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1.
马来酸酐与环氧丙烷开环共聚,所得聚酯具有功能团(C=C),可以通过接技、交联待方法改变其性能,马来酸杆与环氧化物开环共聚合成聚酯,所用催化剂通用有有机金属化合物和稀土 事物等,我们在铁系催化丁二聚合和马来酸酐与苯乙烯共聚的基础上,首次将Fe(acac)3-Al(i-Bu)3-α,α′-联吡啶催化剂用于马来酸酐与环氧化物开环共聚,发现该催化剂催化共聚反应具有时间短、收率高、共聚物交替度高等优点,并测定了共聚合反应动力学的参数。  相似文献   

2.
Chloramine-T is a disinfectant being developed as a treatment for bacterial gill disease in cultured fish. As part of the drug approval process, a method is required for the confirmation of chloramine-T residues in edible fish tissue. The marker residue that will be used to determine the depletion of chloramine-T residues from the edible tissue of treated fish is para-toluenesulfonamide (p-TSA), a metabolite of chloramine-T. The development and validation of a procedure for the confirmation of p-TSA is described. Homogenized fish tissue is dried by mixing with anhydrous sodium sulfate, and the mixture is extracted with methylene chloride. The extract is passed through a silica gel solid-phase extraction column, from which p-TSA is subsequently eluted with acetonitrile. The acetonitrile extract is evaporated, and the oily residue is dissolved in hexane. The hexane solution is shaken with fresh acetonitrile. The acetonitrile solution is evaporated and the residue is redissolved in dilute potassium hydroxide solution. The aqueous solution is extracted with methylene chloride to further remove more of the fat co-extractive. The aqueous solution is reacted with pentafluorobenzyl bromide in presence of tetrabutylammonium hydrogensulfate. The resulting di-(pentafluorobenzyl) derivative of p-TSA is analyzed by gas chromatography/mass spectrometry. This method permits the confirmation of p-TSA in edible fish tissue at 20 ppb.  相似文献   

3.
The spinodal phase decomposition of an immiscible binary polymer blend system is investigated with numerical models in two-dimensional and three-dimensional (3D). The effect of the elastic energy is included. The mechanism of the evolution of the phase separation is studied and the characteristic length R(t) is shown to be proportional to t(13). In the case when the phase separation is directed by a heterogeneously functionalized substrate, the increase in the characteristic length is divided into two stages by a critical time. The R(t) approximately t(13) diagram can be fitted with a straight line in both the first and second stages. The slope of the fitting line significantly decreases after the critical time. The compatibility of the resulting pattern to the substrate pattern is also measured by a factor C(S). It is observed that there is also a critical time in the evolution of the compatibility for the cases with and without elastic energy. The critical time of C(S) is identical with the respective critical time of R(t). The lateral and vertical composition profiles functionalized substrate is observed with the 3D model. The difference mechanism of the cases with and without elastic energy is discussed.  相似文献   

4.
诺氟沙星的交流示波极谱滴定法研究   总被引:1,自引:2,他引:1  
汪秀龄  武维顺 《分析化学》1995,23(10):1189-1192
本文报道了示波极谱滴定法测定诺氟沙星的含量。用PH4.4的HAc-NaAc缓冲溶液溶解药样,并与过量的四苯硼钠作用生成沉淀。过滤后,用硫酸亚铊回滴过量的Na-TPB,由示波极谱图[dE/dt=f(E)]上TPB切口的消失指示滴定络点,进而在该溶液中进行空白实验。  相似文献   

5.
电位滴定法快速测定磷肥中的水溶性磷   总被引:2,自引:0,他引:2  
建立了电位滴定法快速测定磷肥中水溶性磷含量的方法。用蒸饮水溶解磷肥中的水溶性磷,通过硝酸钡和阳离子交换树脂除去干扰离子,用六次甲基四胺-硝酸缓冲溶液制试液的酸度(pH=5.4),在乙醇体系中,用一定浓度的硝酸铅标准溶液进行电位滴定,用二阶微分法确定硝酸铅标准溶液的滴定终点体积。方法的RSD为0.66%-0.97%,回收率为100.00%-100.10%。  相似文献   

6.
引入晶粒边界修正,改进了Mo2C膜表面粗糙化物理模型,将DT2模型推广到包括有温度的情况,对Mo2C膜表面形态进行计算机模拟并统计模拟图的高度分布,确定表面粗糙度随沉积时间和基底温度的变化规律。结果表明:引入晶粒边界修正大大促进了理论与实验结果的一致,Mo2C膜表面粗糙化属快速粗造化,粗造度随基底温度升高而非线性地增大。  相似文献   

