强激光热斑形成及其稳定性研究

在论述热点跟踪及其传热机理时将靶材的比热溶、热传导系、在激光的热藕合系数均考虑成温度和时间的函数，又考虑靶材在运动时将激光辐照物体时热点的建立及其稳定情况作一动态数值模拟，为热点跟踪作准备。     

大规模集成电路用高纯铜及铜合金靶材研究与应用现状

随着大规模集成电路制程向高密集度的方向发展,器件的特征尺寸不断缩小,集成度越来越高。在90 nm后随着布线的宽度变窄,高纯铜及铜合金靶材的应用成为一个研究热点。本文通过多个专利及相关文献的检索,总结了高纯铜及铜合金靶材的分类,分析了高纯铜的纯度、合金元素的种类以及分布对高纯铜靶材溅射性能的影响,展望了今后大规模集成电路靶材的发展趋势。     

AZO靶材的制备与镀膜应用研究

以ZnO和Al2O3粉体为原料，在不同的热压温度下制备AZO靶材。通过阿基米德法测量靶材的密度，压汞法测量靶材的孔径分布，扫描电镜观察靶材的断面形貌。将所制备的靶材作为溅射源，进行射频磁控镀膜测试。采用台阶仪测量膜厚，紫外分光光度计测量薄膜透光率，四探针电阻图谱仪测量薄膜电阻率，XRD分析薄膜结构，研究靶材密度及孔径分...     

集成电路用高纯金属溅射靶材发展研究

高纯金属溅射靶材是集成电路用关键基础材料，对实现集成电路用靶材的全面自主可控，推动集成电路产业高质量发展具有基础性价值。本文分析了集成电路用高纯金属溅射靶材的应用需求，梳理了相应高纯金属溅射靶材的研制现状，涵盖高纯铝及铝合金、高纯铜及铜合金、高纯钛、高纯钽、高纯钴和镍铂、高纯钨及钨合金等细分类别。在凝练我国高端靶材制备关键技术及工程化方面存在问题的基础上，着眼领域2030年发展目标，提出了集成电路用高纯金属溅射靶材产业的重点发展方向：提升材料制备技术水平，攻克高性能靶材制备关键技术，把握前沿需求开发高端新材料，提升材料分析检测和应用评价能力。研究建议，开展“产学研用”体系建设，解决关键设备国产化问题，加强人才队伍建设力度，掌握自主知识产权体系，拓展国际合作交流，以此提升高纯金属溅射靶材的发展质量和水平。     

直热式ITO靶材热压设备的设计北大核心CSCD

随着平面显示技术的发展,氧化铟锡(ITO)靶材的需求大增,然而国内生产的靶材多为低密度的中低端产品,ITO靶材的制备目前多采用的是热压烧结的形式,实现ITO靶材的制备突破研制合适的装备及工艺成为焦点问题。本文结合直热式制备ITO靶材工艺给出了ITO靶材热压炉中核心加热区的设计方法,并利用ANSYS软件对设计完成的石墨模具进行了仿真分析。     

辉光放电质谱法检测AZO靶材中痕量元素及深度分布

利用辉光放电质谱仪(GDMS)对铝掺杂的氧化锌(AZO)靶材中的常微量元素及其深度分布进行分析。首先考察AZO样品中的元素和Ar、H、O、N等气体元素形成的多原子离子干扰。其次利用GDMS和台阶仪对已经进行磁控溅射过的AZO靶材表面进行深度剖析,考察靶材上的主要污染元素随深度的纵向分布,最后利用GDMS对预溅射完后的AZO靶材内部杂质元素进行质谱分析。利用XPS进行验证,两种方法测试得到的Zn和Al的含量相近。分析结果表明GDMS是分析AZO等半导体靶材的有效方法,该方法可以对靶材造成的污染进行预判,避免溅射过程中造成的污染。     

直热式ITO靶材热压设备的设计

随着平面显示技术的发展,氧化铟锡(ITO)靶材的需求大增,然而国内生产的靶材多为低密度的中低端产品,ITO靶材的制备目前多采用的是热压烧结的形式,实现ITO靶材的制备突破研制合适的装备及工艺成为焦点问题。本文结合直热式制备ITO靶材工艺给出了ITO靶材热压炉中核心加热区的设计方法,并利用ANSYS软件对设计完成的石墨模具进行了仿真分析。     

