The microstructures and mechanical properties of Ti–47 at%Ni–3 at%Fe shape memory alloy wire under the condition of severe cold-drawing at room temperature and different postdeformation annealing processes were inte...The microstructures and mechanical properties of Ti–47 at%Ni–3 at%Fe shape memory alloy wire under the condition of severe cold-drawing at room temperature and different postdeformation annealing processes were intensively investigated using transmission electron microscope(TEM),X-ray diffraction(XRD),Vickers microhardness tester and electron tensile tester.It is indicated that the structure of the alloy evolves into a predominant amorphous structure with a trace of nanocrystalline B2 phase after the cold-drawing of 76%areal reduction.Postdeformation annealing process exerted significant influence on the microstructure and mechanical properties.Crystallization occurs when the cold-drawn wire was annealed at 300℃ for 30 min.The ultimate tensile strength and ductility as well as the superelasticity of the wire are improved significantly by cold-drawing plus postdeformation annealing.展开更多
Deformation twins and stacking faults were observed in nanostructure A1-Mg alloys subjected to high pressure torsion. These observations are surprising because deformation twinnings have never been observed in their c...Deformation twins and stacking faults were observed in nanostructure A1-Mg alloys subjected to high pressure torsion. These observations are surprising because deformation twinnings have never been observed in their coarse-grained counterparts under normal conditions. Experimental evidences are introduced on non-equilibrium grain boundaries, deformation twinnings and partial dislocation emissions from grain boundaries. Some of these features can be explained by the results reported from molecular-dynamics simulations of pure FCC metals. Special emphasis is laid on the recent observations of high density hexagonal and rhombic shaped nanostructures with an average size of 3 nm in the A1-Mg alloys processed by high pressure torsion. A possible formation process of these nanostructures is proposed based on molecular-dynamics simulations.展开更多
This paper focuses on how aging can affect performance of safety-related structures in nuclear power plant (NPP). Knowledge and assessment of impacts of aging on structures are essential to plant life extension analys...This paper focuses on how aging can affect performance of safety-related structures in nuclear power plant (NPP). Knowledge and assessment of impacts of aging on structures are essential to plant life extension analysis,especially performance to severe loadings such as loss-of-coolant-accidents or major seismic events. Plant life extension issues are of keen interest in countries (like the United States) which have a large,aging fleet of NPPs. This paper addresses the overlap and relationship of structure aging to severe loading performance,with particular emphasis on containment structures.展开更多
Sleep disturbances are among the most prevalent neuropsychiatric symptoms in individuals who have recovered from severe acute respiratory syndrome coronavirus 2 infections.Previous studies have demonstrated abnormal b...Sleep disturbances are among the most prevalent neuropsychiatric symptoms in individuals who have recovered from severe acute respiratory syndrome coronavirus 2 infections.Previous studies have demonstrated abnormal brain structures in patients with sleep disturbances who have recovered from coronavirus disease 2019(COVID-19).However,neuroimaging studies on sleep disturbances caused by COVID-19 are scarce,and existing studies have primarily focused on the long-term effects of the virus,with minimal acute phase data.As a result,little is known about the pathophysiology of sleep disturbances in the acute phase of COVID-19.To address this issue,we designed a longitudinal study to investigate whether alterations in brain structure occur during the acute phase of infection,and verified the results using 3-month follow-up data.A total of 26 COVID-19 patients with sleep disturbances(aged 51.5±13.57 years,8 women and 18 men),27 COVID-19 patients without sleep disturbances(aged 47.33±15.98 years,9 women and 18 men),and 31 age-and gender-matched healthy controls(aged 49.19±17.51 years,9 women and 22 men)were included in this study.Eleven COVID-19 patients with sleep disturbances were included in a longitudinal analysis.We found that COVID-19 patients with sleep disturbances exhibited brain structural changes in almost all brain lobes.The cortical thicknesses of the left pars opercularis and left precuneus were significantly negatively correlated with Pittsburgh Sleep Quality Index scores.Additionally,we observed changes in the volume of the hippocampus and its subfield regions in COVID-19 patients compared with the healthy controls.The 3-month follow-up data revealed indices of altered cerebral structure(cortical thickness,cortical grey matter volume,and cortical surface area)in the frontal-parietal cortex compared with the baseline in COVID-19 patients with sleep disturbances.Our findings indicate that the sleep disturbances patients had altered morphology in the cortical and hippocampal structures during the acute phase of infection and persistent changes in cortical regions at 3 months post-infection.These data improve our understanding of the pathophysiology of sleep disturbances caused by COVID-19.展开更多