7.
YCF-1 Mobile irradiator is designed by BINE of China. It has been put into running in YanJi city of Jilin province. It is able to be moved to border and distance places and area lumped and spreading out of agricultural products to service. It can play a important role in demonstration and extending irradiation technology in food irradiation, disinfestation, sterilization and quarantine, etc. This paper describes the features and design considerations of mobile irradiator.This irradiator adopted Cesium-137 source. The design capacity of loading source is 9.25PBq (250kCi), A half-time of Cs- 137 is 30.2 years long, exchanging source is not needed utilization rate of energy is higher, and the shielding is thinner, The Weight is lighter, The dose rate on the surface of it is 0.0025mSv/h in accordance with national standard. The internal size of irradiation room is 1800×1800×900mm (L×W×H), The sheilding of irradiation room is a steel shell filled with lead. The thickness of lead is 18cm. The irradiator is installed on a special flat truck. The size of the truck is 7000×3400×4200mm (L×W×H). The weight of irradiator is more than 80 150kw. The main components and parts of irradiator are: source, source racks and hoist, irradiation chamber, storage source chamber, the product's transport system, dose monitoring system, ventilation system and safety interlock system, etc.  相似文献   

8.
A fluoroimmunoassay method using unlabeled Terbium chelate isdescribed.The principle is similar to that of fluoroimmunoassay method usinglanthanide chelate as labels.The procedure is simpte because labeling processis unnecessary.The recovery of HSA and albumin in urine is 107% and95% respectively.The standard deviation is tess than 10%.  相似文献   

9.
程春生  秦福涛  魏振云  任忠宝  明旭 《化学学报》2012,70(10):1227-1231
氟吗啉是一种新型杀菌剂, 合成工艺热危险性和动力学研究将解决工程问题, 并保障安全生产. 采用差示扫描量热-热重分析仪(DSC-TG)测试主要原料、中间体和产品的热稳定性, 采用反应量热仪(RC1)研究反应热行为, 同时开展反应动力学研究. 研究结果显示, 主要中间体(3,4-二甲氧基苯基)(4-氟苯基)甲酮吸热分解温度为559.3 K, 乙酰吗啉吸热分解温度为478.2 K, 氟吗啉吸热分解温度为638.6 K. 氟吗啉合成反应摩尔放热量为15.44 kJ/mol, 绝热温升ΔTad为9.1 K, 本研究合成工艺的热危险性较小. 氟吗啉合成反应动力学方程为:rA=kcAa=8.34×10-3CA0.57, 对主要中间体(3,4-二甲氧基苯基)(4-氟苯基)甲酮的反应级数为0.57 级.  相似文献   

10.
《Analytica chimica acta》1987,203(1):43-54
The method of moments is described for deconvolution of a mixture of identical distributions; it is not necessary to know the type of the individual peak distribution. The algorithm for computing the positions and contributions of the peaks forming the multiplet is presented. The real shape of the peak is used. The computational stability of the method of moments for the deconvolution of various types of convolved triple peaks is shown to be satisfactory. The algorithm is used for deconvolution of some double peaks obtained in neutron activation analysis of rock standards. The program is fast and suitable for microcomputers.  相似文献   

11.
通过采访植物甾醇女士,了解植物甾醇家族的成员、基本性质、生理功能等。揭示了其降低胆固醇、减肥、美容功能的基本原理,了解了抗癌机理,介绍了植物甾醇在食物中的分布、人体吸收困难的原因及对策,为人类健康生活提出膳食建议。  相似文献   

12.
原子吸收光谱法间接测定萤石中的全硫   总被引:1,自引:0,他引:1  
基于SO42-和BaCrO4溶液反应生成BaSO4沉淀, 置换出定量的CrO42-, 通过原子吸收法测定Cr, 建立了间接测定萤石中硫的原子吸收光谱法. 方法的工作曲线范围0.05~20 μg/mL SO42-, 检出限为0.017 μg/mL S, 适用于硫质量分数在0.01%~3%范围内萤石样品的测定.  相似文献   

13.
We present a new method of measuring the electrophoretic mobility of a particle in a concentrated suspension. The method is used to measure the electrophoretic mobility of PMMA particles (diameter 10 microm) suspended in a mixture of liquid hydrocarbons. The particle volume fraction of the suspension is varied from 0 up to 0.30 and the resulting variation of the electrophoretic mobility is discussed. The suspending liquid is such that its refractive index is very close to that of the particles. Thus the suspension is almost transparent and it is possible to follow through a microscope the motion of one particle. The suspension is subjected to a low-frequency electric field (0.5 Hz). The cell containing the suspension is mounted on a piezoelectric crystal. The displacement that compensates for the particle motion (when the particle image is steady) is determined.  相似文献   

