Currently,lakes and artificial reservoirs are increasingly threatened by eutrophication,which is the result of the combined action of many natural and anthropogenic factors.In the past,the effect of nutrient load on the trophic state of water bodies has a
以船体梁腹板开孔为研究对象,考虑船体复杂受力工况,基于含满意度权重因子的折中规划法,对传统双向渐进结构优化(Bidirectional Evolutionary Structural Optimization,BESO)算法进行改进,将体积减轻比作为优化目标,孔边应力作为约束,提出一种适用于船体结构孔型的优化方法。在此基础上,基于ANSYS软件,通过二次开发编写改进BESO算法优化程序,对船体梁腹板的腰圆开孔进行优化设计,得到应力分布均匀且减重明显的开孔型式。优化结果表明,在满足结构强度的条件下,船体梁腹
电力系统安全是国家安全的重要组成部分,以自主可控为核心发展关键技术是国家重大战略方向.传统电力控制保护技术采用通用芯片平台,关键器件高度依赖国外进口,主要知识产权长
含氮污染物是造成水体富营养化的因素之一,必须治理.国家颁布的国家环境保护“十二五”规划将氨氮列为污染物总量控制指标.GB 31570-2015《石油炼制工业污染物排放标准》和GB
Main observation and conclusionrnTwo new bis-quinolizidine alkaloids,neopetrosiasins A (1) and B (2),possessing cis-and trans-quinolizidine nuclei,one known rel
The high-MgO ultramafic volcanic rocks in the NW Ad Dhala province are classified as meimechite according to the IUGS classification scheme.This province represents the southeastern outcrops of the Yemen Volcanic Group(YVG),which constitutes part of the A
Main observation and conclusionrnRing-opening polymerization (ROP) of cyclic esters in the presence of stannous octoate (Sn(Oct)2) is the main way to obtain bio
对比解读国内外权威海上直升机甲板规范,对比各规范对直升机甲板防滑、安全网等设备设施的不同要求,剖析真实案例,为海上设备设施的建造或改造提供合理的支持。
Main observation and conclusionrnTwo ternary clusters,[As3Nb(As3Pb3)]3-1 and [As3Ta(As3Pb3)]3-2,were directly extracted from “K8NbPbAs5” and “K8TaPbAs5” int
Main observation and conclusionrnThe cathode material plays a crucial role in the performances of aqueous zinc-ion batteries (ZIBs).Herein,we report an ammonium