Aerobic muscle function during steady swimming in fish

Axial swimming in fish varies across a range of body forms and swimming modes. Swimming by eels, tunas, mackerels, scup, rainbow trout and bass span this range from high curvature anguilliform swimmers to rigid body thunniform swimmers. Recent work on these and other species has elucidated an impressive array of solutions to the problem of how to use the red (aerobic, slow‐twitch) muscle to power steady or sustained swimming. This review will use a comparative approach to understand the generalities of aerobic muscle function during steady swimming in fish and determine possible rules for the relationships between muscle contractile kinetics, in vivo muscle activity and power output during swimming. Beyond an exploration of the diversity in muscle activity and swimming kinematics, I suggest that analysis of the molecular basis for longitudinal variations in muscle function is needed to complement morphological and physiological research on fish muscle. This will permit both a general understanding of the integrative function of the fish myotome and, perhaps, predictive tools for muscle activity and swimming performance in fish.     

管道补口热收缩带粘接质量的超声检测方法

为解决管道补口热收缩带剥离强度人工抽检效率低、人为因素影响大的问题,通过超声波理论分析以及对不同粘接强度管道补口试件的试验分析,以及采用超声检测技术对管道补口热收缩带的粘接质量进行无损检测,实现剥离强度的定性及半定量评价,确定了能够明显反映管道补口热收缩带剥离强度的超声波特征参数。研究表明：超声波信号平均功率和低频能量两个参量与热收缩带剥离强度呈反比,可用于剥离强度的全面、快速检测。基于这两个参数指标,采用超声波反射法对补口样品的测试结果与补口样品手动机械拉伸测试结果一致,验证了参数选择的有效性。超声波特征参数可为建立补口热收缩带粘接质量的超声无损检测方法提供参考依据。     

混凝土早期体积变化与裂缝的成因

分析了混凝土早期体积的变化以及裂缝的形成与混凝土体积变化的关系。     

Mechanical Performance and Thermology Performance of 20CrMo Steel at High Temperature

Employing the Gleeble-1500D thermal analogue machine and the STA449 synthesis thermal analyzer,the study on hot ductility and parts of thermology performance of 20CrMo steel has been carried out , many consulted foundation data has been obtained, the optimum ductility temperature arrange has been found, contraction of cross sectional area is only 30% between 600 degree and 775 degree, but contraction of cross sectional area is more than 80% between 800 degree and 1 250 degree, contraction of cross sectional area drops to under 60% rapidly between 1 350 degree and melting point,a curve is drawn showing the relationshi Pbetween heat capacity and the variation of temperature for the first time, the counting formulas of the heat capacity are regressed by disjunction. A curve is drawn showing the relationshi Pbetween the coefficient of thermal expansion and the variation of temperature, and their application in continuous casting is discussed herein.     

STRENGTH PROPERTIES OF ROCK MASS WITH BIDIRECTIONAL INTERMITTENT CROSS JOINTS

In this paper,the strength properties of rock mass withrows of intermittent bidirectional cross joints by simulating models arediscussed.Work has been done on finding the failure mechanism of therock mass as well as the influence of joint direction and lateral pressureon tne strength of the rock mass.At the end of the paper,model testresults ahd FEM analyses are presented and strength criteria for thiskind of rock mass are proposed.     

明式家具用料与结构的剖析

明式家具在用材上大部分选用的是重量适宜、材质均匀致密而且坚韧、色泽柔和纹理美观、切削面光滑、耐久性较强的散孔材。在家具结构上,根据各零部件接合部位的要求不同,设计的各种榫接合形式是合乎科学道理的。且加工制作精度高,配合严密,结构强度好。这些说明明式家具在当时无论在造型上或者在用料、结构和制作工艺上都达到了相当高的水平。     

长输管道外防腐补口技术

管道外防腐层补口是防腐系统工程中的重要环节，其质量的优劣直接影响管道的防腐质量。常见的补口方法有沥青热浇涂、热烤沥青缠带、聚乙烯胶粘带、环氧粉末、聚乙烯电热熔套、幅射交联聚乙烯热收缩套、复合结构等。分述了各种补口方法的适用范围、优缺点及国内外使用情况等，论述了正确选择补口方法的重要性，指出应用补口方法时应着重考虑的问题，①补口材料的正确选用；②施工技术要求的合理制定与实施；③全过程、全方位的质量监     

几何突变的人口半群的单调性和FRR性质

研究几何突变人口半群的单调性和FRR性质.证明了q-矩阵Q在l∞生成正的压缩半群;在c0空间上生成连续压缩半群;最小Q-函数P（t）是FRR的,并且给出了其为随机单调的判别标准.     

装载机动臂铰点区域应力场的数值计算与试验研究

以CAT980S装载机动臂为研究对象,分别对装载机在正载插入与掘起联合作业(工况1)、右偏载插入与掘起联合作业(工况2)两种危险工况下动臂上铰点、动臂油缸铰点附近的应力场进行了数值计算。采用有限元与边界元混合求解,集中了有限元与边界元的优点,整体采用有限元求解,铰点局部采用边界元进行分析。在边界元分析中,提出了最小二乘边界元法,有效地模拟了铰点附近复杂的边界形状与边界条件。计算出了铰点附近应力场分布规律。同时,对CAT980S装载机动臂各铰点附近的应力进行了实车测试,并与计算结果进行了对照。