基于不同模型的固体火箭发动机喷射物熔渣特性分析

固体火箭发动机喷射物中的熔渣是航天器防护和空间碎片风险评估关注的对象之一。文章首先介绍国外熔渣建模试验数据及理论模型,主要有NASA熔渣模型、MASTER2005熔渣子模型(以下简称MASTER模型)和麻省理工大学林肯实验室的MIT/LL熔渣模型;再利用NASA和MASTER模型分析熔渣尺寸-数量和质量特性。MASTER模型给出的熔渣数量和质量均低于NASA模型;且MASTER模型认为约91.8%的熔渣尺寸处于25～200 m区间;尺寸大于250 m的熔渣质量占熔渣总质量的88%,但其数量只占熔渣总数量的6.3%。以上研究结果为进一步分析熔渣对空间碎片环境的影响奠定了基础,对我国自主开展熔渣模型研究也有一定的参考价值。

二级麻醉药物喷射与挥发式蒸发器的设计与理论分析

目的:麻醉蒸发器是麻醉机的重要部件之一,针对目前的麻醉蒸发器药物输出浓度受各种因素的影响而无法达到高精度平稳给药的问题,设计二级麻醉药物喷射与挥发式蒸发器。方法:利用计算流体力学方法(CFD)及药物的物理特性对蒸发器内部药物流动、浓度场的变化进行三维计算,并对控制合理性进行论证。结果:计算出建立二级麻醉药物喷射与挥发式蒸发器三维模型的相关数据。结论:通过运用流体力学方法对各种数据进行计算,可为二级麻醉药物喷射与挥发式蒸发器的设计提供理论依据。

堆芯晚期注水对一回路压力的影响分析

分析典型的1000 MW级压水堆核电厂在高压严重事故序列下,堆芯晚期注水对压力容器失效时一回路压力的影响。分析结果表明,在开启1列稳压器卸压阀的情况下,稳压器波动管可能会在压力容器失效之前发生蠕变失效使一回路被动卸压,堆芯晚期注水不会造成一回路压力大幅增大,但波动管失效的时间和尺寸存在较大的不确定性。在开启2列或3列卸压阀的情况下不会发生一回路被动卸压,堆芯晚期注水会增大压力容器失效时一回路的压力,增大熔融物高压喷射的风险;开启3列卸压阀可以将一回路的压力降到较低水平。投入2列安全注入的情况下,压力容器失效时一回路压力比投入1列安全注入的情况略高,但压力容器的失效时间被明显推迟。为了保证充足的衰变热移出能力、减小一回路卸压的不确定性、减小熔融物高压喷射的风险及延缓压力容器失效,较佳的做法是同时开启3列卸压阀并投入2列安全注入。

严重事故专用卸压阀排放能力需求

二代加百万千万级核电站严重事故下卸压过程中高温流体流经卸压阀,可能造成流道变形,甚至造成阀杆下落使得排放流道封闭,造成卸压失败。对严重事故专用卸压阀在卸压过程中可能经历的高温流体状态进行谱分析,获得了不同卸压能力下阀门经受的高温流体状态。开展了高温可能引起的阀门流道变形对卸压效果的影响分析。第二类阀门虽然存在阀门流道变形的可能,但能够获得较长严重事故处置时间,从优化严重事故对策的角度,严重事故专用卸压阀推荐采用第二类阀门排放能力450~600 t/h范围。

Vapor pressure measurement of lead and lead chlorides in FeO_T-CaO-SiO_2-Al_2O_3 system

Vapor pressure of lead and lead chlorides from FeOT？CaO？SiO2？Al2O3 slag system was measured by using Knudsen effusion method. The results suggest that the vapor pressures of lead and lead chlorides increase with increasing temperature. For the slag systems without chlorine, the logarithm of vapor pressure （lnp） shows highly linear dependency on the reciprocal of temperature （1/T）, and higher vapor pressure is observed in the condition where more metallic lead vapor is formed. In this case, the vapor pressure of lead increases with increasing slag basicity （w（CaO）/w（SiO2））, increasing FeO content andw（Fe2＋）/w（Fe3＋） ratio. For the case of slag system with chlorine addition, the total pressures of PbCl2 and PbCl increase with decreasing basicity and FeO content of slag.

星系磁场的形成

星系磁场的形成○任大力天文学家认识到星系中存在磁场迄今已有３０多年，他们对这些磁场起源的争论也几乎延续了３０多年。乍一看，这问题似乎很简单：某一星系的磁场不过是该星系各恒星、行星、气体、尘埃磁场的组合。然而，据美国芝加哥大学天文物理学家罗伯特·罗斯纳...

