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叠氮微烟推进剂宽温域力学性能研究

火炸药学报 2021年第4期44卷 521-525页

作者：宋琴王艳萍廖菊平冯勇湖北航天化学技术研究所航天化学动力技术重点实验室湖北襄阳441003

为了提高gap微烟推进剂的力学性能,通过在gap微烟推进剂中引入适量的PBT黏合剂进行复配,研究了增塑剂种类、增塑剂与黏合剂质量比(增塑比)、扩链剂种类及其官能度、扩链剂含量、固化剂种类以及固化参数对推进剂宽温域(-55℃~+70℃)力学... 详细信息

为了提高gap微烟推进剂的力学性能,通过在gap微烟推进剂中引入适量的PBT黏合剂进行复配,研究了增塑剂种类、增塑剂与黏合剂质量比(增塑比)、扩链剂种类及其官能度、扩链剂含量、固化剂种类以及固化参数对推进剂宽温域(-55℃~+70℃)力学性能的影响。结果表明,添加Bu-NENA增塑剂,可极大地改善推进剂的低温力学性能以及降低推进剂的玻璃化转变温度Tg,并在此基础上通过调节增塑剂与黏合剂增塑比为2.0,叠氮黏合剂/三官能度PET质量比为5∶1;采用TDI为固化剂以及固化参数Rt为1.2时,可使推进剂的Tg不大于-60℃以及在-55℃~+70℃范围内具有良好的力学性能,即在+70℃时抗拉强度大于0.50MPa,-55℃~+70℃时最大伸长率大于45%。

关键词：物理化学叠氮微烟推进剂玻璃化温度力学性能 gap

Water effect on band alignment of gap: A theoretical insight into pyridinium catalyzed CO2 reduction

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Journal of Energy Chemistry 2017年第4期26卷 724-729页

作者： Xue-Ting Fan Mei Jia Ming-Hsien Lee Jun Cheng State Key Laboratory of Physical Chemistry of Solid Surfaces iChEMCollege of Chemistry and Chemical EngineeringXiamen University Department of Physics Tamkang University Department of Chemistry University of Aberdeen

gap has been shown to have good photo-catalytic activity in pyridinium catalyzed COreduction. The photo-excited electrons in the conduction band of gap should have a sufficient reduction potential to drive the reduction of pyridinium and CO. In this work, we have studied water adsorption on the gap surface using density functional theory calculations, and its effect on the band alignment. Our calculations have shown that there are surface states present near the band edges due to unsaturated dangling bonds, and water adsorption can remove these states partially or almost completely depending on the adsorption states of water. More importantly, we have found that water adsorption has considerable effects on the band alignment, shifting up the band positions by up to 0.5 eV compared to the bare surface.The computed level of the conduction band with the adsorption of water is rather close to the reduction level of pyridinium ions, thus suggesting that photo-excited electrons are thermodynamically possible to reduce pyridinium to pyridinyl radicals that further help COreduction.

关键词： Band alignment gap Pyridinium CO2 reduction DFT

Al@gap复合粒子对LLM-105热分解性能的影响

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火炸药学报 2017年第4期40卷 27-32页

作者：曾诚成巩飞艳刘世俊中国工程物理研究院化工材料研究所四川绵阳621900

为防止铝粉在存储中氧化失活,同时为含铝炸药配方设计提供借鉴,采用聚叠氮缩水甘油醚(gap)对不同尺寸Al粉(平均粒径分别为50nm和1~2μm)进行包覆改性,获得Al@gap复合粒子;采用扫描电镜(SEM)、透射电镜(TEM)表征其形貌;用差示扫描量热法(... 详细信息

为防止铝粉在存储中氧化失活,同时为含铝炸药配方设计提供借鉴,采用聚叠氮缩水甘油醚(gap)对不同尺寸Al粉(平均粒径分别为50nm和1~2μm)进行包覆改性,获得Al@gap复合粒子;采用扫描电镜(SEM)、透射电镜(TEM)表征其形貌;用差示扫描量热法(DSC)对不同质量比的(Al@gap)/LLM-105混合体系的热分解过程进行了研究。结果表明,采用两步包覆法获得了不同尺寸Al粉表面包覆gap的核壳结构复合粒子;相较于包覆前的微米级Al粉,加入gap包覆的纳米Al粉后混合体系的热分解峰温明显降低;当Al粉质量分数大于10%时,gap包覆后的(Al@gap)/LLM-105混合体系的熵变(ΔS~≠)和焓变(ΔH~≠)较Al/LLM-105混合体系有所减小;(Al@gap)/LLM-105混合体系的活化能、热爆炸临界温度及热力学参数ΔS~≠和ΔH~≠随纳米Al粉含量的增加而降低,当Al粉质量分数为30%时,较LLM-105分别降低4kJ/mol、3℃、4.3J/(mol·K)、4.2kJ/mol。

