Preparation of Z-L-Phe-OH-NBD imprinted microchannel and its molecular recognition study

An integrated microchip was presented for selective recognition of Z-L-Phe-OH-NBD, using molecular imprinting technique. Molecularly imprinted polymer (MIP) were prepared by copolymerization in the presence of template molecule Z-L-Phe-OH-NBD, in which methacrylic acid and 4-vinylpyridine were used as functional monomers and ethylene dimethacrylate used as crosslinker. Imprinted polymer particles were introduced into a microchannel fabricated with a new material i.e. poly(methylvinylsiloxane) by simply rapid prototyping method. Imprinted effects were evaluated by laser-induced fluorescence (LIF) detection where the results indicated that good selective recognition for Z-L-Phe-OH-NBD in the imprinted polymer was obtained; the adsorption percentage of Z-L-Phe-OH-NBD was 61%. In contrast to conventional molecular imprinting analysis, integration shortened overall analysis time from 4h to 10 min.     

Rhodium(I)‐Catalyzed [4 + 2] Cycloaddition Reactions of 2‐Alkylenecyclo‐butanols with Alkynes and (E)‐2‐Nitroethenylbenzene through C(sp2)—C(sp3) Bond Cleavage

An intermolecular [4 + 2] cycloaddition was realized through C—C bond cleavage in the presence of Rh(I) catalyst. The selective ring opening of 2‐alkylenecyclobutanols enables the generation of active alkenylrhodium species, which underwent smooth cross addition over alkynes and (E)‐2‐nitroethenylbenzene, leading to highly substituted all‐carbon six‐membered rings in a single step and in a complete atom economy.     

Cu，Pd－ZSM－5上NO分解和CO氧化的催化作用

双交换Ｃｕ，ｐｄ－ＺＳＭ－５催化剂（Ｃｕ交换度为１０５％，Ｐｄ交换度分别为３．４％和３３％）对ＣＯ氧化反应有活性增强作用，对ＮＯ分解反应不存在增强效应．双交换催化剂在于交换程序不同，而表面物种不同，活性组分的分布状态不同，因而有不同的活性．先交换Ｃｕ，４００℃焙烧后再交换ｐｄ的Ｃｕ－Ｐｄ－ＺＳＭ－５催化剂，对上述两类反应的活性存双组分催化剂中均为最高．Ｈ_２－ＴＰＲ谱表明，共交换的Ｃｕ－Ｐｄ－ＺＳＭ－５中尚有部分ＣｕＣｌ＋占据了部分交换位置，而使ＣＯ氧化活性稍有下降．Ｎ_２－ＤＴＡ和Ｈ_２－ＴＰＲ谱结果表明，Ｐｄ交换到Ｃｕ－ＺＳＭ－５中后，抑制了吸附水和水合铜化合物的形成，由此提高了在２００—３００℃时氧的吸附量．后者的大小和ＣＯ氧化活性有顺变关系．Ｎ_２－ＤＴＡ谱中３４０—４４５℃的放热峰可能分别表征了和ＮＯ分解活性有关的铜氧桥或把氧桥的形成，该放热峰的峰温愈低，峰面积愈大，则ＮＯ分解活性愈高．     

FT–IR microspectroscopy study of blends of ester functionalized ethylene–propylene copolymer with (vinylidene fluoride-hexafluoropropene) elastomer

An ethylene—propylene (EPR) copolymer functionalized with (1,2-dicarboethoxy)ethyl groups has been blended with a vinylidene fluoride—hexafluropropene elastomer (NML). The existence of intermolecular interactions involving mainly the carbonyl groups of the side chains of the functionalized copolymer and the methylene hydrogens of the fluoroelastomer through hydrogen bonding was shown by means of FT—IR spectroscopy. The structure and composition of some microdomains in the mixture was examined by means of FT—IR microspectroscopy.     

CATALYTIC BEHAVIOR OF DOPED MTiO_3 CATALYSTS FOR OXIDATIVE DEHYDROGENATION OF ETHANE

用Ｌｉ＋部分替代ＭＴｉＯ３（Ｍ＝Ｃａ、Ｓｒ）催化剂中的Ｔｉ４＋，明显地提高了乙烷氧化脱氢（ＯＤＨＥ）反应中乙烯的选择性。在ＣａＴｉ０．９Ｌｉ０．１Ｏ３－δ催化剂上，反应温度为８５０℃时，乙烯选择性为７７．４％，乙烷转化率为８１．７％。Ｌｉ掺杂的作用是增加了催化剂的Ｐ型半导性和未充分还原的氧物种数目。     

A Dynamic Analysis and Numerical Simulation of Explosive Development of an Extratropical Cyclone Over Land

The present paper has made a dynamic and diagnostic study of the process of explosive deepening of an extratropical cyclone over North China on April 25-26, 1983, in order to gain an insight into the physical mechanism of explosive development of cyclone over land. It turns out that this cyclone occurred in the strong baroclinic zone, and the vorticity and thermal advection triggered the initial development of the cyclone. Subsequently, as the rainfall increased, the effect of condensational heating became more and more important. During the time period of rapid intensification (from 1200GMT 25 to 0000GMT 26 April, 1983, the central surface pressure fell down from 998. 2 to 988. 3 hPa), the peak of diabatic heating profile continuously descended, leading to a rapid increase in heating amount in the lower troposphere. This condition is favorable to the explosive development of rotational circulation or vortex. The numerical simulations have further demonstrated the importance of the lowering of heating p     

SO_4~(2-)/M_xO_y型固体超强酸在有机合成中的应用

SO2 -4 /MxOy(M =Ti,Zr,Fe)是一新型的固体超强酸催化剂 .综述了近年来SO2 -4 /MxOy 型催化剂在有机合成中的应用 ,并对其今后的发展趋势作了预测 .     

New labdane-type diterpenoids from Leonurus heterophyllus SW

Five new natural labdane-type diterpenoids (5-9), designated leoheteronins A-E, together with four known diterpenoids (1-4), two phytosterols as a mixture of beta-sitosterol and stigmasterol, and the flavone genkwanin (10) were isolated from the aerial parts of Leonurus heterophyllus SW. (Lamiaceae) collected in northern Vietnam. Compound 1 was isolated for the first time from a Leonurus species, and 10 is considered to be a chemotaxonomic marker of the Leonurus genus. Their structures were determined using spectroscopic analyses.     

Interval estimation of the critical value in a general linear model

Summary This paper concerns interval estimation of the critical value θ which satisfies under the general linear model,Y _i =μ(x _i )+ε _i (i=1,2,···), where for and the functional forms off _j ^′ s are known. From an asymptotic expansion it is shown that, under reasonable conditions, the limiting distribution of is normal. Thus in the large-sample case a confidence interval for θ can be obtained. Such a result is useful when one is interested in carrying out a retrospective analysis rather than designing the experiment (as in the Kiefer-Wolfowitz procedure). In Section 3 a sequential procedure is considered for confidence intervals with fixed width 2d. It is shown that, for a given stopping variableN, is also asymptotically normal asd→0. Thus the coverage probability converges to 1−α (preassigned) asd→0. An example of application in estimating the phase parameter in circadian rhythms is given for the purpose of illustration. Research partially supported by the NSF Grant DMS-8502346.