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Synaptic degeneration in the prefrontal cortex of a rat AD model revealed by volume electron microscopy

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Journal of Molecular Cell Biology 2022年第3期14卷 61-64页

作者： Yi Jiang Linlin Li Keliang Pang Jiazheng Liu Bohao Chen Jingbin Yuan Lĳun Shen Xi Chen Bai Lu Hua Han National Laboratory of Pattern Recognition Institute of AutomationChinese Academy of SciencesBeĳing 100190China School of Artificial Intelligence University of Chinese Academy of SciencesBeĳing 101408China School of Pharmaceutical Sciences IDG/McGovern Institute for Brain ResearchTsinghua UniversityBeĳing 100084China Beĳing Advanced Innovation Center for Structural Biology School of Life SciencesTsinghua UniversityBeĳing 100084China School of Future Technology University of Chinese Academy of SciencesBeĳing 101408China Center for Excellence in Brain Science and Intelligence Technology Chinese Academy of SciencesShanghai 200031China

Alzheimer’s disease(AD),a neurodegenerative disease,is identified as the most common cause of dementia(Goedert and Spillantini,2006).Typical symptoms of AD in neuropathology are closely associated with changes in synapses and neurons(Serrano-Pozo et al.,2011).The prefrontal cortex(PFC)plays a crucial role in executive function,controlling the highest level of cognitive and emotional processes,and is also vulnerable to neurodegeneration in AD(Salat et al.,2001).While synaptic degeneration is believed to underlie the progressive decline of cognition in AD,specific changes in synaptic structures relevant to AD remain elusive due to a shortage of quantitative *** dysfunction,while key to AD pathophysiology,is difficult to monitor and study in human AD patients.

关键词： degeneration cortex Alzheimer

Intraocular pressure measurement over soft contact lens by rebound tonometer: a comparative study

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International Journal of Ophthalmology(English edition) 2015年第3期8卷 540-543页

作者： Senay Asik Nacaroglu Emine Seker un Mehmet Giray Ersoz Yelda Tasci Department of Ophthalmology Tepecik Traning and Research Hospital Department of Ophthalmology Akdagmadeni State Hospital

AIM: To evaluate the intraocular pressure(IOP)measurements by Icare rebound tonometer over a contact lens in comparison with Goldmann applanation tonometry(GAT). METHODS: Fifty patients using contact lens were included in this study. One of the eyes of the patients was selected randomly and their IOP were measured by rebound tonometer with and without contact lens(RTCL,RT respectively) and by GAT, as well as their central corneal thickness(CCT) by optical pachymeter. The results of both methods were compared by correlation analysis, general linear method repeated measure and Bland-Altman ***: Mean IOP values measured by RTCL, RT and GAT were 15.68 ±3.7, 14.50 ±3.4 and 14.16 ±2.8(P und tonometer was found to be higher than what was measured by GAT. Although this difference is statistically significant, it may be clinically negligible in the normal population.

关键词： contact lens intraocular pressure rebound tonometer

Effects of carbonization temperatures on microstructure of carbon fiber precursors prepared from liquefied wood

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Forestry Studies in China 2009年第4期11卷 238-242页

作者： MA Xiao-j un ZHAO Guang-jie College of Packaging ＆ Printing Engineering Tianjin University of Science ＆ Technology Tianjin 300222 E R. China College of Materials Science and Technology Beijing Forestry University Beijing 100083 P. R. China

In order to enlarge the utilization field of wood and decrease the costs of carbon fibers, carbon fiber precursors from liquefied wood were prepared by soaking liquefied wood in a solution containing hydrochloric acid and formaldehyde, after melt-spinning by adding hexamethylenetetramine. The microstructure evolution of the precursor during carbonization was studied by FTIR, X-ray analysis and Raman spectroscopy. The results show that precursors from liquefied wood above 400℃had diffraction peaks corresponding to the （100） crystal plane. When the carbonization temperature reached 500℃, Raman spectroscopy showed the D peak at wave number of 1360 cm^-1 and the G peak at 1595 cm^-1. By increasing the carbonization temperature, the microstructure of the precursors became more ordered. Although the structure of the precursor changed at 500 and 800℃, the peaks at 1632 and 1454 cm^-1 corresponding to the characteristic vibrations of aromatic rings, remained during carbonization. This implies that the precursor from liquefied wood cannot be easily formed into graphite.

