一种新型碾盘碾压辊在线堆焊修复装置

0 前言 中国生产水泥量位居世界第一,水泥的生产程序是十生料经过焙烧成为熟料,熟料粉碎后为水泥.生料的粉碎是由生料立磨,简称立磨完成.粉碎生料是水泥生产中的必要的程序,粉碎生料的立磨是关键的设备.国内的20世纪80年代开始推广,并替代球磨机.     

等离子喷涂典型耐磨涂层材料体系与性能现状研究

等离子喷涂作为重要的热喷涂技术之一,在零件表面强化处理与再制造损伤修复领域具有广泛的应用.由于不同机械零部件工作环境(温度、转速、腐蚀环境、润滑状况等)、基体材质及运动形式等因素存在较大的差异,因而通常需根据其具体服役工况选择最优的表面强化涂层,以满足零件表面摩擦学性能需求,提升机械装备的综合服役性能.基于此,对国内外采用等离子喷涂技术所制备的典型耐磨涂层的材料体系及涂层性能进行了详细地综述,系统介绍了组织成分、物相结构、力学性能、服役工况等因素对典型涂层(包括金属基涂层、陶瓷基涂层及多相复合涂层等)摩擦学性能的影响机理.结果表明,涂层的摩擦学性能受到涂层自身特性相关的内因(包括孔隙率、力学性能、组织成分等)和服役工况相关的外因(包括载荷、频率、润滑状态、工作介质等)的影响;典型金属基耐磨涂层包括Fe基、Ni基和Mo基涂层等,通过表面处理、后处理和工艺优化等手段,可显著改善涂层的摩擦学性能;采取不同的喷涂方式因颗粒熔化程度差异,使陶瓷基涂层产生不同的磨损程度;针对纳米、微米结构的陶瓷基涂层进行对比分析,发现纳米涂层通过吸收应力而降低磨损;复合涂层通过添加润滑相能够降低其摩擦因数、减轻涂层磨损,其中相较于单一润滑相,多组润滑相能通过发挥协同润滑效果,使涂层在不同温度区间下保持良好的耐磨性.最后,对等离子喷涂涂层耐磨性能的提升和优化方向进行了展望.     

油枣多糖的酶法提取及其对多糖分子量分布的影响

本实验用正交试验法优化了油枣多糖的纤维素酶法提取工艺,同时采用分级醇沉和分步醇沉的方法探讨了热水提取与酶法提取的多糖分子量分布。结果表明,纤维素酶法提取油枣多糖的最佳提取条件为:pH4.5,提取温度60℃,酶添加量0.02%,提取时间2h;热水提取与酶法提取的多糖分子量分布无明显差异。     

混流式水轮机转轮倒置安装轴向水推力的计算

目前大中型水电站混流式水轮机轴向水推力大，尾水管中涡带所产生的压力脉动常引起机组振动。如水轮机转化倒置安装，将向下的轴向水推力改为向上，可以抵消机组转动部分的重量；如改变尾水管形状，可以消除涡带压力脉动，减小机组振动。以漫湾电站为例，经过计算说明正常安装与倒置安装轴向推力轴承负荷可大大减小。但倒置安装后其结构问题尚需进一步研究。     

绝热管道表面散热损失测量不确定度的评定

测量结果的不确定度是表示测量结果分散性的参数。文中对管道绝热结构表面散热损失测量结果不确定度进行评定,分析了测量结果不确定的主要来源,规范了节能监测报告中测量结果不确定度的描述与表达,以提高节能监测测量数据的准确可靠性。     

Analysis of inverse synthetic aperture radar imaging in the presence of time-varying plasma sheath

The plasma sheath can induce radar signal modulation, causing not only ineffective target detection, but also defocusing in inverse synthetic aperture radar (ISAR) imaging. In this paper, through establishing radar echo models of the reentry object enveloped with time-varying plasma sheath, we simulated the defocusing of ISAR images in typical environment. Simulation results suggested that the ISAR defocusing is caused by false scatterings, upon which the false scatterings’ formation mechanism and distribution property are analyzed and studied. The range of false scattering correlates with the electron density fluctuation frequency. The combined value of the electron density fluctuation and the pulse repetition frequency jointly determines the Doppler of false scattering. Two measurement metrics including peak signal-to-noise ratio and structural similarity are used to evaluate the influence of ISAR imaging     

