上芒岗金矿床成矿作用过程研究

上芒岗金矿床位于三江褶皱系怒江大断裂西南段，龙陵～瑞丽大断裂(F_1)南东盘，上芒岗次级断裂(F_4)之中。赋矿地层为下二叠统沙子坡组(P_(1s))和中侏罗统勐嘎组(J_(2m))。矿石主要有两种类型，硅质矿石和粘土质矿石；前者主要由石英和少量黄铁矿所组成，金品位平均为2 * 10~(-6)；后者主要由伊利石、高岭石和黄铁矿所组成，金品位一般为2 * 10~(-6) ～ 4 * 10~(-6)。矿石中金星次显微状态，主要元素组合为Au、Ag、As、Sb、Hg、Ba。矿床以强烈的黄铁粘土岩化为特征，热液蚀变作用过程即是金矿化作用过程。根据热液蚀变的矿物共生组合及其生成序次，将金矿化作用过程分为五个阶段：黄铁矿-石英阶段(I)；镁贝得-白云石阶段(II)；辉锑矿-石英阶段(IlI)：黄铁矿-高岭石-伊利石阶段(IV)；网脉状石英阶段(V)。其中黄铁矿-高岭石-伊利石阶段(IV)是金矿化的主成矿阶段。该矿床属于卡林型金矿床。由石英流体包裹体获得不同成矿阶段的温度为，成矿阶段I：210～170 ℃、成矿阶段III：190～160 ℃、成矿阶段V：173～144 ℃。伊利石-水氢同位素温度计测得成矿阶段IV的温度为165 ℃。石英流体包裹体液相成分以K~+、Na~+和Cl~- (F~-)为主，其次为Ca~(2+)、Mg~(2+)和HC0_3~-，由早到晚K~+、Na~+和Cl~-降低，而Ca~(2+)、Mg~(2+)和HC0_3~-升高；气相组分以C0_2为主。石英流体包裹体成分富F，其含量高达8.03 * 10~(-3) mol／kg，正是由于成矿热液富含F，Al才可以与F形成络合物进入热液迁移，即Al成为活动组份，从而形成该矿床所独特的强烈粘土岩化蚀变。稀土元素特征方面，矿石和赋矿地层下二叠统沙子坡以及中侏罗统勐嘎组岩石的稀土配分曲线十分相似，均为右倾型，但是两者的稀土元素总量不同，前者的相对较高。矿石和蚀变岩具有相似的稀土元素配分曲线，但是矿石的稀土元素总量相对较高。与勐嘎组泥岩相比，粘土质蚀变岩和矿石更加富集轻稀土元素，并且更富Eu。这些特征表明，粘土质蚀变岩和矿石是由热液作用形成的，而不是风化作用的产物；矿石与赋矿地层在物质来源上有亲缘关系。不同矿段、不同阶段和不同类型矿石和蚀变岩的Au、Ag、As以及Sb的含量同步变化，这表明在整个成矿作用过程中，成矿流体来源统一，且在成矿体系起主导作用。不同类型的矿石及蚀变岩中Au与Al_20_3，和TFe的含量呈正相关，表明黄铁粘土岩化与成矿关系最为密切。矿石铅同位素~(208)Pb／~(204)Pb、~(207)Pb／~(204)Pb和~(206)Pb/~(204)Pb比值分别为39.12～39.54、15.85～15.95、19.75～20.33；沙子坡组(P_(1s))岩石铅同位素比值分别为:38.407～37.868、15.921～15.589、22.685～22.367;孟嘎组(J_(2m))岩石铅同位素比值分别为：39.499～39.222，15.821～15.772、19.207～18.709。在铅同位素组成相关图中矿石与地层铅的投影点分别集中成群分布。矿石铅与地层铅呈线性分布，而且矿石铅的集中区位于沙子坡组铅集中区和勐嘎组铅集中区之间。这些特征表明矿石铅系由沙子坡组铅和勐嘎组铅混合而成。成矿热液的δ~(18)O由早到晚逐渐升高，I、III、IV、V阶段流体的δ~(18)O值分别为-4.2‰，+0.59‰；+0.76‰，+1.98‰，表现出明显的漂移特征；而δD则表现出高度的一致性，变化范围为-82.5 ～ 79.48‰。由此认为成矿热液系大气降水起源。成矿热液氢、氧同位素组成的这种规律性变化还说明，成矿热液的演化具有继承性和连续性。应用CHILLERR软件包，对上芒岗金矿床的成矿作用过程进行化学反应途径数字模拟。所展示的成矿作用过程为：大气降水沿断裂带下渗，加热循环，获取成矿物质(但不排除有深源成矿物质加入的可能性)；形成起始成矿热液：T = 200℃ P = 228.8bar；pH = 4.4；fs_2 = 10~(-9.89); fo_2 = 10~(-41.28)；aAu(HS)_2~- = 10~(-9.64)，aAuCl_2~- = 10~(-17.86);富含F、Al和Au，贫As、Hg、Zn、Cu和Pb。成矿热液在构造作用的驱动下，上升进入上芒岗断裂上部含水构造破碎带，并与下渗雨水混合而淬冷，形成沿上芒岗断裂呈线状分布的早期硅化石英岩(成矿阶段I)，成矿热液与下渗雨水之比为16:l(成矿阶段I)；继而热液扩散进入下盘破碎带，与白云岩反应，形成矿体下盘的白云石化，水:岩比为193:l(成矿阶段II)。此后成矿热液上升充填裂隙空间，由于热传导而缓慢冷却，成矿体系的温度由189 ℃降为165 ℃，形成含辉锑矿的梳状石英脉(成矿阶段1II)。成矿热液继续上升进入上盘碎屑岩破碎带，停积于构造揉皱的泥质岩，并与之反应，形成上芒岗矿床金矿化的主体—粘占土质矿石，水:岩比为29:1(成矿阶段IV)。最后成矿残液逐渐冷却, 同时伴随C0_2的起泡，形成晚期石英网脉(成矿阶段V)，至此热液金矿化过程结束。由上述可见上芒岗金矿床的成矿作用过程经历了：(初始)成矿热液与下渗大气降水混合(I) → 成矿热液与沙子坡组白云岩反应(II) → 成矿热液缓慢冷却(III) → 成矿热液与勐嘎组泥质岩石反应(IV) → 成矿热液冷却沸腾(V)等5个演化阶段。模拟结果进一步证实了上芒岗金矿床的热液成因。上芒岗金矿床成作用过程化学反应途径数字模拟与地质事实高度吻合，与地球化学研究结果相互印证，再现了上芒岗金矿床的成矿作用过程。由矿床的地质地球化学特征及成矿作用过程化学反应途径模拟结果，归纳出上芒岗金矿床成矿作用过程模型。

