Efficiently Testing Sparse <Emphasis Type="Italic">GF</Emphasis>(2) Polynomials

We give the first algorithm that is both query-efficient and time-efficient for testing whether an unknown function f:{0,1} ⁿ →{−1,1} is an s-sparse GF(2) polynomial versus ε-far from every such polynomial. Our algorithm makes poly(s,1/ε) black-box queries to f and runs in time n⋅poly(s,1/ε). The only previous algorithm for this testing problem (Diakonikolas et al. in Proceedings of the 48th Annual Symposium on Foundations of Computer Science, FOCS, pp. 549–558, 2007) used poly(s,1/ε) queries, but had running time exponential in s and super-polynomial in 1/ε.     

Research and Implementation of Task Management Model in Product Development Process Management

The implementation of product development process management (PDPM) is an effective means of developing products with higher quality in shorter lead time. It is argued in this paper that product, data, person and activity are basic factors in PDPM With detailed analysis of these basic factors and their relations in product developmed process, all product development activities are considered as tasks and the management of product development process is regarded as the management of task execution A task decomposition based product development model is proposed with methods of constructing task relation matrix from layer model and constraint model resulted from task decomposition. An algorithm for constructing directed task graph is given and is used in the management of tasks. Finally, the usage and limitation of the proposed PDPM model is given with further work proposed.     

Effect of pre-existing substructures on the fatigue properties of pure aluminium

Pure aluminium was thermomechanically treated (cold rolled to 80% reduction of thickness and annealed at 200° C for various lengths of time) in order to obtain different kinds of substructures. These aluminium specimens were then fatigued with a stress amplitude of 9×10³ psi or 90% of their ultimate tensile strength. The substructures of the specimens before and after fatigue were compared with each other and were then correlated to their fatigue property. The size and shape of substructure introduced by fatigue depend on the pre-existing substructure formed by thermomechanical treatment. The sub-boundaries of the fatigued specimen are not as well-defined as the pre-existing subgrain. The substructure size of the fatigued specimen increases initially with annealing time and then reaches a saturation value (2.32 m) when the annealing time is longer than 2 h. A peak value of fatigue life against the annealing time was found if the stress amplitude of fatigue is 90% of the ultimate tensile strength. The peak value also occurs at an annealing time of 2 h. The reason why the specimen annealed for 2 h possesses the optimum fatigue and property is discussed in terms of the substructures before and after fatigue.     

呼兰河流域2012年洪水特性分析

对2012年呼兰河流域的暴雨、洪水特性进行了分析,说明了变化规律,认识该流域水文特性,并对其成因及特性进行了归纳,为流域综合治理等提供科学的决策依据,其形成洪水主要是7月25—26日和7月28—29日的两次范围广、强度大的降雨过程。8月4日凌晨呼兰河秦家站出现洪峰,洪峰流量达到1 090 m3/s为2005年迁站以来第一位洪水。     

论唐寅《落花诗册》之反典而诗

唐寅在《落花诗册》中纵横使典,一气数典连用,而又不拘格俗,往往反典而用,以反典借古人景语言一己之情语,既不留行迹,又将自我多种复杂的心境展露无遗。同时,其化数家典故于一体,反典而不落陈套,手法不拘一格,表现了其极高的文学艺术修养。并且,其对于反典的偏爱,既是自我个性的张扬、不平的宣泄,也是对于"自性"的体悟和对"夺胎换骨"的继承,表现了其与禅宗之间甚深渊源。     

我国南方某铀矿井通风系统优化改造研究

在全面分析总结我国南方某铀矿井通风系统存在的问题基础上,以按需分风的通风网络优化技术,对原有通风系统进行优化,提出了矿井通风系统总体改造方案.通过方案实施,氡及氡子体浓度达到了国家辐射防护标准要求,各采掘面平均氡子体浓度下降了22.9%.     

催化重整装置紧急停车系统

介绍固定床半再生催化重整装置紧急停车系统的组成、原理及工作过程，给出调试和维护要点。     

乳胶漆对比率的影响因素

讨论了影响乳胶漆对比率的各种因素。     

锅炉等离子点火技术的应用及燃油系统选择

适用于贫煤、烟煤、褐煤,可连续运行的多根碳棒等离子点火技术,较前苏联采用银棒等离子点火技术具有造价低、使用寿命长等优点。以包头第二热电厂为例,对采用等离子点火技术前后的运行情况分析比较,经济效益可观。针对丰镇电厂三期2×600MW机组,设计采用等离子无油点火技术,对燃油系统进行了优化选择,简化了油罐设置。工程具有显著的经济效益和环境效益。