重力热管两相传热特性影响参数的数值研究

重力热管以其极佳的传热能力广泛应用于工程领域，而对于单根热管传热性能的提升则能够更好地提高换热设备的效率。本文通过数值模拟方法，分析了重力热管参数变化对其传热特性的影响。结果表明：VOF (Volume of Fluid)模型能够捕捉重力热管内部的蒸发冷凝现象；热管热阻随着充液率或加热功率的增大而减小；在一定范围内，热管热阻随热管内径增大而减小，随冷凝段长度增大而先增大后减小，但冷凝段长度过小会导致气液循环效果变差，因此，在实际设计中应考虑热管传热极限及安全长度比，保证热管的安全运行。     

热管设备的强度与寿命

如何保证热管及热管换热设备能长期、高效地工作已成为目前迫切需要研究的问题。本文针对热管的主要失效模式，研究了热管的强度及寿命。对碳钢一水热管的强度及极限操作温度进行了分析，同时还研究了螺旋翅片管的强化作用；特别是通过高温热管的寿命试验，对高温热管的碱金属腐蚀机理进行了探讨．提出了改进目前高温热管制造技术的措施。     

热管滚珠丝杠热性能仿真和实验

针对传统液冷散热滚珠丝杠存在的丝杠表面温度梯度及温度波动性较大、达到热平衡时间较长等问题，设计了内置热管的新型滚珠丝杠。选择热管丝杠充液介质并计算其结构尺寸参数；为验证热管丝杠热性能，提出了含管壁层、冷凝回流层、蒸气腔层的热管丝杠分层等效模型并对其进行仿真；分析螺母位于不同位置时丝杠表面的温度分布，并与传统液冷丝杠散热性能进行对比分析；采用沸腾排气法制备热管丝杠，搭建实验台，测试热管丝杠表面温度并与仿真结果进行对比。研究结果表明，相对传统的液冷散热丝杠，热管丝杠表面具有较小的温度梯度，温度均匀性良好，且达到热平衡的时间短，仿真与实验结果一致，验证了仿真方法的有效性。     

热管在增压柴油机中冷器上的应用研究

介绍热管及热管换热器的特点，设计了试验用热管中冷器。根据发动机台架试验结果分析了热管中冷器对内燃机动力性、经济性和排放性能的影响。     

一种新型热管间接蒸发冷却器的分析

简述了热管技术发展情况及技术特点，介绍了热管在空调热回收、房间空调器、供暖系统中的应用。提出了一种新型热管间接蒸发冷却器，即在热管冷凝段包覆吸水材料，并设置喷淋装置，由此提高了蒸发速度及换热效率，加大了对新风侧的干冷却效果。分析了这一装置的结构形式及其工作原理，并与其它换热器进行了对比，指出了这种新型热管间接蒸发冷却器的优势。     

塑料挤出机中销钉螺杆的设计

为使塑料挤出机中销钉螺杆具有极高的传热能力和传热速度，有利于实现塑料的低温挤出，可将其设计成热管销螺杆。热管销螺杆的通常形式是螺杆本身除有中心孔外，还在螺杆圆周径向分布有常规销(实心销)和热管销(热管销是全部密封的内部充填一定数量工作液的管子)，也可以将深入到螺杆中心孔内的“热管销”端口做成敞口，而把螺杆本身做成“热管”。     

热管换热器在烟气余热回收中的应用

介绍了热管技术，并分析了其传热机理。热管换热器具有许多独特的优点，已经获得了广泛的工业应用，应用主要集中在中低温余热资源回收利用方面，应完善高温热管，以拓宽热管换热器在高温余热资源中的应用。     

冷却温度对平板脉动热管传热特性影响的试验研究

为了探究冷却温度与脉动热管传热性能的关系，以氟代醚HFE-7100,HFE-7300和HFE-7500为工质，改变冷却水浴温度及加热功率，试验研究了加热功率与冷却温度对脉动热管传热的综合影响。结果显示，沸点更低的HFE-7100及HFE-7300脉动热管在30～50 W成功启动，适用于低加热功率，而沸点更高的HFE-7500适用于高加热功率（110～170 W）；当给定加热功率或冷却温度时，分别存在一个最佳冷却温度或加热功率使得脉动热管传热性能最优，因此应根据脉动热管的加热功率及运行温度区间合理选择工质。氟代醚脉动热管受冷却温度的影响较大，高冷却温度下过渡时间明显增加；受沸点影响，HFE-7500过渡时间变化相对较小。高加热功率下，冷却温度对脉动热管的影响减小，过渡时间也减少。低加热功率配合较高冷却温度及高加热功率配合较低冷却温度均可使脉动热管达到最佳运行状态，不同的是低加热功率下脉动热管的最佳运行区间较小，高加热功率下最佳运行区间增大。     

无机传热技术及其工业应用

无机传热技术具有钢-水热管技术的优点，并解决了钢-水热管应用温度范围窄、常用工质热管易爆管和使用寿命短的缺陷。用该技术制造的空气预热器、余热锅炉等设备已成功地应用于石油行业，用于回收余热或进行工艺加热，并取得了良好的社会效益。     

高温热管换热器的研究与工业应用

介绍了以液态金属热管技术为代表的高温热管换热器的研究与工业应用。研究内容涉及液态金属热管传热性能及其传热极限的研究、高温热管换热器整体传热特性及效率的试验研究、液态金属热管工业应用安全性的研究、低合金钢－液态金属热管相容性的研究、高温热管换热器的模拟优化研究。基于理论及实验研究基础，高浊热管换热器得以在工业领域应用，介绍了高温热管热风炉与高温热管取热器的工业应用实例。     

Suprathermal plasma analyzer for the measurement of low-energy electron distribution in the ionosphere

It is commonly believed that an energy transfer from thermal to suprathermal electrons (相似文献   

Contribution of electron energy loss spectroscopy to the development of analytical electron microscopy.

