It is shown that the density dependence of the most favorable frequency of the r. f. electric fie... more It is shown that the density dependence of the most favorable frequency of the r. f. electric field to confine a cusp plasma is consistent with that suggested by a theory taking account of collective response of a plasma. Based on this dependence, automatic tuning of the frequency to the optimum value for the decaying plasma is demonstrated using a feedback system piloted by an ion density measurement.
expressing immunoglobulin mRNA [4], suggesting local lar mortality in end-stage renal disease. pr... more expressing immunoglobulin mRNA [4], suggesting local lar mortality in end-stage renal disease. production of antibodies. OxLDL is detected in athero-Background. Immune response to oxidized low-density lipomatous lesions [5-7], and it can activate lymphocyte clones protein (oxLDL) may modulate the process of atherogenesis [8]. Immunoglobulins extracted from plaques recognize and cardiovascular disease. oxLDL [9], and antibody against oxLDL is present in Methods. We performed a prospective, observational cohort study in 249 patients with end-stage renal disease (ESRD) to serum [6, 10-19]. To date it has not been established examine whether the serum titer of anti-oxLDL antibody can whether immune response to oxLDL is atherogenic or predict cardiovascular mortality.
ABSTRACT A movable graphite limiter with an internal heater has been installed in the heliotron/t... more ABSTRACT A movable graphite limiter with an internal heater has been installed in the heliotron/torsatron type compact helical system (CHS). Comparing discharges with and without the limiter the origin of major impurities and the role of the limiter are discussed. Infrared TV measurements reveal that there are two hot spots on the limiter due to heat loading and their temperatures depend on the electron density and/or the magnetic field direction. Limiter temperature dependence of measured CH/Hγ, CI, CII, OII, CH+3, OV and total radiation loss is compared. From these experiments it is concluded that CH4 molecules produced chemically on the limiter are presumed to recycle rapidly near the limiter and both carbon and oxygen impurities result probably from CO produced chemically on the limiter with oxygen which is predominant in CHS and originates mostly from the first wall. At surface temperatures above 900 ° C the limiter effect on impurities is observable in the main plasma.
ABSTRACT The effects of plasma edge modification on confinement have been investigated on the JFT... more ABSTRACT The effects of plasma edge modification on confinement have been investigated on the JFT-2M tokamak since 1985. In the course of investigations, a new enhanced confinement regime, limiter H-mode, was discovered in 1986. This paper is a review of investigations into edge recycling control methods which extend the H-mode operational regime. In addition to Ti-gettering, the following methods have been shown to reduce edge neutral buildup, to extend the operational regime and to improve n τ of H-mode discharges: (1) optimization of the gas-puff programming (decreased or terminated at the start of auxiliary heating), (2) a toroidally distributed gas-puff system, (3) edge heating by ECH, and (4) particle removal with a pump limiter.
ABSTRACT Increments of peripheral hydrogen/deuterium neutral gas pressures (PH2/PD2) during the a... more ABSTRACT Increments of peripheral hydrogen/deuterium neutral gas pressures (PH2/PD2) during the additional heating phase (neutral beam and RF heatings) have been observed in a D2 gas-puff fueled JFT-2M tokamak with H2-absorbed graphite limiters/divertor plates. In the beam heating phase, a large increment of PH2 raises the plasma density 2 times or more without the degrading energy confinement time. The D2 gas-puff valve is closed in this phase. This improvement is interpreted as being due to “wall fueling”, i.e., fueling by desorbed hydrogen from the graphite wall by energetic particles. The first observation of the H-mode in the INTOR-type stubby open divertor with a short divertor channel (1–8 cm) at the high density regime (4–7 × 1013 cm−3) enhanced by the wall fueling is presented. The improved energy confinement time is comparable to or higher than that of ohmically heated discharges.