探究基于“-TT”结构经监护仪腹内压监测法降低重症患者喂养不耐受发生率的效果。选取2022年8月—2023年8月四川省自贡市第四人民医院抢救监护室(emergency intensive care unit,EICU)60例重症需行肠内营养(enteral nutrition,EN)支持...探究基于“-TT”结构经监护仪腹内压监测法降低重症患者喂养不耐受发生率的效果。选取2022年8月—2023年8月四川省自贡市第四人民医院抢救监护室(emergency intensive care unit,EICU)60例重症需行肠内营养(enteral nutrition,EN)支持的患者作为研究对象,采用随机数字表法将患者分为参照组和试验组,每组各30例。参照组实施常规EN管理,试验组在参照组基础上实施基于“-TT”结构经监护仪腹内压监测法,对比两组患者的喂养不耐受发生率。结果显示,与参照组相比,试验组喂养不耐受发生率较低(P<0.05);试验组达到目标喂养量时间较短(P<0.05);试验组EICU停留时间较短(P<0.05)。研究发现,于EICU重症需行EN支持患者的管理中,基于“-TT”结构经监护仪腹内压监测法具有一定的临床应用价值,通过对患者腹压变化的实时监测,可以及时调整喂养方案,降低其喂养不耐受发生率,缩短患者达到目标喂养量的时间,改善患者预后,值得借鉴。展开更多
Background The nutritional support is one of the important therapeutic strategies for the elderly patients with severe sepsis,but there is controversial in choosing a parenteral nutrition formulation.This study was de...Background The nutritional support is one of the important therapeutic strategies for the elderly patients with severe sepsis,but there is controversial in choosing a parenteral nutrition formulation.This study was designed to compare the therapeutic effects of structured lipid emulsion,physically mixed medium,and long-chain fat emulsion in the treatment of severe sepsis in elderly patients.Methods A total number of 64 elder patients with severe sepsis were enrolled in the study.After a week of enteral nutritional support,the patients were randomly divided into research （structured lipid emulsion as parenteral alimentation） and control groups （physically mixed medium and long-chain fat emulsion as parenteral alimentation）.The alterations of plasma albumin,lipid metabolism,and blood glucose level were recorded after parenteral alimentation and were compared between the two groups.Results The plasma levels of albumin,prealbumin,cholesterol,and triglyceride were decreased in all the patients after one week of enteral nutritional support treatment （t=7.78,P=0.000; t=10.21,P=0.000; t=7.99,P=0.000; and t=10.99,P=0.000）.Further parenteral alimentation with different lipid emulsions had significant effects on the serum prealbumin and albumin （t=3.316,P=0.002; t=3.200,P=0.002）,whilst had no effects on the blood glucose and triglyceride level （t=7.78,P=0.000; t=4.228,P=0.000）.In addition,the two groups had a significantly different Apache Ⅱ score,ventilator time,and hospital stay time （t=-2.213,P=0.031;t=2.317,P=0.024; t=2.514,P=0.015）.Conclusions The structured lipid emulsion was safe as parenteral nutrition for elderly patients with severe sepsis.It was demonstrated to be superior to the physically mixed medium and long-chain fat emulsion with respect to the protein synthesis and prognosis.展开更多
本研究旨在模拟不同狭窄程度和脉搏率的颈动脉搏动血流。采用流-固耦合(FSI)和任意拉格朗日-欧拉(ALE)方法研究了不同狭窄程度、脉搏率和动脉壁性质对周围流体的影响。分别应用Carreau-Yasuda非牛顿超弹性模型和修正Mooney-Rivin超弹性...本研究旨在模拟不同狭窄程度和脉搏率的颈动脉搏动血流。采用流-固耦合(FSI)和任意拉格朗日-欧拉(ALE)方法研究了不同狭窄程度、脉搏率和动脉壁性质对周围流体的影响。分别应用Carreau-Yasuda非牛顿超弹性模型和修正Mooney-Rivin超弹性模型于具有非牛顿行为的血液和超弹性血管壁。结果得到血液的壁面径向位移、压力分布、轴向速度分布和壁面剪切应力。通过增加狭窄的严重程度,轴向速度、血压变化、最大壁面剪切应力和壁面径向位移均呈增长趋势。当脉率在狭窄程度为75%时,最大流量矩、壁面径向位移、压力、轴向速度和壁面剪应力的最大值均增大。此外,与弹性和刚性模型相比,将动脉壁视为超弹性模型,将其周围流体视为非牛顿和非定常,可以使模拟更加真实。在严重程度高达50%的狭窄中,红细胞受到轻微损害,而在严重程度为75%的狭窄中观察到溶血。通过改善动脉粥样硬化,弹性模量从500 k Pa提高到2 MPa,在60 bpm脉率和狭窄程度75%下,剪切应力最大值增长65%。与刚性和弹性动脉壁相比,动脉壁的超弹性模型导致较低的轴向速度、较低的血压、较低的剪切应力和较高的径向位移。展开更多
基金supported by the National Natural Science Foundation of China (No. 50921003)Industry, Education and Research Projects of the China Aviation Industrial (No.cxy2012BH04)
文摘The microstructures and mechanical properties of Ti–47 at%Ni–3 at%Fe shape memory alloy wire under the condition of severe cold-drawing at room temperature and different postdeformation annealing processes were intensively investigated using transmission electron microscope(TEM),X-ray diffraction(XRD),Vickers microhardness tester and electron tensile tester.It is indicated that the structure of the alloy evolves into a predominant amorphous structure with a trace of nanocrystalline B2 phase after the cold-drawing of 76%areal reduction.Postdeformation annealing process exerted significant influence on the microstructure and mechanical properties.Crystallization occurs when the cold-drawn wire was annealed at 300℃ for 30 min.The ultimate tensile strength and ductility as well as the superelasticity of the wire are improved significantly by cold-drawing plus postdeformation annealing.
