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1.
用原子吸收光谱法测定延边地区317名65~108岁老人头发中锌、铜、铁、锰、镁含量,观察不同民族、性别、年龄老人这些元素的差异。结果表明:1.朝鲜旗发锌低于汉族,满族发铜低于汉族、朝鲜族,汉族发镁高于朝鲜族、满族,发铁、发锰在汉、朝、满民族之间无区别。2.汉族、朝鲜族男发锌高于女性,汉族女性发铜高于男性,发铁、发锰、发镁在性别之间无区别。3、90岁组朝鲜族发锰、发镁低于65岁、76岁组,朝鲜族发锌、发铜、发铁在65~108岁之间无统计学意义。  相似文献   

2.
本文测定了依尔福染料黑白片XP1 400在XPI套药中冲洗的染料影像及中间银影像的均方根粒度,同时又测定了在同样曝光条件下的涂层在普通黑白显影液中冲洗的黑白银影像的均方根粒度。结果表明,三种影像粒度随密度变化的规律完全不同。本文又用selwyn公式计算了中间银影像及黑白银影像的单位面积显出颗粒数,测试和计算结果表明,与黑白银影像比较,中间银影像具有均方根粒度明显低和单位面积显出颗粒数高的特点。这与光学显微镜下现察到的中间银影像及黑白银影像的形态是一致的。本文还根据实验及计算结果讨论了DIR成色剂在影像形成过程中的作用。  相似文献   

3.
4.
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   

5.
The addition of 2-amino-1,3,4-thiadiazole derivatives with parallel iodination of differently protected glycals has been achieved using a double molar excess of molecular iodine under mild conditions. The corresponding thiadiazole derivatives of N-glycosides were obtained in good yields and anomeric selectivity. The usage of iodine as a catalyst makes this method easy, inexpensive, and successfully useable in reactions with sugars. Thiadiazole derivatives were tested in a panel of three tumor cell lines, MCF-7, HCT116, and HeLa. These compounds initiated biological response in investigated tumor models in a different rate. The MCF-7 is resistant to the tested compounds, and the cytometry assay indicated low increase in cell numbers in the sub- G1 phase. The most sensitive are HCT-116 and HeLa cells. The thiadiazole derivatives have a pro-apoptotic effect on HCT-116 cells. In the case of the HeLa cells, an increase in the number of cells in the sub-G1- phase and the induction of apoptosis was observed.  相似文献   

6.
S.V. Awate  K. Suzuki 《Adsorption》2001,7(4):319-326
Titania pillared montmorillonite clay was prepared by two different routes viz. 1) conventional ion exchange method and 2) modified method wherein the post hydrothermal treatment after ion-exchange was employed. The influence of the post hydrothermal treatment on the textural properties of titania-pillared clays was studied. The calcined clay was characterized by different physico-chemical techniques such as XRD, EDX, low temperature (77 K) nitrogen adsorption and UV-Vis diffuse reflectance spectroscopy. The content of pillared titania remained unchanged irrespective of the method of preparation. The method of preparation and severity of the conditions employed for the hydrothermal treatment resulted in alteration of the crystallinity and crystallite size of the anatase. The changes in the average pore diameter was found to comensurate with the changes in crystallite size of anatase phase. The increase in total pore volume as a function of the severity of the post hydrothermal treatment resulted in the decrease in micropore volume. The severity of the post hydrothermal treatment governed the extent of the blue shift in UV-Vis DRS spectra.The behaviour of titania pillared clays in adsorptive capacity and in photo-catalytic oxidation of methylene blue and victoria pure blue in aqueous medium was studied as a function of their physico-chemical characteristics. The titania pillared clays prepared by post hydrothermal route has shown enhanced adsorption capacity and photo-catalytic oxidation.  相似文献   

7.
薛慧峰  叶荣  刘满仓  胡之德 《分析化学》2004,32(8):1031-1034
提出了一种用毛细管气相色谱分析工业丙烯腈中微量噁唑及其它杂质的方法。用气相色谱.质谱法对丙烯腈中的噁唑及其它杂质进行了定性,并用化学法验证了噁唑的定性结果。采用有效碳数法计算出噁唑的质量相对校正因子为2.396,内标法测定了国内不同公司生产的丙烯腈中微量杂质的含量。其中噁唑的质量含量为0.001%-0.06%。方法已在某石化公司丙烯腈装置技术改造中应用于噁唑含量的控制分析。  相似文献   

8.
新疆高钠煤中钠的赋存形态及其对燃烧过程的影响   总被引:10,自引:0,他引:10  
采用不同萃取液对中国新疆高钠煤进行逐级萃取实验,利用离子色谱仪和电感耦合等离子体原子发射光谱仪对萃取制得的滤液和固体煤样进行相应的元素分析,并通过逐级萃取后煤样的着火温度、燃尽温度和综合燃烧特性指数来分析高钠煤中不同存在形式钠对其燃烧特性的影响.结果表明,中国新疆高钠煤中的钠主要以水溶钠为主,有机钠和不可溶钠含量较少.影响高钠煤中水溶钠含量的主要因素有煤颗粒内部孔隙结构和颗粒粒径,且高钠煤中有机钠在各个粒径范围都保持了相对稳定的含量.煤种不同会导致煤中水溶钠与水溶氯的存在形式不同.煤中水溶钠的存在不利于高钠煤的着火温度和燃尽温度的降低与燃烧特性的提高,相反煤中的有机钠却对其具有促进作用.  相似文献   

