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Study on Temperature Distribution and Smoke Spreading Behavior of Different Fire Source Locations in the UnderwaterW-Shaped Island-Crossing Tunnel

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Frontiers in Heat and Mass Transfer 2024年第4期22卷 1129-1151页

作者： Zhisheng Xu juan Wang Zihan yu Jiaming zhao School of Civil Engineering Central South UniversityChangsha410075China CABR Fire Safety Science&Technology Co. Ltd.Beijing100013China

Called island-crossing tunnels,some specific underwater tunneling projects face constraints imposed by geological and water conditions,necessitating their passage through artificial or natural *** longitudinal of the tunnel follows aW-shaped *** congestion situation does not allowfor immediate longitudinal smoke exhaust at the early stage of the fire,and the natural spread of smoke is *** exhaustive investigation was carried out to analyze the smoke behaviors during a fire incident,employing the fire dynamics software FDS,considering five slopes and four fire *** simulation results reveal that the layer of high-temperature smoke becomes thicker as one gets closer to the fire *** thermal pressure difference significantly impacts the temperature distribution within the tunnel and the distance of smoke *** value of the thermal pressure difference is significantly affected by changes in *** reaches a maximum of 157 Pa at a 5%slope,while it is only 41 Pa at a 1%slope when the fire occurs at the *** hazards vary across locations within the W-shaped tunnel,necessitating separate consideration of the V-point and inverted V-point fire *** mass flow rate in small and large slope tunnels shows different decay rates due to variations in the main forces acting on the ***,two equations have been developed to predict the smoke mass flow rate,indicating a nonlinear relationship with the tunnel slope and the distance fromthe fire *** tunnel slope inversely affects the smoke mass flowrate at the same *** results can be utilized as a reference for conducting evacuation operations and aiding rescues during aW-shaped tunnel fire.

关键词： Tunnel fire tilted tunnel smoke movement temperature distribution

基于分子束外延技术可控制备Bi原子团簇的研究

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原子与分子物理学报 2025年第2期42卷 79-84页

作者：马玉麟郭祥丁召贵州大学大数据与信息工程学院贵阳550025 贵州省微纳电子与软件技术重点实验室贵阳550025 半导体功率器件可靠性教育部工程研究中心贵阳550025

本研究基于分子束外延(MBE)技术在Si(111)衬底表面成功制备金属Bi原子团簇.首先,分别在100℃、125℃、150℃、175℃、200℃的生长温度下,制备了大小均一、密度不同的Bi原子团簇.实验结果表明,可以通过改变生长温度来精细控制Bi原子团簇... 详细信息

本研究基于分子束外延(MBE)技术在Si(111)衬底表面成功制备金属Bi原子团簇.首先,分别在100℃、125℃、150℃、175℃、200℃的生长温度下,制备了大小均一、密度不同的Bi原子团簇.实验结果表明,可以通过改变生长温度来精细控制Bi原子团簇的密度,当温度升高100℃,密度从1.05×10^(11)cm^(-2)降低至2.5×10^(7)cm^(-2),实现对团簇密度4个数量级的可控调节,并且发现Bi原子团簇密度对生长温度的依赖性符合经典成核理论.其次,分别在10 s、15 s、20 s的沉积时长下,制备了密度相同、尺寸各异的Bi原子团簇.实验结果表明,可以通过改变沉积时长来精细控制Bi原子团簇的尺寸:当沉积时长增加10 s,高度和直径分别从8.5 nm和65 nm增大到13.7 nm和100 nm,实现对团簇尺寸在10 nm高度、80 nm直径范围的可控调节,并且发现Bi原子团簇尺寸对沉积时长的依赖性符合晶体生长动力学.与分子束外延制备传统的Ⅲ族(Al,Ga,In)原子团簇做对比,这些结果可以为制备Ⅴ族原子团簇提供实验参考和指导,从而促进纳米级含Bi材料的制备.

关键词：分子束外延 Bi原子团簇生长温度沉积时长经典成核理论晶体生长动力学

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基于分子束外延技术可控制备Ga原子团簇的研究

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原子与分子物理学报 2025年第3期42卷 77-84页

本研究基于分子束外延(Molecular Beam Epitaxy,MBE)技术在Si(100)衬底表面成功制备金属Ga原子团簇.通过控制变量法,研究其尺寸形貌与工艺参数之间的关系.第一组对照实验分别在940℃、970℃、1000℃的Ga源温度下制备Ga原子团簇.实验结... 详细信息

