完整系统的能量方程及其积分

由完整系统所遵循的能量方程，不仅能导出保守系统在拉格朗日函数不显含时间ｔ的广义能量积分，而且对于一般系统在其拉格朗日函数里含时间ｔ的情况下，同样有可能得到一个广义能量积分．     

鲫鱼体内金属元素含量及其分布状况的研究

本文用原子吸收分光光度法测定了钙，镁锌，鳃铜５种金属元素在鲫鱼的头部、躯干部和尾部和含量。在鲫鱼体内，从头到尾，同种金属元素的含量并不相同，它们在各部分的含量之间有一定的比例关系。     

中华鳖的解剖研究Ⅱ、肌肉系统

中华鳖在水中游泳及陆地爬行时,主要依靠附肢,故分布在肩带、前肢和腰带、后肢的肌肉特别发达、粗壮而有力。由于它的头、颈、附肢及尾部都能缩入背、腹甲间前、后端的大孔内,故有许多肌肉起于背甲、腹甲,止于有关各骨以牵引头、颈、附肢及尾部,如背甲乌喙骨肌、背肩胛乌喙骨肌、背甲肱骨肌、乌喙腕骨肌、背甲肩胛骨肌,附着于肩带和前肢;腹甲耻骨肌、臀大肌、臀小肌、壳髂肌、背甲髂骨肌、尾跗骨肌等附着于腰带和后肢。其中背甲肩胛骨肌、背甲髂骨肌、乌喙腕骨肌、尾跗骨肌,末见于其它动物。此外还有牵引颈部的背甲颈椎肌、背甲颈皮肌,牵引尾部的背甲尾肌。至于颈长肌更是特别长大从尾端及背甲助骨板内表面起一直伸展到头部止于基枕骨是牵引头部的长肌。     

AIF分子外场效应的量子化学研究

选取密度泛函B3LYP方法和6—311＋＋g（d,P）基组对AlF分子在不同外电场（-0．015～0．015 a.u．）及没有外场下分子基态的稳定电子结构进行计算,研究了外电场对AlF分子基态总能量、键长、偶极矩、能隙、电荷分布及红外光谱等的影响．结果表明,随着Al→F方向外电场的增加,分子键长和偶极矩递减,原子电荷也递减,总能量升高,能隙增大,频率随Al→F方向外电场的增加而增加,其红外强度则递减;在外电场作用下,AlF基态分子势能曲线升高,离解能增大。     

白条锦蛇的故事

白条锦蛇是一种无毒蛇,其头部背面有一个明显的黑褐色斑纹,躯干部和尾部背面呈黄褐色,且具三条黄白色纵纹,其中最宽大的一条纵纹自头后部延伸至尾端,背部还有若干个不规则的暗褐色短斑。白条锦蛇分布于我国长江流域及以北的广大地区,在辽宁西部为优势种。     

野牛状橡胶卡食品宠物玩具

该实用新型公开了野牛状橡胶卡食品宠物玩具,包括野牛尾部橡胶件二次成型于含螺牙的尼龙杆上,含螺母的野牛头部橡胶件单独成型;食品圈卡入套啤好含螺牙的尼龙杆的野牛尾部橡胶件上,再装上含螺母的野牛头部橡胶件进行旋转扭紧,以供宠物咬食,同时可玩耍,增加了宠物对玩具的乐趣重复性。     

异步复相角神经网络模型的能量函数研究

证明了具有零对角的厄米联结矩阵的异步离散复相角神经网络模型在其动力学演化过程中，网络的能量函数单调递减，网络最终将稳定在一个不动点吸引子上；当网络的神经元个数远大于存贮图象数时，随机存贮图象在能量函数空间中对应一能量极小点，因此存贮图象为网络的不动点吸引子。     

氦原子电子激发跃迁的绝对广义振子强度测量

在2．5keV碰撞能量下，采用改进后的高能量角分辨的电子能量损失谱仪，我们测量了作为能量损失E和动量转移K函数的氮原子1s1s→1s2s，1s1s→1s2p电子激发跃迁的绝对广义振子强度(GOSs)，GOS实验数据同Kim及Inokuti的基于第一玻恩近似的理论计算符合得非常好．     