Chemical equilibrium analysis and CFD simulation of coal combustion and NOx formation

A full two-fluid model of reacting gas-particle flows with an algebraic unified second-order moment (AUSM) turbulence-chemistry model is used to simulate Beijing coal combustion and NOx formation. The sub-models are the k-epsilon-kp two-phase turbulence model, the EBU-Arrhenius volatile and CO combustion model, the six-flux radiation model, coal devolatilization model and char combustion model. The blocking effect on NOx formation is discussed. In addition, the chemical equilibrium analysis is used to predict NOx concentration at different temperature. Results of CID simulation and chemical equilibrium analysis show that, optimizing air dynamic parameters can delay the NOx formation and decrease NOx emission, but it is effective only in a restricted range. In order to decrease NOx emission near to zero, the re-burning or other chemical methods must be used.

Design and Fabrication of Low-microwave loss Coplannar Waveguide and precise V groove on Silicon Substrate for Optoelectronic Packaging - art. no. 601938

Optoelectronic packaging has become a most important factor that influences the final performance and cost of the module. In this paper, low microwave loss coplanar waveguide(CPW) on high resistivity silicon(HRS) and precise V groove in silicon substrate were successfully fabricated. The microwave attenuation of the CPW made on HRS with the simple process is lower than 2 dB/cm in the frequency range of 0 similar to 26GHz, and V groove has the accuracy in micro level and smooth surface. These two techniques built a good foundation for high frequency packaging and passive coupling of the optoelectronic devices. Based on these two techniques, a simple high resistivity silicon substrate that integrated V groove and CPW for flip-chip packaging of lasers was completed. It set a good example for more complicate optoelectronic packaging.