ABSTRACT Oxidation behavior at the tips of several stress corrosion cracking (SCC) crack, includi... more ABSTRACT Oxidation behavior at the tips of several stress corrosion cracking (SCC) crack, including intergranular SCC (IGSCC) and transgranular SCC (TGSCC) cracks, in heat-treated 304L stainless steel in high temperature oxygenated water was studied using a field emission gun-analytical transmission electron microscopy (FEG–ATEM). These SCC cracks were produced during SCC tests in two different heat-treated 304L stainless steels in high temperature pure water with two different levels of dissolved oxygen (DO). The study showed that oxygen played a key role in nucleation and propagation of SCC cracks. For the IGSCC crack, oxidation took place followed by nucleation and growth of microcracks in the oxide ahead of the crack tip on the grain boundary plane. The IGSCC crack then propagated by linkage with these microcracks. Oxides formed in the high temperature water with different DO had different configurations and microstructures. In the case of low DO, separate oxides of Cr2O3 and Fe3O4 types were formed, while the oxide formed in high DO consisted of mixed FeCr2O4 and Fe3O4. For the TGSCC crack, oxidation along deformation bands and nucleation and growth of microcracks within oxide were important mechanisms. It was found that Si was preferentially oxidized ahead of the crack tip, promoting SCC crack propagation. Ni enrichment at some SCC crack tips was also revealed.
... Semiempirical evaluations of the relationships between CTSR and engineering parameters were m... more ... Semiempirical evaluations of the relationships between CTSR and engineering parameters were made by Ford et al. ... (4) is a useful approach for relative comparison of strain ... is strongly dependent on strain redistribution associated with the growing crack for the fast crack growth ...
ABSTRACT A pump limiter is applied to the JFT-2M tokamak in order to reduce edge gas buildup. Abo... more ABSTRACT A pump limiter is applied to the JFT-2M tokamak in order to reduce edge gas buildup. About 12% of the effective loss flux is removed by the pump limiter and the fueling efficiency is improved by 30%. In the high density regime, the gas buildup is successfully reduced and edge cooling by cold gas-puffing is prevented by the pump limiter. The pump limiter also improves the density limit and the energy confinement time. Improvement in the nτ value is about 34%. This pump limiter is shown to be compatible with the limiter H-mode.
The low-temperature phase (LTP) MnBi is one of the few rare-earth free compounds that exhibit a l... more The low-temperature phase (LTP) MnBi is one of the few rare-earth free compounds that exhibit a large magnetocrystalline anisotropy energy in the order of 10 6 J/m 3 . A large coercive field (l 0 H cj ) above 1 T can be obtained readily by reducing the crystallite size (D) through mechanical grinding (MG). The room-temperature H cj values follow a phenomenological expression l 0 H cj = l 0 H a (d/D) n where the anisotropy field (l 0 H a ) is $4 T, the Bloch wall width (d) is 7 nm and the exponent (n) is about 0.7 in our study. The grain refinement upon MG is accompanied by suppression of the spin reorientation transition temperature (T SR ) from 110 K to below 50 K. The coercive field starts to exhibit positive temperature dependence approximately 50 K above T SR and the room-temperature magnetic hardening induced by MG could partially be brought about by the lowered onset of this positive temperature dependence. The suppression of T SR by MG is likely to be induced by the surface anisotropy with which the 2nd order crystal field term is enhanced. One of the shortcomings of LTP-MnBi is its poor phase stability under the ambient atmosphere. The spontaneous magnetization decreases considerably after room-temperature aging for 1 week. This is due to oxidation of Mn which leads to decomposition of the MnBi phase. Hence, the surface passivity needs to be established before this material is considered for a permanent magnet in practical uses. Another shortcoming is the limited spontaneous magnetization. The theoretical upper limit of the maximum energy product in LTP-MnBi remains only a quarter of that in Nd 2 Fe 14 B. Nevertheless, owing to the unique positive temperature dependence of the first-order anisotropy constant (K 1 ), the hardness parameter (j) of LTP-MnBi is enhanced above room temperature; j reaches as large as 2.8 at 580 K. This makes LTP-MnBi a possible candidate for the hard phase in rare-earth free nanocomposite magnets.