本研究基于分子束外延(Molecular Beam Epitaxy,MBE)技术在Si(100)衬底表面成功制备金属Ga原子团簇.通过控制变量法,研究其尺寸形貌与工艺参数之间的关系.第一组对照实验分别在940℃、970℃、1000℃的Ga源温度下制备Ga原子团簇.实验结果表明,Ga源温度的升高导致Ga的蒸发量增加,进而沉积在Si衬底表面的Ga原子增多,Ga原子自组装成团簇,最终表现为Ga原子团簇的高度升高.第二组对照实验分别在3 s、6 s、10 s、40 s、50 s、60 s的沉积时长下制备Ga原子团簇.实验结果表明,沉积时长增加导致团簇的高度逐渐增加,主要由新吸附原子和竞争效应驱动.第三组对照实验分别在0 s、60 s、300 s的退火时长下制备Ga原子团簇.实验结果表明,退火时长的增加导致团簇的高度下降和团簇内的原子重新排列和分布有关.第四组对照实验分别在420℃、500℃的退火温度下制备Ga原子团簇.实验结果表明,升温至500℃退火会促进Ga原子团簇呈现有序排列,是表面原子的热运动和Ga原子团簇与Si(100)的晶格匹配度的共同作用的结果.

关键词： MBE Ga原子团簇 Ga源温度沉积时长退火时长

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High-Performance Sb-Doped GeTe Thermoelectric Thin Film and Device

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Acta Metallurgica Sinica(English Letters) 2023年第10期36卷 1699-1708页

作者： Zhenqing Hu Hailong yu juan He Yijun Ran Hao Zeng Yang zhao Zhi yu Kaiping Tai School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

GeTe-based materials have attracted significant attention as high-efficiency thermoelectric materials for mid-temperature ***,GeTe thin-film materials with thermoelectric performances comparable to that of their bulk counterparts have not yet been reported,because of their unsatisfactory electrical and thermal properties caused by their poor crystal quality and high carrier ***,a series of Sb-doped GeTe films and devices with remarkable thermoelectric performances are *** films are prepared through magnetron sputtering deposition at 553 K and exhibit a unique microstructure that consists of coarse-and fine-sized grains with high crystallization *** fine grains enhance the scattering associated with phonon transport and the coarse grains provide electron transport channels,which can suppress the thermal conductivity without obviously sacrificing the electrical ***,Sb doping can effectively optimize the carrier concentration and increase the carrier effective mass,while introducing point defects and stacking faults to further scatter the phonon transport and decrease the thermal ***,a peak power factor of 22.37μW cm−1 K−2 is obtained at 703 K and a maximum thermoelectric figure of merit of 1.53 is achieved at 673 K,which are substantially larger than the values reported in the existing literature.A flexible thermoelectric generator is designed and fabricated using Sb-doped GeTe films deposited on polyimide and achieves a maximum output power density of 2.22×103 W m−2 for a temperature difference of 300 K.

关键词： Thermoelectric thin film GeTe-based materials Sb doping Carrier concentration Thermoelectric generator

A comparison of core–shell Si/C and embedded structure Si/C composites as negative materials for lithium-ion batteries

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Rare Metals 2021年第9期40卷 2440-2446页

作者： Shuai-Jin Wu zhao-Hui Wu Sheng Fang Xiao-Peng Qi Bing yu juan-yu Yang Grinm Group Co. Ltd.Beijing 100088China General Research Institute for Nonferrous Metals Beijing 100088China China Automotive Battery Research Institute Co. Ltd.Beijing 101407China

Silicon materials have attracted wide attention as negative materials due to exceptional gravimetric capacity and abundance. The strategy of using nano-silicon materials as structural units to construct nano/micro-structured silicon-based negative materials for lithium-ion batteries has come into sight in recent years. In order to provide guidance for the material structure design of micro-sized silicon-based negative materials in practical application, in this work, two commercialized nano/micro-structured silicon-based negative materials with a specific capacity of about 650 mAh·g^(-1) were investigated and compared in the aspects of material microstructure, electrochemical performance of half cells, and electrode morphological evolution during cycling. The cycling performance(with capacity retention ratio of about 17% higher after 100 cycles) and electrode structure maintenance of the embedded structure Si/C material are superior to those of core–shell Si/C material. This research can provide guidance on design and application of nano/micro-structured silicon-based negative materials.

关键词： Lithium-ion battery Negative materials Silicon-based materials Material structure

Automatic Normalization and Equivalent-Width Measurement of High-Resolution Stellar Spectra

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Chinese Journal of Astronomy and Astrophysics 2006年第6期6卷 689-696页

作者： Jing-Kun zhao Gang zhao yu-Qin Chen Jian-Rong Shi yu-juan Liu Ju-Yong Zhang National Astronomical Observatories Chinese Academy of Sciences Beijing 100012

It is well known that normalization, radial velocity correction and equivalent-width measurement of high-resolution stellar spectra are time-consuming work. In order to improve the efficiency we present an automatic method for these routines. The continuum is determined by fitting the ＇high points＇ in the spectrum. After continuum normalization, the program automatically searches for the position of the Ha line and obtains a rough radial velocity, then computes an accurate radial velocity by cross-correlation between the given spectrum and the solar spectrum. In this method, the equivalent-width is automatically measured using Gaussian fitting. A comparison between our results and those from traditional analysis shows that the typical error for equivalent width is around 3.8% in our method. Developing such automatic routines does not mean to replace the interactive reduction method： it is just for a quick extraction of information from the spectra, especially those obtained in large sky surveys.

