铁路机械冷藏车气密性指标确定及性能优化

目的 针对铁路机械冷藏车气密性检测指标滞后,难以反映车辆漏风特性的问题,对其气密性指标展开研究,寻求现有装备气密性设计方面存在的缺陷,进而提出新造铁路机械冷藏车的气密性指标和车体气密性结构优化设计方法。方法 按照GB/T 5600要求,运用压差法对B23型、B23A型和B10型铁路机械冷藏车进行气密性试验,分析运行速度与压差、漏气量之间的关系;通过测试和实地调研,掌握现有铁路机械冷藏车漏气量偏大的原因,为改进优化提供依据。结果 我国现有B23,B23A,B10型铁路机械冷藏车在50 Pa压差条件下的漏气量分别为27.0,34.1,26.1 m3/h,当压差升至125,250 Pa时,车厢漏气量约上升90%~320%。上述压差条件大致对应40,65,90 km/h的车辆运行速度。在此基础上,分析给出了新造铁路机械冷藏车的气密性指标,提出了改进优化的具体策略。结论 新造铁路机械冷藏车的漏气量标准应设定为在50 Pa压差条件下不大于10 m3/h,比现有标准规定减少了75%。此外,通过使用新工艺和新技术,改进车厢、车门和排水口结构,减少车体漏泄点,有效提高了车厢气密性能。     

极端气温条件下空调建筑能耗状况的模拟与分析

本文分析了极端气温条件下空调建筑热状况研究的必要性，并建立了外墙外表面热平衡模型、壁体传热模型、外墙内表面热平衡模型和室内空气热平衡模型，以北京市各种气象条件下，通过联立求解的方式，最终掌握建筑的能耗状况。结果表明上述模型能较好的反应极端气候条件下空调建筑的热特性，并可为空调建筑能耗状况的整体评价提供保障。     

冷藏运输装备技术及经济性分析和若干建议

对我国易腐产品市场现状、我国现有冷藏运输装备特点及发展进行探讨,并集中介绍了我国常见冷藏运输装备的主要技术性能。以具有代表性的冷藏运输装备B6冰冷车、B22铁路机械冷藏车、45英尺冷藏集装箱、公路冷藏车（BXL5200XLC／XBW型号）为例,建立冷藏运输装备经济性模型。结合我国冷藏运输装备行业发展特点,提出发展冷藏运输装备行业相关建议。     

JB80型制冷机组的试制及试用

一、概述一九七五年——七七年间我国先后两批从国外引进 B20型九节式机械冷藏车组三十二列(货物车262辆,乘务发电车38辆,共300辆)。该车组配属广州机械保温车辆段使用。B20型机械冷藏车的端墙上方各装有一台 FAL056/2型制冷加热设备,以用于运送在夏季日平均外气温+36℃,冬季最低温度-45℃的环境下,要求货间温度保持+14°～-24℃的易腐货物,以及用于冷却没有予冷的水果和蔬菜。经六年来的运行考核,     

热机械循环对B/Al复合材料拉伸性能及显微结构的影响

热机械循环是复合材料所面临的苛刻空间环境因素.对B/Al复合材料进行温度变化范围为-125～125℃,外加拉伸载荷为30MPa的热机械循环试验,通过室温拉伸试验测量了B/Al复合材料的拉伸性能,利用SEM及TEM分析了复合材料的拉伸断口形貌及显微结构,研究了热机械循环对B/Al复合材料拉伸性能及显微结构的影响.研究表明,热机械循环造成了B纤维与Al基体之间界面的弱化,产生了可测的弹性模量的降低;同时,引起基体塑性应变,造成基体内位错密度增加.在热机械循环初期,B/Al复合材料的抗拉强度是增加的,但随即随热机械循环周次的增加而下降.     

