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1.
报导在尿素存在下通过均相沉淀法由硝酸铜和重铬酸铵制备复合均匀胶体粒子的结果.研究了一些实验参数对其组成、形态和粒子大小的影响.确定了胶体粒子的制备条件.结果观测到,由硝酸铜和重铬酸铵溶液形成了球形的多刺的粒子,它的组成为水含铅酸铜.  相似文献   

2.
粉末多孔镍电极电化学阻抗谱及其数学模型   总被引:4,自引:0,他引:4  
镍电极反应动力学在大多情况下是受固态质子扩散过程控制的,以此为出发点建立了具有明确物理意义的镍电极电化学阻抗谱(EIS)的数学模型.并以该模型为基础,讨论了一些模型参数如双电层电容C(d1)、质子扩散系数D及活性物质位于半径γ0等的改变,电极的不同行电状态以及多孔镍电极中的传质过程对镍电极阻抗谱的影响.理论模型较好地解释了一些实验结果.  相似文献   

3.
报道了深圳南山区712名0~6岁儿童头发中铁的平均值为31.36×10-6.男童缺铁106例,占29.2%:女童缺铁171例.占50%。临床上表刚,有大部分几童存在缺铁性贫血但也有一些为非缺铁性贫血。女童缺铁明显高于男童.有显著性意义:发铁指标可用作诊断由缺铁而引起的一些疾病。  相似文献   

4.
报道了一种磺苄青霉素药物电极,以十六烷基三辛基碘化铵为载体,用邻苯二甲酸二壬酯为增塑剂,运用序贯淘汰水平法对膜组成进行了优化;确定了电极最佳膜组成,讨论了一些因素对电极性能的影响。电极响应快速,选择性、稳定性、重现性均较好。电极检测下限可达1.66×10^-6mol/L,线性范围为6.03×10^-6~1.0×10^-1mol/L,斜率为28.0mV/pC,回收率为96.1%~100.4%。可用…  相似文献   

5.
烷氧桥相连的四苯基双金属卟啉配合物的红外光谱研究   总被引:1,自引:1,他引:1  
研究了烷氧桥相连的四苯基双卟啉及其Mn(Ⅱ),Fe(Ⅲ),Co(Ⅱ)配合物的红外光谱(3600~150cm^-1),对一些主要吸收谱带进行了经验归属,金属敏感谱带出现1558.2(以H2P-H2P为例)、1477.2,1401.9,1350.5,1001.7,965.9,877.3和798.8cm^-1附近,金属和烷氧桥都敏感的谱带出现在1595.1(以H2P为例)、1491.1,851.1和72  相似文献   

6.
Cu以其优异的导电性、导热性和易加工性广泛用于工农业生产中.自然Cu的腐蚀和防腐成为人们很关注的问题.人们已经注意到,Cl-对Cu的腐蚀有影响,并进行过一些研究.但目前使用光电化学方法研究这一问题的文章尚不多见,特别是利用测量开路光电压及其瞬态波形这一现场的、无损的、灵敏的监测方法研究户对Cu电极腐蚀全过程的文章尚未见到.本文正是利用如上方法及XPS,AES方法,研究了Cl-对Cu电极腐蚀的全过程,取得了一些有意义的结果.1实验方法Cu电极用99.99%(质量分数)的Cu制成,面积约为39mm2;电极底部由Cu导线焊接引出,…  相似文献   

7.
中药中微量元素的存在状态与生物活性关系的研究   总被引:12,自引:0,他引:12  
本题实质上是中药有效化学成分(ECC)的研究.得出了下列一些研究结果,1.提出了中药TE和中药ECC的研究思路即以中药中TE的存在状态为核心,以中药中TE和有机成分(OC)的相互作用为基础来开展中药TE和中药ECC的研究工作.2.根据中医药理论,运用系统论的原则和方法论以及贝塔朗菲定律.以大量实验结果为基础.提出了“中药有效化学成分的配位化学学说”。其核心是:(1)中药中的有效化学成分可以是OC,也可能是TE;(2)中药中的ECC更有可能是二者的配合反应所形成的配合物.3.在中药中OC和TE的相互配合反应中.即改变了TE的存在在状态后.发现了生物活性和药理作用变化的规律性:(1)有的配合物具有原来二种成分的生物活性;(2)有的配合物则可提高某一成分的生物活性或降低其毒副作用;(3)有的配合物测产生二者所不具备的新的生物活性;(4)TE的生物利用度均有所提高.4.从实验中发现了一些有较好生物活性和药理作用的配合物.为新型配合物中药新药的研制提出了一个新思路.新方向.新方法.5.采用了配位化学的理论和研究方法,把pH电位法和计算机平衡模拟技术相结合,为中药ECC和中药TE的研究工作提供了新的方法.  相似文献   

8.
小儿厌食是常见病,异食癖也时有发生,一般补锌后会有好转,但还有相当一些患儿补锌后症状无改善.本组15例补锌后厌食、异食癖无改善的患儿在治疗前均测发硒,其平均值为0.18×10-6.治疗后,疗效明显改善,复查发硒,均值已接近正常.  相似文献   

9.
含微量元素的中药对老年病的治疗   总被引:16,自引:0,他引:16  
微量元素摄取过多或不足,会引发老年病.中药含有微量元素,根据不同药物含的微量元素不同.来治疗因微量元素缺乏发生的老年病有一定价值.本文综合报道了一些老年病治疗.  相似文献   

10.
描述非绝热电子转移的半经典模型,揭示了对称双势阱非绝热电子转移的过渡态能垒与Arrhenius活化能关系的一些新特征。在4-31G加负离子sp弥散函数水平上优化了共线反应的反应物、络合物和过渡态的构型,成功地进行了电子定域UHF诱导自洽场计算,获得电子转移矩阵元VAB为7.OkJ/mol,活化能垒Ec为28.4kJ/mol,300K时反应速率常数k为9.2×108/s,讨论了理论模型及计算结果。  相似文献   

11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.  相似文献   

12.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

13.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

14.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.  相似文献   

15.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

16.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

17.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

18.
A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.  相似文献   

19.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

20.
A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.  相似文献   

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