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本文合成了含酰胺基团和不含酰胺基团的两类Gemini阳离子表面活性剂,测定了其表面活性参数,研究了酰胺基团对表面活性剂的表面活性和聚集行为的影响。结果表明,酰胺基团提高了Gemini阳离子表面活性剂的临界胶团浓度,降低了胶团聚集数,增强了胶团微极性,增大了表面活性剂的饱和吸附量。 相似文献
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自20世纪初期,德国化学家EmilFischer首先合成了甘氨酸二肽片段,并第一次提出“peptide”(多肽)这一名词,多肽化学的研究已经历了100多年的发展.1953年,Vigneand小组首次完成了生物活性肽催产素的合成,并因此于1955年获得了诺贝尔化学奖.1963年,Merrifield提出了多肽固相合成法,并发明了第一台多肽自动合成仪,大大简化了多肽合成的流程、提高了合成的效率,从而促使多肽化学实现了飞跃式发展,Merrifield也因此获得了1984年诺贝尔化学奖.1965年,我国科学家完成了牛结晶胰岛素的合成, 相似文献
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在高中新课程改革的背景下,利用自行设计的问卷,对南宁市高中化学教师素质进行了调查,分析了其素质现状和特点,探索了素质优化途径,并根据调查结果,提出了相应的建议。 相似文献
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对微粒运动实验的仪器、用品作了改进,重新设计实验装置,使实验装置达到了小型化、封闭化、简洁化,实验达到了绿色环保要求,满足了大面积的学生探究实验操作使用,取得了良好的效益。 相似文献
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对富锌排铅咀嚼片(RZLR)进行了急性毒性试验、Ames试验、骨髓微核试验、精子畸形试验和30 d喂养试验。结果表明,小鼠急性毒性LD50(BW)>21 500 mg/kg,属无毒级;Ames试验、小鼠骨髓微核试验、精子畸形试验和30 d喂养试验结果均为阴性;30 d喂养试验也未显示明显毒性。本研究证实RZLR是一种安全、无毒副作用的保健食品。 相似文献
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Harada T Narazaki R Nagira S Ohwaki T Aoki S Iwamoto K 《Chemical & pharmaceutical bulletin》2006,54(8):1072-1075
The purpose of this study was to demonstrate the usefulness and broad-applicability of a simple disintegration test method for orally disintegrating tablets (ODT). Eight types of commercial famotidine 20 mg orally disintegrating tablets with different physical properties (formulation, manufacturing method, tablet weight, shape, diameter, thickness, etc.), were used. Disintegration times of these tablets were evaluated employing human sensory test, conventional disintegration test, and the new proposed disintegration test. The human sensory test was performed in 5 healthy volunteers. In the conventional disintegration test, the disintegration apparatus described in the Japanese Pharmacopeia (JP 1(st)) was used. Our proposed new test which is characterized by a rotating shaft with a low weight (10, 15 g) and rotation speed (10, 25, 50 rpm) was evaluated using tablets with and without storage under severe conditions (60 degrees C/75%RH for 1 week). The disintegration times of famotidine 20 mg orally disintegrating tablets in human sensory test varied from 9 to 32 s. In contrast, disintegration times in the conventional test were prolonged to over 300 s. Disintegration times in the new proposed test were close to those in human sensory test. Especially, when the new test was conducted with 15 or 10 g weight and 25 rpm, the slope (human sensory test vs. new proposed test) was almost 1. We were able to demonstrate that the new proposed test was useful to estimate the actual human disintegration time. 相似文献
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The thermodynamic consistency of binary vapor–liquid equilibrium data has been examined for 46 binary alcohol + hydrocarbon systems with 310 data sets in total (145 isobaric and 165 isothermal sets) using the PAI test proposed in our previous study. The PAI test permits an overall check of the data by combining three tests: a point test, an area test, and an infinite dilution test. In this work, the PAI test was incorporated with the NRTL equation for fitting data. The results of the PAI test for the vapor–liquid equilibrium data showed that the PAI test was able to strictly select reliable data. 相似文献
