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11.
以三苯胺为单体, 无水三氯化铁为催化剂, 二甲醇缩甲醛为外交联剂, 通过机械球磨不同比例的三苯胺、 三氯化铁和二甲醇缩甲醛, 合成了PAF-106s(PAF-106a~PAF-106c, PAF: porous aromatic framework). 红外光谱、 元素分析、 X射线光电子能谱和固体核磁共振波谱等表征结果证明发生了聚合反应. 氮气吸附结果表明, 三苯胺、 三氯化铁和二甲醇缩甲醛的比例影响PAF-106s的多孔性能. 三氯化铁和三苯胺摩尔比从3∶1增加到12∶1时, PAF-106c的BET比表面积从PAF-106a的135 m2/g增加到280 m2/g. 引入二甲醇缩甲醛后, PAF- 106d~PAF-106g的BET比表面积随三氯化铁和二甲醇缩甲醛摩尔比的增加而逐渐降低. 在273和298 K下, 测试了PAF-106c的C2烃吸附性能, 并采用理想吸附溶液理论计算了C2H2/C2H4和C2H6/C2H4分离比. 相似文献
12.
以热氧化剥离法得到的超薄石墨相氮化碳(g-C3N4)纳米片为载体,首次在室温条件下,制备了系列Ag3PO4量子点/g-C3N4纳米片复合光催化剂;通过透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)、X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、紫外-可见漫反射光谱(UV-Vis DRS)、荧光光谱(PL),对复合光催化剂的形貌、结构和光学性质进行了表征,考察了系列光催化剂对苯甲醇的光催化选择性氧化性能。 结果表明,粒径为3~5 nm Ag3PO4颗粒均匀分散g-C3N4纳米片上,结晶度良好。 以乙腈为溶剂时,当m(Ag3PO4)/m(g-C3N4)=0.6时,苯甲醇具有32.1%的最大转化率,对产物苯甲醛具有90%的最高选择性;活性物种捕捉实验结果表明,该催化氧化反应的主要活性物是光生空穴的氧化作用,能带计算结果表明,该复合催化剂结构具有合适的苯甲醇的氧化电位而选择性生成苯甲醛。 相似文献
13.
Li WS Li Y Hill CM Lum KT Raushel FM 《Journal of the American Chemical Society》2002,124(14):3498-3499
The phosphotriesterase from Pseudomonas diminuta has been shown to selectively cleave the pro-R p-nitrophenolate substituent from bis-p-nitrophenyl alkyl phosphothioate esters. When the alkyl substituent is methyl, ethyl, or isopropyl the enantiomeric excess of the product is >/=99%. Manipulation of the active site through mutagenesis has enabled the preparation of protein variants that preferentially hydrolyze the pro-S substituent of the target substrates. This methodology thus permits the preparation of chiral products from prochiral precursors. 相似文献
14.
I.IntroductionInthestudyofundcrwatcrtargctidcntification,moreandmoreattentionhasbcenpaidtotheinversescatteringprob1cm.Alargekindofobjcctscanbesimplificdintocylinders,spheresore11ipsoidswhilcstudyingtheirscattcringficIds.Thedirectprob1cmhasbeendeve1opedwel1andpcop1caredevotingtothcstudyofthcinvcrscprob1emfortargctidentification.Thedirectprob1emofthescatteringfrome1asticcylindcrsortubcsandtheinverseproblcmofthescat-teringfromsofttubcshavebccninvcstigatcd.['-']Inthispapcr,thedircctandinvcrsepro… 相似文献
15.
A series of novel chiral heterometal tetrahedral clusters have firstly been separated on cellulose tris-(3,5-dimethylphenylcarbamate) stationary phase by high-performance liquid chromatography using n-hexane as the mobile phase containing different alcohols as modifiers. The effects of concentration and structures of alcohols in the mobile phases and structures of chiral heterometal tetrahedral clusters on enantioseparation were investigated. The results showed that the concentration and structures of alcohols had large effects on enantioseparation. It also was found that both the metal in the tetrahedral core and the ligand coordinated to the atom in tetrahedral core had significant effects on their chromatographic behavior. 相似文献
16.