Wideband radar cross-section reduction using plasma-based checkerboard metasurface

For stealth technology, in order to overcome the limitations of thin-layer plasma for electromagnetic waves attenuation and further broaden the radar cross-section (RCS) reduction (RCSR) band of the metasurface, the plasma-based checkerboard metasurface composed of plasma and checkerboard metasurface is investigated to achieve better RCSR. We designed a checkerboard metasurface which can achieve abnormal reflection to reduce RCS and whose −10 dB RCSR bandwidth is from 8.1 to 14.5 GHz, the RCSR principle of it lies in the backscattering cancellation, which depends on the phase difference of artificial magnetic conductor (AMC) units. The designed plasma-based checkerboard metasurface is a thin composite structure, including a checkerboard metasurface, a plasma layer, and an air gap which is between them. Full wave simulations confirm that the plasma-based checkerboard metasurface's ‒10 dB RCS reduction bandwidth and RCS reduction amplitude, are both increased under different polarized waves compared with the only single plasma or the only metasurface. We also introduced the reason and mechanism of the interaction between plasma and the checkerboard metasurface to improve the RCSR effect in detail. As plasma-based checkerboard metasurface does not need the plasma to be too thick for plasma stealth, its application in practical scenarios is easier to implement.     

Inverse synthetic aperture radar range profile compensation of plasma-sheath-enveloped reentry object

The scattering points in a plasma sheath characterized with coupled velocities can cause pulse compression mismatching, which results in displacement and energy diffusion in the one-dimension range profile. To solve this problem, we deduce the echo model of the plasma-sheath-enveloped reentry object. By estimating the coupled velocities, we propose a compensation method to correct the defocus of an inverse synthetic aperture radar (ISAR) image in range dimension to improve the quality of the ISAR images. The simulation results suggest that the echoes from different regions of the surface of the reentry object have various coupling velocities, and the higher the coupled velocity, the more serious the displacement and energy diffusion in the range dimension. Our proposed method can correct the range dimension aberration. Two measurement metrics were used to evaluate the improvement of the compensation method.     

磨溪天然气净化厂中水回用可行性探讨

文章对磨溪天然气净化厂外排废水的来源、水量、水质、处理工艺和达标情况进行了研究，探讨了工厂外排废水处理的中水回用的可行性，证明磨溪净化厂中水可用于厂内绿化，既可减少污染物排放，降低能耗，又可增加新鲜水资源，经济和环境效益明显。     

高阶类型化软件体系结构建模和验证及案例

根据权威统计数据，软件测试中发现的70%以上的错误由需求获取或体系结构设计引起.因此，应用软件体系结构在设计阶段的正确性验证非常重要.现有的软件体系结构设计方法不支持需求满足验证，需求满足验证需要其他验证工具的支持.面向主流Web应用软件的体系结构设计及其需求满足验证，提出了一种高阶类型化软件体系结构建模和验证语言（SAML）与软件体系结构建模和验证方法（SAMM）.SAML语言通过定义类型和项的语法及语义，描述软件体系结构中类型和对象的构造，通过定义类型规则及其类型检查算法来判定Γ|-t：T和Γ|-R（T₁，T₂）是否成立.SAMM给出了软件体系结构建模范式，包括构建接口类型M_cls（type interface）、组件M_cmpt（component）、容器M_cont（container）、框M_frm（frame）和框架M_frwk（framework）这5层建模过程，以及生成层内与层间类型之间关系对应的类型规则，同时定义了接口类型方法调用图（G_SA）用以刻画软件体系结构设计要求，定义了类型序列及其正确性用以刻画需求期望的性质，并给出了相应的验证算法.设计实现了基于该方法的原型工具系统SAMVS，其中，模型编辑环境支持应用软件的设计过程，验证环境支持设计满足需求的自动化验证.通过一个实际案例，完成了一个较大规模"互联网+"应用软件系统的体系结构建模和验证.