浅析液体CO2冷藏车的运行经济性

以液体CO2为代表的第三代新冷源的开发与利用成为冷藏运输技术发展的重要研究课题.液体CO2冷藏车与机械式、冷板冷藏车相比,无论在经济上还是环保性能上都有较大的优势.对以上三种冷藏方式从初投资、设备折旧和维修费以及能耗费几个方面进行了运行经济性分析,得出机械冷藏车的制冷费用比液体CO2冷藏车的高42%;冷板式的制冷费用比液体CO2式高28%.     

对国产机械冷藏车车内设计温度的商榷

机械冷藏车(以下简称“机冷车”)能在不同温度的条件下运输各种易腐货物,而且可以提供比加冰冷藏车更低和更均匀的车内温度,并可根据所运货物的要求进行适当的调节。因此,目前在国内外都得到广泛的采用。我国在1959年即自行设计制造机冷车,现已能批量生产的B19型机冷车,填补了我国在铁路货车制造方面的一项空白,取得了很好的成绩。但B19     

发展经济型铁路冷藏车有广阔的市场前景

铁路冷藏运输历年亏损使铁道部对铁路冷藏车的投入大为减少,面对这种状况,根本措施是发展适合国情的经济盈利型铁路冷藏车。本文对此进行了探索,提出将到期的冰保车加改成经济盈利型机械冷板车。     

一种室内空气热状况模型简化的新方法—理论分析与实验研究

本文通过实验数据和数学模拟结果,分析了现有建筑物室内空气热状况的数学模型——整体集总参数模型及混掺与活塞推进相结合模型的缺陷,提出了一种能较准确地反映被控区域空气热动态过程、计算量又小的合理简化室内空气热过程数学模型的方法,即分区集总参数法。由于该模型输出被控区域的空气参数及反映区域空气热平衡的回风区参数,故很适用于以开发调试空调系统自控装置为目的的空调系统实时仿真软件中建筑物内空气热动态过程的模拟。     

热-机械载荷下H13钢力学响应行为实验和数值分析

采用MTS热-机械疲劳测试系统,同时建立电-磁-热-力多物理场耦合数值模型,研究了H13钢在200～600℃范围,对称拉、压机械应变(0. 7%和0. 9%)控制下同相位(In-phase,IP)和反相位(Out-of-phase,OP)应力-应变响应行为。另外,基于实验和模拟数据,结合寿命预测模型对H13钢进行了寿命预测。结果表明H13钢在准稳定热-机械循环阶段,随着循环次数的增加,最大拉、压应力不断降低;热-机械循环高温半周相较于低温半周会产生更大的非弹性应变;以同相位机械应变为0. 7%模拟数据为例,在最大拉、压机械应变下,应力最值分别为598 MPa和-1 148 MPa; H13钢在机械应变为0. 7%时,同相位和反相位的实测疲劳寿命(周)分别为287和266,机械应变为0. 9%时疲劳寿命分别为207和189;依据实验和模拟数据,结合Ostergren模型得出了预测寿命,并与实测寿命进行比较分析。     

检定和校准证书的异同与应用

本文介绍了检定和校准以及证书的两点相同、五点不同之处,说明了对检定证书和校准证书的正确应用。     

Synthesis and luminescent properties of alkali-metal and ammonium fluorosulfatozirconates and fluorosulfatohafnates

We have synthesized a variety of alkali-metal and ammonium fluorosulfatometallates (titanates, zirconates, and hafnates). The alkali fluorosulfatozirconates and fluorosulfatohafnates have been shown to exhibit efficient roentgenoluminescence (RL) in the UV through visible spectral region, with a maximum at 390–440 nm. Their RL spectra depend significantly on their composition (cation, anion, and water content), coordination of KF and K₂SO₄, and relative amounts of fluorine and SO₄ groups. We have examined the effect of heat treatment on the RL of these compounds. The rubidium and cesium fluorosulfatozirconates Rb₃Zr₂F₉SO₄ · 2H₂O, Cs₂ZrF₂(SO₄)₂ · 2H₂O, Cs₈Zr₄F₂(SO₄)₁₁ · 16H₂O, and Cs₂ZrF₄SO₄ offer the most efficient RL.     