Elevated urinary albumin excretion (UAE) has been associated with insulin resistance and is sugge... more Elevated urinary albumin excretion (UAE) has been associated with insulin resistance and is suggested to be elevated in prediabetic individuals. Upper body obesity, especially visceral obesity, predicts insulin resistance and development of type 2 diabetes. We examined whether UAE clusters with obesity-associated insulin resistance traits in healthy glucose-tolerant normotensive subjects. There were 49 volunteers with a wide range of body fat and body fat distribution studied. All had normal blood pressure and glucose tolerance and were maintained on a controlled diet for 2 weeks. UAE was assessed from three overnight urine collections, and body composition was assessed by whole-body dual-energy X-ray absorptiometry scanning and abdominal computed tomography scanning. Fasting insulin and insulin responses to oral glucose were significantly increased in obese subjects, who also tended to have more dyslipidemia, greater blood pressure, and more visceral fat than lean subjects. These differences were more apparent in upper body obese subjects. UAE was normal in obese and upper body obese subjects and not different from that of lean subjects. UAE ranged from 0.3 to 8.3 micrograms/min in lean subjects and from 0.2 to 7.2 micrograms/min in obese subjects. UAE was not significantly correlated with body composition, plasma insulin, glucose, or lipids. Obese subjects (even upper body obese subjects) with increased visceral and total body fat, high plasma insulin and triglycerides, and low HDL cholesterol concentrations do not have elevated UAE. This suggests that UAE is not closely associated with these characteristics and implies a later onset of abnormal albuminuria in the course of the insulin resistance syndrome.
OBJECTIVE -To assess the impacts of insulin resistance and renal function on plasma total homocys... more OBJECTIVE -To assess the impacts of insulin resistance and renal function on plasma total homocysteine (tHcy) levels in patients with type 2 diabetes with a wide range of nephropathy.
OBJECTIVE -ACE inhibitors are known to be effective in preventing the progression of diabetic nep... more OBJECTIVE -ACE inhibitors are known to be effective in preventing the progression of diabetic nephropathy. Activation of the renin-angiotensin system (RAS) is reported to contribute to intrarenal hemodynamic abnormality in diabetic patients. We examined whether RAS blockade by captopril induces intrarenal hemodynamic changes in normotensive patients with type 2 diabetes.
Strain concentration at grain boundaries and grain boundary microstructure in cold worked Alloy 6... more Strain concentration at grain boundaries and grain boundary microstructure in cold worked Alloy 600 were characterized. Excluding the annealing twin boundaries, the base and 20% cold worked alloys exhibited higher random grain boundary fractions than the 8% and 40% cold worked alloys. An increased low angle boundaries and decreased annealing twins were observed with deformation. The 20% cold worked alloy displayed a maximum strain concentration at grain boundaries. The stress corrosion cracking growth in cold worked Alloy 600 in high temperature water showed a strong correlation with the strain concentration at grain boundaries.
It is shown that the density dependence of the most favorable frequency of the r. f. electric fie... more It is shown that the density dependence of the most favorable frequency of the r. f. electric field to confine a cusp plasma is consistent with that suggested by a theory taking account of collective response of a plasma. Based on this dependence, automatic tuning of the frequency to the optimum value for the decaying plasma is demonstrated using a feedback system piloted by an ion density measurement.
expressing immunoglobulin mRNA [4], suggesting local lar mortality in end-stage renal disease. pr... more expressing immunoglobulin mRNA [4], suggesting local lar mortality in end-stage renal disease. production of antibodies. OxLDL is detected in athero-Background. Immune response to oxidized low-density lipomatous lesions [5-7], and it can activate lymphocyte clones protein (oxLDL) may modulate the process of atherogenesis [8]. Immunoglobulins extracted from plaques recognize and cardiovascular disease. oxLDL [9], and antibody against oxLDL is present in Methods. We performed a prospective, observational cohort study in 249 patients with end-stage renal disease (ESRD) to serum [6, 10-19]. To date it has not been established examine whether the serum titer of anti-oxLDL antibody can whether immune response to oxLDL is atherogenic or predict cardiovascular mortality.
ABSTRACT A movable graphite limiter with an internal heater has been installed in the heliotron/t... more ABSTRACT A movable graphite limiter with an internal heater has been installed in the heliotron/torsatron type compact helical system (CHS). Comparing discharges with and without the limiter the origin of major impurities and the role of the limiter are discussed. Infrared TV measurements reveal that there are two hot spots on the limiter due to heat loading and their temperatures depend on the electron density and/or the magnetic field direction. Limiter temperature dependence of measured CH/Hγ, CI, CII, OII, CH+3, OV and total radiation loss is compared. From these experiments it is concluded that CH4 molecules produced chemically on the limiter are presumed to recycle rapidly near the limiter and both carbon and oxygen impurities result probably from CO produced chemically on the limiter with oxygen which is predominant in CHS and originates mostly from the first wall. At surface temperatures above 900 ° C the limiter effect on impurities is observable in the main plasma.
