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排序方式: 共有233条查询结果,搜索用时 250 毫秒
1.
Ye Jingyao Al-Jobory Alaa Zhang Qian-Chong Cao Wenqiang Alshehab Abdullah Qu Kai Alotaibi Turki Chen Hang Liu Junyang Ismael Ali K. Chen Zhong-Ning Lambert Colin J. Hong Wenjing 《中国科学:化学(英文版)》2022,65(9):1822-1828
Science China Chemistry - Destructive quantum interference (DQI) provides a unique approach to controlling the leakage current in the OFF state of molecular devices. However, the DQI in... 相似文献
2.
报道一种新型1,2,4-噁二唑衍生物,N-[2,6-二氯-4-(1,2,4-噁二唑-3-基)苯基]-2-甲氧基烟酰胺(C15H10Cl2N4O3)的合成,其结构通过1H NMR、13C NMR、HRMS以及X-射线单晶衍射进行表征。该晶体结构属于三斜晶系, P 1(—) 空间群,晶胞参数 a = 7.1291 (9), b = 8.4352 (10), c = 14.0021 (18) ?, α = 73.834 (3), β = 77.407 (3), γ = 70.019 (3)°, Mr = 366.18, V = 752.97 (16) ?3, Z = 2, Dc = 1.611 g/cm3, μ(MoKα) = 0.454 mm-1, F(000) = 372.0 , 晶体尺寸为 0.36 × 0.2 × 0.1 mm,Rint = 0.023。初步活性研究发现,该化合物对LoVo, A549, SK-BR-3, HeLa这四种肿瘤细胞株具有明显的抑制作用,尤其是对HeLa细胞的抑制活性与阳性药物5-氟尿嘧啶 (5-FU)相当。 相似文献
3.
A facile blending strategy to fabricate multishape memory polymers (SMPs) with only one sort of phase transition material has been reported. In this work, olefin block copolymer (OBC) and styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene (SEBS), which are both physically crosslinked, are blended with crystalline paraffin together. Due to the different interactions between polymer matrices and paraffin, the paraffin penetrated in OBC and SEBS exhibit separated melting transitions. It is quite interesting that merely paraffin distributed in OBC also shows two distinct melting transitions with enough OBC content in composites. Therefore, excellent quadruple shape memory effect can be achieved with a maximum of three melting transitions. Furthermore, through adjusting the polymer species and content, the mechanical and rheological properties can be conveniently tuned to a great extent. Compared with the reported strategies, this simple and controllable method sheds light on rapid design of multi‐SMPs using inexpensive raw materials, which greatly paves the way for multi‐SMPs from laboratory to factory.
4.
离散元方法是近年发展起来的一种新数值方法,但原则上只能用于动态问题。从静力平衡条件出发建立了离散元系统的准静态演化方程并证明了系数矩阵具有对称正定、稀疏、带状分布等特点,适用于“有效列”方法求解,该解法比高斯消去法节省更多的内存和机时。通过引入广义Maxwell体的元间作用模型建立起线性粘弹性材料准静态响应的离散元模拟方法。该方法独立于传统动态离散元方法,是传统动态离散元方法的拓展,可望在更多领域获得应用。 相似文献
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New Conjugated Molecules with Two and Three Dithienyldiketopyrrolopyrrole (DPP) Moieties Substituted at meta Positions of Benzene toward p‐ and n‐Type Organic Photovoltaic Materials 下载免费PDF全文
Chenmin Yu Dr. Chang He Yang Yang Zhengxu Cai Hewei Luo Wenqiang Li Dr. Qian Peng Dr. Guanxin Zhang Dr. Zitong Liu Prof. Deqing Zhang 《化学:亚洲杂志》2014,9(6):1570-1578
Two conjugated molecules, TADPP3 and TADPP2‐TT , are reported, in which three and two dithienyldiketopyrrolopyrrole (DPP) moieties, respectively, are substituted at the meta positions of benzene. Based on cyclic voltammetry and absorption data, TADPP3 and TADPP2‐TT possess similar HOMO and LUMO energies of about ?5.2 and ?3.4 eV, respectively. Thin films of TADPP3 and TADPP2‐TT exhibit p‐type semiconducting behavior with hole mobilities of 2.36×10?3 and 3.76×10?4 cm2 V?1 s?1 after thermal annealing. Molecules TADPP3 and TADPP2‐TT were utilized as p‐type photovoltaic materials to fabricate organic solar cells after blending with phenyl C71 butyric acid methyl ester ( PC71BM ) and phenyl C61 butyric acid methyl ester ( PC61BM ). The relatively low JSC and fill factor values can be attributed to poor film morphologies based on AFM and XRD studies. A solar cell with a thin film of TADPP3 with PC71BM in a weight ratio of 1:2 exhibits a high open‐circuit voltage (VOC) of 0.99 V and a power conversion efficiency (PCE) of 2.47 %. Interestingly, TADPP3 can also be employed as an n‐type photovoltaic material. The blended thin film of TADPP3 with P3HT in a weight ratio of 1:2 gave a high VOC of 1.11 V and a PCE of 1.08 % after thermal annealing. 相似文献
7.