基金Project(50971087) supported by the National Natural Science Foundation of ChinaProject supported by the Research Council of Norway under the Strategic University Program on Light Metals Technology Projects(67692, 71594) supported by the Hungarian National Science Foundation
文摘Deformation twins and stacking faults were observed in nanostructure A1-Mg alloys subjected to high pressure torsion. These observations are surprising because deformation twinnings have never been observed in their coarse-grained counterparts under normal conditions. Experimental evidences are introduced on non-equilibrium grain boundaries, deformation twinnings and partial dislocation emissions from grain boundaries. Some of these features can be explained by the results reported from molecular-dynamics simulations of pure FCC metals. Special emphasis is laid on the recent observations of high density hexagonal and rhombic shaped nanostructures with an average size of 3 nm in the A1-Mg alloys processed by high pressure torsion. A possible formation process of these nanostructures is proposed based on molecular-dynamics simulations.
文摘This paper focuses on how aging can affect performance of safety-related structures in nuclear power plant (NPP). Knowledge and assessment of impacts of aging on structures are essential to plant life extension analysis,especially performance to severe loadings such as loss-of-coolant-accidents or major seismic events. Plant life extension issues are of keen interest in countries (like the United States) which have a large,aging fleet of NPPs. This paper addresses the overlap and relationship of structure aging to severe loading performance,with particular emphasis on containment structures.
基金supported by grants from Major Project of Science and Technology of Guangxi Zhuang Autonomous Region,No.Guike-AA22096018(to JY)Guangxi Key Research and Development Program,No.AB22080053(to DD)+6 种基金Major Project of Science and Technology of Guangxi Zhuang Autonomous Region,No.Guike-AA23023004(to MZ)the National Natural Science Foundation of China,Nos.82260021(to MZ),82060315(to DD)the Natural Science Foundation of Guangxi Zhuang Autonomous Region,No.2021GXNSFBA220007(to GD)Clinical Research Center For Medical Imaging in Hunan Province,No.2020SK4001(to JL)Key Emergency Project of Pneumonia Epidemic of Novel Coronavirus Infection in Hunan Province,No.2020SK3006(to JL)Science and Technology Innovation Program of Hunan Province,No.2021RC4016(to JL)Key Project of the Natural Science Foundation of Hunan Province,No.2024JJ3041(to JL).
文摘Sleep disturbances are among the most prevalent neuropsychiatric symptoms in individuals who have recovered from severe acute respiratory syndrome coronavirus 2 infections.Previous studies have demonstrated abnormal brain structures in patients with sleep disturbances who have recovered from coronavirus disease 2019(COVID-19).However,neuroimaging studies on sleep disturbances caused by COVID-19 are scarce,and existing studies have primarily focused on the long-term effects of the virus,with minimal acute phase data.As a result,little is known about the pathophysiology of sleep disturbances in the acute phase of COVID-19.To address this issue,we designed a longitudinal study to investigate whether alterations in brain structure occur during the acute phase of infection,and verified the results using 3-month follow-up data.A total of 26 COVID-19 patients with sleep disturbances(aged 51.5±13.57 years,8 women and 18 men),27 COVID-19 patients without sleep disturbances(aged 47.33±15.98 years,9 women and 18 men),and 31 age-and gender-matched healthy controls(aged 49.19±17.51 years,9 women and 22 men)were included in this study.Eleven COVID-19 patients with sleep disturbances were included in a longitudinal analysis.We found that COVID-19 patients with sleep disturbances exhibited brain structural changes in almost all brain lobes.The cortical thicknesses of the left pars opercularis and left precuneus were significantly negatively correlated with Pittsburgh Sleep Quality Index scores.Additionally,we observed changes in the volume of the hippocampus and its subfield regions in COVID-19 patients compared with the healthy controls.The 3-month follow-up data revealed indices of altered cerebral structure(cortical thickness,cortical grey matter volume,and cortical surface area)in the frontal-parietal cortex compared with the baseline in COVID-19 patients with sleep disturbances.Our findings indicate that the sleep disturbances patients had altered morphology in the cortical and hippocampal structures during the acute phase of infection and persistent changes in cortical regions at 3 months post-infection.These data improve our understanding of the pathophysiology of sleep disturbances caused by COVID-19.