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The isochore concept in the human genome sequence was challenged in an analysis by the International Human Genome Sequencing Consortium (IHGSC). We argue here that a statement in the IHGSC's analysis concerning the existence of isochores is misleading, because the homogeneity was not examined at a large enough length scale and consequently an inappropriate statistical test was applied. A test of the existence of isochores should be equivalent to a test of homogeneity or equality of windowed GC%. The statistical test applied in the IHGSC's analysis, the binomial test, is a test of whether individual bases are independent and identically-distributed (iid). For testing the existence of isochores, or homogeneity in windowed GC%, we propose to use another statistical test: the analysis of variance (ANOVA). It can be shown that DNA sequences that are rejected by the binomial test may not be rejected by the ANOVA test. 相似文献
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电感耦合等离子体原子发射光谱同时测定不锈钢食用器皿铬、镍、镉溶出量 总被引:1,自引:0,他引:1
庞晋山 《分析测试技术与仪器》2003,9(4):247-250
用4%醋酸溶液浸泡取自不锈钢食用器皿钢片样品,在室温条件下浸泡24h,将浸泡液按6:1浓缩.通过优化试验确定实验条件,用电感耦合等离子体发射光谱仪准确测定浸泡液中Cr、Ni、Cd的浓度。实验过程操作简单,多种元素同时测定节约试验时间,精密度试验和回收率试验说明该方法检测结果准确可靠。 相似文献
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The biochemicals utilized in the Charm MRL beta-Lactam test (8 min test) were applied to faster flowing lateral components to create a new 3 min, one-step beta-lactam test called Charm MRL-3 (Charm Sciences Inc., Lawrence, MA). This new test was validated at T&V-ILVO according to Commission Decision 2002/657/EC. The following analytical parameters were checked: test specificity, detection capability, and test robustness (impact of deviation of the test protocol, and impact of the milk composition, batch differences of reagents). Further, the suitability of the Charm MRL-3 to screen heat-treated milk or milk from animal species other than the cow was also tested. Finally, the test was integrated in the monitoring of dairy samples to check the occurrence of false-negative or false-positive results, and the test was also included in a national ring trial and an international proficiency study. The results proved that the Charm MRL-3 is a fast, simple, and reliable cows' milk test that can be used at the farm level in order to prevent tanker milk contamination, or at the entrance of the dairy plant to screen tanker milk for the presence of beta-lactam antibiotics. 相似文献
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文章就t,F显著性检验在同一个问题上检验判断的不一致性,提出在对一种分析结果(或测试结果)实施鉴定时,有必要同时进行t,F的联合检验,而只有当联合检验一同被接受之后,所作用出的判定结论才是完整和可信赖的。 相似文献
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A novel non-destructive integrity test for microporous and ultraporous membranes has been developed that is far more sensitive to detecting defects than a conventional gas–liquid diffusion test. The test developed here uses a binary gas mixture and is based on the principle of differing gas permeabilities through the liquid layer of a wetted membrane that results in a concentration enhancement of the faster permeating gas. In an integral membrane, the permeate composition can be predicted based on the transport properties of the gases permeating through the liquid layer and the known operating conditions. A deviation from the expected concentration is an indication of the presence of a defect or open pores. Unlike the gas–liquid diffusion test, the binary gas test has low sensitivity to membrane porosity, liquid layer thickness, and membrane area. Consequently, integral devices will exhibit a relatively narrow range of test values, resulting in a superior defect signal-to-noise ratio. In this study, a binary gas integrity test method was developed and applied to a newly developed virus clearance filter. The binary gas test was demonstrated to provide a significantly higher level of virus retention assurance compared to the air–water diffusion test, and can be implemented by the filter manufacturer as an additional quality assurance test prior to shipping the product to users. 相似文献