14.
The shape of expanded graphite is a netted and hollow structure.It is very easy to adsorb molecules and adsorption power is better. The research has proved:the expanded graphite had its ability to adsorb weigh oil etc. The capacity of adsorptive materials has been expressed by the iodimetric adsorption value, but the iodimetric adsorptive value of expanded graphite has not been reported until so far.The paper measures the iodimetric adsorption value by the iodimetry, and the apparatus is used easily and simply. The operation is not more difficult and the accuracy is higher, and the reagent is usual.  相似文献   

15.
膨润土负载壳聚糖制备吸附剂   总被引:12,自引:1,他引:12  
马勇  王恩德  邵红 《应用化学》2004,21(6):597-0
将壳聚糖与膨润土混合制得一种吸附剂。将其用于染料溶液的脱色、陈醋的澄清、中药注射液中鞣酸的清除等,脱色率为97%,鞣酸脱除率为50%,陈醋的透光率为25.8%。通过X射线衍射图讨论了膨润土的改性机理。改性后膨润土的片状层结构未发生变化,壳聚糖仅仅吸附在膨润土的内外表面。  相似文献   

16.
Image-analyzing interferometry is used to measure the apparent contact angle and the curvature of a drop and a meniscus during condensation and evaporation processes in a constrained vapor bubble (CVB) cell. The apparent contact angle is found to be a function of the interfacial mass flux. The interfacial velocity for the drop during condensation and evaporation is a function of the apparent contact angle and the rate of change of radius of curvature. The dependence of velocity on the apparent contact angle is consistent with Tanner's scaling equation. The results support the hypothesis that evaporation/condensation is an important factor in contact line motion. The main purpose of this article is to present the experimental technique and the data. The equilibrium contact angle for the drop is found experimentally to be higher than that for the corner meniscus. The contact angle is a function of the stress field in the fluid. The equilibrium contact angle is related to the thickness of the thin adsorbed film in the microscopic region and depends on the characteristics of the microscopic region. The excess interfacial free energy and temperature jump were used to calculate the equilibrium thickness of the thin adsorbed film in the microscopic region.  相似文献   

17.
The construction of the detector is described and its performance is assessed for 1,4-benzoquinone by flow-injection analysis. The detection limit is 0.5 ng and the relative standard deviation of the peak current is 0.4% for a 102-ng sample. The peak current is highly sensitive to temperature changes of the mercury electrode system. The relative temperature coefficient is 15% K-1, whereas the corresponding value with respect to the mobile phase is 0.6% K-1. The dependence of the peak current on the volume flow rate is described and explained by appropriate models.  相似文献   

18.
在聚氨酯生产中,环氧丙烷中醛类物质含量直接影响聚醚质量,需要严格检查、控制。醛类物质的测定,目前国内外一般采用色谱法或比色法。也有用Hg~(2+)盐安培滴定法测定芳香醛。用2,4-二硝基苯肼直流极谱法测定醛,用原子吸收法测定低分子量醛和酮。我们根据间苯二酚与丙醛在果糖和浓盐酸作用下生成红色醌式产物的特性,较详细地研究了间苯二酚光度法测定环氧丙烷中微量丙醛的最佳条件和干扰因素。结果表明,本法灵敏度高、稳定性好,应用范围广。  相似文献   

19.
Safavi A  Haghighi B 《Talanta》1997,44(6):1009-1016
A flow injection gas-phase molecular absorption spectrophotometric method is described for the determination of sulphite in aqueous solution. The sulphite solution, 200 microl, is introduced into a stream of distilled water. The carrier stream containing a sulphite zone is reacted, in the first mixing coil, with a stream of sulphuric acid (1 M). The evolved sulphur dioxide is purged to the segments of nitrogen flow through the second mixing coil. The gaseous phase is separated from the liquid stream by the use of a purpose built gas-liquid separator and then is swept into a purpose built flow-through cell. The absorbance of the gaseous phase is measured at 200 nm using a UV/VIS spectrophotometer. Up to 440 microg of sulphite is determined. The limit of detection is 0.8 microg and the R.D.S. for the determination of 70 and 220 microg of sulphite are 1.02 and 0.76%, respectively. Up to 40 samples h(-1) can be analyzed. The effect of several anions and cations on the determination of sulphite was studied and the results showed that the method is relatively free from interferences. The proposed method was applied to the determination of sulphite in a synthetic sample, water sample and lemon juice.  相似文献   

20.
冶金炉料中二氧化硅和碳化硅的联合测定   总被引:1,自引:0,他引:1  
提出冶金炉料中二氧化硅及碳化硅的联合测定方法,硝酸-氢氟酸-盐酸溶解二氧化硅,用硅氟酸钾容量法测定,残渣经焦硫酸钾溶解杂质,不溶碳化硅以重量法测定,经试样全分析及精密度考证,方法简便、可靠.  相似文献   

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