The combined use of an electron energy loss spectrometer and an electron microscope provides some chemical information at the nanometer scale. The physics of the interaction processes between the incident electron beam and the thin sample foil is reviewed in terms of energy and momentum transfer. This analysis of the content of an electron energy loss spectrum allows us to establish rules for a satisfactory use of the information and to discuss the detection limits of this newly developed microanalytical technique.     

Complex diagnostics of a high-current accelerator during generation of high-power bremsstrahlung

A diagnostic system has been developed for the YHH-10 high-current electron accelerator with a beam current of ≤ 60 kA, an electron energy of ≤4 MeV, and a pulse duration of ≤80 ns. The X-ray diagnostic method is used in the diagnostic system to determine the energy of accelerated electrons at the entrance into the converter target. A measuring transducer of the electron energy is based on determining the static transfer characteristic of the converter target, which relates (under the known conditions) the energy of accelerated electrons to the beam current and the dose rate at a selected point of the bremsstrahlung field on the electron beam transport axis. Physically, the transducer is located in the target unit of the accelerator.     

Monte Carlo modeling of cathodoluminescence generation using electron energy loss curves

This work demonstrates the validity of approximating cathodoluminescence generation throughout the electron interaction volume by the total electron energy loss profile. The energy loss profiles in multilayer specimens were accurately calculated using the Monte Carlo simulation CASINO. Resolution of cathodoluminescence images can be estimated from the electron beam spot diameter, the electron penetration range, and the minority carrier diffusion length.     

Absolute calibration of image plates for electrons at energy between 100 keV and 4 MeV

We measured the absolute response of image plate (Fuji BAS SR2040) for electrons at energies between 100 keV and 4 MeV using an electron spectrometer. The electron source was produced from a short pulse laser irradiated on solid density targets. This paper presents the calibration results of image plate photon stimulated luminescence per electron at this energy range. The Monte Carlo radiation transport code MCNPX results are also presented for three representative incident angles onto the image plates and corresponding electron energy depositions at these angles. These provide a complete set of tools that allows extraction of our absolute calibration to other spectrometer setting at this electron energy range.     

Resolution in low voltage scanning electron microscopy

As the energy of an electron beam is reduced, the range falls and the secondary electron yield rises. A low voltage scanning electron microscope can therefore, in principle, examine without damage or charging samples such as insulators, dielectrics or beam sensitive materials. This paper investigates the way in which the choice of beam energy affects the spatial resolution of a secondary electron image. It is shown that for samples which are thin compared to the electron range, the edge resolution and contrast in the image improve with increasing beam energy. In samples that are thicker than the electron range, the resolution can be optimized at either high or low energies, but low energy operation will produce images of higher contrast. At an energy of 2 keV or less beam interaction limited resolutions of the order of 3 nm should be possible.     

Absolute energy calibration for relativistic electron beams with pointing instability from a laser-plasma accelerator

The pointing instability of energetic electron beams generated from a laser-driven accelerator can cause a serious error in measuring the electron spectrum with a magnetic spectrometer. In order to determine a correct electron spectrum, the pointing angle of an electron beam incident on the spectrometer should be exactly defined. Here, we present a method for absolutely calibrating the electron spectrum by monitoring the pointing angle using a scintillating screen installed in front of a permanent dipole magnet. The ambiguous electron energy due to the pointing instability is corrected by the numerical and analytical calculations based on the relativistic equation of electron motion. It is also possible to estimate the energy spread of the electron beam and determine the energy resolution of the spectrometer using the beam divergence angle that is simultaneously measured on the screen. The calibration method with direct measurement of the spatial profile of an incident electron beam has a simple experimental layout and presents the full range of spatial and spectral information of the electron beams with energies of multi-hundred MeV level, despite the limited energy resolution of the simple electron spectrometer.     

Imaging of specimens at optimized low and very low energies in scanning electron microscopes.

The modern trend towards low electron energies in scanning electron microscopy (SEM), characterised by lowering the acceleration voltages in low-voltage SEM (LVSEM) or by utilising a retarding-field optical element in low-energy SEM (LESEM), makes the energy range where new contrasts appear accessible. This range is further extended by a scanning low-energy electron microscope (SLEEM) fitted with a cathode lens that achieves nearly constant spatial resolution throughout the energy scale. This enables one to optimise freely the electron beam energy according to the given task. At low energies, there exist classes of image contrast that make particular specimen data visible most effectively or even exclusively within certain energy intervals or at certain energy values. Some contrasts are well understood and can presently be utilised for practical surface examinations, but others have not yet been reliably explained and therefore supplementary experiments are needed.     

透射电子显微技术在RIPP炼油催化剂表征中的应用

利用透射电子显微技术对加氢催化剂以及积炭催化裂化催化剂进行了表征。扫描透射电子结合X射线能谱技术确定了氧化态加氢催化剂中的微粒为活性金属组分的适度聚集；能量过滤透射显微技术获得了积炭催化裂化催化剂的Al、C的元素分布像。     

Parameters of the Electron Beams Generated by the РАДАН-220 and РА ДАН-ЭКСПЕРТ Accelerators

The measured parameters of the electron beams generated by small-sized nanosecond direct-action Р АДАН-220 and РАДАН-ЭКСП Е РТ accelerators are presented. The measuring techniques and the designs of electron detectors developed for this purpose are described. The fluence of electrons and the energy density, uniformity, and energy spectrum of the electron beam have been measured.