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51.
Self‐assembled plasmonic logic gates that read DNA molecules as input and return plasmonic chiroptical signals as outputs are reported. Such logic gates are achieved on a DNA‐based platform that logically regulate the conformation of a chiral plasmonic nanostructure, upon specific input DNA strands and internal computing units. With systematical designs, a complete set of Boolean logical gates are realized. Intriguingly, the logic gates could be endowed with adaptiveness, so they can autonomously alter their logics when the environment changes. As a demonstration, a logic gate that performs AND function at body temperature while OR function at cold storage temperature is constructed. In addition, the plasmonic chiroptical output has three distinctive states, which makes a three‐state molecular logic gate readily achievable on this platform. Such DNA‐based plasmonic logic gates are envisioned to execute more complex tasks giving these unique characteristics.  相似文献   
52.
Three commercialized flame retardants, 1,2‐bis(diphenylphosphinoyl)ethane (EDPO), 6,6‐(1,2‐phenethyl)bis‐6H‐dibenz[c,e][1,2]oxaphosphorin‐6,6‐dioxide (HTP‐6123), and hexa‐phenoxy‐cyclotriphosphazene (HPCTP), were used to prepare the flame retardant diglycidyl ether of bisphenol A (DGEBA) epoxy resin (EP) under the same experimental conditions. The effects of Tg, thermal stability, and water absorption properties of EP caused by the three flame retardants were investigated and compared, together with their flame retardant efficiency. Results showed that the introduction of the three flame retardants improved the flame retardant performance of EP but led to decreases in Tg and decomposition temperature. EDPO showed higher flame retardant efficiency than the other two flame retardants. EP/EDPO showed higher thermal stability, better flame retardant performance, higher Tg value, and lower water absorption than EP/HTP‐6123 and EP/HPCTP. The study discovered that EDPO and HTP‐6123 primarily act through the gas phase flame retardant mechanism, while HPCTP is primarily driven by the condensed phase mechanism.  相似文献   
53.
A variety of benzofuranone‐based spiroisochromenes were originally designed and synthesized to gain insight into the oxa‐6π electrocyclic reaction of cis,cis‐1,8‐dioxatetraene for the first time. The stability of the 1,8‐dioxatetraene intermediate is governed by its steric congestion and can be fine‐tuned through modification of the backbone structure, leading to the reactivity differences in the 6π electrocyclic reaction and the emergence of photochromic properties.  相似文献   
54.
A double-T-shaped ligand (H4BPTC) and bis(2-benzimidazole)alkanes as the spacers have been firstly used to direct the assembly of a 2D coordination polymer with wavy parquet network topology, [Zn(BPTC)0.5(H2C2EIm)(H2O)]n (1, C24H18ZnN4O5, Mr = 507.79, H4BPTC = biphenyl-3,3',4,4'-tetracarboxylic acid, H2C2EIm = 2,2'-(1,2-ethanediyl)-bis(1H-benzi- midazole), which was determined by single-crystal X-ray diffraction analysis. The crystal belongs to the monoclinic system, space group P21/n with a = 1.1844(5), b = 1.4019(5), c = 1.4026(5) nm, β = 108.359(5)°, V = 2.2104(15) nm3, Z = 4, Dc = 1.526 g/cm3, μ(MoKα) = 1.156 mm-1, F(000) = 1040, S = 1.038, the final R = 0.0427 and wR = 0.0793 for 3834 reflections with I > 2σ(I). The compound units are linked through BPTC ligands into a wavilness parquet 2D layer and further connected into a 3D framework via π-π packing interactions between the adjacent H2C2EIm ligands and weak N-H…O hydrogen bonding between uncoordinated carboxylate and the nitrogen atoms of H2C2EIm as well as the free water molecules.  相似文献   
55.
Using native cellulose as the starting material, cellulose acetate-graft-ploy (l-lactide) (CA-g-PLA) copolymers were successfully synthesized by “one-pot” process in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). In this process, cellulose was first reacted with acetic anhydride, yielding cellulose acetate (CA), and then ring opening graft copolymerization of l-lactide was carried out from the residual hydroxyl groups of CA in the same solution using 4-dimethylaminopridine (DMAP) as the catalyst. Both acetyl and ploy (l-lactide) contents in CA-g-PLA copolymers could be well controlled by changing reaction conditions. The structures and thermal properties of CA-g-PLA copolymers were characterized. The glass transition temperature Tg of copolymers decreased with increasing PLA content. Compared to the pure PLA and cellulose-graft-PLA copolymers, the CA-g-PLA copolymers possessed better thermo mechanical properties in a temperature range of 60–130 °C. When the molar substitution of PLA (MSPLA) was above 1.71, the CA-g-PLA copolymers exhibited thermoplastic behavior and could be processed by conventional thermal processing methods, such as injection molding and melt spinning.  相似文献   
56.