Effects of Baffle Design on Fluid Flow and Heat Transfer in Ammonothermal Growth System of Nitrides

Efforts have been made in growing bulk single crystals of GaN front supercritical fluids using the ammonothermal method, which utilizes ammonia as fluid rather than water as in the hydrothermal process. Different mineralizers such as amide or azide and temperatures in the range of 200-600degreesC have been used to increase the solubility. The pressure is from 1 to 4 kbar. Modeling of the ammonothermal growth process has been used to identify factors which may affect the temperature distribution, fluid flow and nutrient transport. The GaN charge is considered as a porous media bed and the flow in the charge is simulated using the Darcy-Brinkman-Forchheimer model. The resulting governing equations are solved using the finite volume method. The effects of baffle design and opening on flow pattern and temperature distribution in an autoclave are analyzed. Two cases are considered with baffle openings of 15% and 20% in cross-sectional area, respectively.

Design guidelines and characteristics of beam-shaping microstructure optical fibers

Microstructure optical fibers with flat-top fundamental mode are first proposed by introducing a low-index inner core into the core of index-guiding microstructure optical fibers. The design guidelines and characteristics of beam-shaping microstructure optical fibers are demonstrated. The interrelationships of inner-core index with laser wavelength, air hole diameter and size of inner core are investigated. The influence of the relative size of inner core on the spatial profile of the fundamental mode is demonstrated. Moreover, sensitivity of the flat-top fundamental mode profile from the slight change of the optimum inner-core index value is studied. Starting from these results we deduce that it is possible to fabricate beam-shaping microstructure fibers with nowadays technique. (C) 2005 Elsevier B.V. All rights reserved.

Dynamic analysis of V-folded cavity for TEM00 operation of end-pumped solid-state laser

Based on graphic analysis design method of optical resonator, a simple design expression of V-folded cavity of end-pumped solid-state lasers with TEM00 operation is described, which satisfies two criterias of the resonator design. We give numerical simulation of spot size as a function of thermal focal length using this design approach whose advantages are validated experimentally.

Design of high-efficiency diffraction gratings based on total internal reflection for pulse compressor

We present designs of high-efficiency compression grating based on total internal reflection (TIR) for picosecond pulse laser at 1053 nm. The setup is devised by directly etching gratings into the bottom side of a prism so that light can successfully enter (or exit) the compression grating. Dependence of the -1 order diffraction efficiencies on the constructive parameters is analyzed for TE- and TM-polarized incident light at Littrow angle by using Fourier modal method in order to obtain optimal grating structure. The electric field enhancement within the high-efficiency TIR gratings is regarded as another criterion to optimize the structure of the TIR gratings. With the criterion of high diffraction efficiency, low electric field enhancement and sufficient manufacturing latitude, TIR compression gratings with optimized constructive parameters are obtained for TE- and TM-polarized incident light, respectively. The grating for TE-polarized light exhibits diffraction efficiencies higher than 0.95 within 23 nm bandwidth and relatively low square of electric field enhancement ratio of 5.7. Regardless of the internal electric field enhancement, the grating for TM-polarized light provides diffraction efficiencies higher than 0.95 within 42 nm bandwidth. With compact structure, such TIR compression gratings made solely of fused silica should be of great interest for application to chirped pulse amplification (CPA) systems. (c) 2007 Elsevier B.V. All rights reserved.

Optimization of thin-film design for multi-layer dielectric grating

Thin-film design used to fabricate multi-layer dielectric (MLD) gratings should provide high transmittance during holography exposure, high reflectance at use wavelength and sufficient manufacturing latitude of the grating design making the MLD grating achieve both high diffraction efficiency and low electric field enhancement. Based on a (HLL)H-9 design comprising of quarter-waves of high-index material and half-waves of low-index material, we obtain an optimum MLD coating meeting these requirements by inserting a matching layer being half a quarter-wave of Al2O3 between the initial design and an optimized HfO2 top layer. The optimized MLD coatings exhibits a low reflectance of 0.017% under photoresist at the exposure angle of 17.8 degrees for 413 nm light and a high reflectance of 99.61% under air at the use angle of 51.2 degrees for 1053 nm light. Numerical calculation of intensity distribution in the photoresist coated on the MLD film during exposure shows that standing-wave patterns are greatly minimized and thus simulation profile of photoresist gratings after development demonstrates smoother shapes with lower roughness. Furthermore, a MLD gratings with grooves etched into the top layer of this MLD coating provides a high diffraction efficiency of 99.5% and a low electric field enhancement ratio of 1.53. This thin-film design shows perfect performances and can be easily fabricated by e-beam evaporation. (c) 2006 Elsevier B.V. All rights reserved.