凝固科学技术与材料

从凝固科学与实践发展的角度介绍了当前凝固材料体系的基本框架和凝固科学主要发展阶段的基本理论。作为材料科学与工程的基本组成，凝固科学技术正在现代科学理论的基础上针对传统材料的改性提高和新材料的发展需求，以控形、控构、控性为目标开展优质铸件的定向、晶体生长、快凝、深过冷及各种新型和超常领域凝固过程的研究，并介绍了其中某些方面和展望了可能的发展趋势。     

Heat and Mass Transfer and Modeling and Prediction of Environmental Catastrophes

Basic definitions and concepts of the physicomathematical theory of natural catastrophes are given. Possibilities of mathematical modeling of natural and technogenic catastrophes are discussed in the context of the theory of heat and mass transfer and the mechanics of reacting media. The importance of taking into account conjugate heat and mass exchange in modeling catastrophes is emphasized. A formula for evaluating the probability of a collisional catastrophe is given.     

Multi-ferroic and magnetoelectric materials and interfaces

The existence of multiple ferroic orders in the same material and the coupling between them have been known for decades. However, these phenomena have mostly remained the theoretical domain owing to the fact that in single-phase materials such couplings are rare and weak. This situation has changed dramatically recently for at least two reasons: first, advances in materials fabrication have made it possible to manufacture these materials in structures of lower dimensionality, such as thin films or wires, or in compound structures such as laminates and epitaxial-layered heterostructures. In these designed materials, new degrees of freedom are accessible in which the coupling between ferroic orders can be greatly enhanced. Second, the miniaturization trend in conventional electronics is approaching the limits beyond which the reduction of the electronic element is becoming more and more difficult. One way to continue the current trends in computer power and storage increase, without further size reduction, is to use multi-functional materials that would enable new device capabilities. Here, we review the field of multi-ferroic (MF) and magnetoelectric (ME) materials, putting the emphasis on electronic effects at ME interfaces and MF tunnel junctions.     

CellML and associated tools and techniques

We have, in the last few years, witnessed the development and availability of an ever increasing number of computer models that describe complex biological structures and processes. The multi-scale and multi-physics nature of these models makes their development particularly challenging, not only from a biological or biophysical viewpoint but also from a mathematical and computational perspective. In addition, the issue of sharing and reusing such models has proved to be particularly problematic, with the published models often lacking information that is required to accurately reproduce the published results. The International Union of Physiological Sciences Physiome Project was launched in 1997 with the aim of tackling the aforementioned issues by providing a framework for the modelling of the human body. As part of this initiative, the specifications of the CellML mark-up language were released in 2001. Now, more than 7 years later, the time has come to assess the situation, in particular with regard to the tools and techniques that are now available to the modelling community. Thus, after introducing CellML, we review and discuss existing editors, validators, online repository, code generators and simulation environments, as well as the CellML Application Program Interface. We also address possible future directions including the need for additional mark-up languages.     

The shape and stability of wall-bound and wall-edge-bound drops and bubbles

The behavior of wall-bound drops and bubbles is fundamental to many natural and industrial processes. Key characteristics of such capillary systems include interface shape and stability for a variety of gravity levels and orientations. Significant solutions are in hand for axisymmetric pendent drops for a variety of uniform boundary conditions along the contact line with gravity acting normal to a planar wall. The special case of a wall-bound drop or bubble that is also pinned at an edge (i.e. a ‘wall-edge-bound’ drop) is considered here where numerical solutions are obtained for interface shape and stability as functions of drop volume, contact angle, fluid properties, and uniform gravity vector. For a semi-infinite zero-thickness planar wall (plate), a critical contact angle is identified below which wall-edge-bound drops are always stable. The critical contact angle is computed as a function of the gravity vector. The numerical procedure, which makes no account for contact angle hysteresis, predicts that such wall-edge-bound drops are unconditionally unstable for any gravity field with a component that is tangent to the wall while inwardly normal to the edge. Select experiments are conducted that support the conclusions drawn from the numerical results.