9.
The measurement uncertainty in the calculation of the amount of blocked and reactive lysine (as determined by the furosine method) was evaluated according to the procedure described in the Eurachem/CITAC guide. The analytical method involves the chromatographic determination of lysine and furosine after acid hydrolysis. The calculation of blocked and reactive lysine in the initial protein is based on known conversion factors. The estimation of the uncertainty was performed in two steps: (1) determination of the uncertainty in the chromatographic determination of lysine and furosine, and (2) determination of the uncertainty in the calculation of blocked and reactive lysine. The individual contributions to the final uncertainty were identified, quantified, and combined in uncertainty budgets. The largest contribution to the calculation of blocked lysine came from estimating the conversion factor of blocked lysine into furosine during acid hydrolysis. For the calculation of reactive lysine, the main contribution came from the chromatographic determination of lysine. The uncertainty estimates were compared to available validation data (in-house and collaborative standard deviations of reproducibility).  相似文献   

10.
 在无溶剂及二(2-乙基己基)丁二酸酯磺酸钠(AOT)/异辛烷/磷酸盐缓冲液微乳液体系中,研究了黑曲霉脂肪酶催化红花油水解反应的动力学. 结果表明,无溶剂及微乳液体系中反应的活化能分别为32.205和7.391 kJ/mol. 酶在无溶剂体系中的热稳定性高于微乳液中. 无溶剂及微乳液体系中的表观米氏常数分别为0.135和0.101 mol/L. 在两种体系中,乙醇对水解反应的抑制作用均为竞争性可逆抑制,且均在底物浓度大于0.819 mol/L时出现底物抑制现象. 结合胶团催化理论和酯键水解机理对两种体系中酶水解性能的差异进行了解释.  相似文献   

11.
高效液相色谱法测定山药样品中尿囊素的含量   总被引:10,自引:1,他引:10  
用薄层扫描方法确定了山药中尿囊素的提取条件;用高效液相色谱方法测定了山药中尿囊素的含量,考察了不同产地山药样品中尿囊素含量的差异.该法平均回收率为96.8%,相对标准偏差为4.0%.生长环境、气候等外界条件对山药中尿囊素含量有明显的影响,不同产地山药中尿囊素含量有明显差异.此高效液相色谱法用于山药中尿囊素的含量测定,灵敏度高,重现性好,可供山药质量标准研究参考使用.  相似文献   

12.
The formation of reversed micellar systems composed of phosphatidylcholine (PC) and fatty acid was newly demonstrated by a significant increase in water content in the organic ethyl oleate phase when the micelles were prepared by the contact method. The solubilized water concentration in the reversed micellar organic phase reached 3 wt%. The new systems are expected to be used as highly biocompatible reversed micellar systems. The structure of the reversed micelles composed of PC and oleic acid was characterized by determining the water concentration and by small-angle X-ray scattering analysis. The reversed micelles composed of PC and oleic acid formed in ethyl oleate were spherical. The radius of gyration was between 30 and 50 Å. The size of the reversed micelles decreased with an increase in the oleic acid concentration and was independent of the PC concentration. Experimental results indicated that the structure of the reversed micellar system was determined by the oleic acid concentration. An increase in the PC concentration caused an increase in the number of reversed micelles of the same size. These reversed micellar systems are expected to be used as solubilization media in pharmaceutical and food industries because they are not toxic.  相似文献   

13.
李好丽  赵春霞  张俊杰  傅佳骏  王瑛  路鑫  许国旺 《色谱》2013,31(12):1182-1188
为了分析烤烟中游离氨基酸含量与烤烟香型、产地的关系,以国内14个烟草种植省份的138个调制后的烤烟中部叶片为材料,采用柱前衍生-超高效液相色谱-单重四极杆质谱法对烤烟中的20种游离氨基酸进行分析。方法表征结果显示该方法满足分析要求,适合烤烟中游离氨基酸的检测。对调制后烤烟中部叶片的游离氨基酸分析结果显示,烤烟的游离氨基酸含量在产地间差异很大(28.50%~94.20%),其中天冬酰胺、谷氨酰胺含量的相对标准偏差(RSD)超过80%;在3种典型香型(浓香型、清香型和中间香型)烤烟中,浓香型烤烟游离氨基酸含量的RSD大于其他两种香型。对同一香型的不同种植省份和同一省份不同香型的烤烟游离氨基酸分析结果显示,其含量呈现一定的规律。  相似文献   