文摘探究基于“-TT”结构经监护仪腹内压监测法降低重症患者喂养不耐受发生率的效果。选取2022年8月—2023年8月四川省自贡市第四人民医院抢救监护室(emergency intensive care unit,EICU)60例重症需行肠内营养(enteral nutrition,EN)支持的患者作为研究对象,采用随机数字表法将患者分为参照组和试验组,每组各30例。参照组实施常规EN管理,试验组在参照组基础上实施基于“-TT”结构经监护仪腹内压监测法,对比两组患者的喂养不耐受发生率。结果显示,与参照组相比,试验组喂养不耐受发生率较低(P<0.05);试验组达到目标喂养量时间较短(P<0.05);试验组EICU停留时间较短(P<0.05)。研究发现,于EICU重症需行EN支持患者的管理中,基于“-TT”结构经监护仪腹内压监测法具有一定的临床应用价值,通过对患者腹压变化的实时监测,可以及时调整喂养方案,降低其喂养不耐受发生率,缩短患者达到目标喂养量的时间,改善患者预后,值得借鉴。
文摘Background The nutritional support is one of the important therapeutic strategies for the elderly patients with severe sepsis,but there is controversial in choosing a parenteral nutrition formulation.This study was designed to compare the therapeutic effects of structured lipid emulsion,physically mixed medium,and long-chain fat emulsion in the treatment of severe sepsis in elderly patients.Methods A total number of 64 elder patients with severe sepsis were enrolled in the study.After a week of enteral nutritional support,the patients were randomly divided into research （structured lipid emulsion as parenteral alimentation） and control groups （physically mixed medium and long-chain fat emulsion as parenteral alimentation）.The alterations of plasma albumin,lipid metabolism,and blood glucose level were recorded after parenteral alimentation and were compared between the two groups.Results The plasma levels of albumin,prealbumin,cholesterol,and triglyceride were decreased in all the patients after one week of enteral nutritional support treatment （t=7.78,P=0.000; t=10.21,P=0.000; t=7.99,P=0.000; and t=10.99,P=0.000）.Further parenteral alimentation with different lipid emulsions had significant effects on the serum prealbumin and albumin （t=3.316,P=0.002; t=3.200,P=0.002）,whilst had no effects on the blood glucose and triglyceride level （t=7.78,P=0.000; t=4.228,P=0.000）.In addition,the two groups had a significantly different Apache Ⅱ score,ventilator time,and hospital stay time （t=-2.213,P=0.031;t=2.317,P=0.024; t=2.514,P=0.015）.Conclusions The structured lipid emulsion was safe as parenteral nutrition for elderly patients with severe sepsis.It was demonstrated to be superior to the physically mixed medium and long-chain fat emulsion with respect to the protein synthesis and prognosis.
文摘本研究旨在模拟不同狭窄程度和脉搏率的颈动脉搏动血流。采用流-固耦合(FSI)和任意拉格朗日-欧拉(ALE)方法研究了不同狭窄程度、脉搏率和动脉壁性质对周围流体的影响。分别应用Carreau-Yasuda非牛顿超弹性模型和修正Mooney-Rivin超弹性模型于具有非牛顿行为的血液和超弹性血管壁。结果得到血液的壁面径向位移、压力分布、轴向速度分布和壁面剪切应力。通过增加狭窄的严重程度,轴向速度、血压变化、最大壁面剪切应力和壁面径向位移均呈增长趋势。当脉率在狭窄程度为75%时,最大流量矩、壁面径向位移、压力、轴向速度和壁面剪应力的最大值均增大。此外,与弹性和刚性模型相比,将动脉壁视为超弹性模型,将其周围流体视为非牛顿和非定常,可以使模拟更加真实。在严重程度高达50%的狭窄中,红细胞受到轻微损害,而在严重程度为75%的狭窄中观察到溶血。通过改善动脉粥样硬化,弹性模量从500 k Pa提高到2 MPa,在60 bpm脉率和狭窄程度75%下,剪切应力最大值增长65%。与刚性和弹性动脉壁相比,动脉壁的超弹性模型导致较低的轴向速度、较低的血压、较低的剪切应力和较高的径向位移。
