ~ 0.22). We then present quantitative magnetic susceptibility and DC charge transport results that reveal the very high-quality nature of the studied crystals. Using XPS on cleaved samples, we furthermore demonstrate that it is possible to obtain large surfaces of good quality. These characterization measurements demonstrate that Hg1201 should be viewed as a model high-temperature superconductor, and they provide the foundation for extensive future experimental work.
The investigation of the physical properties of high-TC superconductors (HTSCs) is complicated by... more The investigation of the physical properties of high-TC superconductors (HTSCs) is complicated by several materials-related obstacles. In order to obtain reliable experimental results, homogeneous single crystals are needed, which are difficult to obtain due to chemical and/or electronic disorder. HgBa2CuO4+δ (Hg1201) is a particularly interesting HTSC, since it possesses the highest superconducting transition temperature (TC=97 K) among single Cu-O layer compounds, a simple crystal structure, and the property to confine disorder relatively far a way from the superconducting pivotal Cu-O layers. Recently, we reported a new recipe for the growth of unprecedentedly large, gram-sized monocrystals of Hg1201 [1]. Here, we demonstrate that it is possible to select samples of the highest quality, with very few vortex pinning centers, and to dope them uniformly over a wide range of hole concentration. Furthermore, we show that those crystals can be cleaved and contacted with high-quality electrical contacts. These results make Hg1201 a particularly interesting model system for extensive experimental investigation. [1] X. Zhao et al., Adv. Mater. 18, 3243 (2006)
The International journal of social psychiatry, Jan 14, 2016
In China, since the rural labor, leaving their children in the hometown to other caregivers is a ... more In China, since the rural labor, leaving their children in the hometown to other caregivers is a trend that has been increasing, and the impact of parental absence on the well-being of left-behind children is increasingly drawing attention in the Chinese society. However, there is a lack of study on the potential impacts of being left behind on later psychosocial outcomes in adolescence and associated protective factors. This study was conducted on a large sample of Chinese college students to test the moderating effect of resilience between left-behind experience and mental health problems. The Connor-Davidson Resilience Scale and Symptom Checklist as well as a self-reported questionnaire about left-behind experience designed by the authors were adopted for a survey with 2,968 Chinese college students as respondents. Totally, 1,063 students (35.8%) had 1 year or more left-behind experience. Compared to those who had no left-behind experience, the students who had left-behind experi...
Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi Chinese Journal of Parasitology Parasitic Diseases, Apr 1, 2013
To compare the laboratory tests of the imported Plasmodium ovale infection and analyse the geneti... more To compare the laboratory tests of the imported Plasmodium ovale infection and analyse the genetic character. After Giemsa staining and microscopy, CareStart rapid detection and nested PCR were used to detect two cases with P. ovale infection returning from Congo (Brazzaville) in Henan Province. Sequencing was performed after PCR amplification using the 18S rRNA genus-specific primers. Their genetic characteristics were analyzed and the sequence homology analysis was performed in the NCBI. The two cases were confirmed as P. ovale infection by morphological examination microscopically. Amplified bands were produced by 18S rRNA nested PCR, which was the same with P. ovale in size, whereas the results of CareStart rapid detection test were all negative. A sequence of 906 bp in length was obtained by sequencing their 18S rRNA genes in which GC accounted for 35.4%, and the sequence showed 99% homology to the corresponding part of the known P. ovale 18S rRNA gene (GenBank accession No. AB182492). Both the nested PCR and microscopy confirm the infection of P. ovale. A negative result of CareStart rapid detection can not ruled out the Plasmodium infection.
Cu2O truncated octahedral crystals exposing the active basal (110) facets are synthesized from a ... more Cu2O truncated octahedral crystals exposing the active basal (110) facets are synthesized from a mixture of CuO and Cu using NaOH/KOH (1:1) as a flux (autoclave, 0.2 GPa, 300-600°C, 6 h). The samples are characterized by powder XRD, SEM, and XPS. Cu2O crystallizes in the cubic space group Pn3m with Z = 2 (single crystal XRD). The synthesis method is an effective, novel, and green way for large scale production of Cu2O in the chemical industry. -(LI, B.; WANG, X.; XIA, D.; CHU, Q.; LIU*, X.; LU, F.; ZHAO, X.; J. Solid State Chem. 184 (2011) 8, 2097-2102, http://dx.doi.org/10.
Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi Chinese Journal of Parasitology Parasitic Diseases, Dec 1, 2013
Thirty-seven blood samples from Plasmodium vivax-infected patients were collected in Henan Provin... more Thirty-seven blood samples from Plasmodium vivax-infected patients were collected in Henan Province in 2011. The gene for circumsporozoite protein (PvCSP) was amplified by nested PCR. According to the epidemiological data, among the 37 Plasmodium vivax malaria cases, 26 were indigenous cases and 11 were imported cases. A fragment of 750 bp was obtained in the 37 blood samples. The 750 bp PCR product was digested with restriction endonuclease Alu-I and Mva-I, and genetic polymorphism was investigated with PCR-RFLP. PCR-RFLP analysis of PvCSP revealed that the parasites were PV-I type (97.3%, 36/37) and PV-II type (2.7%, 1/37). 26 samples from indigenous cases were exclusively PV-I type with PV-I-b type (57.7%, 15/26) and PV-I-a type (42.3%, 11/26). Among 11 samples from imported cases, PV-I-a type accounted for 90.9% (10/11), and 1 PV-II type accounted for 9.1% (1/11), no PV-I-b type were detected.