关键词：物理化学纳米Al粉聚叠氮缩水甘油醚 gap 耐热炸药 LLM-105 热分解

Synchronization of home departure and arrival times in dual earner households with children:Panel regression model of time gaps

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Journal of Traffic and Transportation Engineering(English Edition) 2019年第5期6卷 504-513页

作者： Bilin Han Harry Timmermans Urban Planning Group Eindhoven University of Technology

Organizing schedules and allocating time to different activities is always a challenge in dual-earner households,especially when they have children.Parents may need to link their schedule to those of their children to allow them escorting their children to school or to take care or be with their children at home.This paper reports the results of an analysis of the degree of synchronization of home departure and arrival times in dual earner households with children,where the degree of synchronization is defined as the gap between departure and arrival times of a parent and child.Using activity-travel diary data of different household members,a random parameters regression model is estimated to examine differences in time gaps in home departure and arrival times between parents and children as a function of gender,day of the week,age of the youngest child,and other socio-demographic characteristics.The results of the analysis provide insight into factors influencing the degree of synchronization and coordination of double activity-travel scheduling decisions in households with children.Findings indicate that gender,number of children in the household,age of the youngest child,travel within or outside peak hours,day of the week,transport mode used for the work commute and household income level significantly affect time gaps,especially arrival time gaps.

关键词： Home departure and arrival times Synchronization Time gap Dual-earner households Random parameters panel regression model

Mechanical performance of rock bolts under combined load conditions

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International Journal of Mining Science and Technology 2020年第2期30卷 167-177页

作者： P.C.Pinazzi A.J.S.(Sam)Spearing K.V.Jessu P.Singh R.Hawker Department of Mining and Metallurgical Engineering Western Australian School of MinesCurtin UniversityKalgoorlieWA 6430Australia Minova Global NowraNSW 2541Australia

Rock bolts are subjected to different loading conditions along their lengths such as axial,bending,and/or shear forces,which can cause failure at lower loads than those considered for design purposes.The common existing methodologies do not consider the actual loading of the rock bolts and assume it is only pure axial or pure shear.This study was conducted to investigate the un-grouted rock bolt performance under combined load conditions.Two loading regimes were evaluated:the effect of initial shear displacement on axial load capacity and displacement,and the effect of axial displacement on the shear load capacity.The first regime was also conducted for shear with a gap,when there is a spacing between the shear interfaces.The results of this study showed that the rock bolt can resist higher axial loads than shear under pure or combined load conditions.Under combined load conditions,the rock bolt capacity decreased significantly for both regimes.However,when applying the shear load with a gap,the rock bolt load capacity was not affected significantly.Also,the total bar deformation was improved for shear and axial.The findings of this study show the need to improve the rock bolt design considering the complex loading conditions in situ with/without a gap.

关键词： Rock bolt Combined load gap test Failure mechanism Axial load Shear load

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二维冲箱式造波机的间隙和形状效应数值研究

Journal of Marine Science and Application 2020年第1期19卷 101-115页

作者： Amir H.Nikseresht Harry B.Bingham Department of Mechanical Engineering Technical University of DenmarkDK-2800 Kgs LyngbyDenmark Department of Mechanical Engineering Shiraz University of TechnologyShiraz 71555-13876Iran

The installation of plunger-type wave makers in experimental tanks will generally include a gap between the back of the wedge and the wall of the tank.In this study,we analyze the influence of this gap on the wave making performance of the plunger using two-dimensional(2 D)CFD calculations for a range of nearly linear wave conditions and compare the results with both experimental measurements and linear potential flow theory.Three wedge-shaped profiles,all with the same submerged volume,are considered.Moreover,the generated waves are compared with the predictions of linear potential flow theory.The calculations are made using the commercial ANSYS FLUENT finite-volume code with dynamic meshes to solve the Navier-Stokes equations and the volume of fluid scheme to capture the air-water interface.Furthermore,the linear potential flow solution of Wu(J Hydraul Res 26:481-493,1988)is extended to consider an arbitrary profile and serve as a reference solution.The amplitude ratios of the generated waves predicted by the CFD calculations compare well with the predictions of linear potential flow theory for a simple wedge,indicating that viscous effects do not influence this ratio for small-amplitude motions in 2 D.By contrast,significant higher harmonic components are produced by larger amplitude motions.Also,the simple wedge is found to produce the smallest spurious higher harmonic content in the far-field wave.