Retrieval of Electron Return Time from High-order Harmonics Generated in a Mixture of He and Ne Gases

In terms of single-atom induced dipole moment by Lewenstein model, we present the macroscopic high-order harmonic generation from mixed He and Ne gases with different mixture ratios by solving three-dimensional Maxwell＇s equation of harmonic field. And then we show the validity of mixture formulation by Wagner et al. [Phys. Rev. A 76 （2007） 061403（R）] in macroscopic response level. Finally, using/east squares fitting we retrieve the electron return time of short trajectory by formulation in Kanai et al. [Phys. Rev. Lett. 98 （2007） 153904] when the gas jet is put after the laser focus.

Combustion and emission characteristics of diesel/n-butanol blends with split-injection and exhaust gas recirculation stratification

Oxygen fuels have broad application prospects and great potential for realizing efficient and clean combustion,and hence this study applies diesel/n-butanol blends to explore the influence of split-injection strategy on combustion and emission characteristics.Simultaneously,changing the way of exhaust gas recirculation(EGR)gas introduction forms uneven in-cylinder components distribution,and utilizing EGR stratification optimizes the combustion process and allows better emission results.The results show that the split-injection strategy can reduce the NO_(x)emissions and keep smoke opacity low compared with the single injection,but the rise in accumulation mode particles is noticeable.NO_(x)emissions show an upward trend as the injection interval expands,while soot emissions are significantly reduced.The increase in pre-injection proportion causes the apparent low-temperature heat release,and the two-stage heat release can be observed during the process of main combustion heat release.More pre-injection mass makes NO_(x)gradually increase,but smoke opacity reaches the lowest point at 15%pre-injection proportion.EGR stratification can optimize the emission results under the split injection strategy,especially the considerable suppression of accumulation mode particulate emissions.Above all,fuel stratification coupled with EGR stratification is beneficial for further realizing the in-cylinder purification of pollutants.

An Enhanced Physically Based Scour Model for Considering Jet Air Entrainment

Based on systematic experiments on the influence of air entrainment on rock block stability in plunge pools impacted by high-velocity jets,this study presents adaptations of a physically based scour model.The modifications regarding jet aeration are implemented in the Comprehensive Scour Model(CSM),allowing it to reproduce the physical-mechanical processes involved in scour formation concerning the three phases;namely,water,rock,and air.The enhanced method considers the reduction of momentum of an aerated jet as well as the decrease of energy dissipation in the jet diffusive shear layer,both resulting from the entrainment of air bubbles.Block ejection from the rock mass depends on a combination of the aerated time-averaged pressure coefficient and the modified maximum dynamic impulsion coefficient,which was found to be a constant value of 0.2 for high-velocity jets in deep pools.The modified model is applied to the case of the observed scour hole at the Kariba Dam,with good agreement.

Seismic volcanostratigraphy of large, extrusive complexes in continental rift basins of Northeast China：Analysis of general bedding patterns in volcanostratigraphy and their seismic reflection configurations

The aim of this work is to establish volcanic seismic reflection configuration models in the rift basins of Northeast China from a new perspective,the volcanostratigraphic structure.Accordingly,the volcanostratigraphic structure of an outcrop near the Hailaier Rift Basin was analyzed to understand the characteristics and causal factors of physical boundaries.Further,3D seismic reflection data and analysis of deep boreholes in the Songliao Rift Basin were used to establish the relationship between volcanic seismic reflection configurations and volcanostratigraphic structures.These studies suggested that in volcanic successions,physical boundaries coincide with volcanic boundaries,and their distributions are controlled by the stacking patterns of volcanic units.Therefore,volcanic seismic reflection configurations can be interpreted in terms of the stacking patterns of volcanic units.These are also referred to as general bedding patterns in volcanostratigraphy.Furthermore,four typical seismic reflection configurations were identified,namely,the chaotic,the parallel continuous,the hummocky,the multi-mound superimposed and the composite.The corresponding interpretation models comprised single massive unit,vertical,intersectional,lateral multi-mound,and composite stacking patterns.The hummocky and composite reflection configurations with intersectional and composite stacking patterns are the most favorable for the exploration of volcanic reservoirs in rift basins.

Investigation on Water Jet Treated Polyester/cotton Blended Cambric

Analytical examination was made to ascertain the effect of the high pressure water flow on the fabric properties.Polyester/cotton blended cambric was spurted by high pressure water flow. Fabric properties such as handle,thickness, tensile strength , stiffness and air permeability after the water treatment were investigated.

Atmospheric-pressure Air Plasma Treatment of Polyester Fabrics for Inkjet Printing with Pigment Inks

Without any preprocessing,polyester fabric has lower ability to hold on water and inks due to the smooth morphology of polyester fibers. Therefore, patterns directly printed with pigment inks have poor color yields and bleed easily. Pretreatments of polyester fabric were carried out with atmospheric air plasma under different experimental conditions. After plasma treatment the samples were printed with magenta pigment ink. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses indicated that the enhanced color performance was mainly contributed by not only the etching effect but also oxygen-containing polar groups induced onto fiber surfaces through plasma treatment. Thereby the surface modification of polyester fabrics using atmospheric-pressure air plasma offers a potential way to fabric pretreatment for pigment inkjet printing with the advantages of environmental friendly and energy saving over traditional pretreatment methods.

