车辆防护座椅性能及缓冲吸能器性能分析

抗爆炸冲击座椅广泛应用于我国军用车辆,其缓冲吸能组件特性直接决定座椅防护性能的优劣。为使乘员损伤达到最小,针对某型军用车辆在底部爆炸环境下乘员防护性能进行研究。通过实车底部爆炸试验获取的座椅安装点冲击信号,利用座椅冲击试验台测量不同参数缓冲吸能组件载荷-位移特性,通过有限元模型对试验进行验证和优化。以AEP55乘员伤害准则为目标,研究某军用车辆座椅防护性能提升方法。结果表明,改进后的缓冲吸能组件载荷-位移特性曲线能够显著降低乘员损伤并充分利用座椅行程。为后续座椅缓冲吸能组件设计优化提供导向。     

爆炸冲击下座椅底部防护性能改进及参数分析研究

爆炸冲击下座椅底部防护性能的研究日益受到关注。针对某特种车辆爆炸冲击环境下乘员防护座椅受到瞬时高强度冲击时的防护性能进行研究,建立整车爆炸环境,利用仿真计算与试验所得座椅安装点加速度及乘员响应对有限元模型进行验证,通过改进座椅安装方式分析对比座椅底部防护性能,借鉴AEP55乘员伤害准则,对乘员约束系统中弹簧刚度、粘性阻尼系数、坐垫刚度3因素运用拉丁超立方试验设计进行座椅参数影响分析,研究发现：座椅侧面安装方式相对底部安装方式能够达到14.5%的综合防护能力提升;弹簧刚度、粘性阻尼系数及坐垫刚度对座椅防护性能有显著影响并呈现一定相关效应。为后续底部防护座椅设计优化提供导向。     

爆炸冲击下座椅底部防护性能改进及参数分析

爆炸冲击下座椅底部防护性能的研究日益受到关注。针对某特种车辆爆炸冲击环境下乘员防护座椅受到瞬时高强度冲击时的防护性能进行研究,建立整车爆炸环境。利用仿真计算与试验所得座椅安装点加速度及乘员响应对有限元模型进行验证,通过改进座椅安装方式分析对比座椅底部防护性能,借鉴AEP55乘员伤害准则,对乘员约束系统中弹簧刚度、黏性阻尼系数、坐垫刚度3因素运用拉丁超立方试验设计进行座椅参数影响分析。研究发现:座椅侧面安装方式相对底部安装方式能够达到14.5%的综合防护能力提升;弹簧刚度、黏性阻尼系数及坐垫刚度对座椅防护性能有显著影响并呈现一定相关效应。为后续底部防护座椅设计优化提供导向。     

垂向强冲击载荷下车辆缓冲座椅的安全带系统防护性能分析及优化

针对特种车辆受到垂向强冲击时缓冲座椅的安全带系统防护性能进行研究,建立了地板-座椅-乘员系统的有限元模型,对驾驶室地板结构施加冲击位移输入,应用数值仿真方法比较分析了缓冲座椅分别匹配两点式、三点式、四点式和六点式安全带时对乘员的约束效能。在垂向强冲击载荷下,具有六点式安全带的缓冲座椅可有效地减小腰椎轴向压力峰值,同时降低乘员与车身结构发生冲击碰撞的可能性。进一步对六点式安全带的预紧特性和限力特性参数进行了多设计方案分析和优化,具有匹配优化后的预紧特性和限力特性的六点式安全带可使乘员的腰椎轴向压力峰值比优化前降低10.7%,比三点式安全带显著地提高了缓冲座椅抗垂向强冲击的安全性。     

基于正交试验的座椅靠背气囊对乘员保护的优化

在汽车正面碰撞事故中,对于后排乘员的保护尤为重要.为了减小正碰时后排乘员的损伤,使用LS-PREPOST软件建立了后排乘员约束系统和前排座椅简化模型,以50百分位HybridⅢ男性假人代替后排乘员,仿真分析驾驶员座椅靠背气囊对后排乘员的保护效果.在初始建立的简化模型基础上,对各因素进行灵敏度分析,选定气囊放置角度、前排座椅靠背倾角和气囊泄气孔面积作为进一步优化的因素;为分析不同工况下乘员的损伤,选取各因素的水平并采用正交试验优化,以加权伤害准则WIC(weighted injury criterion)作为评估标准,使用极差法推出最优方案.对比分析优化前后的假人损伤数据可知,头部损伤指标HIC(head injury criteria)下降21.15％,WIC下降20.39％,证明靠背气囊对后排乘员的安全保护效果显著.     