14.
头发微量元素及钙含量测定的应用价值评价   总被引:5,自引:1,他引:5  
以125例2~5岁儿童为对象,测定其全血和头发铅、锌、铁、钙含量;以全血铅、锌、铁、钙含量为标准,应用诊断试验评价方法评价头发铅、锌、铁、钙测定的应用价值。结果表明,头发铅测定的灵敏度可达88.3%,应用串联试验,头发铅测定的特异度可提高至81.8%,阳性预测值达69.6%,阴性预测值达78.8%。头发锌测定的灵敏度可达86.1%,特异度为52.4%,阳性预测值75.6%,阴性预测值为68.8%。头发铁测定的灵敏度为72.0%,特异度为77.5%,阳性预测值为83.6%,阴性预测值为63.3%,头发钙测定的灵敏度为78.9%,特异度为69.1%,阳性预测值为69.8%,阴性预测值为78.4%。锌缺乏、铁缺乏、钙缺乏,或铅负荷过高,或数种微量元素缺乏及铅中毒并存是当前严重影响儿童健康成长的常见原因。运用现代检测技术早期发现微量元素缺乏及铅中毒患儿并及时采取防治措施对促进儿童正常生长发育至关重要。头发样品容易采集、运送和保存,因此头发微量元素含量测定适合在中小城镇及农村使用。但其应用价值应进行科学评价。  相似文献   

15.
红花水溶性多糖CTP的结构研究   总被引:4,自引:0,他引:4  
微囊藻毒素(Microcystins,MCs)是由淡水蓝绿藻产生的一类最常见的环七肽缩氨酸肝毒素,它们通过抑制蛋白质磷酸酶的活性产生强烈的促肝癌作用,对人和其它生物产生较大威胁,人类长期饮用微量含有MCs的水,将导致原发性肝癌(PLA),常见的MCs如MCLR,MCYR和MCRR的LD50值通常为50,70和600μg/kg(mouse,i.P.)。  相似文献   

16.
Simultaneous anodic oxidation and cathodic reduction of aldoses in a divided flow cell were studied. The stream of the anolyte was an aqueous solution containing D-glucose, sodium bromide, and sodium bicarbonate. The stream of the catholyte was also an aqueous solution containing xylose and sodium sulfite. The factors which affected both the anodic and cathodic reactions were studied. The results indicate that the flow rates and temperatures of the anolyte and the catholyte, concentrations of the aldoses, pH values and the material of electrodes significantly affect both anodic and cathodic yields. The selectivities of gluconic acid in the anode and xylitol in the cathode were very high. The power consumption of paired electrolysis in the flow system was less than paired electrolysis in a batch system.  相似文献   

17.
The kinetics of the hydrolysis of fenuron by hydrochloric acid in aqueous methanol solution was studied spectrophotometrically. The influence of cationic micelles of cetyltrimethylammonium bromide and anionic micelles of sodium lauryl sulfate on the rate of hydrolysis of fenuron have also been studied. The anionic micelles increased the rate of reaction, while the cationic micelles decreased the rate of hydrolysis. The reaction followed first-order kinetics in [fenuron]. The rate of reaction was increased with increase in [HCl] in lower range, but become constant at higher concentration in aqueous and micellar pseudophases. The reaction starts with the protonation of amino group of fenuron followed by rate-determining attack of water. The results in micellar media are accounted for on the basis of distribution of substrate into micellar and aqueous pseudophases.  相似文献   

18.
The reduction of 4-nitrophenol catalyzed by nitroreductase in the presence of NADH was investigated in this paper.4-Amino- phenol and 4-bydroxylamino-phenol were found in the reductive products.The relationship between reaction time and the reductive ratio were studied.The similar reducing ratios of 4-nitrophenol were obtained under aerobic and anaerobic conditions.The results indicated that an oxygen-insensitive reaction was proceeded in the reduction of 4-nitrophenol and nitroreductase was an oxygen- insensitive enzyme.The reductive products of 4-nitrophenol were determined by HPLC and MS.  相似文献   

19.
杨科大 《高分子科学》2015,33(11):1562-1573
The morphological, dynamic and rheological characteristics in the viscoelastic phase separation(VPS) of sheared polymer solutions are investigated by three-dimensional(3D) numerical simulations of viscoelastic model. The simulations are accelerated by graphic process unit(GPU) to break through the limitation of computation power. Firstly, the morphological and dynamic characteristics of VPS under shear are presented by comparing with those in classic phase separation(CPS). The results show that the phase inversion and phase shrink take place in VPS under shear. Then, the roles of bulk and shear relaxation moduli in VPS are investigated in details. The bulk relaxation modulus slows down the phase separation process under shear, but not affects the dynamic path of VPS. The dynamic path can be divided into three stages: freezing stage, growth stage and stable stage. The second overshoot phenomenon in the shear stress is observed, and explained by the breakdown and reform of string structures. The shear modulus affects morphology evolution in the late stage of VPS under shear.  相似文献   

20.
以乙酰磺酸为磺化剂制备磺化度为3~15mol%的磺化聚苯乙烯(SPS)并中和成盐.在一定的温度和搅拌速率下,加水将SPS乳化成水包油的稳定水基微乳液.用乳化过程中体系电导率和粘度的变化表征了乳化相反转过程.研究了溶剂的极性和离子含量对聚苯乙烯离聚体溶液可乳化性和乳化过程及乳液稳定性的影响.  相似文献   

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