发酵法黄腐酸磺化产物减水性能的研究   总被引:2,自引:0,他引:2  
吴京平  栾之春  王纯 《化学通报》2001,64(10):655-658
以腐植酸(HA)类新技术产品-发酵法黄腐酸(BFA)的磺化(磺甲基化)产物为研究对象,就其物化特性和泡沫性能以及表面活性、水泥净浆流动度和减水率等一系列减水性能进行了较系统的考察和研究,并与常用减水剂木钙(木质磺酸钙)对比,提出发酵法黄腐酸应用于混凝土减水剂的可能性。文中还对BFA磺化(磺甲基化)产物的减水机理进行了探讨。  相似文献   
57.
The Er3+:Y3Al5O12 as an upconversion luminescence agent, which can transform visible light into ultraviolet light, was synthesized by nitrate?Ccitrate acid and calcined method. Then, a novel photocatalyst, Er3+:Y3Al5O12/TiO2?CZrO2, was prepared using ultrasonic dispersion and liquid boiling method. The samples were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). In succession, the degradation process of organic dye was monitored by UV?CVis spectrum and ion chromatography for verifying the photocatalytic activity of Er3+:Y3Al5O12/TiO2?CZrO2. The influences on its photocatalytic activity such as Ti/Zr molar ratio, heat-treated temperature, and time were studied. In addition, the influences of initial concentration, Er3+:Y3Al5O12/TiO2?CZrO2 amount, solar light irradiation time, and organic dye category on the photocatalytic degradation efficiency were also investigated. It was found the photocatalytic activity of Er3+:Y3Al5O12/TiO2?CZrO2 was superior to Er3+:Y3Al5O12/TiO2 and Er3+:Y3Al5O12/ZrO2. Therefore, the Er3+:Y3Al5O12/TiO2?CZrO2 is a useful photocatalytic material for the wastewater treatment duo to efficient utilization of solar light.  相似文献   
58.
采用均相沉淀法制备了Ag@SiO2@(Y,RE)(OH)CO3.H2O(RE=Eu,Tb)核壳结构微球,经过700℃焙烧后成功制备出Ag@SiO2@Y2O3:RE3+(RE=Eu,Tb)核壳结构发光材料。XRD谱图表明Ag核具有结晶良好的面心立方结构;SiO2层为无定型;Y2O3层为立方晶系。FTIR谱图表明核壳之间以化学键相结合。TEM照片表明合成了核壳结构的表面光滑的复合微球,分散良好,大小均匀,Ag核的粒径分布为50±20 nm;SiO2层的厚度为20~30 nm;Y2O3:RE3+(RE=Eu,Tb)层厚度约为125 nm。电子衍射图像表明Ag@SiO2@Y2O3:RE3+(RE=Eu,Tb)为多晶结构。UV-Vis光谱表明表面包覆使Ag离子的等离子体共振吸收峰发生了红移。荧光光谱表明Ag@SiO2@Y2O3:Eu3+具有Eu3+的特征红光发射,Ag@SiO2@Y2O3:Tb3+具有Tb3+的特征绿光发射,但是发光强度均比纯的Y2O3:RE3+有所减弱,说明贵金属的引入对稀土Y2O3:RE3+(RE=Eu,Tb)的发光起到了荧光猝灭的作用。  相似文献   
59.
VOCs控制催化剂的研制   总被引:5,自引:1,他引:5  
以堇青石蜂窝陶瓷体为第一载体、γ-Al2O3为第二载体,制成的含稀土La和过渡金属元素的复合氧化物催化剂,在连续流动的反应体系上评价了催化剂对苯、氰氢酸、乙酸和氯苯等VOCs的氧化反应活性.结果表明: 采用LaCuMn组合制备的催化剂,La的含量在7%~10%左右、Cu的含量在5.5%左右、Mn的含量在7.5%左右时,第二载体γ-Al2O3的负载以采用半胶、pH值4~5、加入某些活性剂、负载量以7%~10%、活化温度为400~500 ℃时制成的催化剂的活性最好,研制的VOCs控制催化剂对各种VOCs均具有很高的催化活性.  相似文献   
60.
杨云  栾伟  罗学军  李攻科 《分析化学》2004,32(6):775-778
研究了微波辅助萃取-固相微萃取联用、气相色谱-质谱联用测定土壤中除草剂扑草净的分析方法。采用正交设计实验优化了萃取溶剂种类和体积、微波辐射时间和微波功率等微波辅助萃取条件;研究了SPME萃取涂层、搅拌速度、萃取时间和解吸时间等对萃取效率的影响。方法的检出限为0.01ng/g;线性范围为0.2—200μg/L。在优化的条件下测定了5和50ng/g的合成土壤样品,回收率分别为90.1%和91.6%;相对标准偏差分别为9.4%和8.8%(n=6)。本法综合了微波辅助萃取和固相微萃取的优点,操作简便.灵敏度高,特别适合于固体样品中痕量有机物的萃取分离。  相似文献   
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