关键词： carbon fiber liquefied wood microstructure temperature

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盘式制动器热-机耦合渐变可靠性灵敏度分析

东北大学学报（自然科学版） 2022年第1期43卷 48-55,64页

作者：杨周朴银成权哲优东北大学机械工程与自动化学院辽宁沈阳110819 平壤交通运输大学机械工程学院朝鲜平壤999093 朝鲜国家科学院机械工程研究所朝鲜平壤999093

为了解决盘式制动器由于摩擦温度过高而导致可靠性降低的问题,以某种汽车的通风盘式制动器为例,进行了热-机耦合渐变可靠性灵敏度分析.利用Workbench的"Coupled Field Transient"模块进行热-机耦合分析,得到了在紧急制动工况下制动器瞬... 详细信息

为了解决盘式制动器由于摩擦温度过高而导致可靠性降低的问题,以某种汽车的通风盘式制动器为例,进行了热-机耦合渐变可靠性灵敏度分析.利用Workbench的"Coupled Field Transient"模块进行热-机耦合分析,得到了在紧急制动工况下制动器瞬态温度场分布,然后通过与实验结果对比分析,确定有限元模型的准确性.根据制动器最高温度不能超过许用温度的关系推测,利用自适应Kriging代理模型理论建立制动器热-机耦合可靠性功能函数模型.采用自适应Kriging-Monte Carlo模拟(adaptive Kriging-Monte Carlo simulation, AK-MCS)方法进行热-机耦合渐变可靠性灵敏度分析,确定设计参数对可靠性的影响程度,并用Monte Carlo法进行结果的验证.结果表明:制动盘单侧厚度对可靠性的影响最为明显,制动盘的导热系数、比热容和散热加强筋厚度次之,制动盘密度影响最小.

关键词：盘式制动器热-机耦合分析自适应Kriging代理模型热-机耦合渐变可靠性可靠性灵敏度分析

Design Consideration of 650-MHz Circular Electron-Positron Collider Klystron and Simulation of Its Beam Tester

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Chinese Physics Letters 2017年第1期34卷 27-31页

作者： un-Nisa Zaib Shigeki Fukuda 周祖圣董东王盛昌肖欧正陆志军裴国玺 Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049 university of Chinese Academy of Sciences Beijing 100049 Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049 High Energy Accelerator Research Organization KEKOhoIbaraki 305-0801Japan

We present the first phase R&D for the 800 kW cw, 650MHz klystron for the future circular electron-positron collider (CEPC) project in China. The CEPC requires 192 klystrons and it is desired to be designed in the Institute of High Energy Physics, CAS, and manufactured domestically. Therefore, we present the manufacturing schedule of this project; the three-stage development from the beam test tube to the klystron having a high efficiency structure. Design of the beam test tube that comprises electron gun and collector is presented. First, gun simulation having a modulating anode is performed using DGun software. The uniform beam trajectories with a beam perveance of 0.64 mu A/V-3/2 are simulated. We employ a Ba-dispenser cathode of radius 35mm with phi 10 hole at the center and obtain a current density on cathode less than 0.45 A/cm(2). The beam trajectories are also simulated over beam test tube of length about 2m with a magnetic field of 213 Gauss. Thermal analysis of the collector is performed using the ANSIS-CFX code and hence the cooling structure is determined. Mechanical design is almost carried out and it is in manufacturing stage.

关键词： Electron guns

Design and high-power test of 800-kW UHF klystron for CEPC

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Chinese Physics B 2022年第8期31卷 154-159页

作者：肖欧正 Shigeki Fukuda 周祖圣 un-Nisa Zaib 王盛昌陆志军裴国玺 Munawar Iqbal 董东 Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China High Energy Accelerator Research Organization KEKOhoIbaraki 305-0801Japan

To reduce the energy demand and operation cost for circular electron positron collider(CEPC), the high efficiency klystrons are being developed at Institute of High Energy Physics, Chinese Academy of Sciences. A 800-k W continuous wave(CW) klystron operating at frequency of 650-MHz has been designed. The results of beam–wave interaction simulation with several different codes are presented. The efficiency is optimized to be 65% with a second harmonic cavity in three-dimensional(3D) particle-in-cell code CST. The effect of cavity frequency error and mismatch load on efficiency of klystron have been investigated. The design and cold test of reentrant cavities are described, which meet the requirements of RF section design. So far, the manufacturing and high-power test of the first klystron prototype have been *** the gun operated at DC voltage of 80 k V and current of 15.4 A, the klystron peak power reached 804 k W with output efficiency of about 65.3% at 40% duty cycle. The 1-d B bandwidth is ±0.8 MHZ. Due to the crack of ceramic window, the CW power achieved about 700 kW. The high-power test results are in good agreement with 3D simulation.

关键词： klystron cavity beam–wave interaction circular electron positron collider(CEPC) high-power test

Accelerated precipitation behavior of cast Mg-Al-Zn alloy by grain refinement

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Journal of Materials Science & Technology 2018年第2期34卷 265-276页

作者： Sang-Hoon Kim Jong un Lee Ye Jin Kim Jun Ho Bae Bong Sun You Sung Hyuk Park School of Materials Science and Engineering Kyungpook National University Implementation Research Division Korea Institute of Materials Science

