The induced circular dichroism of helically shaped racemic bilatrienes

Summary The imperfect mirror image relationship of the circular dichroism of (M) and (P) helical biliverdins bound to a homochiral entity (ICD) has been studied using the kinetically stable racemates (M+P)2 and (M+P)3. The phenomena associated with and eventual implications for the interpretation of ICD spectra of naturally occurring kinetically labile biliverdins in terms of chiral recognition are discussed.Dedicated to ProfessorKarl Schlögl on the occasion of his 70^th birthday     

Discrimination between ethanol inhibition models in a continuous alcoholic fermentation process using flocculating yeast

Discrimination between different rival models for describing the inhibitory effect of ethanol both on yeast growth and on fermentation was studied for a continuous process of alcoholic fermentation in a tower reactor with recycling of flocculating cells. Models tested include linear, parabolic, hyperbolic, exponential, and generalized nonlinear power-law types. The best expressions were identified under the criteria that all the kinetic parameters should assume acceptable values in a feasible range and should result in the best fit of the experimental data. The kinetic parameters were estimated from steady-state data of several sugar concentrations in feeding stream (S₀ = 160, 170, 180, 190, 200 g/L), constant dilution rate (D = 0.2 h^-1), recycle ratio (α = 13.6), and temperature (T = 30°C). The best model for the yeast growth was of power-law type, whereas for the product formation the best model was of linear type. These models were able to reproduce the trends of the process variables satisfactorily.     

Improving splitless injection with electronic pressure programming

An experimental injection port has been designed for split or splitless sample introduction in capillary gas chromatography; the inlet uses electronic pressure control, in order that the column head pressure may be set from the GC keyboard, and the inlet may be used in the constant flow or constant pressure modes. Alternatively, the column head pressure may be programmed up or down during a GC run in a manner analogous to even temperature programming. Using electronic pressure control, a method was developed which used high column head pressures (high column flow rates) at the time of injection, followed by rapid reduction of the pressure to that required for optimum GC separation. In this way, high flow rates could be used at the time of splitless injection to reduce sample discrimination, while lower flow rates could be used for the separation. Using this method, up to 5 μl of a test sample could be injected in the splitless mode with no discrimination; in another experiment, 2.3 times as much sample was introduced into the column by using electronic pressure programming. Some GC peak broadening was observed in the first experiment.     

相同的文学主题,不同的艺术表现--谈郁达夫与劳伦斯对性行为和性心理活动的描写

露骨的性描写和性心理活动的刻画是郁这夫和劳伦斯作品中突出的相同的艺术主题。然而,在他们表面相似 的性爱描写的背后,实际上隐藏着彼此不同的文化内涵,体现出他们之间的差异性。     

高效液相色谱法同时测定化妆精油中的七种性激素

建立了用高效液相色谱法同时测定化妆品中七种性激素的有效方法.试样经脱脂、提取、清洗、浓缩后,采用ODS-C18色谱柱,乙腈与水为流动相,进行梯度洗脱,应用二极管阵列检测器、荧光检测器的串联技术对样品中的七种性激素进行测定和鉴定,获得了良好的效果.七种性激素最低检出浓度为5μg/g,变异系数在3.4%以下,样品加标回收率在83%以上,标准曲线在5～150μg/nL的线性范围内,相关系数均大于0.999.     

△形网路的风向判别与解的唯一性

探讨了△形网路，主要结论有二：一是其网路解算有唯一解，二是其角联风路的风向判别与风量有关     

布氏四鼠的嗅觉通讯Ⅱ──2种不同方法下气味辨别实验的重复测量方差分析

利用重复测量方差分析，研究2种不同的实验设计方法对布氏四鼠气味辨别实验的影响．结果表明：给予单个气味刺激和同时给予多个气味刺激的2种不同实验方法，所得到的数据结果没有显著性差异，都能够反映出动物对气味的辨别能力．     

基于有限状态机的被动测试错误诊断

针对被动测试错误诊断算法只能推测出被测系统可能存在错误却无法准确定位错误的问题，提出了一种逐步定位系统实现错误的层次递进的方法．先利用测试序列的输入输出信息并结合错误模型生成初始诊断错误集合，再依据测试套上下文使用错误检测算法对该集合进行筛选，最后经连续观察或结合主动测试进行错误区分．实例验证结果表明，所提方法能够对绝大多数有单个实现错误的有限状态机模型进行错误定位．     

MD110程控交换机的话务限制

针对在日常使用和维护MD110程控交换机时,经常需要进行话务限制的情况,主要介绍了MD110程控交换机进行话务限制时所需的3个参数(TCD类别、话务连接矩阵、用户组CUST),给出了话务限制数据的设置原则和编写步骤,对实际工作中存在的问题加以举例说明,并给出了相应的解决方法,力求做到全局话务持续限制合理有效,使系统运行可靠稳定。     

文山苗族称谓辨析

一些史料或史论常用几个简单的、宽泛的甚至含混不清的称谓来论述苗族支系。从族名本意、语言差异、服饰工艺特点和地理区位特点看，各支系称谓实际蕴含着细微的文化差异。