化学探头法与荧光光谱法测定水中溶解氧量

探讨了化学探头法和荧光光谱法测定水中溶解氧的关系。分别用F检验和t检验对两组数据进行了比较,结果表明两组数据的精密度和系统误差都没有显著差异,两种方法测定溶解氧的相对标准偏差(RSD,n=9)分别为0.35%,0.33%。进而又探讨了溶解氧与NaCl含量、温度之间的关系,结果表明溶解氧含量随NaCl含量的增加、温度的升高而逐渐降低。     

A proposed mechanism for hydrodynamically-controlled onset of significant void in microtubes

Data and analysis have shown that bubble nucleation and ebullition phenomena in microchannels are different than in large channels. The macroscale models and correlations often fail to predict data representing bubble ebullition processes in microchannels. It is hypothesized here that hydrodynamically-controlled onset of significant void in microchannels is due to bubble departure from wall cavities, and the latter process may be controlled by thermocapillary and aerodynamic forces that act on the bubble. Accordingly, the limited available relevant experimental data are semi-analytically modeled, and the soundness of the proposed hypothesis is shown.     

应用型本科院校物理化学考核模式的构建与实践

针对应用型本科院校现有的物理化学课程考核模式存在的问题,采取过程化考核和终结性考核相结合的方式,构建了新的物理化学考核模式,并在教学中进行了实践。实践表明:通过考核模式改革,化学专业学生物理化学成绩相对其他不同专业或相同专业不同年级的学生而言,物理化学课程成绩产生了显著性差异,且明显提高;激发了学生的学习兴趣,调动了学生学习的积极性、主动性,提升了学生专业素养。     

我国人口时间序列的变系数预测模型

根据1952-2005年我国人口总量和GDP总量数据,建立变系数模型.采用逐步回归的方法来选择显著滞后变量子集,推导出系数函数的样条估计表达式,最后运用Bootstrap思想,进行点预测和区间预测。运算结果表明:对于该组数据,变系数模型能较理想地描述数据之间的内在结构,且具有较少的预测误差.     

结合隐藏技术的新颖语音检索算法

采用一种新颖的结合信息隐藏技术的语音检索算法，该算法将保密语音和伪语音分割成多段，利用经典的LSB算法分别隐藏到不同的音频，并存储在磁盘空间中．提取语音码流时，利用小波变换第一级细节分量系数能量的大小找到相应的载体音频，提取其中的语音码流，并建立语音库．利用特定人语音检索技术，检出相应的语音码流，合并语音码流得到真正的保密语音．研究表明：新算法的查准率和查全率可以达到很高的水平，为信息隐藏技术的发展开辟了一条新的研究道路，同样扩大了语音检索技术的应用范围。     

Synthesis and biological evaluation of novel 2,4,5-triaryl-1 H-pyrazol-3(2H)-ones as inhibitors of ALK5

A series of 2,4,5-triaryl substituted 1H-pyrazol-3(2H)-ones,as ALK5 inhibitors,were desigened,synthesized and evaluated in vitro.Most compounds exhibited noticeable ALK5 inhibition activities at 1 μmol/L and displayed no significant cytotoxicities at 30 μmol/L.     

有效数字在环境监测中的应用

对实验中常用的玻璃量具如单标线吸管、容量瓶、比色管、刻度吸管等进行分析,确定了直读式数据的读数规则及有效位数。如10mL单标线吸管有效数字位数为5位,而10mL刻度吸管随移取溶液体积不同其有效数字位数可能为2,3或4位。分析了环境监测中间接式数据的来源,如标准溶液的浓度、标准曲线的截距、斜率、样品最终浓度等,这些数据应当遵守一定的修约及运算规则,由此确定了间接式数据应当保留合理的有效位数。研究结果可以为环境监测人员开展实验及数据处理提供依据。     

FORTRAN语言双精度运算的扩展应用

本文利用ＦＯＲＴＲＡＮ语言中不同类型变量的性质及数运算的特点，讨论了一种能将双精度实数运算扩展到整数运算中的方法，使整数运算也能得到接近双精度实数所具有的有效位数的整型结果。     

ADSORPTION OF 2,4-D ON MODIFIED HYPERCROSSLINKED POLYSTYRENE （NDA-99） AND XAD-4 RESIN

The adsorption behavior of pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution has been investigated using a hypercrosslinked polystyrene adsorbent (NDA-99) modified by dimethylamine group as well as a nonionic macroporous adsorbent (XAD-4). The Langmuir and Freundlich isotherm models were employed to fit the experimental data to describe adsorption mechanism. It shows that NDA-99 resin exhibits an adsorption affinity for 2,4-D higher than XAD-4 resin owing to its exceptional micropore structure and the amine group of the hypercrosslinked matrix.Further studies indicate that the hydrogen bonding interaction and the stronger π-π conjugation play a significant role in the course of the adsorption of 2,4-D on NDA-99 resin, which is in agreement with the IR spectroscopic results and the △E values of HOMO (the highest occupied molecular orbit) of adsorbent and LUMO (the lowest unoccupied molecular orbit) of adsorbate calculated from the MINDO/3 model.     

Study on the Dynamics of Blending of Glucomannan with Carrageenan and Guaran Gum

In order to prove up the interaction between konjac glucomannan (KGM) and other amyloses, by using KGM, guaran gum and carrageenan as materials, their blending in different external conditions was modeled by means of molecular dynamics (MD) method. The result showed that 323 K was a significant turning point for the formation of hydrogen bond, and KGM and guaran gum were just juxtaposed together via intermolecular hydrogen bond; but with the addition of carrageenan, KGM, guaran gum and carrageenan were spirally twisted together, and when their blending proportion is 3:2:9 the combination was the most compact. Moreover, the research result has provided the sequent studies afterwards on amyloses with some references.