真空离子镀金靶材的镶嵌复合工艺与靶型的研制

本文介绍了金靶材与阴极背板结合时所采用的镶嵌复合工艺，以及利用这种工艺对矩形或圆柱形磁控溅射靶进行金靶材形状的改进，最终可使金靶材的利用率提高到７０％～８０％。而且这种工艺也适用于金合金靶材与阴极背板的结合上，因此这一制靶工艺的开发，对真空离子镀金技术的进一步推广和应用具有十分重要的意义     

ITO靶材第二相In_4Sn_3O_(12)的结构及其对靶材性能的影响

以自制的纳米ITO气化粉为原料,采用注浆成型工艺制备了不同SnO_2含量的ITO靶材,并采用不同烧结温度对SnO_2含量为10%(质量分数)的靶材进行了烧结,通过SEM分析了不同SnO_2含量ITO靶材的组织及第二相在靶材中的数量、形貌、分布。结果表明,在1 575℃烧结温度下,随着SnO_2含量的增加,靶材晶粒得到细化,晶界交汇处第二相数量明显增多;当烧结温度提高至1 600℃时,晶界处第二相发生分解,并向母相中转移。采用王水对1 575℃烧结的SnO_2含量为10%的靶材进行腐蚀,提取第二相,并通过EDS、XRD、TEM、TGA分析了第二相的组分、物相结构及热重情况。研究表明,10%SnO_2含量ITO靶材晶界交汇处形成的第二相为六方结构的In_4Sn_3O_(12),且靶材的氧含量与In_4Sn_3O_(12)有关。通过对不同SnO_2含量ITO靶材在密度、电阻率和热扩散系数方面的分析,间接研究了第二相对靶材性能的影响,发现SnO_2含量的增加有利于靶材密度的提高,同时使靶材电阻率增大、氧含量增高、热扩散系数减小。     

放电等离子烧结技术制备复合梯度靶材的研究

采用放电等离子烧结技术制备了TbFeCo／Ti和Bi2O3／Cu复合梯度靶材,利用扫描电子显微镜和能谱分析仪对材料的微观组织形貌及成分进行了分析。结果表明,合成的复合梯度靶材具有宏观组织不均匀性和微观组织连续性的特征,显微组织中不存在微裂纹。与单一靶材相比,TbFeCo／Ti复合梯度靶材解决了在制造和使用过程中容易碎裂的问题,Bi2O3／Cu复合梯度靶材解决了在溅射过程中的散热问题。     

Electrical breakdown mechanism of liquid nitrogen in the presence of thermally induced bubbles

An investigation of the electrical breakdown behaviour of liquid nitrogen in the presence of a local hot spot on an electrode has been performed to determine the breakdown mechanism of liquid coolant in cryoresistive or superconducting apparatus under quenching conditions. It has been found that the vapour bubbles are generated at a hot spot and the manner of the vapour generation and the vapour structure depend strongly on the ambient pressure, the heat transfer rate at a hot spot and the applied voltage. Electrical breakdown took place through various series of composites of liquid and gas phases, depending on the pressure and the heating power applied to a hot spot. Therefore, the breakdown characteristic of liquid nitrogen under hot spot conditions depended to a marked degree on these factors.     

用滑动窗多项式拟合法实时预测运动目标轨迹

提出了滑动窗多项式拟合数学模型。该模型用多项式拟合法处理一段目标位置历史数据序列,计算目标未来时刻位置,并随时刻推移不断更新目标数据,实现了实时预测。该模型误差小且稳定,克服了一般拟合预测中误差随时间推移增大的缺点。仿真结果说明,该方法参数固定、计算量小、速度快、精度高,利于实时预测跟踪。     

弱小目标检测与跟踪算法

低对比度小目标检测与跟踪算法的研究是电视跟踪领域的关键技术之一。针对弱小目标的目标特性，按USAN原则进行目标检测，利用目标的特征参数及目标运动的一致性、连续性排除噪声干扰，实现对目标的稳定跟踪。实验采用VC＋＋仿真平台验证该算法的可行性和有效性，并移植到DSP专用图像处理平台上，达到了工程的5可靠性与实时性要求。     