关于磁场力的功

本文通过对磁场力F^→（洛化兹力的一部分）的两个分力f1^→、f2^→做功的讨论,进一步认识总的磁场力永远不做功及其分力做功的特征,即其分力做功只在实现能量转化中起传递作用,而没有直接使磁场能量发生转化,另外也说明了做功的相对性。     

基于颈腰部肌电及脑电信号的疲劳驾驶检测

为了有效判别驾驶员的疲劳状态,结合生物力学分析提取了驾驶过程中的颈腰部肌电信号EMG和头部脑电信号EEG,并分析其特征参数在驾驶过程中的变化规律.结果表明:颈肌样本熵、颈肌复杂度、腰肌样本熵、腰肌复杂度、脑电样本熵、脑电复杂度这6个生理信号的特征参数值都随着驾驶时间的延长而逐渐降低,通过主成分分析可实现特征参数间的合理组合.基于多元回归理论,建立了能够有效预测疲劳驾驶的数学模型.状态验证结果表明,该模型对疲劳状态判别的正确率可达95%以上.     

药型罩锥角对聚能杆式侵彻体成型的影响

聚能杆式侵彻体主要用来对付新型防护装甲和混凝土工事、武装直升机和大型水面舰艇等目标。本文就药型罩锥角对聚能杆式侵彻体成型的影响进行研究，根据射流形成理论分析得到了射流微元头尾速度比与药型罩锥角和压垮角之间的关系，并采用观察不同锥角的药型罩结构所形成的侵彻体，在远距离飞行下的断裂情况，来验证射流微元头尾速度比与药型罩锥角和压垮角的关系，实验结果表明射流微元头尾速度比随着压垮角的增大而增大，与理论分析吻合。     

"二十四幅花卉册页":《儒林外史》的结构形态

文章根据作家在楔子里的提示,指出<外史>采用的结构类似王冕画的册页,由头、身、尾三个有机部分组成.册身具有时间性、逻辑性、层次性、对照性、条贯性等五个特点.     

体操摆动动作系统的结构分析

本文从运动生物力学的角度,对摆动动作结构的传统理论进行深入研究,提出了新的观点,可供体操教学训练参考。(1) 摆动动作系统由准备阶段和完成阶段组成。(2) 准备阶段的任务是储备足够的机械能和肌肉能。主要技术特点:一是把身体抛高,增加重力位能,并远离下摆,增加转动动能;二是身体有关关节或做爆发式的振浪,或做渐进式的折屈动作,提高原动肌群的张力。(3) 完成阶段的任务是合理利用能量准确完成动作。主要技术特点:一是身体有关关节“弯屈--伸展”,使重心靠近转轴;二是身体的“伸展--(弯屈)”,使能量重新分配,巧妙地完成动作。     

Biomechanics: hydrodynamic function of the shark's tail

The tail of most sharks has an elongated upper lobe that differs from the externally symmetrical tail structure common among bony fishes, but the hydrodynamic purpose of this asymmetric tail shape is unclear. Here we quantify water flow patterns in the wakes of freely swimming dogfish sharks and find that they have a ring-within-a-ring vortex structure, in contrast to the single rings shed by symmetrical fish tails. The branched-ring vortex is generated by the inclined angle of the tail's trailing edge and by its motion at an angle to the horizontal body axis; the vortex directs water backwards and downwards, which may increase the shark's vertical manoeuvrability.     

高速列车底部结构参数对气动阻力作用规律

高速列车的转向架区域是气动减阻研究的重点.通过样条曲线方法建立了高速列车底部结构的7参数化模型,采用计算流体力学及超拉丁立方抽样试验设计方法,研究了底部结构参数对高速列车气动阻力的影响规律.结果表明:底部结构参数对于三车总阻力、头、中、尾各节车气动阻力的影响分别为27%、37%、39%和22%,三车气动阻力对裙板高度、排障器厚度、舱前缘倒角最为敏感.但头、中、尾车影响规律不同于三车,有必要考虑对头、中、尾三车底部结构分别进行气动设计,以达到最优的减阻效果.底部结构参数主要影响列车底部平均流速改变底部结构所受气动阻力,进而影响高速列车气动阻力.     

