Structural Analysis of the Complex between Penta-EF-Hand ALG-2 Protein and Sec31A Peptide Reveals a Novel Target Recognition Mechanism of ALG-2

ALG-2, a 22-kDa penta-EF-hand protein, is involved in cell death, signal transduction, membrane trafficking, etc., by interacting with various proteins in mammalian cells in a Ca²⁺-dependent manner. Most known ALG-2-interacting proteins contain proline-rich regions in which either PPYPXnYP (type 1 motif) or PXPGF (type 2 motif) is commonly found. Previous X-ray crystal structural analysis of the complex between ALG-2 and an ALIX peptide revealed that the peptide binds to the two hydrophobic pockets. In the present study, we resolved the crystal structure of the complex between ALG-2 and a peptide of Sec31A (outer shell component of coat complex II, COPII; containing the type 2 motif) and found that the peptide binds to the third hydrophobic pocket (Pocket 3). While amino acid substitution of Phe⁸⁵, a Pocket 3 residue, with Ala abrogated the interaction with Sec31A, it did not affect the interaction with ALIX. On the other hand, amino acid substitution of Tyr¹⁸⁰, a Pocket 1 residue, with Ala caused loss of binding to ALIX, but maintained binding to Sec31A. We conclude that ALG-2 recognizes two types of motifs at different hydrophobic surfaces. Furthermore, based on the results of serial mutational analysis of the ALG-2-binding sites in Sec31A, the type 2 motif was newly defined.     

一种提高变频器网络通讯效率的接口适配器

设计了一种提高变频器网络通讯效率的接口适配器.详细介绍该接口适配器的软硬件设计和工作原理.实验结果表明,这种适配器有效地提高了变频器网络通讯效率,具有很好的实用性.     

多总线兼容的板级测试系统设计

由于不同板卡的总线接口不同,对板卡的测试也需要多种测试系统,因此成本较高。针对以上问题,设计了一种能兼容多种总线的板级自动化测试系统。介绍了系统的硬件构建方法和工作原理,重点论述了多种总线接口兼容和不同种类信号切换的实现途径。实际应用表明,该系统具有通用性强、速度快、可靠性高等优点。     

甲烷/空气预混合气在定容燃烧室内的燃烧试验

为研究进气温度、进气压力、当量燃烧比、射流引燃、压燃(自燃)等对甲烷燃烧的影响,以提高点燃式天然气发动机的性能,在定容燃烧室(CVCC)内进行甲烷/空气预混合气的燃烧试验,通过火焰高速摄影和气体压力测量等手段,获取试验结果并进行分析.试验发现,在燃烧室内安装带通孔的横隔板后,有利于加快火焰传播速度、提高燃烧峰值压力和燃烧的稳定性,在某些试验条件下,下燃烧室会出现混合气压燃(自燃)现象.     

虚拟仪器中的科学计算可视化系统

介绍了虚拟仪器中科学计算可视化的特点和实现方法。通过软件适配器的方法和基于区域配置的策略，实现多区域、多显示模式的混合和自由切换显示，通过多次细化等方法，加速图形显示来满足虚拟仪器对图形显示实时性的要求。研制了一种通用的虚拟仪器科学计算可视化环境，给出了该可视化系统在典型虚拟仪器中的应用。     

基于四管同步升降压变换器汽车适配器设计

讨论了四管同步Buck-Boost升降压变换器的工作原理.这种变换器有同步降压Buck、降升压Buck-Boost、同步升压Boost三种工作模式.详细分析了输入和输出接近相等时,四管同步降压及升压Buck-Boost模式的工作原理.降压Buck-Boost模式中电感先深去磁,再短时间的深激磁,然后长时间的浅激磁;升压Buck-Boost模式中电感先深激磁,再短时间的深去磁,然后长时间的浅去磁,从而维持低纹波的输出电压调节.还介绍了具有12V/24V通用电池电压输入范围的汽车电池适配器的设计过程,讨论了电感的计算和选取方法,以及PCB的设计原则.     

CAN总线通信适配卡驱动程序的开发

描述了CAN总线的特点和通讯适配卡的工作原理,以及基本的通讯协议,然后详细阐述了通过DDE通讯在组态软件环境下对CAN适配卡的驱动编程,最后说明了上位机与CAN节点通讯的组态实现。     

SN388仪器XDEV适配器的原理及井口信号的记录

SN388仪器采用XDEV(extra device)适配器配合MACHA DTX爆炸机系统可自动完成对井口时间的记录,增强了SN388仪器的适用性,方便了野外地震数据的采集工作。本文详细地介绍了SN388仪器XDEV适配器的结构及原理。     

Design and Performance of Miniaturized Piezoelectric Step-Down Transformer

Piezoelectric transformers are expected to be small, thin and highly efficient, and which are attractive as a transformer with high power density for step down voltage. For these reasons, we have attempted to develop a step-down piezoelectric transformer for the miniaturized adaptor. we propose a piezoelectric transformer, operating in thickness extensional vibration mode for step-down voltage. This transformer consists of a multi-layered construction in the thickness direction. In order to develop the step-down piezoelectric transformers of 10 W class and turn ratio of 0.1 with high efficiency and miniaturization, the piezoelectric ceramics and piezoelectric transformer designs are estimated with a variety of characteristics. The basic composition of piezoelectric ceramics consists of ternary yPb(Zr_xTi_{1 – x})O₃–(1–y)Pb(Mn_1/3Nb_1/3Sb_1/3)O₃. In the piezoelectric characteristics evaluations, at y = 0.95 and x = 0.505, the electromechanical coupling factor(k_p) is 58%, piezoelectric strain constant (d₃₃) is 270 pC/N, mechanical quality factor(Q_m) is 1520, permittivity ( ₃₃^T/₀) is 1500, and Curie temperature is 350C. At y = 0.90 and x = 0.500, k_p is 56%, d₃₃ is 250 pC/N, Q_m is 1820, ₃₃^T/₀ is 1120, and Curie temperature is 290C. It shows the excellent properties at morphotropic phase boundary regions. PZT-PMNS ceramic may be available for high power piezoelectric devices such as piezoelectric transformers. The design of step-down piezoelectric transformers for adaptor proposes a multi-layer structure to overcome some structural defects of conventional piezoelectric transformers. In order to design piezoelectric transformers and analyze their performances, the finite element analysis and equivalent circuit analysis method are applied. The maximum peak of gain G as a first mode for thickness extensional vibration occurs near 0.85 MHz at load resistance of 10 . The peak of second mode at 1.7 MHz is 0.12 and the efficiency is 92%.     

同步CDMA系统带后端自适应的线性去相关多用户检测算法

本文提出了一种在后端附加自适应的线性去相关多用户检测算法,详细分析了该算法的性能并进行了仿真。分析与仿真结果均表明,这种算法既具有优良的抗远近效应能力又具有较低的误码率