校车座椅乘员约束系统参数优化设计

为研究校车两点式约束系统对中学生乘员损伤防护效果,利用显式有限元分析软件LS-DYNA建立某款校车座椅约束系统数值仿真模型.基于国家标准要求,在实测减速度波形加载下,分析模型中假人头部HIC值,胸部3 ms加速度值和大腿轴向压力值,通过优化约束系统参数进一步提升中学生乘员损伤防护效果.结果表明:减小座椅靠背刚度可以改善中学生乘员腿部损伤防护效果;沿X方向后移安全带固定点位置可明显降低中学生乘员胸部损伤;在合理范围内增大安全带织带刚度可明显降低中学生乘员头部和胸部损伤.     

内置式儿童安全座椅侧面碰撞安全性研究

建立了一款置于汽车后排中间位置的内置式儿童安全座椅模型,采用MADYMO与LS-DYNA耦合的方法进行仿真计算,并对该模型进行滑车试验验证.首先对无扶手、面式扶手、杆式扶手以及面式扶手及侧翼相结合的4种不同类型的座椅进行侧面碰撞仿真试验,其次对扶手高度不同的座椅模型进行侧面碰撞仿真试验,最后对仿真结果进行对比分析.结果表明,扶手能限制儿童乘员从座垫滑落而有效避免安全带约束儿童颈部造成的窒息死亡,侧翼能有效保护儿童乘员的颈部和胸部,侧翼和扶手组合式儿童安全座椅模型保护效果最好;扶手高度适中的座椅能对儿童乘员提供最好的保护.     

保护后排乘员安全的前排座椅参数研究

在汽车发生正面碰撞时,后排乘员由于惯性向前移动,十分容易与前排座椅发生二次碰撞而造成伤害。为了在轿车正碰时减小后排乘员与前排座椅发生碰撞时造成的损伤,本文提出一种基于前排座椅参数的优化方法。以提高正面碰撞中轿车后排乘员安全性为目标,根据2012年版中国新车评价规程[C-NCAP管理规则(2012年版)]的要求,以后排5百分位女性假人为研究对象,研究两排座轿车前排座椅参数对后排乘员的防护效果。在MADYMO软件中建立轿车后排乘员正碰数学模型,并用实车试验进行验证,在此基础上,分析了前排座椅头枕参数中的头枕水平距离和头枕刚度,以及前排座椅靠背参数中的靠背刚度、靠背距离、靠背倾角和靠背坐垫连接铰刚度这6个主要因素对后排乘员保护效果的影响。采用灵敏度分析的方法探寻对于后排乘员安全性影响最为显著的因素,并使用正交试验的理论,对这几项因素进行综合优化,得到最佳匹配方案。优化设计结果使正面碰撞时后排乘员伤害最严重的头部伤害值HIC降低了25.26%,左大腿力和右大腿力分别下降了13.67%和14.33%,完全伤害指标WIC值降低17.91%,优化效果显著,可以为今后轿车前排座椅设计提供参考。     

车辆受垂向强冲击时座椅安全带的防护效果比较分析与锚点位置优化

针对特种车辆受垂向强冲击时座椅安全带对乘员防护性能问题研究较少的情况,该文应用数值仿真方法分析评价了分别配置5种形式安全带的座椅—乘员系统模型的垂向强冲击响应,在此基础上进行了5点式、6点式安全带的锚点位置优化研究,并分析检验了该优化方案在车辆正面、侧面碰撞工况的防护效果。研究结果量化评价了多点式安全带结构形式差异对乘员防护效果的显著影响,实现了以乘员的垂向冲击防护为主要目标的座椅安全带锚点位置优化分析,对于特种车辆座椅安全带系统的综合优化设计具有技术指导意义。     

两种典型安全带布局对乘员的保护比较

为了探究飞机坠毁过程中,安全带座椅系统对乘员的保护情况,利用DYTRAN软件结合ATB数字假人进行了有限元仿真计算。分别针对装备斜三点式和四点式安全带的两种典型的座椅系统,参照FAA对航空用座椅实验的要求设置了两组冲击载荷。通过对比其碰撞动态响应并评估可能的乘员损伤情况,总结了两种安全带形式各自的优缺点。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-