CONTINUOUS COOLING OF WET FOUNDRY SAND USING A FLUIDIZED BED

In order to establish the optimum cooling system for hot returned sand in metal casting processes, a mathematical model including simultaneous heat and mass transfer has been constructed. The present study is especially directed towards clarifying the dynamical behavior of sand cooling in a one-pass fluidized bed. A series of continuous cooling experiments has been made for various conditions. Characteristics of both transient and steady-state bed temperature are explained reasonably by the present model. Furthermore, a possible proposal has been given on the optimal operation, which raises heat exchange efficiency in fluidization cooling of hot molding sand.     

CONTINUOUS COOLING OF WET FOUNDRY SAND USING A FLUIDIZED BED

Abstract

In order to establish the optimum cooling system for hot returned sand in metal casting processes, a mathematical model including simultaneous heat and mass transfer has been constructed. The present study is especially directed towards clarifying the dynamical behavior of sand cooling in a one-pass fluidized bed. A series of continuous cooling experiments has been made for various conditions. Characteristics of both transient and steady-state bed temperature are explained reasonably by the present model. Furthermore, a possible proposal has been given on the optimal operation, which raises heat exchange efficiency in fluidization cooling of hot molding sand.     

Berechnung der Temperaturfelder in Bremssystemen

This paper presents an iterative method for the investigation of the quasi-stationary temperature field of frictional hot spot moving on the infinite half-space. The nonlinear differential equation of heat transfer has been transformed to a nonlinear integral equation. It was assumed that the thermal conductivity coefficient and the specific heat strongly depend on the actual temperature. In the case of a graphite half-space the dependence of contact temperature on the contact pressure as well as on the velocity has been presented. The temperature distribution, taking into consideration the thermal sensitivity of physical parameters, has been illustrated perpendicularly to the surface of half-space. The results can allow the thermal analysis of brake systems.     

提高光电经纬仪跟踪快速运动目标能力的一种方法

考虑到系统稳定性，光电经纬仪跟踪伺服系统一般设计成Ⅰ型系统。Ⅰ型系统存在速度、加速度动态滞后误差。动态滞后误差的大小不但与跟踪系统有关，还与目标运动特性有关。在跟踪快速运动目标时，会因速度、加速度动态误差的增大，导致目标脱离视场，丢失目标。因此提高光电经纬仪跟踪快速运动目标的能力，一直是光电跟踪伺服系统努力的方向。本文给出了一种提高光电经纬仪跟踪快速运动目标的能力的方法：动态1 Ⅰ控制法，并利用SIMULINK建立了跟踪伺服系统动态1 Ⅰ控制法仿真模型。仿真结果表明动态1 Ⅰ控制法是一种提高光电经纬仪踊跃快速运动目标能力的有效方法。     

纯角度跟踪的球面坐标降维算法

从解决目标跟踪中的非线性问题入手,分析了不同的解决方法,并结合地面红外搜索跟踪（IRST）系统单独使用时的实际特点,提出了球面坐标降维模型,给出了相应的目标纯角度跟踪算法。目标状态方程和量测方程得到了简化。最后进行了目标跟踪的仿真试验,结果表明这种纯角度跟踪算法具有很好的性能。     

Finite element numerical simulation on thermo-mechanical behavior of steel billet in continuous casting mold

The thermo-mechanical behavior of a thin, growing shell during the early stages of solidification in a continuous casting mold is very important to the ultimate quality of the final billet. A two-dimensional, transient finite element model has been developed to treat the heat flow and deformation of the solidifying shell in the continuous casting billet mold as a coupled phenomena. The major application of the model is to predict the extent of the gap between the mold and the shell and focus on the influence of mold taper on the thermo-mechanical behavior of the steel billet to help to understand the formation of off-corner cracks and break-outs in the solidifying shell. The calculations indicate that the gap is initially formed at the corner of the billet, where heat transfer is greatly reduced. Insufficient mold taper contributes to a hot spot in the off-corner region, which corresponds to the lowest shell thickness. At the same time, the solidifying front on the diagonal of the billet is subjected to an excessive mechanical strain, which causes the off-corner cracks and even the break-outs.