A New Comb Circular Polarizer Suitable for Millimeter‐Band Application

This letter presents a new polarizer which has a simple comb structure inside a circular waveguide. The electrical performance of the proposed comb polarizer is optimized by a circular waveguide radius and by the physical parameters of the comb plates. This polarizer is suitable for providing good performance in millimeter‐band application because of its simple structure and low fabrication cost. In our experiments the dual‐band comb polarizer designed in band 1(K) and band 2(Ka) showed good electrical performance without any tuning elements.     

碳纤维缠绕复合材料在潜水外压容器上的应用

在铝合金圆筒体外以浸渍树脂碳纤维进行缠绕复合增强，增强后的筒体耐静水外压能力大幅度提高；整体缠绕的全复合材料筒体，在耐静水外压能力及减轻自身重量方面也获得了明显的效果。此外，在铝合金细长圆管的外壁复合缠绕碳纤维，能有效地提高圆管对轴向压载荷的抗失稳与抗屈曲破坏能力。     

固定波形时间保护间隔OFDM系统循环卷积特性研究

针对固定波形时间保护间隔OFDM系统接收端OFDM信息符号和信道冲击响应之间不具有循环卷积特性的系统特点,本文提出一种简单有效的信号处理算法对该系统接收端OFDM信息符号和信道冲击响应之间的循环卷积特性进行恢复。理论分析和计算机仿真表明,该算法能够恢复接收端此循环卷积特性;在时延扩展和AWGN信道条件下,系统误符号性能受到的影响微弱。     

高效辐射换热器的研制

本文所介绍的高效辐射换热器是指在其环缝通道中安装有网状二次传热面的辐射换热器，用对比实验方法研究了它们在空气预热温度、给热系数和阻力系数上的差别．实验表明：高效辐射换热器可强化空气侧的传热，其综合传热系数达５９Ｗ／（ｍ２·℃），而阻力系数可控制在３０００Ｐａ以内．     

Local artificial boundary conditions for Schrödinger and heat equations by using high-order azimuth derivatives on circular artificial boundary

The aim of the paper is to design high-order artificial boundary conditions for the Schrödinger equation on unbounded domains in parallel with a treatment of the heat equation. We first introduce a circular artificial boundary to divide the unbounded definition domain into a bounded computational domain and an unbounded exterior domain. On the exterior domain, the Laplace transformation in time and Fourier series in space are applied to achieve the relation of special functions. Then the rational functions are used to approximate the relation of the special functions. Applying the inverse Laplace transformation to a series of simple rational function, we finally obtain the corresponding high-order artificial boundary conditions, where a sequence of auxiliary variables are utilized to avoid the high-order derivatives in respect to time and space. Furthermore, the finite difference method is formulated to discretize the reduced initial–boundary value problem with high-order artificial boundary conditions on a bounded computational domain. Numerical experiments are presented to illustrate the performance of our method.     

The Resource-Energy Nexus as a Key Factor for Circular Economy

The extraction of raw materials is associated with energy input and CO₂ emissions. What is obvious for extraction from mining, however, also applies to recycling. Mostly, recycling is preferred for reasons of climate protection or because of the geological scarcity of raw materials, which is controversially discussed. While in mining, the declining ore grade is a driver for the energy demand, in case of recycling it is the dissipation of materials into products or waste. As concentration decreases, the effort required also increases disproportionately. The “closing the loop” metaphor of Circular Economy is therefore inappropriate in its stricter meaning. It is rather about optimizing the overall system and finding the optimal recycling rate. However, first, it must be clarified what the political goals for Circular Economy are.     

选煤厂取料机料耙液压泵站控制系统设计

针对目前选煤厂取料机料耙液压泵站电动机大多采用直接启动方式,液压油的温度检测采用模拟仪表实现,存在着对设备冲击大、油温检测精度不高、可靠性差等问题,提出了基于软启动器和PLC的新型液压泵站控制系统设计方案。该系统通过PLC采集液压泵站油温及设备运行状态,根据设定的工作模式对其进行控制,并可实时在线显示液压泵站运行状态、故障诊断报警信息,具有油温超限、滤油器堵塞、电动机过流等多种保护功能。     

关于传统空间缓冲区生成算法的分析

本文通过对各类空间缓冲区生成的算法思想及算法实现进行分析与比较,给出了避免在缓冲区生成结果的过程中出现的失真与尖角等问题的最适合的解决方法。     

Point Set pattern matching ind-dimensions

In this paper we apply computational geometry techniques to obtain an efficient algorithm for the following point set pattern matching problem. Given a setS ofn points and a setP ofk points in thed-dimensional Euclidean space, determine whetherP matches anyk-subset ofS, where a match can be any similarity, i.e., the setP is allowed to undergo translation, rotation, reflection, and global scaling. Motivated by the need to traverse the sets in an orderly fashion to shun exponential complexity, we circumvent the lack of a total order for points in high-dimensional spaces by using an extension of one-dimensional sorting to higher dimensions (which we call circular sorting). This mechanism enables us to achieve the orderly traversal we sought. An optimal algorithm (in time and space) is described for performing circular sorting in arbitrary dimensions. The time complexity of the resulting algorithm for point set pattern matching is O(n logn+kn) for dimension one and O(kn^d) for dimensiond2.Supported in part by CNPq-Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (Brazil) under Grants 200331/79, 300157/90-8, and 500787/91-3.Supported in part by the National Science Foundation under Grant CCR 8901815.