This study demonstrates that the precipitation behavior of 13-Mg17Al12 phase during aging and the resultant variation in hardness and mechanical properties of cast Mg-Al-Zn alloy are strongly dependent on initial grain size. Grain size reduction accelerates discontinuous precipitation at the early stage of aging treatment by increasing the area fraction of grain boundaries that can act as nucleation sites for discontinuous precipitates （DP）, but it does not influence DP growth rate. Grain refinement also prematurely terminates continuous precipitation because the formation of a large number of DP reduces the amount of AI dissolved in the matrix, which is required for the formation of continuous precipitates （CP）. This promotion of DP formation and early termination of CP formation significantly decrease the peak-aging time to one-third. The enhanced precipitation behavior also leads to an additional hardness improvement in the aged alloy, along with an increase in hardness owing to grain boundary strengthening by grain refinement. The amount of increase in hardness changes with aging time, which is determined by the variation of three variables with aging time： DP fraction difference between refined and nonrefined alloys, hardness difference between DP and matrix, and matrix hardness difference between the two alloys. Grain refinement improves both tensile strength and ductility of the homogenized alloy owing to grain boundary strengthening and suppression of twinning activation, respectively. However, the loss of ductility after peak-aging treatment is greater in the refined alloy because of the larger amount of DP acting as a crack source in this alloy.

关键词： Magnesium Grain refinement Aging Precipitation Tensile properties

Dynamic recrystallization behavior and microstructural evolution of Mg alloy AZ31 through high-speed rolling

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Journal of Materials Science & Technology 2018年第10期34卷 1747-1755页

作者： Jeong Hun Lee Jong un Lee Sang-Hoon Kim Seok Weon Song Chong Soo Lee Sung Hyuk Park Ulsan Regional Division Korea Institute of Industrial Technology School of Materials Science and Engineering Kyungpook National University Technical Research Laboratories POSCO Graduate Institute of Ferrous Technology Pohang University of Science and Technology

High-speed rolling （HSR） is known to improve the workability of Mg alloys significantly, which makes it possible to impose a large reduction in a single pass without fracture. In the present study, dynamic recrystallization （DRX） behavior and microstructural and textural variations of Mg alloy AZ31 dur-ing a HSR process were investigated by conducting rolling with different imposed reductions in the range of 20%-80% at a high rolling speed of 470 m/min and 400℃. High-strain-rate deformation during HSR suppresses dislocation slips but promotes twinning, which results in the formation of numer-ous twins of several types, i.e., {10-12} extension twins, {10-11} and {10-13} contraction twins, and {10-11}-{10-12} double twins. After twinning, high strain energy is accumulated in twin bands because their crystallographic orientations are favorable for basal slips, leading to subsequent DRX at the twin bands. Accordingly, twinning activation and twinning-induced DRX behavior play crucial roles in accommodating plastic deformation during HSR and in varying microstructure and texture of the high- speed-rolled （HSRed） sheets. Area fraction of fine DRXed grains formed at the twin bands increases with increasing rolling reduction, which is attributed to the combined effects of increased strain, strain rate, and deformation temperature and a decreased critical strain for DRX. Size, internal strain, and texture intensity of the DRXed grains are smaller than those of unDRXed grains. Therefore, as rolling reduction increases, average grain size, stored internal energy, microstructural inhomogeneity, and basal texture intensity of the HSRed sheets gradually decrease owing to an increase in the area fraction of the DRXed grains.

关键词： Magnesium alloy High-speed rolling Twinning Dynamic recrystallization Microstructure

Morphotaxonomy and seasonal distribution of planktonic and benthic Prorocentrales in Karachi waters,Pakistan Northern Arabian Sea

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Chinese Journal of Oceanology and Limnology 2013年第2期31卷 267-281页

作者： Sonia MunIR Zaib-un-nisa BURHAN Tahira NAZ P.J.A.SIDDIQUI Steve L.MORTON Centre of Excellence in Marine Biology University of Karachi-75270Pakistan National Oceanic and Atmospheric Administrations 219 Fort Johnson RoadCharleston SC29412USA

Morphotaxonomy and seasonal a.undance of dinoflagellates of the genera Prorocentrum and Mesoporos(Prorocentrales) were studied from nutrient-rich waters,Karachi Harbor and the mouth of the Manora Channel,Pakistan during May 2002-July *** both light and scanning electron microscopy,13 species of Prorocentrales were identified according to cell shape,size,ornamentation of thecal plates,and architecture of apical platelets,apical pore area,marginal pores,and intercalary ***,***,***,***,***,***,***,***,***,and Mesoporos perforatus constitute new records for sindh coast of *** most a.undant species were ***/***(4.5×103 cells/L),***(1.1×103 cells/L),***/***(2.5×102 cells/L) and ***(6.6×103 cells/L) at temperatures of 29-31℃ and salinities of *** a.undance was observed in winter and lower a.undance in *** was no significant change in the distribution of species between stations except for the benthic species which occurred close to Karachi Harbor *** positive correlations were observed between Prorocentrum *** temperature(R 2 =0.27) and negative correlations with salinity(R 2 =-0.32) except for *** and *** which has negative correlation with temperature(R 2 =-0.24) and positive with salinity(R 2 =0.08,0.19).The finding of potential okadaic-acid producing species of benthic Prorocentrum call for monitoring for possible human health problems in this region.

关键词：季节性分布巴基斯坦水域阿拉伯海扫描电子显微镜卡拉奇港负相关性原甲藻