低温冰型在骨组织支架成形中的应用

将低温冰型快速成形工艺应用于骨组织工程细胞载体支架的成形。研究了成形工艺和材料制备的要点和要求，提出了成形工艺流程。用冰型工艺成形出具有200μm～500μm的交错贯通的孔结构的骨组织工程三维支架，并完成相关生物学试验。     

喷射成形制造工艺

喷射成形是一种先进的材料制备技术,该技术具有近终形制造的特点,近年来已广泛应用于研究和开发多种高性能快速凝固材料.文中介绍了喷射成形工艺过程、特点,并回顾了喷射成形工艺的发展历程及现在所达到的技术水平.     

结构材料喷射成形技术与雾化沉积高温合金

喷射成形是利用快速凝固方法直接制备金属材料坯料或半成品的先进材料制造技术 ,喷射沉积高温结构材料的冶金性能好、生产效率高、成本低 ,因而在近几年得到了迅速发展 .本项研究的主要目的是要通过喷射成形工艺参数的调整、最大限度地直接减少喷射成形坯中的孔隙度 ,进而得到优质坯料 .利用优化的雾化喷射沉积技术制备了多种高温合金沉积坯 ,沉积坯整体致密、晶粒细小、组织均匀、无宏观偏析、含气量低、力学性能提高 .还简要地比较了喷射成形高温合金与用常规铸锭冶金工艺和粉末冶金工艺制备高温合金的异同 ;总结了航空材料研究院喷射成形高温材料近年来的研究状况 ,包括专用高温材料喷射成形装置和技术及其应用 .     

喷射成形超高碳钢的微观组织与工艺研究

通过喷射成形工艺制备超高碳钢材料可以极大地优化其微观组织，提高性能，但是如果喷射成形工艺参数控制有误，就可能使组织恶化，性能下降。本文通过分析喷射成形工艺制备超高碳钢材料过程中因为参数控制等原因出现的组织缺陷，探讨了产生组织缺陷的原因，并结合喷射工艺原理和喷射成形设备具体分析了喷射成形工艺过程中的参数控制，提出了改进工艺参数，消除材料组织缺陷的方法。     

热等静压对喷射成形TiAl基合金孔隙率的影响

着重研究了气体辅助喷射成形和离心喷射沉积形成的Ｔｉ－４８Ａｌ－２Ｍｎ－２Ｎｂ金属间化合物的孔隙率以及热等静压工艺对合金孔隙率的影响，利用Ｑｕａｎｔｉｍｅｔ图象分析仪定量测试了各种状态样品的孔隙率。结果表明，气体雾化成形合金的孔隙率约３．２９％，离心喷射盛开有合金的孔隙率约２．２０％，孔隙率的大小与喷射成形工艺密切相关。     

喷射成形颗粒增强金属基复合材料研究进展

喷射成形是将熔融金属雾化和沉积过程相结合,直接由熔融金属制备具有快速凝固组织特征坯体的新型金属材料成形工艺。被引入到非连续增强体金属基复合材料制备领域后,先后发展出了预混喷射成形、反应喷射成形和喷射沉积等工艺方法。介绍了上述颗粒增强金属基复合材料喷射成形工艺方法的基本原理、特点及研究现状。通过对比分析发现喷射沉积技术由于其成形条件限制较少,适用范围广等特点得到了更为广泛的发展,最后结合自身研究对传统喷射沉积技术进行了一定的改进,采用气体-增强颗粒两相流作为雾化介质以期获得提高雾化效率和改善增强颗粒分布均匀性的双重效果。     

电弧喷涂快速成形技术研究现状

电弧喷涂成形是新近发展起来的一项重要金属快速成形技术。对比分析电弧喷涂快速成形技术与近终喷射成形和等离子喷涂成形技术之间的差异与特点,综述电弧喷涂在模具快速制造领域的研究应用现状,并讨论了电弧喷涂成形材料,以及喷涂成形雾化与沉积工艺过程中的传热传质、残余应力和氧化行为等关键性问题。最后,展望了电弧喷涂厚成形技术的重点研究方向与解决途径。     

喷射成形超高碳钢的超塑性及热加工后的综合性能

采用喷射成形工艺制取超高碳钢，并对其超塑性及热加工后的综合性能进行了研究。研究结果表明，喷射成形超高碳钢不仅具有优良的显微组织，而且还有独特的超塑性，在热加工后其综合性能得到明显提高。     