ABSTRACT The effects of plasma edge modification on confinement have been investigated on the JFT... more ABSTRACT The effects of plasma edge modification on confinement have been investigated on the JFT-2M tokamak since 1985. In the course of investigations, a new enhanced confinement regime, limiter H-mode, was discovered in 1986. This paper is a review of investigations into edge recycling control methods which extend the H-mode operational regime. In addition to Ti-gettering, the following methods have been shown to reduce edge neutral buildup, to extend the operational regime and to improve n τ of H-mode discharges: (1) optimization of the gas-puff programming (decreased or terminated at the start of auxiliary heating), (2) a toroidally distributed gas-puff system, (3) edge heating by ECH, and (4) particle removal with a pump limiter.
ABSTRACT Increments of peripheral hydrogen/deuterium neutral gas pressures (PH2/PD2) during the a... more ABSTRACT Increments of peripheral hydrogen/deuterium neutral gas pressures (PH2/PD2) during the additional heating phase (neutral beam and RF heatings) have been observed in a D2 gas-puff fueled JFT-2M tokamak with H2-absorbed graphite limiters/divertor plates. In the beam heating phase, a large increment of PH2 raises the plasma density 2 times or more without the degrading energy confinement time. The D2 gas-puff valve is closed in this phase. This improvement is interpreted as being due to “wall fueling”, i.e., fueling by desorbed hydrogen from the graphite wall by energetic particles. The first observation of the H-mode in the INTOR-type stubby open divertor with a short divertor channel (1–8 cm) at the high density regime (4–7 × 1013 cm−3) enhanced by the wall fueling is presented. The improved energy confinement time is comparable to or higher than that of ohmically heated discharges.
ABSTRACT Oxidation behavior at the tips of several stress corrosion cracking (SCC) crack, includi... more ABSTRACT Oxidation behavior at the tips of several stress corrosion cracking (SCC) crack, including intergranular SCC (IGSCC) and transgranular SCC (TGSCC) cracks, in heat-treated 304L stainless steel in high temperature oxygenated water was studied using a field emission gun-analytical transmission electron microscopy (FEG–ATEM). These SCC cracks were produced during SCC tests in two different heat-treated 304L stainless steels in high temperature pure water with two different levels of dissolved oxygen (DO). The study showed that oxygen played a key role in nucleation and propagation of SCC cracks. For the IGSCC crack, oxidation took place followed by nucleation and growth of microcracks in the oxide ahead of the crack tip on the grain boundary plane. The IGSCC crack then propagated by linkage with these microcracks. Oxides formed in the high temperature water with different DO had different configurations and microstructures. In the case of low DO, separate oxides of Cr2O3 and Fe3O4 types were formed, while the oxide formed in high DO consisted of mixed FeCr2O4 and Fe3O4. For the TGSCC crack, oxidation along deformation bands and nucleation and growth of microcracks within oxide were important mechanisms. It was found that Si was preferentially oxidized ahead of the crack tip, promoting SCC crack propagation. Ni enrichment at some SCC crack tips was also revealed.
... Semiempirical evaluations of the relationships between CTSR and engineering parameters were m... more ... Semiempirical evaluations of the relationships between CTSR and engineering parameters were made by Ford et al. ... (4) is a useful approach for relative comparison of strain ... is strongly dependent on strain redistribution associated with the growing crack for the fast crack growth ...
ABSTRACT A pump limiter is applied to the JFT-2M tokamak in order to reduce edge gas buildup. Abo... more ABSTRACT A pump limiter is applied to the JFT-2M tokamak in order to reduce edge gas buildup. About 12% of the effective loss flux is removed by the pump limiter and the fueling efficiency is improved by 30%. In the high density regime, the gas buildup is successfully reduced and edge cooling by cold gas-puffing is prevented by the pump limiter. The pump limiter also improves the density limit and the energy confinement time. Improvement in the nτ value is about 34%. This pump limiter is shown to be compatible with the limiter H-mode.
