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1.
1 INTRODUCTIONDuringEMC process,thecontinuously pouredliquidmetalabovetheingotisconstrainedbytheelec tromagneticforceandformsasect  相似文献   

2.
Recent advances in electrochemistry of sulfide mineral flotation   总被引:8,自引:0,他引:8  
1 ELECTROCHEMISTRYOFFLOTATIONItisnowover 4 0yearssinceNixonproposedanelectrochemicalmechanismtoexplaintheinteractionofthiolflotationcollectorswithsulfidemineralsur facesandprovideameansofreconcilingthedifferenttheoriesthathad previouslybeenresolutelyad v…  相似文献   

3.
Electric arc furnace dust non-isothermal reduction kinetics   总被引:3,自引:0,他引:3  
1 INTRODUCTIONTheairbornefineparticulateElectricArcFur nace (EAF)dustisgeneratedinthesteelmanufactur ingprocesswhenscrapiselectricallymelted .Itisconsideredasahazardouswastebecauseofleachingcharacteristicofheavymetalssuchaslead ,zincandchromium ,whichare p…  相似文献   

4.
1 INTRODUCTIONTheresidualthermalstresscausedbythemis matchofcoefficientsofthermalexpansion (CTE)be tweenreinforcementandmatrixalloyandhighdensi tydislocationsinthevicinityoftheinterfacesresultedfromtherelaxationofresidualstressoncoolinghavegreatinfluenc…  相似文献   

5.
1 INTRODUCTIONAtpresent ,zincisproducedbythehydrometallurgy electroanalysismethodinmostzincsmeltingplants .Eachyear,millionstonsofhydrometallurgicalzincresiduesaredischargedfromChinesesmeltingplants ,whicharehighlyacidicandconsistofgreatdealofsilverandot…  相似文献   

6.
1 INTRODUCTIONThehydroxide ,carbonateandaluminumcon tentsofsodiumaluminatesolutionsarethemostim portantchemicalinformationrequiredforprocesscon trolintheindustrialproductionofaluminumoxide—thekeyrawmaterialfortheproductionofaluminumbymoltenelectrolysis .…  相似文献   

7.
1 INTRODUCTIONAluminummatrixcompositereinforcedwithsili concarbidewhisker (SiCw/Al)asanewtypeofstructuralmaterialnotonlyhascertainadvantagessuchashighspecificstrength ,highspecificmodulus ,lowcoefficientofthermalexpansion (CTE)andsoon ,butalsocanbesecondari…  相似文献   

8.
Separating titania from treated slag by gravity separation or flotation   总被引:9,自引:2,他引:7  
1 INTRODUCTIONChinaisatitaniumrichcountry ,whose92 .4 %oftitaniumresourceisvanadium titaniumbearingmagnetite .About 53%titaniumwereinironconcen trateaftermineralprocessing ,bywhichtheblastfur naceslagcontainingabout 2 5%TiO2 were pro duced[1] .ThecontentofTiO2 insuchs…  相似文献   

9.
1 INTRODUCTIONThedemandsforhigherefficiencyofenergycon vertingsystemsnecessitatesforthemaximumoperat ingtemperaturetobeincreased .  相似文献   

10.
Ordered molecular layer structure of lubricating oil adsorbed films   总被引:2,自引:0,他引:2  
1 INTRODUCTIONBoundarylubricationandthin filmlubricationaretwolubricatingstateswidelyexistinginmetalplasticworkingprocess .In 1919Hardyetal[1] firstadvancedtheconceptofboundarylubrication ,in192 9Tomlinson[2 ] disclosedtheintermoleculareffectofboundarylubricatio…  相似文献   

11.
刷镀镍-磷镀层的生长模型研究   总被引:1,自引:1,他引:0  
罗建东  曾德长  张弢 《表面技术》2009,38(6):6-8,75
以目前应用最广泛的刷镀镀层之一——镍一磷镀层为对象,利用自制多功能刷镀电源、原子力显微镜等设备,测得了刷镀时间与刷镀电流之间的关系,通过数据处理求得了二者之间的函数关系,在此基础上进一步求得了电流密度(刷镀电流/刷镀面积)与刷镀时间之间的函数关系;利用原子力显微镜测得镀层界面处、接近界面处和远离界面处的镀层颗粒形貌,结合刷镀电流密度与刷镀时间之间的关系,建立了刷镀镀层生长的模型。模型具有重要的指导意义:根据所建立的模型可以控制镀层颗粒的大小,改善镀层质量,为实际生产提供参考和指导。  相似文献   

