共查询到20条相似文献,搜索用时 500 毫秒
1.
色谱质谱联用技术研究30%二甲基二乙氧基硅烷70%正硅酸乙酯复合醇盐 … 总被引:1,自引:0,他引:1
采用色谱质谱联用技术研究了1种复合醇盐:30%二甲基二乙氧基硅烷/70%正硅酸乙酯的水解聚合过程,并由此分析了这两种有机-无机醇盐的相互作用机制和聚合方式,实验结果指出,DDS的添加抑制了TEOS的自聚合,使得体系中形成了大量的DDS的自聚合环状分子以及TEOS和DDS的共聚合高分子,由于后者对水解聚合的加速作用,使得30%DDS/70%TEOS系统具有最短的凝胶时间。 相似文献
2.
3.
4.
5.
6.
在电位型尿素酶电极的组装过程中,要求尽量不改变尿素酶的构型和构象,使其在酶膜中保持其自然状态,从而可获得较高的酶活力.用pH玻璃电极作原电极,将尿素酶固定在其表面,常用的有戊二醛交联法[1]和各种聚合物膜法[2~4].本文利用60%季铵化的聚(4-乙... 相似文献
7.
8.
Lei Jiao Dr. Xiang Zhang Dr. Yangyang Feng Dr. Jing Lin Prof. Daqiang Yuan Prof. Yaobing Wang 《Angewandte Chemie (International ed. in English)》2023,62(30):e202306506
Solar-to-electrochemical energy storage in solar batteries is an important solar utilization technology comparable to solar-to-electricity (solar cells) and solar-to-fuel (photocatalytic cells) conversion. Unlike the indirect approach of integrated solar flow batteries combining photoelectrodes with redox-electrodes, coupled solar batteries enable direct solar energy storage, but are hampered by low efficiency due to rapid charge recombination of materials and misaligned energy levels between electrodes. Herein, we propose a design for a coupled solar battery that intercouples two photo-coupled ion transfer (PCIT) reactions through electron-ion transfer upon co-photo-pumping of photoelectrochemical storage cathode and anode. We used a representative covalent organic framework (COF) to achieve efficient charge separation and directional charge transfer between two band-matched photoelectrochemical storage electrodes, with a photovoltage sufficient for COF dual-redox reactions. By pumping these electrodes, the coupled solar battery stores solar energy via two synergistic PCIT reactions of electron-proton-relayed COF oxidation and reduction, and the stored solar energy is released as electrochemical energy during COF regeneration in discharge while interlocking the loops. A breakthrough in efficiency (6.9 %) was achieved, adaptive to a large-area (56 cm2) tandem device. The presented photo-intercoupled electron-ion transfer (PIEIT) mechanism provides expandable paths toward practical solar-to-electrochemical energy storage. 相似文献
9.
Xiaoran Zhang Xiaorong Zhu Shuowen Bo Chen Chen Kai Cheng Jianyun Zheng Shuang Li Xiaojin Tu Wei Chen Chao Xie Xiaoxiao Wei Dongdong Wang Yingying Liu Pinsong Chen Prof. San Ping Jiang Prof. Yafei Li Prof. Qinghua Liu Prof. Conggang Li Prof. Shuangyin Wang 《Angewandte Chemie (International ed. in English)》2023,62(33):e202305447
Electrocatalytic urea synthesis via coupling N2 and CO2 provides an effective route to mitigate energy crisis and close carbon footprint. However, the difficulty on breaking N≡N is the main reason that caused low efficiencies for both electrocatalytic NH3 and urea synthesis, which is the bottleneck restricting their industrial applications. Herein, a new mechanism to overcome the inert of the nitrogen molecule was proposed by elongating N≡N instead of breaking N≡N to realize one-step C−N coupling in the process for urea production. We constructed a Zn−Mn diatomic catalyst with axial chloride coordination, Zn−Mn sites display high tolerance to CO poisoning and the Faradaic efficiency can even be increased to 63.5 %, which is the highest value that has ever been reported. More importantly, negligible N≡N bond breakage effectively avoids the generation of ammonia as intermediates, therefore, the N-selectivity in the co-electrocatalytic system reaches100 % for urea synthesis. The previous cognition that electrocatalysts for urea synthesis must possess ammonia synthesis activity has been broken. Isotope-labelled measurements and Operando synchrotron-radiation Fourier transform infrared spectroscopy validate that activation of N−N triple bond and nitrogen fixation activity arise from the one-step C−N coupling process of CO species with adsorbed N2 molecules. 相似文献
10.
11.
12.
《化学分析计量》2009,(2)
愈演愈烈的金融危机影响着全球的各行各业,尤其是制造型企业面临着前所未有的严峻挑战。但是一场大危机通常也意味着一次大机遇。目前,舜宇光学科技(集团)有限公司在光学行业优胜劣汰的新一轮洗牌中,大胆走出国门,用2102万港元认购韩国力量公司(Power Optics)的新股,从而进一步提升公司研发能力,拓展国际高端市场。韩国力量光学主要从事手机摄像镜头等各类元件的研究、开发和销售,拥有强大的研发能力及良好的客户基础。认购完成后,舜宇对力量光学的持股量将由原先的8.56%增至54.9%,而力量光学亦将成为舜宇光学科技的附属公司之一。舜宇收购韩国力量光学54.9%股份 相似文献
13.
