Identification of new sesquiterpenoids in cephalic secretion of cuckoo bee,Nomada lathburiana (Apoidea,Anthophoridae)

A series of new sesquiterpene ketones and norsesquiterpene ketones could be identified from the cephalic secretion of females of the cuckoo bee,Nomada lathburiana (K.). The major component proved to be 2,6,10-trimethylundeca-(5E)-2,5,9-trien-4-one. Large amounts of high-boiling-point straight-chain hydrocarbons serve as solvents for the volatile, unstable ketones.     

取代2-四氢萘酮的一步合成新方法研究

本文介绍了一步法制备取代2-四氢萘酮的新方法,与常规合成方法相比,该法具有明显的优点:不需要先将羧酸转化成酰氯,避免了三氯化铝以及含氯溶剂的应用,并使催化剂得以循环利用。因此,该方法安全、环保,有望取代常规的付-克反应在工业上的应用。     

Modification of a carbon/carbon composite with a thermosetting resin precursor as a matrix by the addition of carbon black

Carbon/carbon composites were made through the pyrolysis of stabilized PAN felt and phenolic resin with the addition of 5 or 10 wt % carbon black to the matrix and then heat treatment at 600–2500°C. The effects of adding carbon black to the matrix precursor on the physical properties, microstructure, and mechanical properties of the resultant composites were investigated. Adding carbon black not only reduced the weight loss but also limited the shrinkage of the resultant composites. Adding carbon black also accelerated the formation of carbon basal planes in the matrix. At 2500°C, the crystalline stacking height in the composite with 10 wt % added carbon black was 200% greater than that with no additive. The flexural strength of the composite also increased from 15 to 42 MPa (almost 300%). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 333–337, 2006     

十二烷基－二甲基（2－羟基）乙基氯化铵系列季铵盐的缓蚀性能

通过失重法和极化曲线、线性极化两种电化学方法，研究了十二烷基二甲基（２－羟基）乙基氯化铵（１２２）、十四烷基二甲基（２－羟基）乙基氯化铵（１４２）和十六烷基二甲基（２－羟基）乙基氯化铵（１６２）对２０＃碳钢在５％盐酸中的缓蚀作用。并与新洁尔灭（十二烷基二甲基苄基溴化铵）进行了比较。结果表明，它们在酸性介质中具有很好的缓蚀作用。     

TAF-10环氧沥青混合料动态弹性模量及路用性能试验研究

近些年来,环氧沥青混合料以其耐久性好、强度高、冲击韧性优越等特点,广泛地应用于大型桥梁桥面铺装之中.以TAF-10型环氧沥青混合料为研究对象,对其进行不同温度与频率下的动态模量试验,结合时温等效原理,通过Origin数学计算软件,采用西格摩德(Sigmoidal)模型对试验结果进行非线性拟合;并通过高温车辙试验、小梁弯曲试验及冻融劈裂试验,对其高温稳定性、低温抗裂性、水稳定性等路用性能进行检测.结果表明:随着加载频率的增大,TAF-10环氧沥青混合料的动态模量不断增大,而随试验温度的升高其值不断减小;拟合所得到的主曲线方程,可以对任何给定温度与加载频率下该种混合料的动态模量进行有效预估;TAF-10环氧沥青混合料的高温稳定性、低温抗裂性及水稳定性等性能均超出规范要求,满足桥面铺装要求.研究成果可以为TAF-10环氧沥青混合料桥面铺装的动态设计提供参考.     

高冰镍硫酸浸出液萃取净化工艺流程的经济分析和最优化

本文以我国水法冶金的实际应用课题为对象,用系统分析的手法对高冰镍硫酸浸出液以5709和P507为萃取剂的两种萃取净化流程作了技术经济分析和比较.本文基于工艺实验建立的萃取与反萃模型,作为过程模拟和设计的基础.最后确定出该流程的最优操作参数和各单元操作的费用估算.     

Spatio‐temporal geometry fusion for multiple hybrid cameras using moving least squares surfaces

Multi‐view reconstruction aims at computing the geometry of a scene observed by a set of cameras. Accurate 3D reconstruction of dynamic scenes is a key component for a large variety of applications, ranging from special effects to telepresence and medical imaging. In this paper we propose a method based on Moving Least Squares surfaces which robustly and efficiently reconstructs dynamic scenes captured by a calibrated set of hybrid color+depth cameras. Our reconstruction provides spatio‐temporal consistency and seamlessly fuses color and geometric information. We illustrate our approach on a variety of real sequences and demonstrate that it favorably compares to state‐of‐the‐art methods.     

A New Derivation of the Cubature Kalman Filters

This paper investigates the cubature Kalman filtering (CKF) for nonlinear dynamic systems. This third‐degree rule based filter employs a spherical‐radial cubature rule to numerically compute the integrals encountered in nonlinear filtering problems, thereby removing the requirements of explicitly computing the Jacobians. The cubature rule, however, requires computing the intractable integrals over a high‐dimensional spherical region for multidimensional applications. Moreover, the cubature formula that has been used to construct the spherical cubature formula has some demerits, most notably its inconvenient properties in computation and low estimation accuracy. Aimed at these issues, a general class of CKFs that uses only cubature rules is derived in this paper. It can be shown that the conventional CKF is a special case of the proposed algorithm. The paper also includes higher‐degree CKFs, especially two representative types of the fifth‐degree CKFs. Performance of the proposed algorithms is demonstrated via two target tracking problems. The experimental results, presented herein, illustrate the superior performance of higher‐degree CKFs to conventional nonlinear filters.     

Preparation and properties of polyamines. Part I. Polymers containing dinitro substituted aromatic groups

Relatively high molecular weight polyamines with aromatic nitro groups in the repeat units were prepared by the reactions of aliphatic diamines, and 1,5-difluoro-2,4-dinitrobenzene, at elevated temperatures in diphenyl sulfone. The physical characteristics, including solubility, thermal stability, and viscosity of the resulting polyamines were found to be strongly dependent on the aliphatic chain length of the diamines used. All polymers exhibited exceptional solvent resistance. Except for strong acids with bulky counter-ions, including sulfuric, perchloric, and nitric acids, the polymers were found to be insoluble in all common organic solvents at room temperature.     

RLE图像压缩算法优化研究与应用

该文对比了传统的RLE（游程编码）算法,通过对RLE压缩编码的分析,得出RLE压缩算法存在很大的优化空间,并实现了优化后的RLE图像压缩算法,且着重介绍了这种算法的优缺点和优化方向。