关键词： techniques radial velocities - stars abundances

神经性皮炎患者心理状态与血清IgE水平相关性研究

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中国医学前沿杂志（电子版） 2018年第6期10卷 212-215页

作者：杨今言王玉卢娟陈赵慧宋珍珍新疆医科大学第二附属医院皮肤科乌鲁木齐830064 新疆医科大学第二附属医院心身医学科乌鲁木齐830064

目的探究神经性皮炎患者心理状态与其血清Ig E水平的相关性。方法选取2015年1月至2016年10月于本院治疗的神经性皮炎患者126例纳入神经性皮炎组,选择本院同期120例健康体检者纳入健康组。测量并比较两组研究对象的抑郁自评量表(self-rat... 详细信息

目的探究神经性皮炎患者心理状态与其血清Ig E水平的相关性。方法选取2015年1月至2016年10月于本院治疗的神经性皮炎患者126例纳入神经性皮炎组,选择本院同期120例健康体检者纳入健康组。测量并比较两组研究对象的抑郁自评量表(self-rating depressive scale,SDS)评分、焦虑自评量表(self-rating anxiety scale,SAS)评分及血清IgE水平。结果神经性皮炎组患者SDS和SAS评分、血清IgE水平均显著高于健康组(P_均<0.05)。且不同抑郁程度的神经性皮炎患者血清IgE水平比较差异具有显著性(F=9.7856,P<0.0001);血清Ig E水平与抑郁程度呈正相关(r=0.0315,P<0.05)。不同焦虑程度神经性皮炎患者血清IgE水平比较差异具有显著性(F=22.8784,P<0.0001);血清IgE水平与焦虑程度呈正相关(r=0.0473,P<0.05)。结论神经性皮炎患者血清IgE水平随焦虑、抑郁程度加重而升高,检测血清Ig E水平有助于判断患者的心理状态。

关键词：神经性皮炎心理状态 IgE

NEW RESULTS ABOUT THE RELATIONSHIP BETWEEN OPTIMALLY WEIGHTED LEAST SQUARES ESTIMATE AND LINEAR MINIMUM VARIANCE ESTIMATE

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Journal of Systems Science & Complexity 2009年第1期22卷 137-149页

作者： juan zhao yunmin ZHU Department of Electronic Engineering Beijing Institute of Technology Beijing 100081 China. Department of Mathematics Sichuan University Chengdu 610064 China.

The optimally weighted least squares estimate and the linear minimum variance estimateare two of the most popular estimation methods for a linear *** this paper,the authors makea comprehensive discussion about the relationship between the two ***,the authorsconsider the classical linear model in which the coefficient matrix of the linear model is deterministic,and the necessary and sufficient condition for equivalence of the two estimates is ***,under certain conditions on variance matrix invertibility,the two estimates can be identical providedthat they use the same a priori information of the parameter being ***,the authorsconsider the linear model with random coefficient matrix which is called the extended linear model;under certain conditions on variance matrix invertibility,it is proved that the former outperforms thelatter when using the same a priori information of the parameter.

关键词： Conditional expectation linear minimum variance estimation necessary and sufficient condition optimally weighted least squares estimation.

Mechanically Robust Polylactide Fibers with Super Heat Resistance via Constructing in situ Nanofibrils

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Chinese Journal of Polymer Science 2023年第6期41卷 962-971,I0011页

作者： Jun Lu Li-Xiang Yi Yong-Huan zhao Yang Meng Peng-Xiang yu juan-juan Su Jian Han College of Materials and Textiles Zhejiang Sci-Tech UniversityHangzhou 310018China The Key Lab of Industrial Textile Material and Manufacturing Technology Zhejiang ProvinceZhejiang Sci-Tech UniversityHangzhou 310018China

All-PLA fibers with excellent comprehensive performance and recycling convenience are realized *** molecular weight poly(D-lactide)(HPDLA)is incorporated into poly(L-lactide)(PLLA)matrix to construct in situ nanofibrils structure by taking advantages of the microphase separation between HPDLA and *** tensile strength of HPDLA/PLLA composite fibers(HDL-8)is enhanced from 2.1 cN/dtex of neat PLLA-8 fibers up to 2.9 cN/*** boiling water shrinkage(BWS)and shrinkage in hot air(HAS)significantly decrease to 7.8%and 2.8%,*** abundance of in situ nanofibrils creates a grille-like structure that is crucial for both heat and hydrolysis *** strikingly,a hybrid shish-kebab structure induced by the in situ nanofibrils serves as a mechanical *** work paves a new way for heat resistance and self-reinforcement modification of PLA materials.

关键词： materials. fibers lactide