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91.
92.
朱春华 《广东海洋大学学报》1998,(1)
用随机区组试验方法,比较四种不同的选育群体团头鲂的后代和一个对照群体团头鲂的生长性能。结果表明:在同一环境条件下,远交群体比近交群体生长优势明显(|xi-xj|>D0.01);亲本年龄大(3足龄)的群体后代生长性能优于亲本年龄小(2足龄)的群体后代(|xi-xj|>D0.05);对照群体团头鲂与近交群体后代生长性能相当。 相似文献
93.
高压实膨润土热湿力性能测试 总被引:1,自引:0,他引:1
本文介绍了高压实样品的制样特点,测试了高压实膨润土样的导热系数,热膨胀系数,对高压实膨润土热湿力特性研究有较大参考价值。 相似文献
94.
旨在探究养殖水体中添加球形赖氨酸芽孢杆菌对斑马鱼幼鱼生长、抗氧化免疫、肠道菌群与代谢的影响。将初体重为(0.019±0.003) g的270尾斑马鱼随机均分为3组, ZF0组(对照组, 基础饲料)、ZF5组(基础饲料+105CFU/mL球形赖氨酸芽孢杆菌)与ZF7组(基础饲料+107CFU/mL球形赖氨酸芽孢杆菌), 每组3个平行,试验周期为33 d。实验结果表明: (1) 各组间的终末体重、增重率和特定生长率都没有显著性差异(P>0.05)。(2) ZF5和ZF7组的GPT活性显著高于ZF0组(P<0.05), ZF5组AKP的活性显著高于其他组(P<0.05)。(3) ZF7组胰蛋白酶和脂肪酶的活性相对于ZF0和ZF5组显著提高(P<0.05)。(4) ZF7组肠道绒毛高度、V/C都显著高于ZF0与ZF5组(P<0.05); ZF7组的隐窝深度显著低于其他两组(P<0.05)。(5) 从肠道菌群组成来看, 各组间优势菌门均为变形菌门(Proteobacteria), ZF5和ZF7组显著降低了肠道中梭杆菌门(Fusobacteriota)的丰度并显著提高了放线菌门(Actinobacteriota)的丰度(P<0.05)。属水平上, 对照组与试验组的优势菌属为鲸杆菌属(Cetobacterium), 试验组显著减少了邻单胞菌属(Plesiomonas)的丰度同时显著提高了戈登氏菌属(Gordonia)、细杆菌属(Microbacterium)等有益菌属的丰度(P<0.05)。(6)ZF5和ZF7组与ZF0组的肠道代谢物差异明显, 其中Lipoxin a4、Prostaglandin g2和11-dehydrothromboxane b2显著上调(P<0.05), 5''-phosphoribosyl- 5-amino-4-imidazolecarboxamide (aicar)显著下调(P<0.05)。差异代谢物主要富集在ABC转运蛋白、神经活性配体-受体相互作用以及丙氨酸、天冬氨酸和谷氨酸通路中。综上所述,养殖水体中添加球形赖氨酸芽孢杆菌有利于改善斑马鱼幼鱼的肠道消化性能、组织结构和微生物多样性及其代谢产物。 相似文献
95.
分析C 虚拟继承状态下的对象复制语义学.通过分析当前主流C 编译器对这个语义的支持情况,比较了它们之间实现上的差异;最后提出一种基于软件编码的实现方案,并比较了各种方案的性能优劣,以求更大限度的发挥C 的性能. 相似文献
96.
Experimental Study on Response Performance of VIV of A Flexible Riser
with Helical Strakes 总被引:1,自引:1,他引:0
Laboratory tests were conducted on a flexible riser with and without helical strakes. The aim of the present work is to further understand the response performance of the vortex induced vibration (VIV) for a riser with helical strakes. The experiment was accomplished in the towing tank and the relative current was simulated by towing a flexible riser in one direction. Based on the modal analysis method, the displacement responses can be obtained by the measured strain. The strakes with different heights are analyzed here, and the response parameters like strain response and displacement response are studied. The experimental results show that the in-line (IL) response is as important as the cross-flow (CF) response, however, many industrial analysis methods usually ignore the IL response due to VIV. The results also indicate that the response characteristics of a bare riser can be quite distinct from that of a riser with helical strakes, and the response performance depends on the geometry on the helical strakes closely. The fatigue damage is further discussed and the results show that the fatigue damage in the CF direction is of the same order as that in the IL direction for the bare riser. However, for the riser with helical strakes, the fatigue damage in the CF direction is much smaller than that in the IL direction. 相似文献
97.
在原有CHZ重力仪研制基础上,设计新一代海洋重力仪CHZ-Ⅱ并进行硬件搭建与测试。阐述了为CHZ-Ⅱ重力敏感结构设计的测试方案、实验过程及其结果分析,主要包括弹性系统的刚度、交叉耦合效应和漂移效应。实验表明,该结构在目前的测试内容下符合设计要求。 相似文献
98.
文章对2014年12月至2015年2月T639、ECMWF(文中简称EC)及日本数值模式的中期预报产品进行了对比分析和检验。结果表明:三个模式对亚洲中高纬环流形势的调整和演变及850 hPa温度转折性变化具有较好的中期预报性能,但都存在随时效增长的系统性偏差;对北方地区温度的预报, EC模式表现为预报较零场偏高,而T639模式表现为预报较零场偏低;对于海平面气压场,EC模式对冷空气前锋的预报与零场更加一致。 相似文献
99.
《Astroparticle Physics》2011,35(5):266-276
In this paper we introduce the concept of Lateral Trigger Probability (LTP) function, i.e., the probability for an Extensive Air Shower (EAS) to trigger an individual detector of a ground based array as a function of distance to the shower axis, taking into account energy, mass and direction of the primary cosmic ray. We apply this concept to the surface array of the Pierre Auger Observatory consisting of a 1.5 km spaced grid of about 1600 water Cherenkov stations. Using Monte Carlo simulations of ultra-high energy showers the LTP functions are derived for energies in the range between 1017 and 1019 eV and zenith angles up to 65°. A parametrization combining a step function with an exponential is found to reproduce them very well in the considered range of energies and zenith angles. The LTP functions can also be obtained from data using events simultaneously observed by the fluorescence and the surface detector of the Pierre Auger Observatory (hybrid events). We validate the Monte Carlo results showing how LTP functions from data are in good agreement with simulations. 相似文献
100.
Michael A. Minovitch 《Planetary and Space Science》2010,58(6):885-892
The invention of gravity-propelled interplanetary space travel (also known as “gravity-assist trajectories”) in the early 1960s broke the high-energy barrier of classical space travel based on reaction propulsion, and made possible the exploration of the entire solar system with instrumented spacecraft. In this concept, a free-fall spacecraft is launched from a launch planet P1 to a nearby planet P2 such that its gravitational field (superimposed on the gravitational field of the Sun) catapults the vehicle to another planet P3, which in turn is used to repeat the process. Thus, through a series of planetary encounters, a gravity-propelled trajectory P1-P2-P3-P4-…-PN is generated. This paper describes how the invention was conceived and how the difficult mathematical problem of computing the trajectories was solved in order to numerically investigate and use the invention in actual missions. The crucial roles played by the UCLA Computing Facility and the Departments of Mathematics and Physics are also described. 相似文献