Calculations of concentration dependences of chemical shifts for acrylamide in water—DMSO mixed solvent

The lattice model of associated solutions was used to calculate the concentration dependences of the chemical shifts of¹³C magnetic nuclei in the acrylamide molecule in water—DMSO solvent. Each pair of bonds between the acrylamide group containing a magnetic nucleus and the neighboring solvent molecule was assumed to additively contribute to the change in the chemical shift of the nucleus in question. The new approach affords the same accuracy in describing the experimental data at any ratios of the solution components. It was shown that the chemical shifts and the excess heat of mixing of the water—DMSO binary solution can be simultaneously described using the same set of energy parameters of the model. The model makes it possible to employ experimental data on chemical shifts for studying intermolecular interactions in solutions. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1983–1987, October, 1998.     

高比表面积窄孔分布氧化铝的制备研究 Ⅰ.沉淀条件的影响

 以硫酸铝液为原料，以氨水、氢氧化钠和铝酸钠为碱沉淀剂，采用pH摆动法制备了高比表面积、大孔径、窄孔分布、大孔体积氧化铝，考察了沉淀剂、沉淀温度及沉淀时酸侧pH值对氧化铝物性的影响，并对pH摆动法与等pH沉淀法的结果进行了比较．结果表明，通过改变制备参数可以获得高比表面积、大孔体积的氧化铝，当沉淀温度为70℃，pH摆动3或4次时，氧化铝的孔体积可高达1．0ml／g，比表面积仍大于300m2／g．用pH摆动法制得的样品比用等pH沉淀法制得的样品容易酸溶，对挤压成型有利．不同样品在酸溶液中的分散性表明，用氨水沉淀剂可获得相对较小的沉淀粒子．改变沉淀时酸侧的pH值，可导致沉淀粒子的结构发生变化．     

层状正极材料LiNi1/6Co1/6Mn2/3O2的制备及电池性能

0引言为解决目前日益严重的汽车尾气排放对城市空气造成污染问题,作为绿色能源的锂离子电池已成为动力电池的首选对象。国际上,高容量、大功率锂离子电池早于1995年已开始研制。1996年,我国天津电源研究所也进行了大容量锂离子蓄电池及电池组的探索[1]。目前,锂离子电池的正极材料是制约其大规模推广应用的关键。现研究的正极材料主要包括具有层状结构的LiCoO2,LiN iO2和LiM nO2及具有尖晶石结构的LiM n2O4等。其中LiC oO2作为目前唯一已经商业化的正极材料具有理论容量高、可循环性能好等优点,但因Co资源的相对缺乏导致其价格高昂。…     

Pattern-specific neural network design

We present evidence that the performance of the traditional fully connected Hopfield model can be dramatically improved by carefully selecting an information-specific connectivity structure, while the synaptic weights of the selected connections are the same as in the Hopfield model. Starting from a completely disconnected network we let genuine Hebbian synaptic connections grow, one by one, until a desired degree of stability is achieved. Neural pathways are thus fixed notbefore, butduring the learning phase.     

PP回归方法在预测模型中的应用－用PP回归建立“积累”“消费”模型

本文利用ＰＰ回归方法,建立“积累”“消费”回归模型,并与最小二乘法拟合的线性回归模型相比较,说明用ＰＰ回归建立的模型预测精度较高．     

Cluster description of water-in-oil microemulsions near the critical and percolation points

The three-component ionic microemulsion system consisting of AOT/water/decane shows an unusual phase behavior in the vicinity of room temperature. The phase diagram in the temperature-volume fraction (of the dispersed phase) plane exhibits a lower consolute critical point at about 40 degrees centigrades and 10% volume fraction. A percolation line, starting from the vicinity of the critical point, cuts across the plane, extending to high volume fraction side at progressively lower temperatures. In this paper we review the evidence that allows to interpret the phase behavior of our system in terms of interacting spherical droplets. We also investigate the dynamics of droplets, below and approaching the critical point by dynamic light scattering. The first cumulant and time evolution of the droplet density correlation function can be quantitatively calculated by assuming the existence of polydispersed fractal clusters formed by the microemulsion droplets due to attraction. The relaxation phenomena observed in an extensive set of measurements of electrical conductivity and permittivity close to percolation is also reviewed and interpreted through the same cluster-forming mechanism, which reproduces the most relevant features of the frequency-dependent complex dielectric constant of this system. Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994.     

