集中供热系统节能潜力分析

从提高能源利用率出发,论述供热系统能耗的环节和评估.通过对已运行系统能耗情况的调查与评估,分析了能耗相差悬殊的原因,提出依靠科学技术,改造和完善供热系统,并挖掘其节能潜力.     

光电跟踪系统力矩波动干扰抑制的研究

光电跟踪系统的力矩波动是影响其跟踪精度的噪声的角度一个关键问题.基于某光电跟踪控制系统动态模型,从抑制噪声的角度分析了加入电流环对抑制力矩波动的影响,同时还分析了系统速度、电流两环闭环带宽与力矩波动抑制之间的关系.分析表明,加入电流环后的光电跟踪系统抑制力矩波动的能力明显增强,同时较高的速度回路带宽有利于抑制力矩波动引起的干扰,且在速度带宽一定的情况下增加电流用环带宽对抑制力矩波动也有一定作用.因此,在设计光电跟踪系统时,在不影响系统稳定性的前提下应选用尽可能大的速度及电流闭环带宽.     

Deformation behaviour and mechanical properties of polypropylene processed by equal channel angular extrusion: Effects of back-pressure and extrusion velocity

Severe plastic deformation by equal channel angular extrusion (ECAE) is an ingenious deformation process used to modify texture and microstructure without reducing sample cross-section. The application of single ECAE pass to polypropylene (PP) was meticulously investigated at room temperature using a 90° die-angle tooling. The ECAE-induced deformation behaviour was examined in relation to the load versus ram-displacement curves. Depending on extrusion conditions, PP displayed various types of plastic flow. For ram velocities beyond 4.5 mm/min, severe shear bands consisting of successive translucent and opaque bands were observed, accompanied on the top surface by more or less pronounced periodic waves. Although the application of a back-pressure significantly reduced the wave and shear-banding phenomena, slightly inhomogeneous shear deformation was still observed. Shear bands were only suppressed by decreasing extrusion velocity. The strain-induced crystalline microstructure was investigated by X-ray scattering. Shear-banded samples exhibited a strong texturing of the (hk0) planes along the shear direction in the translucent bands whereas perfect crystalline isotropy appeared in the opaque bands. Application of back-pressure and/or reducing ram velocity resulted in uniform texturing along the extruded sample. Yet, texturing changed from single shear to twin-like shear orientation about the shear direction. Mechanical properties changes of the extruded samples due to back-pressure and extrusion velocity effects were analyzed via uniaxial tensile tests. The tensile samples displayed multiple strain localizations in shear-banded materials whereas quite homogeneous deformation appeared for non-banded ones. These effects were connected with the crystalline texturing. The results also revealed significant increase in the strain hardening after ECAE. Digital image correlation technique suitable for large deformation was used for determining the full-field strain of the tensile samples in relation to tensile strain and ECAE conditions.     

有机-无机杂化节能薄膜的制备、性能及应用

通过在有机相中掺杂SiO_2、TiO_2等具有光学性能的无机组分,制备的高紫外光吸收率、高可见光透过率、高红外反射率的有机-无机杂化薄膜可作为玻璃贴膜使用,广泛应用于公用建筑、民用建筑、汽车玻璃等领域,能阻隔50%～78%的热量,节能效果显著.本文介绍了有机-无机杂化节能薄膜的几种制备工艺,包括直接混合法、溶胶-凝胶法、插层复合法、气相沉积法等,比较了其制备工艺条件,分析了各自的优缺点,并对杂化节能薄膜的应用前景进行了展望.     

玻化微珠保温砂浆在建筑保温节能与抗震加固一体化中的应用

介绍了新型建筑材料玻化微珠保温砂浆,分析了其综合性能和应用范围。结合我国建筑节能和抗震加固的要求和现状．提出将玻化微珠保温砂浆用于保温节能和抗震加固一体化施工,阐述了将该材料用于一体化施工的技术可行性和经济合理性。     

热泵除湿机在会所恒温游泳池中的应用

介绍了热泵除湿机在制冷除湿的同时,实现了废热回收利用。通过室内参数的计算与常规系统进行经济性比较,阐明了热泵除湿机应用在游泳池中,既能提高室内舒适度,又能有效地节约能源。     

谈计算机技术与建筑的关系

从建筑画的发展谈起,阐述了计算机辅助建筑设计的发展及其在建筑画表达方面的巨大影响和不足之处。并结合全球能源紧缺的现实,论述了计算机技术在建筑能耗模拟和工况运行监测等新领域的应用情况。     

Behavior of the vorticity vector in a supersonic nonuniform swirl flow of a combustible gas behind a moving curvilinear shock or detonation wave

Expressions for components of the vorticity vector behind a curvilinear shock or detonation wave propagating in a supersonic nonuniform flow of a combustible gas are derived. Plane and axisymmetric gas flows are considered. The free stream in the general case is a vortex flow with a specified distribution of parameters. Formulas for the vorticity components in the plane of the flow for axisymmetric flows are found to have the same form as formulas for steady axisymmetric flows. As in the case of steady flows, the normal-to-wave component of vorticity is demonstrated to remain continuous across the discontinuity surface; in the case of axisymmetric flows, the ratio of the tangential component of vorticity aligned in the plane of the flow to density also remains continuous, though the quantities themselves become discontinuous. __________ Translated from Fizika Goreniya i Vzryva, Vol. 45, No. 2, pp. 68–75, March–April, 2008.     

浅议绿色建筑的发展

现阶段发展绿色建筑非常必要,需要社会各方面的支持,根据绿色建筑的定义和特点,分析目前我国绿色建筑发展过程中存在的一些问题和实例剖析,总结出绿色建筑设计中的一般性原则。     

地下建筑节能设计浅析

地下建筑的运行能耗问题有其特殊性。按照影响地下建筑运行能耗的主要因素:埋深和内扰,对地下建筑进行了分类,指出地下建筑节能的途径、性能性方法和规定性指标;其中,性能性方法的实施依赖于专门针对地下建筑的能耗分析软件。规定性指标方面则主要探讨地下建筑的自然通风和防潮设计。