排序方式: 共有17条查询结果,搜索用时 171 毫秒
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Wang Jenn-Henn Chen Xiaolan Chen Jin-Jian Calderon Jose G. Timmons Richard B. 《Plasmas and Polymers》1997,2(4):245-260
The use of a variable duty cycle pulsed RF plasma is shown to provide film chemistry control during polymerization of saturated (CH2Br2) and unsaturated (CH2=CHCH2Br) bromine containing monomers. With both monomers, the degree of bromine atom retention in the films is observed to increase in a progressive fashion as the RF duty cycle employed during plasma polymerization is decreased. The film deposition rates, when expressed in terms of thickness per Joule of RF energy input, increase rapidly as the RF duty cycles are reduced. Additionally, the film morphology is observed to become increasingly smooth with decreasing RF duty cycles during deposition, as illustrated with the allyl bromide monomer. The film chemistry controllability of this study is demonstrated with monomers possessing the relatively weak C-Br bond. As such, the present work represents an important extension of the pulsed plasma polymerization approach to include retention of a labile bond during film formation. The introduction of reactive surface functional groups, at controlled densities, provides additional molecular tailoring possibilities via subsequent chemical derivatization processes. 相似文献
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合成了2,6-二氨基-3,5-二硝基吡嗪-1-氧化物(LLM-105)2种含能配合物[Cu4O2(C4N6O5H2)2(CH3COO)2(DMF)2]·DMF(1)((C4N6O5H2)2- 为配体LLM-105失去2个H+)和[Co(C4N6O5H3)3]·7H2O(2)((C4N6O5H3)- 为LLM-105失去1个H+),用X射线单晶衍射法测定了其分子结构。配合物1属正交晶系,空间群为Pbca,配合物2属三斜晶系,空间群为R3。用DSC,TG-DTG技术对配体和2个配合物的热分解进行了研究。用Kissinger法和Ozawa-Doyle法对配合物热分解过程中放热峰的表观活化能进行了计算。同时研究了2种配合物对AP热分解催化效果的影响,结果表明,2种配合物使AP的高温分解峰温分别提前117.42和71.85℃,分解放热量增加1916.97和1433.76J·g-1,对AP热分解具有非常显著的催化效果。 相似文献
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Zheng-Feng Wu Han Bao Fa-Yang Zhou Jing-Xin Liu Fan-Cheng Meng Lu Feng Jin-Jian Lu Qing-Wen Zhang Yang Ye Li-Gen Lin 《中国化学快报》2017,28(8):1711-1715
Phytochemical investigation on the seeds of Caesalpinia sappan led to the isolation of five new cassanetype diterpenoids, named 11-oxo-phanginin A(1), caesalsappanins O–Q(2–4) and phanginin U(5),together with five known compounds. The structures of the new compounds were elucidated by extensive analysis of mass spectrometric and 1D and 2D NMR spectroscopic data. All the new compounds showed moderate cytotoxic effects on human breast cancer MCF-7 and human colon cancer HCT116 cell lines. 相似文献
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Six heterometallic Zn(II) coordination polymers, Zn(H2O)3(FNA) (1), [NH4]2[Zn(H2O)2(FNA)2] (2), [ZnNa2(FNA)2]·3H2O (3), [ZnK2(FNA)2]·H2O (4), [ZnRb2(FNA)2]·2H2O (5) and [ZnMg(FNA)2]·4H2O (6) (H2FNA = 4-nitrobenzene-1,2-dicarboxylic acid), were synthesised by introducing different alkali/alkaline earth (AeI/AeII) metals. These complexes exhibit diverse structures with the different AeI/AeII metals used and distinct ligand coordination modes the ions provide. For 1 and 2, the Zn(II) centres with distorted octahedra are connected by FNA to form 1-D chain structures. The Zn(II) centres in 3–6 with distorted tetrahedra are linked by FNA to form 2-D anionic grid layers. For 3–5, these 2-D anionic grid layers are connected by alkali metal (Na, K and Rb) with the O–AeI–O connectivity to exhibit 3-D framework structures, while 6 features a 2-D Zn–Mg network. Luminescence properties of 1–6 have been investigated. 相似文献
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A tutorial review for employing enzymes for the construction of G-quadruplex-based sensing platforms
Dik-Lung Ma Wanhe Wang Zhifeng Mao Chao Yang Xiu-Ping Chen Jin-Jian Lu Quan-Bin Han Chung-Hang Leung 《Analytica chimica acta》2016
With rapid advances in the field of DNA chemistry, nucleic acids and DNA-modifying enzymes have recently emerged as versatile components for the construction of oligonucleotide-based sensors. Meanwhile, the G-quadruplex motif has been widely employed for the development of DNA-based assays due to its diverse structural variety. In this tutorial, we introduce the principles of G-quadruplex-based sensing and the use of DNA-modifying enzymes for sensor platform development. We also highlight recent studies of the application of DNA-modifying enzymes for the development of G-quadruplex-based luminescent detection platforms with a view towards how those enzymes play an important role in sensitivity enhancement. 相似文献
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在碱性条件下,将1,2,4,5-均苯四甲酸(H4BTEC)与过渡金属离子配位,并引入中性紫精组分1-羧乙基-4,4′-联吡啶(CEbpy),构筑了3个同构共晶体[M(H2O)_5(BTEC)0.5]·(CEbpy)(M=Mn(1)、Zn(2)、Co(3))。在紫外灯照射下,3个化合物都发生明显的光致变色现象,这归因于光诱导的电子转移并产生了紫精自由基。同时,在加热的情况下,化合物3还表现出不可逆的失水致变色行为,而化合物1和2则没有。我们讨论了金属离子对变色行为的影响。 相似文献
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Secret Key Distillation for Continuous Variable Quantum Key Distribution against Gaussian Classical Eve 下载免费PDF全文
The continuous variable quantum key distribution is expected to provide high secret key rate without single photon source and detector, while the lack of the effective key distillation method makes it unpractical under the high loss condition. Here we present a single-bit-reverse-reconciliation protocol against Oaussian classical Eve, which can distill the secret key through practical imperfect error correction with high efficiency. The simulation results show that this protocol can distill secret keys even when the transmission fibre is longer than 150 km, which may make the continuous variable scheme to outvie the single photon one. 相似文献
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In this paper, we investigate the quantile regression analysis for semi-competing risks data in which a non-terminal event may be dependently censored by a terminal event. The estimation of quantile regression parameters for the non-terminal event is complicated. We cannot make inference on the non-terminal event without extra assumptions. Thus, we handle this problem by assuming that the joint distribution of the terminal event and the non-terminal event follows a parametric copula model with unspecified marginal distributions. We use the stochastic property of the martingale method to estimate the quantile regression parameters under semi-competing risks data. We also prove the large sample properties of the proposed estimator, and introduce a model diagnostic approach to check model adequacy. From simulation results, it shows that the proposed estimator performs well. For illustration, we apply our proposed approach to analyze a real data. 相似文献
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