一种适用于无线传感器网络定位的新方法

针对无线传感器网络,提出了一种基于恒模算法(constant modulus algorithm,CMA)的新定位方法(CMA-MAP)以及它的一种增强型算法(CMA-MDS)。其中CMA-MAP算法利用通信节点间距离的恒模性质,通过计算求出满足网络拓扑结构的多个局部最优解,并通过比较获得全局最优解。增强型算法(CMA-MDS)则是恒模算法与多维尺度分析技术相结合的一种新方法,模拟表明CMA-MDS可以提高估计的精度,且具有很强的鲁棒性。     

A hybrid hydrogel/textile composite as flame-resistant dress

Currently, the functional and cost-effective flame-resistant textiles(FRTs) are on high demand. However, such FRTs based on general polymer fabrics are always expensive, readily decompose, and their temperatures quickly rise once exposed to thermal environments. Inspired by the large specific heat of water and high decomposition temperature of inorganic substances like SiO_2, this study establishes a simple casting strategy for preparing flameresistant gel/textiles(FR-GTs). The findings showed that active diffusion of aqueous AAM/SiO_2 pre-gel solution into the textile structure enabled the formation of a tough interfacial adhesion between the hydrogel and textiles.The interfacial toughness reached ～272 J/m~2 because the PAAM/SiO_2 nanocomposite hydrogel was filled into textile to form the semi-interpenetrating structure at the interface. The presence of chemical crosslinker(PEGDA)and physical crosslinker(SiO_2) limited the volume expansion of the hydrogel upon swelling. In addition, the PAAM/SiO_2 nanocomposite hydrogel layer prevented burning in high temperature environments(over 100℃),due to the heat dissipation of water during evaporation. This simple strategy provides a guidance towards the fabrication of hybrid hydrogel/textile composites for the applications like household fire resistant materials such as flame-resistant gloves.     

先秦云梯形制辨

该文主要从先秦文献中所载之楼车及云梯形制，说明二者实有相同之功能，即用以窥伺敌军。从汉儒服《左传》时引用《兵法》一书，即提供了一项较少为右来学界注意的材料。后人由于二者名称各不相同，乃以二者并不相涉；文中则典籍所载，提出所谓“飞楼”者，当为设于云梯上用来观察敌情之塔楼，以证二者理应极有关系。     

矿山爆破地震波的测试分析

通过对某矿山爆破地震波形图的分析,说明了在减震爆破工作中,分段时间选择的重要性,并总结出影响爆破地震波传播的诸多因素,如选择分段时间不当,不但达不到减震效果,反而使振动能量叠加,形成大的波峰值.     

A类维生素对环磷酰胺诱发的抗白喉毒素突变型(DT~r)和SCE频率的影响

用新建立的抗白喉毒素突变型检测系统研究维生素A及其四种衍生物在化学诱变作用中的遗传学效应,并与姊妹染色单体互换频率指标进行比较,结果表明A类维生素具有抑制由间接诱变剂诱发的抗白喉毒素突变型频率和姊妹染色单体互换频率的作用.因此,A类维生素的抗肿瘤特性可能并不仅局限于其作用在肿瘤形成的第二步,也可作用在肿瘤形成的第一步(启动阶段).     

The analysis of free-sorting data: Beyond pairwise cooccurrences

Free-sorting data are obtained when subjects are given a set of objects and are asked to divide them into subsets. Such data are usually reduced by counting for each pair of objects, how many subjects placed both of them into the same subset. The present study examines the utility of a group of additional statistics. the cooccurrences of sets of three objects. Because there are dependencies among the pair and triple cooccurrences, adjusted triple similarity statistics are developed. Multidimensional scaling and cluster analysis — which usually use pair similarities as their input data — can be modified to operate on three-way similarities to create representations of the set of objects. Such methods are applied to a set of empirical sorting data: Rosenberg and Kim's (1975) fifteen kinship terms.The author thanks Phipps Arabie, Lawrence Hubert, Lawrence Jones, Ed Shoben, and Stanley Wasserman for their considerable contributions to this paper.     

定积分求解数列极限

定积分是数学的重要概念,在其他学科和各种领域应用广泛,在数学上的应用正向思维比较多,文章从逆向思维的角度,给出了利用定积分求解两种数列的极限的方法.     

赣江上游流域丰水期大型底栖动物群落的分布特征

2009年6—7月间从赣江上游流域的70个采样点共采集到大型底栖动物33种,其中软体动物门23种、环节动物门7种、节肢动物门3种,主要优势种为河蚬(Corbicula fluminea)和耳型河螺(Rivularia auriculata).为了较好地了解大型底栖动物的群落分布特征,根据支流汇流和生境状况,将上游流域划分成6个区域.对6个区域的多样性、多维尺度等的分析结果表明,不同区域间大型底栖动物的群落结构组成存在明显差异,其中受人为扰动最小的区域采集得到的底栖动物种类数最多,丰度和生物量最高,Shannon-Wiener多样性指数和Pielou均匀度指数均处于最高水平.     

益生菌Gan-1的鉴定、理化特性及其降胆固醇作用

从啤酒样品中分离出一株具有较强的耐酸、耐盐、耐胆盐及降胆固醇能力的细菌菌株Gan-1。利用多相分类方法,即通过形态特征、生理生化特性以及16S rRNA核酸序列分析,鉴定菌株Gan-1为干酪乳杆菌（Lactobacillus casei Gan-1）;采用MRS-Broth培养基,模拟人体胃酸环境、渗透压环境和胆盐环境,测定菌株Gan-1在酸性及高胆盐环境作用下菌株Gan-1的生长状况;结果表明,菌株能够耐受pH3的环境、低于6%NaCl的高渗环境以及低于2.0%胆盐环境;菌株具有降解胆固醇的能力,培养至24h时,降解的胆固醇达24%。