产品规范编写中常见问题剖析

从产品规范与设计输入的协调性、技术要素的完整性、技术要求的准确性、标准剪裁的合理性等方面着手,对产品规范编写中常见的问题进行了剖析,指出产品规范的编写质量将直接影响产品质量,提出提高产品规范编写质量的措施.     

Recent advance in nonlinear aeroelastic analysis and control of the aircraft

A review on the recent advance in nonlinear aeroelasticity of the aircraft is presented in this paper. The nonlinear aeroelastic problems are divided into three types based on different research objects, namely the two dimensional airfoil, the wing, and the full aircraft. Different non- linearities encountered in aeroelastic systems are discussed firstly, where the emphases is placed on new nonlinear model to describe tested nonlinear relationship. Research techniques, especially new theoretical methods and aeroelastic flutter control methods are investigated in detail. The route to chaos and the cause of chaotic motion of two-dimensional aeroelastic system are summarized. Var- ious structural modeling methods for the high-aspect-ratio wing with geometric nonlinearity are dis- cussed. Accordingly, aerodynamic modeling approaches have been developed for the aeroelastic modeling of nonlinear high-aspect-ratio wings. Nonlinear aeroelasticity about high-altitude long- endurance （HALE） and fight aircrafts are studied separately. Finally, conclusions and the chal- lenges of the development in nonlinear aeroelasticity are concluded. Nonlinear aeroelastic problems of morphing wing, energy harvesting, and flapping aircrafts are proposed as new directions in the future.     

Uncertain multiobjective redundancy allocation problem of repairable systems based on artificial bee colony algorithm

Based on the uncertainty theory, this paper is devoted to the redundancy allocation problem in repairable parallel-series systems with uncertain factors, where the failure rate, repair rate and other relative coefficients involved are considered as uncertain variables. The availability of the system and the corresponding designing cost are considered as two optimization objectives. A crisp multiobjective optimization formulation is presented on the basis of uncertainty theory to solve this resultant problem. For solving this problem efficiently, a new multiobjective artificial bee colony algorithm is proposed to search the Pareto efficient set, which introduces rank value and crowding distance in the greedy selection strategy, applies fast non-dominated sort procedure in the exploitation search and inserts tournament selection in the onlooker bee phase. It shows that the proposed algorithm outperforms NSGA-II greatly and can solve multiobjective redundancy allocation problem efficiently. Finally, a numerical example is provided to illustrate this approach.     

经济文化信息

10月起全智能伴你游九寨从九寨沟风景区游客安全随护导游系统技术论证会传来消息,《九寨沟风景区安导通随护系统》项目日前正式通过专家评审,有望今年10月与游客见面。届时,进入九寨沟风景区的游客,只需携带一个类似手机的全智能化终端设备,就能随时随地掌握景区的各种信息,景区管理部门也能以最快的速度为游客提供所需信     

腾冲 极边第一城

腾冲,位于滇西边陲,西部与缅甸毗邻,县城距缅甸密支那200公里,距印度雷多602公里,是中国走向南亚的"桥头堡"。两千多年前我国先民开辟的南方丝绸之路,就经腾冲进入缅甸、印度等国家。依托这条古道,腾冲得以较早开放和开发,一度贸易兴盛、经济繁荣,被誉为"极边第一城"。     

民航信息

国航开通成都-东京直达国际航线6月16日,中国国际航空公司西南分公司开通了成都-东京直达航线,改变了两地往来必须经停第三地的现状,该航线是西部地区架起的第一座直飞日本首都的空中桥梁,也是国航服务地方经济、打造成都航空枢纽迈出的重要一步。     

问题牛奶大揭秘:喝得起,伤不起 孩子不明真相,你不能不明真相

近年来,牛奶和乳制品行业可谓出尽了风头,从大头婴儿事件,到三聚氰胺事件,到性早熟奶粉事件,再到近期国家生乳标准,无不吸引了全社会的强烈关注,"不明真相的群众"在围观之余,也越来越心寒,越来越无奈,看着超市牛奶柜台里琳琅满目、促销标签飘扬的各类乳制品,群众们纷纷哀叹:这年头,我们还能喝什么奶?老百姓不敢喝奶,乳制品行业市场自然一片低迷。     

精品图书推荐

《迷航：航空运输经济与营销》 过去的几十年间,全球航空运输量一直保持着较高的增长速度。但令人迷惑的是,航空公司的业绩却始终不尽如人意。许多航空公司即使经营业绩较好,其利润水平也非常低。这到底是为什么呢？航空公司为什么常常迷失方向？本书以通俗易懂的语言解释了其中的缘由。     

2011年美国NBAA年会回顾

由于全球经济复苏缓慢。在今年的NBAA上,欧洲和拉美的采购仍然较为谨慎,而亚洲与中东市场的迅速增长保持了航空业前进的动力,制造商们纷纷推出了新的机型。     

区域物流系统内涵分析

在目前的研究文献中,有关区域物流系统含义的论述尚不多见。从区域经济和系统工程的角度,结合物流本身的含义,试图对区域物流系统的基本内涵、特征及其运行机理进行分析,以求对区域物流系统的规划、建设和调控起到一定的指导作用。