Absorption and Permeability of Air-jet Textured Glass Fiber Yarn and Its Fabric for Resin

The Absorption and permeability of air-jet textured glass fiber yarn and its fabric and bonded tenacity of the fabric have been studied in relation to the main parameters, air supplied pressure and overfeed ratio.It has been observed that increasing the level of main parameters improves the coated ratio of the textured yarn and its fabric as well as the bonded tenacity of the fabric made of textured yarn. Comparison of absorption or permeability between textured and supplied yarns, and comparison of absorption or permeability and bonded tenacity between the two kinds of fabrics have been elucidated.

Mathematical Model Prediction of Heat Losses from a Pilot Sirosmelt Furnace

A mathematical model was developed for simulating heat transfer through the sidewall, bottom and top of a pilot scale TSL （Top-Submerged-Lance） Sirosmelt furnace. With a feed rate of about 50 kg/h, the furnace has been used for investigating the technical feasibility of a variety of pyrometallurgical processes for smelting nonferrous and ferrous metals and for high temperature processing of solid wastes including electronic scraps, etc. The model was based on numerical solution of energy transport equations governing heat conduction in multi-layered linings in the sidewall, bottom and top lid of the furnace as well as convection and radiation of heat from the furnace outer surfaces to the ambient. Imperfect contacts between two neighboring solid lining layers due to air gap formation were considered. Temperature profiles were determined across the furnace bottom, top lid and three sections of the furnace sidewall, from which the heat loss rates through the corresponding parts of the furnace were calculated. The modelling results indicate that approximately 88% of heat is lost from the furnace sidewall, 7-8% from the bottom and 4-5% from the top lid. With increasing melt bath temperature, the proportion of total heat loss from the bottom decreases whereas that from the top lid increases and that from the sidewall is little changed. For a bath temperature of 1,300℃, total absolute heat loss rate from the furnace was found to be close to 12 kW.

Obtaining Thin Film of SnO2/Cu2O and Characterization by X-Ray Diffraction

Thin films of tin and copper oxide forming heterojunction are being studied for applications in photovoltaic systems. The procedure for obtaining such a film was based on the technique of spray pyrolysis with working temperature of 600 ℃. The XRD （X-ray diffraction） showed the formation of tin oxides （SnO2） and copper （Cu2O） and its structural parameters are a, b and c, 4.7534 A^°, 4.7534 A^°, 3.1998 A^° （tetragonal form） and 4.2580 A^°, 4.2580 A^°, 4.2580 A^° （cubic form）, respectively. Highseore Plus program was used for phase identification and DBWSTool2.4 program used for refinement. The grain size was estimated by Williamson-Hall.

Origin and structures of solar eruptions Ⅰ: Magnetic flux rope

Coronal mass ejections(CMEs) and solar flares are the large-scale and most energetic eruptive phenomena in our solar system and able to release a large quantity of plasma and magnetic flux from the solar atmosphere into the solar wind. When these high-speed magnetized plasmas along with the energetic particles arrive at the Earth, they may interact with the magnetosphere and ionosphere, and seriously affect the safety of human high-tech activities in outer space. The travel time of a CME to 1 AU is about 1–3 days, while energetic particles from the eruptions arrive even earlier. An efficient forecast of these phenomena therefore requires a clear detection of CMEs/flares at the stage as early as possible. To estimate the possibility of an eruption leading to a CME/flare, we need to elucidate some fundamental but elusive processes including in particular the origin and structures of CMEs/flares. Understanding these processes can not only improve the prediction of the occurrence of CMEs/flares and their effects on geospace and the heliosphere but also help understand the mass ejections and flares on other solar-type stars. The main purpose of this review is to address the origin and early structures of CMEs/flares, from multi-wavelength observational perspective. First of all, we start with the ongoing debate of whether the pre-eruptive configuration, i.e., a helical magnetic flux rope(MFR), of CMEs/flares exists before the eruption and then emphatically introduce observational manifestations of the MFR. Secondly, we elaborate on the possible formation mechanisms of the MFR through distinct ways. Thirdly, we discuss the initiation of the MFR and associated dynamics during its evolution toward the CME/flare. Finally, we come to some conclusions and put forward some prospects in the future.

Large matrix polymer solar cells fabricated by low cost air-brush spray deposition

In this paper,a 64 mm×64 mm matrix polymer solar cell(PSC) was fabricated by air-brush spray deposition.Although the open-circuit voltage(Voc) and the fill factor(FF) both need to be improved,the efficiency of matrix PSCs still reaches about 1.82%,and especially the current density achieves nearly 20 m A/cm2.The results verify that air-brush spray deposition is a suitable method to prepare large area PSC devices,and the process we use in this paper can be easily transplanted to roll-to-roll production.