喷射成形高合金化材料沉积坯内部疏松成因分析与改善

本文主要研究了大尺寸喷射成形高合金化材料高温合金沉积坯内部疏松成因及其改善工艺。研究认为,高温合金沉积坯中最后凝固部位液相金属补缩不足和断裂应变低是产生疏松的必要条件,而沉积坯的局部收缩变形产生的热应力是造成疏松的重要原因。通过有限元计算,提出一种热控喷射成形工艺,并得到试验验证。该工艺有效减少了坯体内部的疏松等冶金缺陷,改善了沉积坯的质量。     

喷射轧制Fe-4.5%Si硅钢片的组织和性能

采用喷射成形和轧制工艺制备了厚度为0.5mm的Fe-4.5%Si高硅钢片，并对其密度、显微组织和电磁性能进行了测试分析，研究结果表明：在最佳的喷射成形和轧制工艺条件下，所制备硅钢片的磁感应强度B25为1.544T、B50为1.641T；铁损P1050为1.437W/kg、P1550为3.43W/kg，说明喷射成形轧制技术可以制备出高磁感应强度、低铁损的高硅钢片。     

用DC-PCVD装置在绝缘体蓝宝石上沉积TiN

用直流等离子体化学气相沉积装置(简称 DC-PCVD)在绝缘体蓝宝石上沉积了与基体结合力强的 TiN,探讨了机制及影响成膜的因素。     

电子富集物改性双马来酰亚胺的研究

通过对双马来酰亚胺（ＢＭＩ）晶体结构的探讨。研究了电子富集物Ｂ对其溶解性的影响，得出电子富集物Ｂ与ＢＭＩ形成电子复合物的结论。并用ＩＲ测试结果加以说明，同时对含不同二胺量的树脂体系用ＴＧ测试法进行了热稳定性分析，得出有意义的结论。     

Elastic modulus of 316 stainless steel lattice structure fabricated via binder jetting process

This study mainly evaluates the elastic modulus of 316 stainless steel lattice structures fabricated via binder jetting process. In this present research, both solid and lattice samples are designed and fabricated by binder jetting process for two different types of mechanical tests. Besides experimental study, a numerical model based on energy approach has been proposed to predict the effective elastic modulus of fabricated lattice samples. By comparing the calculated results of the proposed numerical model with the experimental results, the established model is proved to be validated. This numerical model can be used to determine the parameters of lattice structures fabricated by binder jetting process for desired mechanical properties. At the end, both advantages and disadvantages of the lattice structures fabricated by binder jetting process are analysed. Based on this analysis, the potential application and future research work are pointed out.     

Performance evaluation of ProJet multi-material jetting 3D printer

The purpose of this paper is to quantitatively evaluate the performance of a multi-material jetting 3D printer, ProJet 5500X, especially the capability for micro manufacturing. Unlike other single material 3D printer, ProJet 5500X uses photopolymers as the build material and wax as the support material. The building performance was evaluated by building a modified version of the standard benchmark model with a high-resolution printing mode. The dimensional error, forming quality and surface roughness of the printed parts have been measured and analysed using a microscope, a 3D coordinate measuring machine and a surface profilometer. Using wax as the support material, fine features as small as 0.25?mm, lateral features and sharper edges could all be properly built, despite the rough side surfaces observed in the printed part. Identical features (3?mm pins) were precisely built with an accuracy of 15?µm. The research provides first-hand detailed performance knowledge in the ProJet system for understanding the working principle and comparison with other 3D printing systems.     

Comparative study of jetting machining technologies over laser machining technology for cutting composite materials

There has been a great interest for improving the machining of composite materials in the aerospace and other industries. This paper focuses on the comparative study of jetting techniques and laser machining technics. This paper concentrates on the machining of composite materials like epoxy pre-impregnated graphite woven fabric and fibre reinforced plastic materials that are used in aerospace industries. While considering machining these materials with the traditional machining there are many disadvantages projected. One of these advantages is that all the traditional machining processes involve the dissipation of heat into the workpiece. This serious shortcoming has been dealt by the jetting technologies, which, contrary to the traditional machining, operate under cold conditions. The two methods in the jetting technologies used for processing materials are water jet machining and abrasive water jet machining. The first of these, water jet machining, has been around for the past 20 years and has paved the way for abrasive water jet technology. Water jet machining and abrasive water jet machining have been used for processing composite materials because of the advantages offered by this technologies as compared to traditional techniques of processing. The high surface and structural integrity required of any technique used for processing composite materials has created an opportunity for abrasive water jet machining. Cutting of composites using laser is also an option, and experiments were also conducted to reveal the extent of using laser technique.     