63 Cu and 199 Hg NMR shifts for an optimally and underdoped HgBa2CuO 4+δ single crystal are repor... more 63 Cu and 199 Hg NMR shifts for an optimally and underdoped HgBa2CuO 4+δ single crystal are reported, and the temperature dependence dictates a two-component description of the uniform spin susceptibility. The first component, associated with the pseudogap phenomenon in the NMR shifts, decreases already at room temperature and continues to drop as the temperature is lowered, without a drastic change at the transition temperature into the superconducting state. The second component is temperature independent above the superconducting transition temperature and vanishes rapidly below it. It increases with doping and is a substantial part of the total spin susceptibility measured at both nuclei.
With widespread deployment of the urban natural gas industry, the energy security is now becoming... more With widespread deployment of the urban natural gas industry, the energy security is now becoming one of the priorities in practice. Gas leakage may occur from the pipeline during the collection and transportation process. This article therefore presented a theoretical study on the urban natural gas pipeline leakage in order to provide the basic theory of the rescue policy making in emergent occasions. The investigation was undertaken through the fundamental analysis based on derivation of gas leakage models. The gas leakage model was applied to analyze the pressure, temperature and flow rate of gas leakage over time under both the steady-state and dynamic conditions. Two main impacting factors, pressure and hole size, were subsequently discussed. It is concluded that for the steady leakage the flow rate increases with the increase of pipeline pressure and hole size. And the distribution of pressure, temperature, density and velocity were calculated along the pipeline. For the unsteady leakage, the time of leakage is very short under different initial pressure and hole size, and the total leakage and average leakage rates were analyzed.
Journal of the Chemical Society, Chemical Communications, 1992
The irreversible direct transformation of ZSM-5 zeolite to ZSM-11 zeolite under high pressure is ... more The irreversible direct transformation of ZSM-5 zeolite to ZSM-11 zeolite under high pressure is observed and characterized by means of X-ray powder diffraction, thermogravimetric analysis and differential thermal analysis.
Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi Chinese Journal of Parasitology Parasitic Diseases, Dec 30, 2010
Imported falciparum malaria data of Henan Province in 2005-2009 were collected and statistically ... more Imported falciparum malaria data of Henan Province in 2005-2009 were collected and statistically analyzed by using Microsoft Office Excel 2003. A total of 84 imported falciparum malaria cases with one death were reported during 2005-2009. The ratio of males to females was 20 : 1(80/4). The average age was (34 +/- 11) years old. Seventy-five patients returned from Africa, occupying 89.3%. The number of annual cases reported in 2008 (24 cases) and 2009 (32 cases) was higher than that in 2005-2007(9-10 cases). The top three high-risk populations were farmers (34 cases), workers (17 cases) and the cadre (13 cases), accounted for 76.2% of all cases. The cases were reported every month, of which 37 cases (44.0%) were reported in June and July. All cases had a history of prior residence in falciparum malaria endemic area, and the initial symptom was fever. The average interval from symptom appearing to diagnosis was (5.9 +/- 8.6) d, only 21.4% (18/84) of the patients was diagnosed within 24h. There were 72 laboratory-confirmed cases (85.7%). Seventeen cases (22.1%) were reported by county level medical treatment units. A total of 83 cases recovered with the treatment of artemisinin-based combination drugs. One case died with serious cerebral malaria. Effective measures should be carried to control the increasing trend of imported falciparum malaria.
We report on the temperature dependence of $^{63}$Cu and $^{199}$Hg NMR magnetic shifts and linew... more We report on the temperature dependence of $^{63}$Cu and $^{199}$Hg NMR magnetic shifts and linewidths for an optimally doped and an underdoped HgBa$_{2}$CuO$_{4+\delta}$ single crystal, as well as the quadrupole splitting and its distribution for $^{63}$Cu. From the $^{63}$Cu and $^{199}$Hg \textit{magnetic shifts} we have recently concluded on the existence of two spin components with different temperature dependencies [J. Haase, D. Rybicki, C. P. Slichter, M. Greven, G. Yu, Y. Li, and X. Zhao, Phys. Rev. B 85, 104517 (2012)]. Here we give a comprehensive account of all data and focus on the linewidths and quadrupole splittings. While the $^{63}$Cu quadrupole coupling and its distribution are by and large temperature independent, we identify three regions in temperature for which the magnetic widths differ significantly: at the lowest temperatures the magnetic linewidths are dominated by the rigid fluxoid lattice that seems to have disappeared above about 60 K. In the intermediate temperature region, starting above 60 K, the magnetic linewidth is dominated by the spatial distribution of the magnetic shift due to the pseudogap spin component, and grows linearly with the total shift up to about \textit{$\sim$}170-230 K, depending on sample and nucleus. Above this temperature the third region begins with an sudden narrowing where the second, Fermi-liquid-like spin component becomes homogeneous. We show that all linewidths, quadrupolar as well as magnetic, above the fluxoid dominated region can be understood with a simple model that assumes a coherent charge density variation with concomitant variations of the two spin components. In addition, we find a temperature independent spin based broadening in both samples that is incoherent with the other broadening for the underdoped crystal, but becomes coherent for the optimally doped crystal.
Uploads
Papers by Xudong Zhao