电感耦合等离子体原子发射光谱法测定镍基单晶高温合金中Mo、W、Ta、Re、Ru时元素之间相互干扰的消除与校正的研究

称取镍基单晶高温合金0.100 0g于聚四氟乙烯烧杯中,先令其与盐酸9mL和硝酸1mL加热反应,待反应缓慢时滴加氢氟酸2mL并继续加热使样品完全溶解。加入500g·L^-1酒石酸溶液2mL,冷却至室温,在塑料容量瓶中加水定容至100.0mL。按仪器工作条件采用电感耦合等离子体原子发射光谱法测定其中5种合金元素(Mo、W、Ta、Re、Ru)的含量,选择分析谱线依次为204.598,207.911,240.063,197.312,240.272nm。结果发现:除了Re外,其余4种元素的测定中均受共存元素的光谱干扰,严重影响了测定结果的准确性。为克服其干扰,除了采用基体匹配法消除镍的基体干扰外,试验采用混合校正系数矩阵法对测定结果进行校准。通过一系列试验计算得到混合校准系数矩阵K,并应用于模拟样品的分析。结果表明:经过矩阵K的校准,所测定的5种元素的准确度显著提高,达到了消除共存元素之间光谱干扰的目的。通过精密度试验,测得上述5种元素测定值的相对标准偏差(n=11)均在1.5%以下,并通过标准加入法进行回收试验,测得5种元素的回收率为97.0%~105%。     

五氯化磷辅助下氨基酸的自组装成肽反应研究

L-α-氨基酸和D-α-氨基酸可与五氯化磷直接发生磷酰化反应，随后自组装成多肽，但β-氨基酸不能成肽，DL-α-氨基酸成肽困难；在SOCl2存在下，α-氨基酸也不能成肽，用电喷雾质谱研究了氨基酸的自组装反应，反应过程中有五元环状的氨基酸五配位磷中间体生成，使用硅烷基保护的氨基酸，在^31PNMR中可观察到五配位磷中间体。     

One-step Beckmann Rearrangement from Ketones and Hydroxylamine in Dry Media under Microwave Irradiation

TheBeckInannrearrangement,theacid-mediatedisomerizationofoximestoamides,wasfirstdiscoveredinl886l.Asoneoftheoldestandmostfamiliartransformationsinorganicchemistry,ithasbeenwidelystudiedandagreatvarietyofmethodstoconductthistfansformationhavebeenreported'.However,mostofthesemethodswerecarriedoutbyusingalargeamountofsolventswithlongreactiontime.Whatismore,thepriorpreparationofthecorrespondingketoximesisusuallyrequired,whichmakestheseprocessesinconvenientandlessattractive.Bytakingadvantageofboth…     

STUDIES ON THE MECHANISM OF VINYL PHOTOPOLYMERIZATION INITIATED BY CONDENSED AROMATIC HYDROCARBON-ANILINE SYSTEMS

Initiation mechanism of the photopolymerization of acrylonitrile and methyl methacrylate, usingbinary condensed aromatic hydrocarbon (CAH)-aniline systems as initiator, was studied. The strongerthe electron-donating ability of the aniline derivatives, the faster the the of photopolymerizationwill be. The radical intermediates produced by photoreaction between anthracene and anilinewere detected with ESR spectra. The initiation scheme involves the formation of exciplex betweenthe excited singlet state of CAH and the ground state of aniline as the first step, and then followedby proton transfer, leading to the generation of two kinds of radicals. From the end-group analysisof the polymers obtained, it is suggested that both kinds of radicals are involved in the initiation.     

Synthesis of Clarithromycin Using Protective Technique of Total Silylation

Clarithromycin, 6- O-methylerythromycin A (CAM), is a semisynthetic macrolide antibiotic of 6 which exhibits strong antibacterial activity toward a wide range of bacteria inclusive of gram positive bacteria, some gram negative bacteria, anaerobic bacteria, Mycoplasma, Chlamidia and Helicobacter pylori, and because of its high stability in the acidic environment of the stomach, it can be orally administered to treat respiratory organ diseases, and also to prevent recurrence of ulcer when used in a combination with other medicines.     

