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61.
62.
就城市集中供热工程造价的控制问题,从对设计阶段的成本、施工过程,加强材料成本、工程结算的控制几方面对其进行了详细的阐述,最后对工料分析与检查方面进行了论述,以提高供热企业的投资效益。 相似文献
63.
罗月泓 《湖南工业大学学报》2006,20(3)
首先分析了城市私房区带来的问题和改造的必然性,然后讨论了国内外私房区改造的经验和启示,最后提出了城市私房区改造的基本思路。 相似文献
64.
The process of dispensing one-component heat-cure adhesives was investigated in order to understand current application processes and to guide new process development. Typical one-component adhesives exhibit non-Newtonian rheological behavior, and hence Newtonian fluid mechanics does not adequately describe the dispensing process. In the present study, the adhesives were modeled as Bingham fluids possessing a yield stress and a steady state viscosity. The model of the dispensing apparatus includes four major flow sections connected in a serial configuration. The fluid mechanics equations derived for Bingham fluids in the individual flow sections were solved by numerical methods in order to understand the interrelationships between the material variables (e.g. yield stress, viscosity, temperature dependencies) and process variables (e.g. pressure, flow geometry, temperature, output). The concept of the model is generic and the details of the model can be modified for any forced-flow adhesive application process.
The adhesive flow properties significantly influence the process output. Dispensing temperature, among the process variables, has the strongest effect on process output. A ± 1.0·C perturbation in the dispensing temperature can cause as much as a 14% variation in the bead size for the range of adhesives studied. Differences in flow characteristics result in differences in processability and non-linear temperature/pressure sensitivity. The non-linear sensitivity can be eliminated by operating the dispensing process isothermally. Finally, the process limits for one-component adhesives, which are susceptible to chemical instability induced by viscous heating during processing, are defined and discussed in terms of a modified Brinkman number that takes into account viscous dissipation, heat conduction and convection, and chemical stability of the material during processing. 相似文献
The adhesive flow properties significantly influence the process output. Dispensing temperature, among the process variables, has the strongest effect on process output. A ± 1.0·C perturbation in the dispensing temperature can cause as much as a 14% variation in the bead size for the range of adhesives studied. Differences in flow characteristics result in differences in processability and non-linear temperature/pressure sensitivity. The non-linear sensitivity can be eliminated by operating the dispensing process isothermally. Finally, the process limits for one-component adhesives, which are susceptible to chemical instability induced by viscous heating during processing, are defined and discussed in terms of a modified Brinkman number that takes into account viscous dissipation, heat conduction and convection, and chemical stability of the material during processing. 相似文献
65.
人类聚居环境学对于居住区规划设计的启示 总被引:1,自引:0,他引:1
以人类聚居环境学的研究方法从若干方面对目前的居住区规划设计进行了一定的探讨,分析规划设计及建设方面目前存在的主要问题,提出以人类聚居环境学为指导的居住区规划设计理念。 相似文献
66.
ABSTRACT: The thermal evolution behavior of the organic free radicals induced in irradiated black pepper was studied by electron spin resonance spectroscopy. To analyze the time-dependent evolution process, we used the theory of transient phenomena, that is, an ordinal differential equation, as well as the nonlinear least squares numerical method. We found that the radical evolution that occurred in the irradiated pepper obeys a single exponential function and yields a unique time constant. The evolution of the organic free radical undergoes a simple reaction process of a single radical species. 相似文献
67.
N. N. Man’kina A. V. Kirilina O. V. Ovechkina B. G. Lyudomirskii B. G. Rubanov Yu. G. Tikhomirov T. Sh. Zakirov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2006,40(5):307-315
Studies conducted on two power-generating units at the Kharanorskaya SAPP relative to the steam-water-oxygen passivation,
preservation, and partial cleaning of all boiler-heating surfaces, including the surfaces of the reheater, and passivation
of the surfaces of the high-pressure heaters on the steam and water sides by the steam-oxygen method, as well as partial passivation,
preservation, and cleaning of turbine blading are presented.
__________
Translated from élektricheskie Stantsii, No. 6, pp. 56–64, May, 2006. 相似文献
68.
C. Guesdon I. Alxneit H.R. Tschudi D. Wuillemin J. Petrasch Y. Brunner L. Winkel M. Sturzenegger 《Solar Energy》2006,80(10):1344-1348
A new experiment has been installed to conduct studies at temperatures as high as 2500 K on chemical reactions that involve solids or melts and the release of condensable gases. The sample is radiatively heated by a 1 kW xenon short arc lamp placed in the upper focus of a vertically oriented ellipsoid of revolution. The optimal optical configuration has been determined by a Monte-Carlo Ray tracing method. Several methods to machine the reflector have been evaluated by experimentally determining the optical quality of the surface of plane test pieces. In the imaging furnace the sample is placed on a water-cooled support and heated by the concentrated radiation. This arrangement allows for fast heating and impedes the reaction of the sample with crucible material. A remotely controlled hammer allows for freezing the high-temperature composition of the sample by a fast quench. Thus, the sample can be later analyzed by conventional methods such as XRD or TEM. To allow for measurements under defined atmospheres and to protect the ellipsoidal reflector from liberated condensable products, the entire sample stage is enclosed by a hemispherical glass dome. The dome itself is protected from condensable compounds by a laminar flow of inert gas. Experiments with an incense cone at the place of the sample to visualize the gas flow showed that a steady layer of inert gas protects the dome from smoke, if the inert gas flow is properly adjusted. Measured peak flux densities clearly exceed 500 W cm−2 required to access temperatures of at least 2500 K. Decomposition experiments on copper sulfides confirmed the operation of the furnace. In the near future flash assisted multi-wavelength pyrometry (FAMP) will be implemented to measure sample temperatures online. Though the imaging furnace was developed to study the decomposition of metal sulfides it is obviously suited to conduct high-temperature studies on most materials relevant for high-temperature solar technology. 相似文献
69.
Higher heating values (HHVs) of fatty acids (C4–C18) were measured and correlated using linear least square regression analysis. Equations were developed for the estimation of the HHVs of saturated fatty acids from their molecular weight (Mw), density (DN) and carbon number (CN). These equations are HHV = 0.0518 Mw + 29.76, HHV = −93.4 DN + 122.67 and HHV = 0.7271 CN + 31.419 with R2 values of 0.9895, 0.9798, and 0.9895, respectively. The correlations may be used for HHV estimation of mixtures of fatty acids developed from vegetable oils. 相似文献
70.
塔河油区奥陶系原油的成熟度较高,且受生物严重降解.不同的生物标志化合物成熟度参数仅对有机质生成原油的不同阶段起到标尺作用,需优选既能较好地抗生物降解且适用于较宽的成熟度范围的指标来分析塔河油气运移的可能途径.三环萜烷/17α(H)-藿烷、重排甾烷/规则甾烷及Ts/(Ts+Tm)的比值是比较适用于塔河油区这种特殊性质的原油的生物标志化合物.根据研究,奥陶系原油油气存在两个注入通道,早期主要是由南向北方向运移,油气成熟度相对较低,成藏较早;晚期由东向西运移,原油成熟度相对于早期的较高,原油成藏稍晚. 相似文献