排序方式: 共有52条查询结果,搜索用时 15 毫秒
41.
Dr. Kohei Takahashi Shunsuke Shimo Dr. Emanuel Hupf Junichi Ochiai Christina A. Braun Dr. William Torres Delgado Letian Xu Prof. Dr. Gang He Prof. Dr. Eric Rivard Prof. Dr. Nobuharu Iwasawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(36):8479-8483
Guest-controlled diastereoselective self-assembly of a diboryltellurophene and a chiral tetrol bearing an indacene backbone was achieved to give either hetero- or homochiral macrocyclic boronic esters, selectively. The heterochiral isomer (hetero-[2+2]Te) exhibited a higher inclusion ability for electron-deficient aromatic guests, leading to effective quenching of phosphorescence from the diboryltellurophene moieties. The reported macrocycles collectively represent a promising arene sensing approach based on phosphorescence. 相似文献
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KT1202事故转子的强度计算及模拟试验分析 总被引:1,自引:0,他引:1
本文对KT1202事故转子做了详细、全面的强度及有限元计算分析,在大量方案计算比较及模拟试验的基础上,找到了事故处理的方法。修复后的转子经二年多的运行实践检验,证明该方法是有效且成功的,为国家带来了巨大的经济效益。 相似文献
44.
以UiO-66为前驱体制得UiO-66/CoSO4复合材料,借助扫描电子显微镜、透射电子显微镜、元素分析和比表面积分析等手段对复合材料的微观形貌和结构进行表征,采用吸附平衡实验,系统考察该复合材料的吸附性能.结果表明,在相同条件下UiO-66/CoSO4复合材料比UiO-66对盐酸左氧氟沙星的去除率提高26.5%,且复合材料在30 min对盐酸左氧氟沙星的吸附达到平衡,最大吸附容量为108.4 mg·g-1,其吸附特性符合假二级动力学模型.该UiO-66/CoSO4复合材料制备过程简单,对实际环境水样和土样中盐酸左氧氟沙星的去除率在94.7%以上,且经过5次再生循环使用后,吸附效率无明显下降. 相似文献
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The hydrosilylation reaction of ladderlike polyvinylsilsesquioxane (Vi-T)with 1, 1, 3, 3-tetramethyldisiloxane (H- MM ) catalyzed by dicyclopentadienyl-dichloroplat-inium (Cp_2PtCl_2) was carried out well in tetrahydrofuran (THF) to produce a soluble whitesolid. This product was characterized by IR, ~1H-NMR, ~(13)C-NMR, ~(29)Si-NMR, DSC, X-raydiffraction method, gel permeation chromatography (GPC), vapour pressure osmometry(VPO), atomic force microscopy (AFM) and molecular simulation. These results provethat the product contains nanoscale tubular structure. 相似文献
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A novel synthesis of 2,3-dihydroimidazo[1,2-a]pyridin-5(1H)-one, and insecticidal derivatives were described. 相似文献
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Beta,gamma-alkynyl aldehydes, generated in situ by treatment of alkynyloxiranes with a catalytic amount of Sc(OTf)3 or BF3.OEt2, are effectively trapped by a variety of allyl nucleophiles to afford homopropargylic homoallylic alcohols in good yield and selectivity. Such products are used as substrates for the synthesis of functionalized vinylcyclopentenols via enyne metathesis. 相似文献
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Dr. Letian Xu Hao Liu Xiaoluo Peng Dr. Pingchuan Shen Prof. Ben Zhong Tang Prof. Zujin Zhao 《Angewandte Chemie (International ed. in English)》2023,62(20):e202300492
Circularly polarized electroluminescence (CP-EL) is generally produced in organic light-emitting diodes (OLEDs) based on special CP luminescent (CPL) materials, while common achiral luminescent materials are rarely considered to be capable of direct producing CP-EL. Herein, near ultraviolet CPL materials with high photoluminescence quantum yields and good CPL dissymmetry factors are developed, which can induce blue to red CPL for various achiral luminescent materials. Strong near ultraviolet CP-EL with the best external quantum efficiencies (ηexts) of 9.0 % and small efficiency roll-offs are achieved by using them as emitters for CP-OLEDs. By adopting them as hosts or sensitizers, commercially available yellow-orange achiral phosphorescence, thermally activated delayed fluorescence (TADF) and multi-resonance (MR) TADF materials can generate intense CP-EL, with high dissymmetry factors and outstanding ηexts (30.8 %), demonstrating a simple and universal avenue towards efficient CP-EL. 相似文献
49.
This paper explores a simple yet powerful relationship between the problem of counting lattice points and the computation of Dedekind sums. We begin by constructing and proving a sharp upper estimate for the number of lattice points in tetrahedra with some irrational coordinates for the vertices. Besides providing a sharper estimate, this upper bound (Theorem 1.1) becomes an equality (i.e. gives the exact number of lattice points) in a tetrahedron where the lengths of the edges divide each other. This equality condition can then be applied to the explicit computation of the classical Dedekind sums, a topic that is the central focus in the second half of our paper. In this half of the paper, we come up with a number of interesting results related to Dedekind sums, based on our upper estimate (Theorem 1.1). Among these findings, Theorem 1.9 and Theorem 1.10 deserve special attention, for they successfully generalize two of Apostol's formulas in [T.M. Apostol, Modular Functions and Dirichlet Series in Number Theory, Springer-Verlag, New York, 1997], and also directly imply the famous Reciprocity Law of Dedekind sums. 相似文献
50.
灰树花β-葡聚糖的高效凝胶渗透色谱行为 总被引:1,自引:0,他引:1
以4种不同蛋白质含量的灰树花β-1,3/1,6-葡聚糖 (GF1,GF2,GF3,GF4) 和1种α-1,4/1,6-葡聚糖 (P100)为研究对象,探讨了它们在不同盐浓度和不同pH下的高效凝胶渗透色谱(HPGPC)行为。结果表明:灰树花β-葡聚糖相对分子质量在低于0.025 mol/L的氯化钠溶液中急剧降低,在0.1~0.2 mol/L的氯化钠溶液中趋于平稳。在pH 3~6时,其相对分子质量随pH增加而急剧增加;在pH 6~9范围内变化较小;pH高于9后又稍微增加。在相同条件下,α-1,4/1,6-葡聚糖的相对分子质量不受盐浓度和pH值变化的影响。灰树花β-葡聚糖在水溶液中可形成超螺旋结构,该结构受溶液盐浓度和pH值变化的影响,导致分子聚集状态不同,从而呈现不同的凝胶渗透色谱行为,表现为相对分子质量升高或降低。 相似文献