1introductionChitosan,adeacetylatedderivativeofchitin,isnatUralpolysaccharideswithfreeaminogroups.Itcanactasanexcellentadsorbenttoadsorbnotonlyvariousorganiccompoundsincludingpolychlorinatedbiphenyls,proteinsandnucleicacids,butalsometalions[1~sl.ChitosanhasbeenwidelyemployedasaneffectivecoagulatingagentinactivatedsludgeplantSandfoodprocessingfactories,andalsoinpreparation,concentTationandpurificationofmetalionsinhydrometallurgy.Chitosanbehavesasanaturalchelatingpolymer.Chitosanundergoeschela… 相似文献
8.
Shuqin Li Xingen Hu Ruisen Lin Wenqiang Sang Wenjun Fang 《Journal of solution chemistry》2001,30(4):365-373
Densities of solutions of glycine, L-alanine, and L-serine have been measured by an oscillating-tube densimeter at 25°C in glycerol–water mixtures with glycerol mass fractions ranging from 0 to 0.50. Apparent molar volumes and limiting partial molar volumes of each amino acid have been calculated. The trends of transfer volumes have been interpreted by the cosphere overlap model. The results show that the presence of glycerol in water decreases the electrostriction caused by the amino acid zwitterion. 相似文献
9.
Wenqiang Yao Yongjun Li Sen Zhang Hao Liu Xiaoyu Huang 《Journal of polymer science. Part A, Polymer chemistry》2011,49(20):4433-4440
A series of fluorine‐containing amphiphilic diblock copolymers comprising hydrophobic poly(p‐(2‐(p‐tolyloxy)perfluorocyclobutoxy)phenyl methacrylate) (PTPFCBPMA) and hydrophilic poly(2‐(diethylamino)ethyl methacrylate) (PDEAEMA) segments were synthesized via successive reversible addition fragmentation chain transfer (RAFT) polymerizations. RAFT homopolymerization of p‐(2‐(p‐tolyloxy)perfluorocyclobutoxy)phenyl methacrylate was first initiated by 2,2′‐azobisisobutyronitrile using cumyl dithiobenzoate as chain transfer agent, and the results show that the procedure was conducted in a controlled way as confirmed by the fact that the number‐average molecular weights increased linearly with the conversions of the monomer while the polydispersity indices kept below 1.30. Dithiobenzoate‐capped PTPFCHPMA homopolymer was then used as macro‐RAFT agent to mediate RAFT polymerization of 2‐(diethylamino)ethyl methacrylate, which afforded PTPFCBPMA‐b‐PDEAEMA amphiphilic diblock copolymers with different block lengths and narrow molecular weight distributions (Mw/Mn ≤ 1.28). The critical micelle concentrations of the obtained amphiphilic diblock copolymers were determined by fluorescence spectroscopy technique using N‐phenyl‐1‐naphthylamine as probe. The morphology and size of the formed micelles were investigated by transmission electron microscopy and dynamic light scattering, respectively. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
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