12.
The non-uniformity of electroformed layers directly affects the mechanical properties and application requirements of micro devices. Therefore, uniformity of electroformed copper foil is significant in ensuring or improving the mechanical properties of micro devices. The influences of duty cycle, current density, power source, and electroforming time on the thickness uniformity of electroformed copper layers were studied, and these parameters were optimised by using the orthogonal experiment method. The thickness distribution rule of electroformed copper foil was also determined. Duty cycle had the largest influence on the uniformity; the uniformity of electroformed layers prepared with pulse reverse current power source was superior to those prepared with direct current power source and pulse current power source. Increasing current density enhanced uniformity. The optimal technical process suggested by this orthogonal experiment adopts pulse reverse current power, 30% of positive duty cycle, 10% of negative duty cycle, 2?A?dm?2 of current density, and 92?minutes of electroforming time. The minimum coefficient of variation reached 1.54%. The thickness of electroformed copper foil varied directionally.  相似文献   

13.
增量型PID恒流恒压控制的Plasma-MIG复合电弧焊接   总被引:2,自引:1,他引:1       下载免费PDF全文
Plasma-MIG复合电弧焊接对电源的外特性输出及焊接过程控制有着很高的要求,以VC++软件开发工具为平台,推导了适合于Plasma-MIG复合电弧焊接的增量型PID控制算法,实现了对复合电弧焊接过程控制及电源外特性的要求.结果表明,增量型PID恒流恒压控制能够满足Plasma-MIG对电源外特性的输出要求.Plasma电弧和MIG电弧并不是相互独立的,两者以共享的电磁空间、导电气氛和焊丝为媒介建立起耦合关系.Plasma-MIG复合电弧焊接过程中,增量型PID控制下的Plasma电弧能够自发的调节自身电参数,来稳定电弧空间的电流密度,使得焊接过程中无飞溅.采用控制后,Plasma-MIG复合电弧焊焊接过程焊缝铺展好,焊接过程稳定,焊缝成形好.  相似文献   

14.
推力磁轴承是磁悬浮系统的重要组成部分,主要用于控制转子的轴向位移。设计获得质量轻巧、损耗较低、性能良好的推力磁轴承是工程中追求的目标。在考虑轴承承载力、温升及磁密限制等约束情况下建立了寻求轴承最优质量的目标函数,利用相应的求解方法获得了轴承的最优结构参数。同时对优化模型进行了有限元分析,得到不同频率下气隙磁密、涡流损耗等参数,揭示了不同工作条件下涡流的影响程度。  相似文献   

15.
In laser+P-GMA hybrid welding,laser-wire distance is an important parameter to describe the distance from laser spot to the center of the pulsed gas metal arc.The experiments results show that the optimal laser-wire distance with the deepest weld penetration increases with welding current and laser power being increased and decreases with welding speed being increased.Welding current,laser power and welding speed determine the hybrid welding heat input in laser+arc hybrid welding process,so there is a correlation between the optimal laser-wire distance and the hybrid heat input welding parameters for the deepest weld penetration: the optimal laser-wire distance increases with the heat input being increased.The positive correlation between the optimal laser-wire distance and the hybrid welding heat input is induced by the characteristics of the limited influence of P-GMA welding process on laser transmission and the dependence of weld penetration of hybrid welding on laser power.  相似文献   