The low-temperature phase (LTP) MnBi is one of the few rare-earth free compounds that exhibit a l... more The low-temperature phase (LTP) MnBi is one of the few rare-earth free compounds that exhibit a large magnetocrystalline anisotropy energy in the order of 10 6 J/m 3 . A large coercive field (l 0 H cj ) above 1 T can be obtained readily by reducing the crystallite size (D) through mechanical grinding (MG). The room-temperature H cj values follow a phenomenological expression l 0 H cj = l 0 H a (d/D) n where the anisotropy field (l 0 H a ) is $4 T, the Bloch wall width (d) is 7 nm and the exponent (n) is about 0.7 in our study. The grain refinement upon MG is accompanied by suppression of the spin reorientation transition temperature (T SR ) from 110 K to below 50 K. The coercive field starts to exhibit positive temperature dependence approximately 50 K above T SR and the room-temperature magnetic hardening induced by MG could partially be brought about by the lowered onset of this positive temperature dependence. The suppression of T SR by MG is likely to be induced by the surface anisotropy with which the 2nd order crystal field term is enhanced. One of the shortcomings of LTP-MnBi is its poor phase stability under the ambient atmosphere. The spontaneous magnetization decreases considerably after room-temperature aging for 1 week. This is due to oxidation of Mn which leads to decomposition of the MnBi phase. Hence, the surface passivity needs to be established before this material is considered for a permanent magnet in practical uses. Another shortcoming is the limited spontaneous magnetization. The theoretical upper limit of the maximum energy product in LTP-MnBi remains only a quarter of that in Nd 2 Fe 14 B. Nevertheless, owing to the unique positive temperature dependence of the first-order anisotropy constant (K 1 ), the hardness parameter (j) of LTP-MnBi is enhanced above room temperature; j reaches as large as 2.8 at 580 K. This makes LTP-MnBi a possible candidate for the hard phase in rare-earth free nanocomposite magnets.
Elevated urinary albumin excretion (UAE) has been associated with insulin resistance and is sugge... more Elevated urinary albumin excretion (UAE) has been associated with insulin resistance and is suggested to be elevated in prediabetic individuals. Upper body obesity, especially visceral obesity, predicts insulin resistance and development of type 2 diabetes. We examined whether UAE clusters with obesity-associated insulin resistance traits in healthy glucose-tolerant normotensive subjects. There were 49 volunteers with a wide range of body fat and body fat distribution studied. All had normal blood pressure and glucose tolerance and were maintained on a controlled diet for 2 weeks. UAE was assessed from three overnight urine collections, and body composition was assessed by whole-body dual-energy X-ray absorptiometry scanning and abdominal computed tomography scanning. Fasting insulin and insulin responses to oral glucose were significantly increased in obese subjects, who also tended to have more dyslipidemia, greater blood pressure, and more visceral fat than lean subjects. These differences were more apparent in upper body obese subjects. UAE was normal in obese and upper body obese subjects and not different from that of lean subjects. UAE ranged from 0.3 to 8.3 micrograms/min in lean subjects and from 0.2 to 7.2 micrograms/min in obese subjects. UAE was not significantly correlated with body composition, plasma insulin, glucose, or lipids. Obese subjects (even upper body obese subjects) with increased visceral and total body fat, high plasma insulin and triglycerides, and low HDL cholesterol concentrations do not have elevated UAE. This suggests that UAE is not closely associated with these characteristics and implies a later onset of abnormal albuminuria in the course of the insulin resistance syndrome.
OBJECTIVE -To assess the impacts of insulin resistance and renal function on plasma total homocys... more OBJECTIVE -To assess the impacts of insulin resistance and renal function on plasma total homocysteine (tHcy) levels in patients with type 2 diabetes with a wide range of nephropathy.
OBJECTIVE -ACE inhibitors are known to be effective in preventing the progression of diabetic nep... more OBJECTIVE -ACE inhibitors are known to be effective in preventing the progression of diabetic nephropathy. Activation of the renin-angiotensin system (RAS) is reported to contribute to intrarenal hemodynamic abnormality in diabetic patients. We examined whether RAS blockade by captopril induces intrarenal hemodynamic changes in normotensive patients with type 2 diabetes.
Strain concentration at grain boundaries and grain boundary microstructure in cold worked Alloy 6... more Strain concentration at grain boundaries and grain boundary microstructure in cold worked Alloy 600 were characterized. Excluding the annealing twin boundaries, the base and 20% cold worked alloys exhibited higher random grain boundary fractions than the 8% and 40% cold worked alloys. An increased low angle boundaries and decreased annealing twins were observed with deformation. The 20% cold worked alloy displayed a maximum strain concentration at grain boundaries. The stress corrosion cracking growth in cold worked Alloy 600 in high temperature water showed a strong correlation with the strain concentration at grain boundaries.
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