ZnO超微粒子薄膜表面精细结构STM研究

利用扫描隧道显微镜对氧化锌超微粒子薄膜在大气环境中进行了观测分析，获得了其表面具有原子数量级尺寸的构像；同时，结合X射线衍射谱图对其表面精细结构进行了研究和探讨，并由此建立了氧化锌超微粒子薄膜的生长、形成机理模型。     

Screening pharmaceutical excipient powders for use in commercial 3D binder jetting printers

Binder jetting is an additive manufacturing technique that creates three-dimensional constructs from a powder feedstock. It is used by several industries, including pharmaceuticals. This additive approach to manufacture provides several functional benefits that are not easily achievable using conventional manufacturing methods. There is currently only limited publicly available knowledge that details the requirements of an effective binder jetting powder. Specifically in the pharmaceutical industry, since the 2015 release of Spritam®, a binder-jetted tablet containing levetiracetam, no new pharmaceutical tablets have been produced using such methods.There appears to be gap in powder technology expertise and the development of 3D printing processes. Our goal is to enhance our knowledge in terms of powder flow, powder wetting and powder binding to link particles with process and build the capability to create a greater range of powders suitable to be binder-jetted into new products. After initially screening several standard pharmaceutical excipient powders for their relevant properties, two candidates showed best fit potential for use in binder jetting, specifically microcrystalline cellulose (Pharmacel 101 and 102) and lactose (Lactohale 200). Using simple formulations of these pharmaceutical excipient powders as a model, we analysed for printability and powder performance using a range of quantitative parameters including dimensional accuracy, construct hardness, friability, porosity and surface finish. In general, formulations of these powders showed good printability, but some powder blends produced constructs with more obvious manufacturing imperfections. Several routes to improve the printability of these pharmaceutical powders are proposed for future works. Ultimately, this work provides a fundamental basis to start to quantitatively assess the potential of standard pharmaceutical excipient powders in binder jetting printers using powder characterisation techniques and print quality outcomes.     

Failure Analysis of Physical Explosion due to Gas Jetting from High-Pressure Pipeline

Jetting of the combustible gas with high pressure is a prelude to bringing into action of the chemistry explosion of gas cloud. Comparing with the leakage and diffusion of combustible gas and the chemistry explosion effect of gas cloud, the distribution of pressure, temperature and velocity formed by high-pressure gas jetting after the destruction of a pipeline, has been paid less attention to in the related field. There are a few fundamental data on the subject of evaluation of physical explosion parameters. In this paper, a physical explosion case of hydrogen gas transported through a high-pressure pipeline is reported, and a cause analysis of the explosion accident is proposed. Numerical simulation yields the field state parameters and the damage characteristics in the process of high-pressure gas jetting. In front of the leakage gas flow, a shock wave forms due to high-pressure gas jetting. The physical explosion can trigger the combustion of leaked hydrogen gas. Though the pressure rapidly attenuates behind the shock wave, a relatively high velocity is maintained until the control valve in the pipeline system is closed down or the jetting finishes. In the given accident case, the shock wave pressure reaches an order of 1 MPa and the temperature reaches 200–300 °C. This temperatures is obviously less than the igniting temperature of hydrogen gas, 400 °C. But the combustion of leaked gas may be triggered by the spark caused by the impact of instrument plates. Since the instrument plates near the leaking port of pipeline has been damaged already before the leaked gas burns, the electric spark from the line short or the strike spark between metal parts are also completely possible to trigger this combustion.     

利用引射结构提高离心泵的汽蚀

 提出在普通转速离心泵的入口处或高速离心泵的前置诱导轮前增加引射装置来提高泵的汽蚀性能，给出单孔喷嘴轴向直引射和环形多喷嘴轴向斜引射两种引射装置的结构示意图．探讨了引射装置设计的理论基础及优化设计的目标，指出采用引射装置是提高泵汽蚀性能的新方法．     

基于数值仿真的气动喷射阀回流间隙的优化

气动喷射阀是微电子封装中不可或缺的封装设备,但现有气动喷射阀在喷射高黏胶液时仍不能完全满足工业界对胶滴一致性的需求,原因在于其喷射高黏胶液时常出现因喷射速度太小而导致的挂胶漏喷现象.要减小上述现象的发生概率,就必须提高现有气动喷射阀的高黏流体喷射能力.回流间隙作为气动喷射阀的关键尺寸,直接影响着喷射阀的喷射能力.为了通过优化回流间隙来提高喷射能力,首先建立气动喷射阀的胶液喷射数值仿真模型并通过实验验证其可靠性,同时基于不同回流间隙的仿真数据建立了相应的高斯拟合模型.然后利用拟合模型以胶滴滴落速度为优化目标对回流间隙进行优化,通过优化前后的喷射对比验证了优化结果的可靠性,最后获得气动喷射阀的最优回流间隙.