16.
洪波  潘应君  张恒  张扬 《表面技术》2015,44(9):23-28
目的优化钼表面直流磁控溅射镀镍薄膜的工艺,提出后续热处理方法。方法设计正交实验,探究溅射功率、溅射气压、负偏压和沉积时间对镍薄膜沉积速率和附着力的影响,从而优化工艺参数。利用扫描电镜和平整度仪对最佳工艺参数下制备的薄膜的组织结构进行表征,并研究后续热处理对薄膜附着力的影响。结果工艺参数对镀镍薄膜沉积速率影响的主次顺序为:功率溅射气压负偏压;对薄膜附着力的影响主次顺序为:负偏压沉积时间功率溅射气压。随溅射功率增大,沉积速率增大,薄膜附着力先增后减;随溅射气压增大,沉积速率和薄膜附着力均先增后减。负偏压增大对沉积速率影响较小,但有利于提高薄膜附着力。随沉积时间延长,薄膜附着力降低。在氢气气氛下进行850℃×1 h的后续热处理,能够促进扩散层的形成,明显提高镍薄膜的附着力。结论最佳镀镍工艺参数为:溅射功率1.8 k W,溅射气压0.3 Pa,负偏压450 V,沉积时间10 min。在该条件下制备的镍薄膜厚度达到1.15μm左右,与基体结合紧密,表面平整、连续、致密。后续增加热处理工序是提高镍薄膜附着力的有效方法。  相似文献   

17.
Based on the program developed to simulate the temperature field for ISM(Induction Skull Melting)process, the effects of power increasing rate and charge mass on the melting throughout time and the energy consumption for TiAl alloys were studied. The results show that the melting throughout time decreases exponentially with the increasing of the power increasing rate and it linearly increases with the increasing of the charge mass. There is a critical power increasing rate for different charge masses. At this critical power increasing rate, the charge can be molten when the melting power just reaches 300 kW. There exists an optimal power increasing rate, i.e. 1.3 kW/s. At the optimal power increasing rate, the energy consumption for melting the charge is the minimum. The charge mass has noticeable influence on the energy consumed by unit mass and the ratio of effective energy.  相似文献   

18.
EXPERTOPTIMIZEDCONTROLTECHNIQUEFORELECTROLYTICDEPOSITIONPROCESSOFHYDROMETALLURGYOFZINC①YangChunhua,GuiWeihua,YeWenwuInformati...  相似文献   

19.
目的 在高世代薄膜晶体管(Thin Film Transistor, TFT)产线的栅极刻蚀制程,明确大气压等离子体(Atmosphere Pressure Plasma, APP)清洗功率、清洗时间及刻蚀时间对刻蚀性能(关键尺寸偏差、均一性、坡度角)的影响规律,并获得最佳工艺条件,进而提升良率。方法 以APP清洗功率、清洗时间和刻蚀时间为影响因素,以关键尺寸偏差(CD Bias)、均一性、坡度角作为因变量,开展正交试验,明确因素影响重要性顺序;然后,对Cu电极坡度角的形成和刻蚀均一性变化进行分析;最后,采用回归分析获得刻蚀性能与刻蚀时间的函数关系式。结果 结果表明:刻蚀时间对刻蚀性能的影响最大,对APP清洁时间和功率的影 响较小。刻蚀时间延长,关键尺寸偏差(CD Bias)增加、均一性变差、坡度角变大。为改善均一性和平缓坡度角,应缩短刻蚀时间。最佳工艺组合为:刻蚀时间85 s,APP电压9 kV,APP传输速度5 400 r/min。结论 刻蚀时间延长,未被光刻胶覆盖的Cu膜层被完全刻蚀,形成台阶,该台阶使刻蚀液形成回流路径。沿着回流路径,刻蚀液浓度、温度逐渐下降,刻蚀均一性由此恶化,坡度角因此增加。采用回归分析得到的刻蚀性能与刻蚀时间的函数关系式,为预测刻蚀效果和优选刻蚀时间提供了依据。  相似文献   

20.
郑兵  王慧钧  王其隆 《焊接学报》1996,17(3):150-155
对同步方波交流电源(SYNCROWAVE-300(S)方波交流电源)的负半波时间随总电流增加而增加的原因进行了详细的试验研究和理论分析。结果表明:这种陡降特性的可控硅-电抗器式的交流电源的总电流的增加必须通过增加负半波的时间才能实现。这将会造成铝合金交流TIG焊和等离子弧焊在大电流焊接时钨极严重烧损,降低电弧和焊缝成型的稳定性。该结论不但对更好地理解可控制硅-电抗器式方波交流电源的工作原理有重要的  相似文献   

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