几种海水养殖鱼类化学组成的比较

对广东地区主要海水养殖鱼类青石斑鱼Epinephelus awoara、黄鳍鲷Sparus latus、银鲳Pampus argenteus、美国红鱼Sciaeunops ocellatus的全鱼及肌肉化学组成进行了测定.比较了几种鱼的肌肉水分、蛋白质、脂肪和灰分含量的差异,同时进一步检测了这几种鱼肌肉结构氨基酸的组成,为今后的营养研究提供必要的数据.     

纯电动汽车车身多目标拓扑优化设计

为解决纯电动汽车车身设计中仍沿用传统车身,未同时考虑碰撞相容性和正面碰撞安全性的问题,基于混合元胞自动机拓扑优化方法,以在约束条件下吸收碰撞能量最大化为优化目标,对车身结构进行多工况概念设计,从而确定出合理的电动汽车车身布局,设计出了一种满足正面碰撞安全性与碰撞相容性的车身头部结构.结合拓扑优化结果进行有限元模型验证与厚度分析,结果表明:2~3mm的汽车头部厚度可在满足正面碰撞安全性条件下平衡碰撞过程中车体结构的纵向错位,保证碰撞力的均匀分布,实现车身轻量化.     

Effect of the CaO/SiO2 mass ratio and FeO content on the viscosity of CaO–SiO2–"FeO"–12wt%ZnO–3wt%Al2O3 slags

An effective process for recycling lead from hazardous waste cathode ray tubes (CRTs) funnel glass through traditional lead smelting has been presented previously. The viscous behavior of the molten high lead slag, which is affected by the addition of funnel glass, plays a critical role in determining the production efficiency. Therefore, the viscosities of the CaO–SiO2–"FeO"–12wt%ZnO–3wt%Al2O3 slags were measured in the current study using the rotating spindle method. The slag viscosity decreases as the CaO/SiO2 mass ratio is in-creased from 0.8 to 1.2 and also as the FeO content is increased from 8wt% to 20wt%. The breaking temperature of the slag is lowered sub-stantially by the addition of FeO, whereas the influence of the CaO/SiO2 mass ratio on the breaking temperature is complex. The structural analysis of quenched slags using Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy reveals that the silicate network structure is depolymerized with increasing CaO/SiO2 mass ratio or increasing FeO content. The [FeO6]-octahedra in the slag melt increase as the CaO/SiO2 mass ratio or the FeO content increases. This increase can further decrease the degree of polymerization (DOP) of the slag. Furthermore, the activation energy for viscous flow decreases both with increasing CaO/SiO2 mass ratio and increasing FeO content.     

The mechanism by which influenza A virus nucleoprotein forms oligomers and binds RNA

Influenza A viruses pose a serious threat to world public health, particularly the currently circulating avian H5N1 viruses. The influenza viral nucleoprotein forms the protein scaffold of the helical genomic ribonucleoprotein complexes, and has a critical role in viral RNA replication. Here we report a 3.2 A crystal structure of this nucleoprotein, the overall shape of which resembles a crescent with a head and a body domain, with a protein fold different compared with that of the rhabdovirus nucleoprotein. Oligomerization of the influenza virus nucleoprotein is mediated by a flexible tail loop that is inserted inside a neighbouring molecule. This flexibility in the tail loop enables the nucleoprotein to form loose polymers as well as rigid helices, both of which are important for nucleoprotein functions. Single residue mutations in the tail loop result in the complete loss of nucleoprotein oligomerization. An RNA-binding groove, which is found between the head and body domains at the exterior of the nucleoprotein oligomer, is lined with highly conserved basic residues widely distributed in the primary sequence. The nucleoprotein structure shows that only one of two proposed nuclear localization signals are accessible, and suggests that the body domain of nucleoprotein contains the binding site for the viral polymerase. Our results identify the tail loop binding pocket as a potential target for antiviral development.