<正>从南京市质监局获悉,不久前质监部门出台了多项措施,支持民营和混合所有制企业发展。其中一些措施也让老百姓受惠,如计量器具校准测试费用在原来的基础上降低了20%,产品质量委托检测费也降低10%。除此之外,质监部门还将在市政务服务中心增设质监便民窗口,方便企业就近或者集中办理组织机构代码登记和跨区域特种设备开工告 相似文献
14.
高纯C0_2在电子工业、医疗分析、低温绝热、激光技术、分压测定、分光光度计、吸收光谱以及色谱检测器的校正等方面有许多特殊的应用。为了满足有关单位发展新技术的需要,我所于83年度将制备高纯CO_2正式列入科研计划。84年8月研制出99.99%纯级CO_2,同年10月又研制出99.999%高纯级CO_2。 相似文献
15.
无溶液形成的固态化学反应具有“一旦发生,就必完全”的特质,但因为固体的非流动性,它常常会因严重的传质困难而有始无终。为了克服这个困难,作者提出了少溶剂固态化学反应(LSR)的概念,即通过使用少量的溶剂赋予固体流动性,使反应物固体部分溶解,再使用搅拌反应器解决其“三传”问题,使之完全反应,从而达到使一些化学工业过程绿色化的目的。本文用平衡热力学数值计算的方法图解了几种代表性LSR的Gibbs自由能随反应进度的关系,进而指出:(ⅰ) LSR的中间阶段如同没有溶液形成的固态化学反应,两端像溶液化学反应,因此,LSR虽继承了混合自由能导致的化学平衡,但其平衡点比溶液化学反应更接近100%完全。特别地,在LSR即将结束时,通过逐步移除溶剂以使反应物和产物固体持续存在而延长中段,能推动反应达到100%完全;(ⅱ)对于连串反应,LSR仍有可能通过控制反应物的物质的量之比来获得中间产物;(ⅲ)对于ΔrGmΘ略小于零的反应,可以通过使用较多的溶剂跨越可能的早期平衡态,或者使用大量的产物固体“种子”使所有的产物一直与其饱和溶液平衡,最终通过逐渐蒸发溶剂推动反应进行到底;(ⅳ) LSR的反应速度与反应物或产物的溶解度关系不大,但与反应物的溶解速度、化学反应速度和产物的结晶速度紧密相关。本文还讨论了使一些竞争反应、非自发反应进行到底的方法,获得高度的反应控制能力。 相似文献
16.
17.
有机叠层太阳能电池可以克服单节器件吸光能力和范围有限等问题,是提高有机太阳能电池光伏效率的一个重要策略.最近一项研究采用在可见和近红外区域具有良好互补吸收的子电池,构筑了效率高达17.3%的有机叠层太阳能电池.这一结果表明,经过合适的材料选择与器件构筑,有机太阳能电池有望获得与其他光伏技术电池相当的光伏效率. 相似文献
18.
以维生素C及常用于其注射液中作稳定剂的焦亚硫酸钠为例, 测定了两组平行反应(维生素C无氧降解和有氧降解; 维生素C和焦亚硫酸钠的氧化反应)的动力学参数, 建立了维生素C的降解动力学方程. 结果表明维生素C无氧降解为零级反应; 在维生素C和焦亚硫酸钠的氧化反应中, 维生素C和焦亚硫酸钠的反应级数都为零, 溶解氧为一级; 维生素C溶液的吸光度变化在一定范围内和浓度降解量成线性关系. 根据建立的动力学方程, 从理论上计算得在维生素C溶液中加(或不加)焦亚硫酸钠时的贮存期分别为444 d(或152 d), 表明加入焦亚硫酸钠能显著延长维生素C溶液的贮存期. 相似文献
19.
Dr. Pengbo Han Dr. Chengwei Lin Erhan Xia Jiawei Cheng Qing Xia Prof. Dezhi Yang Prof. Anjun Qin Prof. Dongge Ma Prof. Ben Zhong Tang 《Angewandte Chemie (International ed. in English)》2023,62(43):e202310388
Aggregation-induced emission (AIE) luminogens (AIEgens) are attractive for the construction of non-doped blue organic light-emitting diodes (OLEDs) owning to their high emission efficiency in the film state. However, the large internal inversion rate (kIC(Tn)) between high-lying triplet levels (Tn) and Tn-1 causes a huge loss of triplet excitons, resulting in dissatisfied device performance of these AIEgens-based non-doped OLEDs. Herein, we designed and synthesized a blue luminogen of DPDPB-AC by fusing an AIEgen of TPB-AC and a DMPPP, which feature hot exciton and triplet-triplet annihilation (TTA) up-conversion process, respectively. DPDPB-AC successfully inherits the AIE feature and excellent horizontal dipole orientation of TPB-AC. Furthermore, it owes smaller kIC(Tn) than TPB-AC. When DPDPB-AC was applied in OLED as non-doped emitting layer, an outstanding external quantum efficiency of 10.3 % and an exceptional brightness of 69311 cd m−2 were achieved. The transient electroluminescent measurements and steady-state dynamic analysis confirm that both TTA and hot exciton processes contribute to such excellent device performance. This work provides a new insight into the design of efficient organic fluorophores by managing high-lying triplet excitons. 相似文献