智能型机译规则库系统IMT-RB/EC

重组在知识库系统中具有十分重要的地位。本文提出了依属性对文法规则库进行多重重组的观点和方法,并介绍了一个基于此观点之上的智能型机译规则库系统IMT-RB/EC,该系统本质上是一个具有学习功能和自组织能力的知识库系统,它具有结构清晰,便于表达知识、分类、精选、检索和可扩充及修改更新的特点。     

聚乳酸耐热改性的研究进展

聚乳酸(PLA)是一种兼具良好生物相容性、力学以及加工性能的生物基可降解脂肪族聚酯,因此,在医药、食品包装等领域得到广泛应用。然而,PLA结晶速率慢、所得制品结晶度低、耐热性差,严重制约了其在高温环境下的使用。本文综述了国内外聚乳酸耐热改性方面的研究进展,重点阐述通过化学共聚、交联、共混以及外场作用(热处理、拉伸)等手段提高PLA耐热性的方法,并对耐热聚乳酸材料的发展前景进行了展望。     

时滞反应扩散方程初边值问题奇摄动

本文考虑了在生物数学、生物化学等应用问题中常见的较广泛的一类奇摄动时滞反应扩散方程初边值问题。应用合成展开法构造了所述问题的形式渐近解，借助上、下解理论证明了形式解的一致有效性和原问题的解的存在性。     

EXISTENCE AND ESTIMATION OF SOLUTIONS FOR SINGULARLY PERTURBED VECTOR IMPULSIVE PROBLEMS

ＥＸＩＳＴＥＮＣＥＡＮＤＥＳＴＩＭＡＴＩＯＮＯＦＳＯＬＵＴＩＯＮＳＦＯＲＳＩＮＧＵＬＡＲＬＹＰＥＲＴＵＲＢＥＤＶＥＣＴＯＲＩＭＰＵＬＳＩＶＥＰＲＯＢＬＥＭＳＸｕＹｕｘｉｎｇ（许玉兴）＆ＺｈａｎｇＸｉａｎｇ（张祥）（ＡｎｈｕｉＮｏｒｍａｌＵｎｉｖｅｒｓ...     

AlOx prepared by atomic layer deposition for high efficiency-type crystalline silicon solar cell

The influence of atomic layer deposition parameters on the negative charge density in AlOx film is investigated by the corona-charge measurement. Results show that the charge density can reach up to -1.56×10^12 cm%-2 when the thickness of the film is 2.4 nm. The influence of charge density on cell conversion efficiency is further simulated using solar cell analyzing software （PC1D）. With AlOx passivating the rear surface of the silicon, the cell efficiency of 20.66% can be obtained.     

双光子激发ZnSe自由载流子超快动力学研究

采用Z扫描和抽运-探测实验技术, 在波长为532 nm、脉冲宽度为41 fs的条件下测得ZnSe晶体的双光子吸收系数, 并获得了不同激发光强下的自由载流子吸收截面、电子-空穴带间复合时间和电子-声子耦合时间. 研究发现, 随着激发光强的增大, 自由载流子吸收截面减小, 复合时间变短. 当激发光强增大导致载流子浓度大于10¹⁸ cm^-3时, 抽运-探测信号出现明显改变, 原因归结为强光场激发导致样品在短时间内带隙变窄和电子-空穴等离子体的形成.     

全印刷碳纳米管薄膜晶体管构建及电性能研究

利用纳米压印和电刷镀技术在PET基体上制作出大面积金源、漏电极阵列。分别采用钛酸钡复合材料为介电层,印刷银电极为顶电极,聚芴-二噻吩基吡咯并吡咯二酮(PF8DPP)分离的半导体碳纳米管为有源层,在柔性基体上构建出全印刷碳纳米管薄膜晶体管器件和反相器。全印刷碳纳米管薄膜晶体管的开关比和迁移率分别达到4×10⁴和6 cm²·V^-1·s^-1,且器件表现出零回滞特性。构建的反相器在V_dd =8 V时,其增益可以达到12。     

Parameters of Isotope Shifts for 2s2p~(3,1)P_1→ 2s~(2 1)S_0 Transitions in Heavy Be-Like Ions

The field shift and mass shift parameters of the 2s2p~(3,1)P_1→ 2s~(2 1)S_0 transitions in Be-like ions(70 ≤ Z≤ 92)are calculated using the multi-configuration Dirac–Hartree–Fock and the relativistic configuration interaction methods with the inclusion of the Breit interaction and the leading QED corrections. We find that the mass shift parameters of these two transitions do not change monotonously along the isoelectronic sequence in the high-Z range due to the relativistic nuclear recoil effects. A minimum value exists for the specific mass shift parameters around Z= 80, especially for the 2s2p~(3,1)P_1→ 2s~(2 1)S_0 transition. In addition, the field shifts and mass shifts of these two transitions are estimated using an empirical formula, and their contributions are compared along the isoelectronic sequence.     

GPRS技术在农村用水远程自动抄表系统中的应用

目前许多偏远农村地区用水长期以来一直采用的是包月制方式,这种模式的特点是不论用户的月用水量是多少,只要每月交付一定的水费即可。用水量与用水费的严重不一致,不仅不利于供水部门对用户用水的实时监管,更不利于环保节水的实现。农村地区地理位置比较分散,考虑目前移动网络覆盖范围之广,利用中国移动或中国联通的GPRS网络在实验室搭建无线自动抄表系统。实验结果表明,GPRS技术在农村用水监管系统中的应用,一方面可以降低传统人工抄表员的工作强度;另一方面抄读回的计量数据精确无误,完全克服了人工抄表的缺点。     

Effect of Flow-rate Induced Cation Mixing and Particle Size Tuning on the Structure and Electrochemical Properties of LiNi0.8Co0.1Mn0.1O2 Synthesized by Spray Drying

Lithium ion battery cathode material LiNi0.8Co0.1Mn0.1O2(NCM811)was synthe-sized via a spray drying method.The effect of different spray drying flow-rates(200,250,300,and 400 mL·min^-1)on the structural and electrochemical properties of NCM811 are investigated.We find that the contents of Ni,Co,and Mn in the NCM811 cathode materials do not change significantly with the changing flow-rate,but the lattice parameter and morphology of the materials are significantly affected.Under the optimal spray drying flow-rate(250 mL·min^-1),the obtained NCM811 cathode(250NCM811)exhibits the best crystallinity,with the highest ratio of I(003)/I(104)in the XRD pattern.SEM images reveal the spherical morphology of 250NCM811 and the average diameter of about 5 mm.The results of electrochemical test show that the reversible capacity of 250NCM811 reaches 210 mA·g^-1 at 0.2 C(1 C=280 mA·g^-1).After 100 charge-discharge cycles at 1 C,the battery retains more than 94%of its initial capacity.Overall,spray drying flow-rate demonstrates great effect on the electrochemical properties of NCM811.