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131.
132.
P-正则半群的双序集 总被引:1,自引:0,他引:1
本文刻划了双序集E为某P-正则半群的幂等元双序集的充要条件.所得定理不仅推广了D.Easdown关于带的双序集的结论,而且导出了正则*-半群的幂等元双序集的一个刻划.进而还对P-正则半群的若干特殊情形及向非正则半群的推广进行了讨论. 相似文献
133.
本实验应用体外分散垂体细胞动力学培养的方法,观察了LHRH脉冲幅度和频率以及LHRH连续刺激对雄性大鼠垂体前叶细胞LH分泌活动的影响。结果表明,LHRH在1×10~(-10)—1×10~(-6)mol/L范围内,与LH分泌的剂量-效应关系曲线呈线性。LHRH脉冲频率使LH分泌产生双相反应,随着刺激频率的增高,LH基础水平升高,LH/脉冲减少。当LHRH脉冲幅度在1×10~(-9)mol/L或以上,刺激频率在3脉冲/h或以上时,可观察到LH分泌达最高峰并随之逐渐下降至基础水平,即明显的自身激发作用和脱敏作用。增加LHRH的脉冲幅度可减少引起激发作用所需要的脉冲频率,增加高幅度LHRH脉冲的频率可使激发作用更快产生。另外,低浓度的LHRH(1×10~(-10)mol/L)连续刺激细胞也可产生自身激发作用,但需要较长时间的刺激。这些结果提示:垂体前叶LH细胞的分泌型式依赖于LHRH脉冲的幅度和频率,这有助于阐明体内的LH脉冲波动的动力学机理。 相似文献
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135.
本文提出用铝环一双层压片法制备样片,经验系数法校正元素间效应,对少量土壤样品中的化学元素进行定量测定。取样量500mg,制样与测量精度小于5%,用本法对标样的分析表明,分析值与推荐值基本一致,本法具有简单、快速、成本低的特点,适用于少量样品的分析。 相似文献
136.
——Phase Behavior of the Aqueous Solution of Poly(vinyl methyl ether) Sensitive to Temperature and the Modification of the Behavior by Using Poly(acrylic acid) The phase behavior of the aqueous solution of poly(vinyl methyl ether) (PVME) sensitive to temperature and the modification of the behavior by using poly(acrylic acid) (PAA) have been studied by ultrasonic attenuation measurements and fluorescence probe techniques. It has been observed that PVME solution is transparent at room temperature and becomes turbid upon heating. The solution turns clear again as soon as the temperature is decreased to room temperature. The heating and cooling process can be repeated for many times. The phase behavior of the solution sensitive to temperature is attributed to the conformational changes of the polymer. PVME may adopt an open coil conformation at room temperature. With this conformation, the polymer is well miscible with the solvent, water, and thereby the system is a real solution. The polymer may adopt a compact coil conformation when the temperature is higher than a specific value, which is called the LCST (the lower critical solution temperature) of PVME. In this case, the polymer tangles to each other and forms various aggregates, which can scatter incident light and ultrasonic waves greatly, resulting in the phase separation. Introduction of PAA decreases the temperature sensitivity of the phase behavior of the polymer. The nature of the inhibition is attributed to the complexation of PAA with PVME and the strong hydrophilicity of PAA. Results from fluorescence probe studies are in accordance with those from ultrasonic attenuation measurements, indicating again that the ultrasonic attenuation method can be successfully used for the qualitative studies of polymer conformations and complexation between polymers. 相似文献
137.
A novel water soluble ditopic guest, the quaternary ammonium salt of N,N'-bis(ferrocenylmethylene)-diaminobutane (1), and a known water soluble ditopic host, benzenetetracarboxylic dianhydride bridged bis(β-cyclodextrin)s (2), have been synthesized and characterized. ^1H NMR spectra and cyclic voltammogram (CV) studies revealed the host-guest interactions between them in aqueous solution. The supramolecular interaction also exists in solid state as confirmed by the studies of the solid samples, which were obtained by frozen-drying the solution sampies, using FTIR spectroscopy and differential scanning calorimetry (DSC) techniques. TEM measurement demonstrated that wire-shaped supramolecular aggregates exist in the aqueous solution of the two compounds. The lengths of the aggregates could reach micrometers. 相似文献
138.
本文提出以透明胶纸作为少量粉末样品的支持物来制备样片,采用透空照射法,在日本理学3080E3型X-射线荧光光谱仪上实现了蒙脱石中化学元素的定量测定。本法样品实际用量约10mg,制样与测量精度较好,标样及样品的分析结果与推荐值及AAS法分析结果基本一致,方法具有简单、快速、准确和成本低的特点,适用于少量样品和单矿物的分析。 相似文献
139.
IntroductionCalorimetryhasbeenusedinmonitoringcellularmetabolismbymeansofheatmeasurements ,especiallyinstudyingmetabolismincellsandwholeorganism .1,2 Mi crocalorimetryisalsousedinmeasuringtheeffectsofvar ioussubstancesandcultureconditionsonmetabolism .Mile… 相似文献
140.
The optimized method of extending the omni-photonic band gap (omni-PBG) was discussed based on analyzing the P-wave reflectivity characteristics in one-dimensional (1D) periodic multilayer film.A visible omnidirectional reflector with hybrid structure was designed using P-wave compensated overlapping in angle domain.The experimental result was in good agreement with the theoretical simulation. 相似文献