基于移位原理的顺序控制器研究

本文根据PLC顺序控制程序的设计思路,阐述了用常用集成数码移位寄存器、电力电子开关电路和少量外围电子元件构成移位控制器的原理,根据此设计思路制作的移位控制器经过在实验室环境下运行,证明了设计方案的可行性。     

Nanotribological study of PECVD DLC and reactively sputtered Ti containing carbon films

Amorphous carbon film, also known as DLC film, is a promising material for tribological application. It is noted that properties relevant to tribological application change significantly depending on the method of preparation of these films. These properties are also altered by the compositions of these films. DLC films are well known for their self-lubricating properties, as well. In view of this, the objective of the present work is to compare the tribological properties of diamond like carbon (DLC) film obtained by plasma enhanced chemical vapour deposition (PECVD) with the Ti containing nanocrystalline carbon (Ti/a-C:H) film obtained by unbalanced magnetron sputter deposition (UMSD) in nN load range. Towards that purpose, DLC and Ti/a-C:H films are deposited on silicon substrate by PECVD and UMSD processes respectively. The microstructural features and the mechanical properties of these films are determined by scanning electron microscope (SEM), transmission electron microscope (TEM) and nano indenter. The surface topographies and the friction force surfaces of these films are evaluated by means of an atomic force microscope (AFM). The results show that although PECVD DLC film has higher elastic modulus and higher hardness than UMSD Ti/a-C:H film, the surface roughness and the friction coefficient of PECVD film is significantly higher than that of UMSD Ti/a-C:H film.     

地形变异条件下长江口南港河段水动力变化

1958—2010年,长江口南港河段河槽断面形态呈“U”型和“W”型交替变化。基于二维潮流数学模型,模拟了1958,1973,1997和2010年长江口地形条件下的水动力变化,进而分析了地形变化对潮波传递和潮流运动的影响。研究表明,南港河段水动力与地形变化密切相关。自1958年以来,南港河段潮差逐渐减小,潮波变形逐渐加剧;潮流与瑞丰沙发展变化联系紧密;1997年,瑞丰沙范围最大时,南港流速平面上呈复式分布,长兴水道为涨潮占优,其他年份,落潮占优,南港主槽始终为落潮占优;南港落潮分流比自1958至1973年明显降低,1973年后趋于稳定,为50%左右,随地形变化较小。     

Fe3O4-H2O2类Fenton体系催化降解苯酚

为提出基于新型磁纳米Fe3 O4催化剂的类Fenton体系,采用化学共沉淀法制备磁纳米Fe3 O4,用四甲基氢氧化铵（ TMAH）对所制备的磁纳米Fe3 O4进行表面改性,就Fe3 O4－H2 O2类Fenton体系对苯酚废水的处理效果进行探讨,考察催化剂投量、H2 O2浓度、pH、反应时间等因素对COD和挥发酚去除率的影响．结果表明：磁纳米颗粒平均粒径为30 nm,并在20～100 nm内呈现良好的粒度分布．不同剂量TMAH包覆的3种催化剂经超声预处理后,在室温（13℃）下对50 mg／L苯酚（相当于112 mg／L COD）的降解效果基本一致．当催化剂投量为0．8 mmol／L、H2 O2浓度为2．0 mmol／L、pH为4．5、反应时间180 min时,COD去除率最高可达72％;催化剂投量为0．4 mmol／L、H2 O2浓度为2．0 mmol／L、 pH为4．5、反应时间为90 min时,挥发酚的去除率接近100％．而在重复使用方面,3＃Fe3O4－TMAH（2 mL）催化剂的回用性最好,4次反应COD的去除率分别为73％、29％、28％、26％,挥发酚去除率分别为100％、84％、67％、54％．该类Fenton体系具有不产生多余泥量的优点,且磁纳米催化剂在外磁场作用下可实现快速分离回收．     

Finite difference method for dynamic response analysis of anchorage system简

Based on some assumptions, the dynamic analysis model of anchorage system is established. The dynamic governing equation is expressed as finite difference format and programmed by using MATLAB language. Compared with theoretical method, the finite difference method has been verified to be feasible by a case study. It is found that under seismic loading, the dynamic response of anchorage system is synchronously fluctuated with the seismic vibration. The change of displacement amplitude of material points is slight, and comparatively speaking, the displacement amplitude of the outside point is a little larger than that of the inside point, which shows amplification effect of surface. While the axial force amplitude transforms considerably from the inside to the outside. It increases first and reaches the peak value in the intersection between the anchoring section and free section, then decreases slowly in the free section. When considering damping effect of anchorage system, the finite difference method can reflect the time attenuation characteristic better, and the calculating result would be safer and more reasonable than the dynamic steady-state theoretical method. What is more, the finite difference method can be applied to the dynamic response analysis of harmonic and seismic random vibration for all kinds of anchor, and hence has a broad application prospect.     

《环境监测》课程工学结合一体化模式的探索性开发

为提高高职院校教学质量,培养企业需要的高素质技能型专门人才,将《环境监测》课程进行工学结合一体化模式的探索性开发。通过这种模式的改革,一方面可以提升高职院校《环境监测》课程教学效果,另一方面也可以培养学生良好的综合实践能力,使他们毕业以后能够更好地适应企业提供的实际工作岗位。     

直线磁场调制电机推力特性关键参数分析

直线磁场调制电机由于材料成本受行程长度影响较小,适合于长行程应用场合。为获得更好的推力特性,本文从理论研究入手,分析了直线磁场调制电机推力的解析公式,进而确定气隙磁密谐波含量影响推力特性。为了提高气隙磁密的正弦度,电机采用Halbach永磁阵列,相比于传统法向充磁直线磁场调制电机平均推力提高18%,但推力波动率也增大了3.4%。为了尽量降低推力波动,利用有限元法对Halbach永磁体结构、电枢齿靴宽度、调磁块的尺寸和形状等结构参数进行参数化分析与改进设计。最终平均推力为783N,相比于传统法向直线磁场调制电机平均推力提高了44.5%,推力波动率从16.1%降低到8.3%。     

Solid-state phase equilibria in the Gd–Co–Al ternary system at 1173 K

A portion of the isothermal section (1173 K) of the phase diagram of the Gd–Co–Al ternary system (up to 33.3 at.% Gd) were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) techniques. Fourteen single-phase regions (including solid solution regions of the binary compounds), twenty-five two-phase regions and twelve three-phase regions were found to exist at this isothermal section. In the GdCo₂–GdAl₂ system, the existence of the GdCo_0.74Al_1.26 phase is identified and it has a composition range of 30–45 at.% Al, the maximum solid solubility of Al in GdCo₂ is about 15 at.%, and Co in GdAl₂ is about 16 at.%. Besides, the maximum solid solubility of Al in Co, Gd₂Co₁₇ and GdCo₅ is about 6, 17 and 25 at.%, respectively, the maximum solid solubility of Gd in Co, CoAl is below 2 at.% and the solid solubility range is from 47 to 61 at.% Al in CoAl phase. In this work, no new ternary compounds were observed.     

山区小流域水土流失综合治理经济评价与效益分析——以天台县祥和溪等5条小流域为例

从天台祥和溪等5条小流域水土流失现状分析和水土流失综合治理措施出发,通过对坡改梯、水保林、经济林和小型水土保持工程的投入和效益分析,论证了水土流失综合治理的基础效益、生态效益和经济效益;同时通过对项目进行国民经济评价,经济内部收益率(EIRR)、经济净现值(ENPV)和效益费用比(EPCR)3项指标均达到要求。