求解点覆盖问题的拟物转换及算法

本文首先基于CNF－SAT问题已有的拟物型的求解思想,将点覆盖问题转换为连续情形的目标优化问题,进而提出一种新的竞争式下降梯度方法,从而获得了求解点覆盖问题的高效实用的快速算法．     

C4NP-无铅倒装晶片焊凸形成生产工艺与可靠性数据

受控倒塌芯片连接新工艺是一种由IBM公司开发、由Suss Micro Tec公司推向商品化的新型焊凸形成技术。受控倒塌芯片连接新工艺采用各种无铅焊料合金致力于解决现有的凸台。形成技术限定,使低成本小节距焊凸形成成为可能。受控倒塌芯片连接新工艺是一种焊球转移技术,熔焊料被注入预先制成并可重复使用的玻璃模板(模具)。这种注满焊料的模具在焊料转入圆片之前先经过检查以确保高成品率。注满焊料的模具与圆片达到精确的接近后以与液态熔剂复杂性无关的简单工序转移在整个300mm(或300mm以下)圆片上。受控倒塌芯片连接新工艺技术能够在焊膏印刷中实现小节距凸台形成的同时提供相同合金选择的适应性。这种简单的受控倒塌芯片连接新工艺使低成本、高成品率以及快速封装周期的解决方法对于细节距FCiP以及WLCSP凸台形成均能适用。     

壬基酚和辛基酚联合染毒的尿液代谢组学研究

运用代谢组学方法研究壬基酚和辛基酚联合染毒对大鼠尿液代谢的影响.在高效液相色谱-飞行时间质谱技术检测的基础上,通过主成分分析观察了联合染毒的时间-毒效应和剂量-毒效应.根据主成分分析和判别分析,结合t检验,筛选出染毒组和对照组中具有明显差异的化合物,并在Metlin Scripps Center for Mass Spectrometry代谢物数据库中查询,推断其可能的代谢标志物.结果表明,壬基酚和辛基酚联合染毒后,尿液中可能出现的生物标志物有5种,分别为4,8-二羟基喹啉-2-甲酸(黄尿酸)、色氨酸及N-乙酰-5-羟色胺、RG- 13022和十六碳烯酸.由这些物质涉及的代谢途径,推测壬基酚和辛基酚联合染毒可能对生物体的蛋白质代谢、神经系统和心血管系统、生物节律、细胞抗氧化、性激素的平衡等方面产生毒效应,另外还可能影响细胞的信号传递和脂类代谢.     

Noise‐induced sampling of alternative Hamiltonian paths in quantum adiabatic search

We numerically simulate the effects of noise‐induced sampling of alternative Hamiltonian paths on the ability of quantum adiabatic search (QuAdS) to solve randomly generated instances of the NP‐complete problem N‐bit Exact Cover 3. The noise‐averaged median runtime is determined as the noise‐power and number of bits N are varied, and power‐law and exponential fits are made to the data. Noise is seen to slowdown QuAdS, though a downward shift in the scaling exponent is found for N > 12 over a range of noise‐power values. We discuss whether this shift might be connected to arguments in the literature that suggest that altering the Hamiltonian path might benefit QuAdS performance. © 2008 Wiley Periodicals, Inc. Complexity, 2009     

P ≠ NP for all infinite Boolean algebras

We prove that all infinite Boolean rings (algebras) have the property P ≠ NP according to the digital (binary) nondeterminism.     

On the complexity of the circular chromatic number

Circular chromatic number, χ_c is a natural generalization of chromatic number. It is known that it is NP ‐hard to determine whether or not an arbitrary graph G satisfies χ(G)=χ_c(G). In this paper we prove that this problem is NP ‐hard even if the chromatic number of the graph is known. This answers a question of Xuding Zhu. Also we prove that for all positive integers k ≥ 2 and n ≥ 3, for a given graph G with χ(G) = n, it is NP ‐complete to verify if . © 2004 Wiley Periodicals, Inc. J Graph Theory 47: 226–230, 2004     

Application of carbon-based nanomaterials in sample preparation: A review

In this paper, a broad overview on the applications of different carbon-based nanomaterials, including nanodiamonds, fullerenes, carbon nanotubes, graphene, carbon nanofibers, carbon nanocones-disks and nanohorns, as well as their functionalized forms, in sample preparation is provided. Particular attention has been paid to graphene because many papers regarding its application in this research field are becoming available. The distinctive properties, derivatization methods and application techniques of these materials were summarized and compared. According to their research status and perspective, these nanomaterials were classified in four groups (I: graphene and carbon nanotubes; II: carbon nanofibers; III: fullerenes; and IV: nanodiamonds, carbon nanocones/disks and carbon nanohorns) and characteristics and future trends of every group were discussed.     

INTEL网络处理器IXP425应用分析

本文分析了Intel IXP425的硬件结构特点,对FlexcommFIDS425系列开发平台进行了介绍,对IXP425的应用进行了分析,给出了IXP425在SOHO网关应用中的解决方案.     

一种时延和时延抖动受约束的启发式多播路由算法

多播路由算法在组播应用中是至关重要的,对视频会议等交互式实时组播业务来说,不仅要考虑时延约束,而且要考虑时延抖动约束。本文提出了一种基于最短时延路径的时延和时延抖动约束的启发式算法,仿真结果表明该算法复杂度较低,而且性能也较好,在算法复杂度和性能之间达到了很好的折中。     

关于销售集团投资设置销售分店问题的IP模型

针对一个实际投资实例建立了一个基于 0 -1背包问题的数学模型 ,并利用多个算法加以求解 ,并对结果进行了比较 .该模型具有很高的应用价值和参考价值 .