Synthesis of 4(3H)-Quinazolinone Derivatives and Their in vitro Antitumor Activity

Classical antifolates containing L-glutamic acid moiety in molecule have shortcomings such as drug resistance which is originated from the defective cell transport by mutation, and toxicity to the host which is due to unnecessarily long retention inside normal cells.[1] One strategy to overcome these shortcomings is to design nonclassical lipophilic inhibitors of folate requiring enzymes by deleting or modifying L-glutamic acid component from the folate analogues.     

钠硼解石——水体系溶解和相平衡的研究(英)

Ulexite dissolution in water has been studied in the wide temperature range from 10℃ to 93℃ and two higher temperatures at 120 ℃ and 240 ℃. The analytical results showed that ulexite dissolved congruently from 10 ℃ to 35 ℃ and incongruently from 40 to 68 ℃. The solid component of ulexite, NaCaB₅O₆(OH)₆·5H₂O was dehydrated to form NaCaB₅O₆(OH)₆·H₂O from 50 to 68 ℃ and finally amorphous solid at 68 ℃. This amorphous solid converted into priceite at 71 ℃ and then converted completely to priceite at the boiling point(93℃) of the solution. At both 120 and 240 ℃, the dissolution of ulexite was an incongruent process. Above 120 ℃, ulexite became amorphous solid and then transformed into priceite. In addition to the solid to solid transformation, crystallization of priceite from the solution has also been observed. Based on our experimental results, mechanisms of dissolution, transformation, and crystallization of borate in ulexite-water system are discussed.     

Study on EPR Spectra of Three Gadolinium Complexes With Noncyclic Polyether Schiff Bases

The EPR spectra of three new gadolinium complexes with noncyclic polyether Schiff bases in powder and those of these complexes in organic solvents were investigated at different temperatures. It was observed that EPR spectra of nine and four peaks of Gd(Ⅲ) complexes in polycrystalline powder and freezing samples appeared at low temperature respectively for the first time. The interpretations of these results obtained on the basis of spin Hamiltonian of s = 7/2 system are satisfactory. The correlations of EPR feature between crystal-field strength in complexes and local symmetry around Gd3+ ions were revealed. The crystal-field parameters b20 and the asymmetry parameters λ' of complexes were estimated. A series of interesting regularity and new results were obtained.     

聚合物复合材料填充剂的表面性质及其分散性的研究

本文通过反气相色谱技术研究了未处理的、硅烷偶联剂处理的和钛酸酯偶联剂处理的三种Al(OH)_3粉末的表面性质,并通过塑化仪和扫描电子显微镜研究了Al(OH)_3填充聚丙烯体系的流变行为及其在聚丙烯中的分散效果.结果表明Al(OH)_3的表面性质对其在聚丙烯介质中的分散效果有着重要的影响.     

异亚硝基乙酰乙酸乙酯亚胺Pd(Ⅱ)配合物的合成、表征和tran Pd(p-CH3C6H4-IEAI)2的晶体结构

Six palladium(Ⅱ) complexes with isonitrosoethylacetoacetate imine Schiff base ligands, Pd(R-IEAI)₂, were prepared and characterized by IR, Raman and electronic spectra. Complex tran Pd(p-CH₃C₆H₄-IEAI)₂ (2) cry- stallizes in the monoclinic system, space group P2₁/c,with a=1.2002(2),b=0.9972(2),c=1.1121(2)nm,β=90.43(3)°,Z=2,F(000)=616,μ=7.44cm^-1. The final R and wR are 0.0244 and 0.0625 for 2620 ob-served reflections with I≥2σ(I), respectively. The geometry around the Pd(Ⅱ) ions in those complexes has a distorted PdN₄ square plane, the Schiff base ligands R-IEAI^- being coordinated through their oximino-nitrogen atoms and imino-nitrogen atoms.