西门子S7-200可编程控制器在气化油点火技术中的应用

以西门子S7—200PLC为核心。利用火检探头。温度、压力等传感器，结合STEP 7 MicmwIN V3．1以及ProTool Pro CS工业组态软件完成了对点火过程的自动控制。实现了西门子S7—200PLC在大型发电厂410吨级蒸汽锅炉“气化油直接点燃煤粉技术”中的应用。提高了锅炉点火系统运行的自动化水平。     

水平井现场地质导向方法及其应用

为了降低水平井的钻探工程成本，要尽量不钻或少钻导眼井段。根据水平井在钻前准备、深度预测、稳定井斜、水平导入4个阶段的不同作业特点，依据现场施工经验，归纳提出了利用公式法、小导眼法、曲线指示法、扭矩与dc指数法等方法进行地质导向的成功实践。利用这些方法，可以有效地指导现场钻井人员，将钻井轨迹比较准确地导入目的层中。     

钢筋混凝土结构内的钢筋腐蚀监测

用钢筋混凝土修建的建筑物和构筑物，因受外界因素的影响，其内部钢筋可能会受到腐蚀而生锈，锈蚀严重者将危及安全。根据钢筋在混凝土内的锈蚀是一个电化学过程的特点，在不损伤钢筋混凝土结构的条件下，利用腐蚀监测仪，测量钢筋混凝的电化学特性值，并以此特性值绘制等值线图，利用该图能正确评估混凝土内钢筋受腐蚀的情况。     

青城子矿田小佟家堡子金银矿床地质特征及成矿物质来源探讨

小佟家堡子金银矿床赋存在辽河群大石桥组PtLd^5 3和PtLd^4 3的互层带之中。矿体受层间滑脱构造控制。容矿岩石以自云石大理岩和硅质岩为主，矿体呈层就、似层就。矿石中的金以不可见金为主，金古量与毒砂关系最密切。成矿物质来源于地层——即海底火山喷气和喷流作用形成含矿热卤水，经运移在海盆边缘沉积形成矿源层或维集区，经区域变质作用和岩浆作用的改造，在印支期就位。矿床成因类型为同生沉积-变质一岩浆热液叠加再造型金银矿床。     

Stochastic iterative algorithms for signal set design for Gaussianchannels and optimality of the L2 signal set

We propose a stochastic iteration approach to signal set design. Four practical stochastic iterative algorithms are proposed with respect to equal and average energy constraints and sequential and batch modes. By simulation, a new optimal signal set, the L2 signal set (consisting of a regular simplex set of three signals and some zero signals), is found under the strong simplex conjecture (SSC) condition (equal a priori probability and average energy constraint) at low signal-to-noise ratios (SNR). The optimality of the L1 signal set, the confirmation of the weak simplex conjecture, and two of Dunbridge's (1967) theorems are some of the results obtained by simulations. The influence of SNR and a priori probabilities on the signal sets is also investigated via simulation. As an application to practical communication system design, the signal sets of eight two-dimensional (2-D) signals are studied by simulation under the SSC condition. Two signal sets better than 8-PSK are found. Optimal properties of the L2 signal set are analyzed under the SSC condition at low SNRs. The L2 signal set is proved to be uniquely optimal in 2-D space. The class of signal sets S(M, K) (consisting of a regular simplex set of K signals and M-K zero signals) is analyzed. It is shown that any of the signal sets S(M, K) for 3⩽K⩽M-1 disproves the strong simplex conjecture for M⩾4, and if M⩾7, S(M, 2) (the L1 signal set) also disproves the strong simplex conjecture. It is proved that the L2 signal set is the unique optimal signal set in the class of signal sets S(M, K) for all M⩾4. Several results obtained by Steiner (see ibid., vol.40, no.5, p.721-31, 1994) for all M⩾7 are extended to all M⩾4. Finally, we show that for M⩾7, there exists an integer K'相似文献   

Optimal phases for a family of quadriphase CDMA sequences

Signature sequences with good even even and odd (or polyphase) correlations are crucial for asynchronous code-division multiple access (CDMA). When the data sequence is random, the even and odd (or polyphase) correlations are equally important. However, for most known signature sequences, only their even correlations were analyzed. It appears that determining the odd (or the polyphase) correlations is generally a very hard problem since the odd (or the polyphase) correlations depend on the phases of the signature sequences. Sole (1989), Boztas, Hammons, and Kumar (1992) found a family of quadriphase sequences that are asymptotically optimal. These sequences gain a factor √2 in terms of their maximum periodic even correlations when compared with the best possible binary phase-shift keying (BPSK) sequences. We find the optimal phases of these sequences. The optimality is in the sense that at these phases, the mean square values of the even, odd, and the polyphase correlations are minimal, and achieve the Welch (1974) bound-equality simultaneously. Furthermore, we show that at these phases, the average user interference of these sequences is always smaller than that of the ideal random signature sequences. Comprehensive analytical and numerical results show that good phase sequences can offer a nonnegligible amount of gain over bad phase sequences at modest and high signal-to-noise ratios     

校园IC卡系统设计与管理信息系统

本文通过一个实际的IC卡应用系统一校园IC卡系统的设计与实现过程，给出了开发研制IC卡应用系统的基本方法．本文还对校园IC卡管理信息系统作了介绍．该系统的管理软件采用数据库语言FoxProforWindows编写，具有人机界面友好直观、多画面、多窗口、安全可靠等特点．     

改善高平均功率固体激光器光束质量的研究

本文首先概述了内含热透镜的激光谐振腔的分析方法，提出影响高平均功率固体激光器光束质量的主要因素是激光介质的热效应，尤其是非对称的热透镜象差。因此，改善光束质量的途径是补偿或修正透镜象差，使光束质量达到非相干多模振荡的理论值。     

Chaotic frequency hopping sequences

This letter describes a novel family of frequency hopping sequences generated by chaotic systems. The sequences give a uniform spread over the entire frequency bandwidth. In addition to having good Hamming correlation properties, they possess ideal linear span. The sequences produce almost as good performance as random hopping patterns when used in frequency hopping code-division multiple-access (FH/CDMA) systems. Many numerical examples based on a digital chaos generator are presented