Separation of hematite from banded hematite jasper (BHJ) by magnetic coating

The separation of iron oxide from banded hematite jasper(BHJ) assaying 47.8% Fe, 25.6% Si O2 and 2.30%Al2O3 using selective magnetic coating was studied. Characterization studies of the low grade ore indicate that besides hematite and goethite,jasper, a microcrystalline form of quartzite, is the major impurity associated with this ore. Beneficiation by conventional magnetic separation technique could yield a magnetic concentrate containing 60.8% Fe with 51% Fe recovery. In order to enhance the recovery of the iron oxide minerals, fine magnetite, colloidal magnetite and oleate colloidal magnetite were used as the coating material. When subjected to magnetic separation, the coated ore produces an iron concentrate containing 60.2% Fe with an enhanced recovery of56%. The AFM studies indicate that the coagulation of hematite particles with the oleate colloidal magnetite facilitates the higher recovery of iron particles from the low grade BHJ iron ore under appropriate conditions.     

Strain rate dependency and fragmentation pattern of expanding warheads

For the characterization of the behaviors of a metal material in events like expanding warheads, it is necessary to know its strength and ductility at high strain rates, around 104e105/s. The flyer plate impact testing produces the uniform stress and strain rates but the testing is expensive. The Taylor test is relatively inexpensive but produces non-uniform stress and strain fields, and the results are not so easily inferred for material modeling. In the split-Hopkinson bar(SHB), which may be used in compression, tension and torsion testing, the strain rates never exceeds 103/s. In the present work, we use the expanding ring test where the strain rate is 104e105/s. A streak camera is used to examine the expanding ring velocity, and a water tank is used to collect the fragments. The experimental results are compared with the numerical simulations using the hydrocodes AUTODYN, IMPETUS Afea and a regularized smooth particle(RSPH) software. The number of fragments increases with the increase in the expansion velocity of the rings. The number of fragments is similar to the experimental results. The RSPH software shows much the same results as the AUTODYN where the Lagrangian solver is used for the ring. The IMPETUS Afea solver shows a somewhat different fragmentation characteristic due to the node splitting algorithm that induces pronounced tensile splitting.     

提高水电站的自动化水平

为了评估6座水电站的自动化、人员编制和责任,美国陆军工程师团委托的可行性研究更多地考虑了成本和效益。     

Optical Properties of One-dimensional Three-component Photonic Band Gap Structure

1　IntroductionMaterialswithPhotonicBandGaps (PBG’s)havebeenwidelystudiedboththeoreticallyandex perimentallyinthepastfew years[1～ 4] .Theexis tenceofgaps,which prohibitthepropagationofelectromagnetic (EM )wavesinacertainrangeoffrequencies,canhavesignificantimpactsbothinsci enceandtechnology .Manypracticalapplicationsofthesestructureshavebeensuggestedanddemon strated ,suchasPhotonicCrystal (PC)microcavi ties[5] ,infraredPC[6] ,PClens[7] ,suppressingspontaneousemission ,manipulatinglight…     

硫酸厂主鼓风机的主要设计准则

论述现代硫酸厂主鼓风机设计时必须考虑的关键因素，通过实例讨论操作费用与投资之间的平衡关系以及对装置竞争力的影响。建议在硫酸厂严酷的操作条件下改进风机特性，提高耐磨性并采用维修友好的设计。     

High Power Fiber Bundle Array Coupled LDA Module

1 Introduction High power laser diode arrays (LDA) have many advan- tages such as small volume, long working life, high slope efficiency and high optical density, so they have many applications in medical treatment, material pro- cessing, and for the pumping source of solid laser and etc. But unfortunately, the LDA can not be easy to use directly in these fields because of their poor beam quality and extremely asymmetric divergent beams (!x≈ 5°～10°and !y≈20°～35°, for example), so it …     

Formation of Arrayed Droplets by Soft Lithography and Two-Phase Fluid Flow, and Application in Protein Crystallization

This paper presents an overview of our recent work on the use of soft lithography and two-phase fluid flow to form arrays of droplets. The crucial issues in the formation of stable arrays of droplets and alternating droplets of two sets of aqueous solutions include the geometry of the microchannels, the capillary number, and the water fraction of the system. Glass capillaries could be coupled to the PDMS microchannels and droplets could be transferred into glass capillaries for long-term storage. The arrays of droplets have been applied to screen the conditions for protein crystallization with microbatch and vapor diffusion techniques.     

澳大利亚蒂汶海奥利弗气田古油藏潜力定量评价

砂岩岩心和钻屑中的含油流体包裹体代表了隐蔽的石油显示。含有此类包裹体的石英颗粒的数目(GOI数)反映了砂岩储层中曾经历过最大的古含油饱和度，而与现今流体相无关。含油饱和度高的样品比含油饱和度低的样品的GOI数至少高一个数量级。因此，在原始油被后期填充气取代的井中，可根据这些流体包裹体的资料确定古油柱并划分原始油一水界面。此外，若能利用详细的GOI图精确确定原始油一水界面的位置，那么就可以确定古油柱的高度并估算原始石油地质储量。奥利弗(Oliver)油气田位于澳大利亚蒂汶海(Timor)，现在含有一个178．5m的油气柱，其中气柱高164m，位于14．5m油柱之上。该油气田已填充至溢出点。奥利弗-1井的GOI图显示，在现在的气柱内古油柱的总高度曾在99-132m之间，原始石油地质储量高达2亿bbl，明显高于现在4500万bbl的储量。高达1．55亿bbl的油从奥利弗构造转移到其上倾方向的倾斜断块，从而大大改善了该断块构造的勘探远景。GOI制图法是一种储层描述新方法。它能可靠探测现在被气充填的圈闭中的古油储。在新井钻探之前，利用这些资料可以定量描述气藏及其附近未测试构造的油藏潜力。     

High Temperature Property Development of Bauxite Based Bricks

Physical properties and microstructural evolution on firing of 3 types of bauxite based refractory bricks were carried out using techniques such as porosimetry,XRD and SEM.The groups differed from each other by progressive refining of the matrix or bond phase.It is revealed that such a refinement of the matrix can improve the high temperature properties of the bricks made from poor grade materials.     

The Algorithm and Its Application of a Multi-Channel Adaptive Decision-Feedback Equalizer

1　IntroductionOneofthekeyproblemsinhigh speeddigitalradiocommunicationistheInter Symbol Interfer ence (ISI)causedbythemulti pathbetweenthetransmitterandthereceiver.Becauseoftherelativemovementbetweenthereceiverandthetransmitterandthecontinuouschangeoftransmissionmedia,ISIisusuallytime variant.Inthepasttwotothreedecades,abroadstudyofthetype ,structureandadaptivealgorithmofadaptiveequalizershasbeencarriedouttomitigateISI[1～ 7] .Withtheintroductionofadaptiveantennasanddiversityreceptiontec…