Wang Jia Liu Yuan Deng Xiling Zhao Na Ying Xue Ye Bang-Ce Li Yingchun 《Mikrochimica acta》2017,184(10):3893-3900
Microchimica Acta - The authors describe an electrochemical sensor for ultrasensitive voltammetric of histamine (HA) by using a gold electrode that was modified with a film consisting of... 相似文献
17.
Xuening Fei Yingchun Gu Yunquan Lan Bin Shi Baolian Zhang 《Journal of chemical crystallography》2011,41(8):1232-1236
Abstract
The title compound of Thiazole Orange derivative was synthesized by the reaction of benzothiazolium and 4-methyl quinoline salts, which was determined by 1HNMR and MS. A crystalline hydrate of thiazole orange derivative was obtained when the crystal formed and characterized by single-crystal X-ray diffraction. The crystal belongs to the Triclinic system, and the cell parameters of space group P-1 were a = 10.162(2) ?, b = 10.501(2) ?, c = 11.040(2) ?, α = 92.17(3)o, β = 117.10(3)o, γ = 92.28(3)o, V = 1045.9(4) ?3, Z = 2, Dc = 1.380 mg/m−3, μ = 0.2 mm−1, F(000) = 460, and the final R = 0.0625 and wR = 0.1862 for 3658 observed reflections (I > 2σ(I)). The two aromatic rings linked by the methylene bridged chain are a coplanar structure. 相似文献18.
一个素变数的Diophantine不等式 总被引:3,自引:3,他引:0
设1<C<13/12.本文证明了存在N(C)>0使得对任意实数N>N(C),下面的不等式|++ -N|<N- )logsN有素数解p1,p2,p3,其中s=2(15). 相似文献
19.
光学目标模拟器是光学成像制导仿真系统中的关键设备之一。本文在介绍圆弧导轨式和框架式两种光学目标模拟器机械结构方案的基础上,详细分析了框架式机械结构的诸多优点。最后,总结了框架式目标模拟器研制中的一些关键技术 相似文献
20.
Monitoring the quality consistency of Weibizhi tablets by micellar electrokinetic chromatography fingerprints combined with multivariate statistical analyses,the simple quantified ratio fingerprint method,and the fingerprint–efficacy relationship 下载免费PDF全文
Yingchun Liu Guoxiang Sun Yan Wang Lanping Yang Fangliang Yang 《Journal of separation science》2015,38(12):2174-2181
Micellar electrokinetic chromatography fingerprinting combined with quantification was successfully developed and applied to monitor the quality consistency of Weibizhi tablets, which is a classical compound preparation used to treat gastric ulcers. A background electrolyte composed of 57 mmol/L sodium borate, 21 mmol/L sodium dodecylsulfate and 100 mmol/L sodium hydroxide was used to separate compounds. To optimize capillary electrophoresis conditions, multivariate statistical analyses were applied. First, the most important factors influencing sample electrophoretic behavior were identified as background electrolyte concentrations. Then, a Box–Benhnken design response surface strategy using resolution index RF as an integrated response was set up to correlate factors with response. RF reflects the effective signal amount, resolution, and signal homogenization in an electropherogram, thus, it was regarded as an excellent indicator. In fingerprint assessments, simple quantified ratio fingerprint method was established for comprehensive quality discrimination of traditional Chinese medicines/herbal medicines from qualitative and quantitative perspectives, by which the quality of 27 samples from the same manufacturer were well differentiated. In addition, the fingerprint–efficacy relationship between fingerprints and antioxidant activities was established using partial least squares regression, which provided important medicinal efficacy information for quality control. The present study offered an efficient means for monitoring Weibizhi tablet quality consistency. 相似文献