Novel method for design of surface relief guided-mode resonant gratings at normal incidence

We demonstrate that the surface relief guided-mode resonant gratings with specified central wavelength and FWHM in the visible wavelength range can be designed by analyzing the complex poles of Reflectance and transmission coefficient matrix algorithm (RTCM), a variant of S-matrix propagation algorithm proposed for calculation of multilayer gratings. In addition, FWHM is computed with couple-mode (CM) theory of resonant gratings which is firstly extended by Norton et al. in calculation of waveguide grating. Furthermore, the side band reflections of the filter can be reduced to less than 5% in the visible wavelength with the antireflection (AR) design technique widely used in the thin-film field. (C) 2008 Elsevier B.V. All rights reserved.

Optimization by orthogonal array design and humoral immunity of the bivalent vaccine against Aeromonas hydrophila and Vibrio fluvialis infection in crucian carp (Carassius auratus L.)

Aeromonas hydrophila and Vibrio fluvialis are the causative agents of a serious haemorrhagic septicaemia that affects a wide range of freshwater fish in China. In order to develop a bivalent anti-A. hydrophila and anti-V. fluvialis formalin-killed vaccine to prevent this disease, an orthogonal array design (OAD) method was used to optimize the production conditions, using three factors, each having three levels. The effects of these factors and levels on the relative per cent survival for crucian carp were quantitatively evaluated by analysis of variance. The final optimized formulation was established. The data showed that inactivation temperature had a significant effect on the potency of vaccine, but formalin concentration did not. The bivalent vaccine could elicit a strong humoral response in crucian carp (Carassius auratus L.) against both A. hydrophila and V. fluvialis simultaneously, which peaked at 3 or 5 weeks respectively. Antibody titres remained high until week 12, the end of the experiment, after a single intraperitoneal injection. The verification experiment confirmed that an optimized preparation could provide protection for fish at least against A. hydrophila infection, and did perform better than the non-optimized vaccine judged by the antibody levels and protection rate, suggesting that OAD is of value in the development of improved vaccine formulations.

Thermal effects investigation and cavity design in passively mode-locked Nd:YVO4 laser with a SESAM

A diode-pumped passively mode-locked Nd YVO4 laser with a five-mirror folded cavity is presented by using a semiconductor saturable absorber mirror (SESAM). The temperature distribution and thermal lensing in laser medium are numerically analyzed to design a special cavity which can keep the power density on SESAM under its damage threshold. Both the Q-switched and continuous-wave mode-locked operation are experimentally realized. The maximum average output power of 8.94 W with a 9.3 ps pulse width at a repetition rate of 111 MHz is obtained under a pump power of 24 W, correspondingly the optical slope efficiency is 39.2%. (C) 2008 Elsevier B.V. All rights reserved.

Design of the low-temperature AlN interlayer for GaN grown on Si(111) substrate

We have investigated the effect of the thickness and layer number of the low-temperature A1N interlayer (LT-A1N IL) on the stress relaxation and the crystal quality of GaN epilayers grown on Si (111) substrate by metalorganic chemical vapor deposition. It is found that the stress decreases with the increase of the LT-AIN IL thickness, but the crystal quality of the GaN epilayer goes worse quickly when the LT-AIN IL thickness is larger than 16 nm. This is because the increase of the LT-AIN IL thickness will increase the coalescence thickness of its upper GaN layer, which sensitively affects the crystal quality of the epilayer. Using multiple LT-AIN ILs is an effective method not only to reduce the stress, but also to improve the crystal quality of the GaN epilayer. With the increase of the interlayer number, the probability that dislocations are blocked increases and the probability that dislocations are produced at interfaces decreases. Thus, dislocations in the most upper part of GaN are reduced, resulting in the improvement of the crystal quality. Finally, it is suggested that when the total thickness of the epilayer is fixed, both the thickness and the number of the LT-AIN IL should be carefully designed to reduce the stress and improve the crystal quality of the epilayer simultaneously. (c) 2004 Elsevier B.V.. All rights reserved.

Design and fabrication of 1.06 mu m resonant-cavity enhanced reflective modulator with GaInAs/GaAs quantum wells

A resonant-cavity enhanced reflective optical modulator is designed and frabricated, with three groups of three highly strained InGaAS/GaAs quantum wells in the cavity, for the low voltage and high contrast ratio operation. The quantum wells are positioned in antinodes of the optical standing wave. The modulator is grown in a single growth step in an molecular beam epitaxy system, using GaAs/AIAs distributed Bragg reflectors as both the top and bottom mirrors. Results show that the reflection device has a modulation extinction of 3 dB at -4.5 V bias.