气相色谱法分析阳离子醚化剂中残存的环氧氯丙烷和1,3-二氯丙醇

建立了液体阳离子醚化剂中残存的环氧氯丙烷、1,3-二氯丙醇的气相色谱分析法。用苯甲酸甲酯萃取样品,对两组分都有很高的萃取率。选用HP-5 30　m毛细管柱,一次进样能同时测定两组分,两组分达到完全分离,且均在萃取剂前出峰,因而减少了峰扩散,提高了检测灵敏度。检测的线性范围:环氧氯丙烷5～590 mg/kg,1,3-二氯丙醇21～480 mg/kg;检测限:环氧氯丙烷1.2 mg/kg,1,3-二氯丙醇2.2 mg/kg;回收率：环氧氯丙烷95.93%～103.42%,相对标准偏差(RSD)2.4%～10.     

西安地裂缝活动趋势分析

西安地裂缝的形成及活动主要受构造活动及人类活动因素影响, 而近来地裂缝的超常活动主要与过量抽取地下水引起的地面不均匀沉降有关。根据对抽水及地面荷载引起地层压密固结过程的分析、地下水位变化趋势的分析以及应用 Ver-hulst模型计算、预测结果, 西安地裂缝的强烈活动将有减缓或逐渐稳定的趋势。有关地裂缝活动的最新实际监测数据已显示出一些相应的征兆。     

New phenylpyridone derivatives from the Penicillium sumatrense GZWMJZ-313, a fungal endophyte of Garcinia multiflora

Citridones E-G (1-3), three new phenylpyridone derivatives together with two known curvularins (4 and 5) were isolated from the solid culture of the endophytic fungus Penicillium sumatrense GZWMJZ-313 in Garcinia multiflora. The structures of new compounds were determined in the light of spectroscopic data,X-ray and ECD calculation. Compounds 1 and 3 are racemates, while compound 2 is optically pure.Compounds 1 and 4 showed antibacterial and antifungal activities against Staphylococcus aureus,Pseudomonas aeruginosa, Clostridium perfringens, Escherichia coli and Candida albicans with MIC values ranging from 8 μg/mL to 64 μg/mL.     

Base-catalyzed diborylation of alkynes: synthesis and applications of cis-1,2-bis(boryl)alkenes

An efficient, transition-metal free, and practical approach to cis-bis(boryl)alkenes from various alkynes was disclosed in the presence of a catalytic amount of K_2CO_3 under mild conditions. Meanwhile, tetrasubstituted alkenes and phenanthrene derivatives were readily constructed from the target diborylalkenes via Suzuki-Miyaura cross coupling.     

随机温度场的渐近-最大熵分析

针对具有随机参数的稳态温度场分析,利用拉普拉斯多维积分的渐近展开及函数的泰勒级数展开等方法,求得了节点温度响应的原点矩近似解析表达式。在最大熵原理基础上,获得了节点温度响应的概率密度函数。算例将该方法与Monte-Carlo模拟法进行比较,表明该方法具有较好的精度,且在参数变异性较大时也能获得较满意的结果。     

大口径毛细管气相色谱法测定工业2-甲基呋喃

2-甲基呋喃（2-methylfuran）是至今尚不能用石化原料合成,而仅用农林废料生产的一种重要的有机化工原料。它是呋喃族杂环化合物的一员,主要用于有机合成和选择性溶剂,并在含氮、含硫杂环化合物和功能性取代脂肪族化合物的生产中用作原料。国外有人用气相色谱和色谱-质谱联用技术测定了桦木燃烧烟雾中的2-甲基呋喃及其同系物;目前我国尚未有工业2-甲基呋喃含量测定的国家标准和行业标准。鉴于近年来2-甲基呋喃产量不断增加,其含量的高低已成为最重要的质量控制指标之一,本项研究结合我国实际情况,参照作者于2003年主持修订的国家推荐标准（GB／T1926．2）中的方法建立了一种测定工业2-甲基呋喃的大口径毛细管气相色谱法。该方法准确度高,重复性和再现性好,可用于工业2-甲基呋喃的质量控制。     

Sb和S修饰Pt电极上1,3 -丁二醇氧化的原位红外反射光谱研究

运用电化学原位ＦＴＩＲ反射光谱研究了１,３－丁二醇在以Ｓｂ和Ｓ修饰的Ｐｔ电极上的氧化过程。结果表明Ｓｂ和Ｓ修饰都能抑制１,３丁醇的解离吸附。红外数据指出Ｓｂ的存在使１,３丁二醇氧化产物同时含有羰基物种和ＣＯ２,而Ｓ修饰的Ｐｔ电极上以羧酸物种为主。     

Amorphous Structures in Laser Cladding of ZL111 Aluminum Alloy:Semi-quantitative Study by Differential Thermal Analysis (DTA)

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Amorphous Structures in Laser Cladding of ZL111 Aluminum Alloy:Semi-quantitative Study by Differential Thermal Analysis (DTA)

This paper deals with amorphous structures in the laser cladding. ZL111 alloy is the substrate and Ni-Cr-Al alloy is sprayed on the substrate as the coating material. The coating is clad by a 5 kW transverse flow CO2 laser. The observation of SEM and TEM reveal that in the laser cladding there are amorphous structures of two different morphologies: one is space curved flake-like, and exists in the white web-like structures; the other is fir leaf-like, and exists in the grain-like structures. Differential thermal analysis (DTA) is used to semi-quantitatively determine the content of the amorphous structures. A relation is obtained between the content of amorphous structures and the dimensionless laser cladding parameter C. We also show the changes of the amorphous structures after annealing.     

基于区间因子法的不确定性桁架结构动力响应分析

研究了不确定性桁架结构的动力响应分析问题.在桁架结构的物理参数、几何尺寸和荷载幅值均为区间变量时,从结构响应的Dulaamel积分式出发,利用区间因子法、区间运算和振型叠加法导出了结构动力响应区间变量的表达式.通过算例考察了结构参数和作用荷载的区间分散性对结构动力响应分散性的影响,经与蒙特卡洛数值模拟结果的比较,表明文中所提出的计算模型和分析方法的合理性和可行性.