浮动电极对屏蔽栅沟槽型MOSFET特性的影响

提出了在屏蔽栅沟槽型MOSFET(SGT)的沟槽侧壁氧化层中形成浮动电极的结构,通过改善电场分布,优化了特征导通电阻与特征栅漏电容。在传统SGT结构的基础上,仅通过增大外延层掺杂浓度,改变浮动电极的长度和位置以及氧化层厚度,最终得到击穿电压为141.1 V、特征导通电阻为55 mΩ·mm²、特征栅漏电容为4.72 pF·mm^-2的浮动电极结构。与相同结构参数的SGT结构相比,在击穿电压不变的条件下,浮动电极结构的特征导通电阻降低了9.3%,Baliga优值提升了13%,特征栅漏电容降低了28.4%。     

High-Performing Quasi-2D Perovskite Photodetectors with Efficient Charge Transport Network Built from Vertically Orientated and Evenly Distributed 3D-Like Phases

Quasi-two-dimensional (Q-2D) perovskites are emerging as one of the most promising materials for photodetectors. However, a significant challenge to Q-2D perovskites for photodetection is their insufficient charge transport ability, which is mainly attributed to their hybrid low-dimensional n-phase structure. This study demonstrates that evenly-distributed 3D-like phases with vertical orientation throughout the film can greatly facilitate charge transport and suppress charge recombination, outperforming the prevalent phase structure with a vertical dimension gradient. Based on such a phase structure, a Q-2D Ruddlesden−Popper perovskite self-powered photodetector achieving a combination of exceptional figures-of-merit is realized, including a responsivity of 0.45 AW⁻¹, a peak specific detectivity of 2.3 × 10¹³ Jones, a 156 dB linear dynamic range, and a rise/fall time of 2.89 µs/1.93 µs. The desired phase structure is obtained by utilizing a double-hole transport layer (HTL), combining hydrophobic PTAA and hydrophilic PEDOT: PSS. Besides, the dependence of the hybrid low-dimensional phase structure is also identified on the surface energy of the buried HTL substrate. This study gives insight into the correlation between Q-2D perovskites’ phase structure and performance, providing a valuable design guide for Q-2D perovskite-based photodetectors.     

Low complexity inter coding scheme for Versatile Video Coding (VVC)

The latest coding standard Versatile Video Coding (VVC) developed by the Joint Video Experts Team (JVET) and Video Coding Experts Group (VCEG) was finalized in 2020. By introducing several new coding techniques, VVC improves the compression efficiency by 50% compared with H.265/HEVC. However, the coding complexity increases dramatically, which obstructs it from real-time application. To tackle this issue, a fast inter coding algorithm utilizing coding information is proposed to speed up the coding process. First, by analyzing the coding areas of the neighboring CUs, we predict the coding area of the current CU to terminate unnecessary splitting modes. Then, the temporally optimal coding mode generated during the prediction process is further utilized to shrink the candidate modes to speed up the coding process. Finally, the distribution of neighboring prediction modes are exploited to measure the motion complexity of the current CU, based on which the unnecessary prediction modes can be skipped earlier. Experimental results demonstrate that the proposed method can reduce the coding complexity by 40.08% on average with 0.07 dB BDPSNR decrease and 1.56% BDBR increase, which outperforms the state-of-the-art approach.     

Thermal decomposition of transition metal carboxylates

Thermal solid-phase decomposition of anhydrous copper(ii) formate has been studied at 120–180 ° The rate of gas evolution during the decomposition depends on the depth of conversion and can be presented as the sum of first-order reaction rates and the rate of the autocatalytic process (a second-order reaction). The evolution of the solid phase during thermolysis has been observed by optical microscopy. The decomposition of copper formate is a complex topochemical process, a combination of homogeneous and heterogeneous transformations and dispersion of large crystals.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. l, pp. 72–76, January, 1996.