关键词： Wave maker Plunger-type Berkeley wedge Hyperbolic sine profile gap Dynamic mesh Volume of fluid

Migration of mesoscale eddies across a leaping or penetrating western boundary current in the vicinity of a gap

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Journal of Oceanology and Limnology 2018年第6期36卷 2098-2109页

作者：宋新新袁东亮李锐祥王铮 Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of Sciencesand Function Laboratory for Ocean Dynamics and ClimateQingdao National Laboratory for Marine Science and TechnologyQingdao 266071China Key Laboratory of Marine Science and Numerical Modeling First Institute of OceanographyState Oceanic Administrationand Laboratory for Regional Oceanography and Numerical ModelingQingdao National Laboratory for Marine Science and TechnologyQingdao 266061China University of Chinese Academy of Sciences Beijing 100049China South China Sea Marine Survey and Technology Center State Oceanic AdministrationGuangzhou 510300China

A 1.5-layer quasi-geostrophic reduced gravity ocean circulation model is used to study the propagation of mesoscale eddies across a western boundary current(WBC) either leaping across or penetrating in an anti-cyclonic path through the gap. The steady leaping WBC nearly blocks all eddies from propagating across it through the gap completely. However, both cyclonic and anti-cyclonic eddies can migrate across a penetrating WBC in the vicinity of a gap, while inducing an opposite type of eddies on the cyclonic side of the WBC by weakening or strengthening the intrusion of the WBC. Both type of eddies gained strength from the WBC in the course of the propagation across the WBC in the gap. Eddies approaching the gap from the upstream are found to migrate more easily into the western basin due to the advection of the WBC. The migration speeds of the eddies are almost unchanged by the presence of the WBC in all experiments.

关键词： mesoscale eddy Western Boundary Current gap

Coronary Computed Tomographic Angiography for Suspected Stable Coronary Artery Disease： gap Between the 2013 European Society of Cardiology Guideline Recommendations and Clinical Practice

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Chinese Medical Journal 2016年第2期129卷 239-241页

作者： Fu-Cheng Sun Department of Cardiology Beijing Hospital Beijing 100730 China

Coronary computed tomographic angiography （CCTA） as a noninvasive diagnostic technique for the evaluation of coronary anatomy is widely used clinically. Its advantages include high sensitivity and specificity for th... 详细信息

关键词： Coronary Computed Tomographic Angiography Coronary Artery Disease gap Guideline Practice

Highest Achievable Detection Range for SPR Based Sensors Using Gallium Phosphide （gap） as a Substrate： a Theoretical Study

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Photonic Sensors 2016年第2期6卷 181-186页

作者： Rajneesh K. VERMA Akhilesh K. MISHRA Department of Physics Central University of Rajasthan (India) BandarSindri Ajmer 305817 India Department of Electrical Engineering Technion - Israel Institute of Technology Haifa 32000 Israel

在现在的学习，我们理论上为基于的表面电浆子回声(SPR ) 建模察觉到由镓 phosphidee 组成利用棱柱的薄片。它在学习被发现了折射索引从气体的媒介开始到高度集中的液体的一个大范围能被在光谱的可见区域使用一个单个薄片察觉到。有察... 详细信息

在现在的学习，我们理论上为基于的表面电浆子回声(SPR ) 建模察觉到由镓 phosphidee 组成利用棱柱的薄片。它在学习被发现了折射索引从气体的媒介开始到高度集中的液体的一个大范围能被在光谱的可见区域使用一个单个薄片察觉到。有察觉到区域的敏感以及察觉精确性的变化折射索引详细被分析了。与大动态范围一起的敏感的大价值是察觉到探查的礼品的有益的特征。

关键词： SPR传感器检测范围磷化镓 gap 表面等离子体共振底物传感芯片大动态范围