Effect of a negative DC bias on a capacitively coupled Ar plasma operated at different radiofrequency voltages and gas pressures

The effect of a negative DC bias,|V_(dc)|,on the electrical parameters and discharge mode is investigated experimentally in a radiofrequency(RF)capacitively coupled Ar plasma operated at different RF voltage amplitudes and gas pressures.The electron density is measured using a hairpin probe and the spatio-temporal distribution of the electron-impact excitation rate is determined by phase-resolved optical emission spectroscopy.The electrical parameters are obtained based on the waveforms of the electrode voltage and plasma current measured by a voltage probe and a current probe.It was found that at a low|V_(dc)|,i.e.inα-mode,the electron density and RF current decline with increasing|V_(dc)|;meanwhile,the plasma impedance becomes more capacitive due to a widened sheath.Therefore,RF power deposition is suppressed.When|V_(dc)|exceeds a certain value,the plasma changes toα–γhybrid mode(or the discharge becomes dominated by theγ-mode),manifesting a drastically growing electron density and a moderately increasing RF current.Meanwhile,the plasma impedance becomes more resistive,so RF power deposition is enhanced with|V_(dc)|.We also found that the electrical parameters show similar dependence on|V_(dc)|at different RF voltages,andα–γmode transition occurs at a lower|V_(dc)|at a higher RF voltage.By increasing the pressure,plasma impedance becomes more resistive,so RF power deposition and electron density are enhanced.In particular,theα–γmode transition tends to occur at a lower|V_(dc)|with increase in pressure.

Continuum and Discrete Element Coupling Approach to Analyzing Seismic Responses of a Slope Covered by Deposits

Numerical analyses of earthquake effects on the deformation, stability, and load transfer of a slope covered by deposits are traditionally based on the assumption that the slope is a continuum. It would be problematic, however, to extend these approaches to the simulation of the slide, collapse and disintegration of the deposits under seismic loading. Contrary to this, a discrete element method （DEM） provides a means to consider large displacement and rotation of the non-continuum. To take the advantages of both methods of continuum and non- continuum analyses, seismic responses of a slope covered by deposits are studied by coupling a twodimensional （a-D） finite difference method and a 2-D DEM, with the bedrock being modelled by the finite difference grids and the deposits being represented by disks. A smooth transition across the boundaries of the continuous/discontinuous domains is obtained by imposing the compatibility condition and equilibrium condition along their interfaces. In the course of computation, the same time-step value is chosen for both continuous and discontinuous domains. The free-field boundaries are adopted for lateral grids of bedrock domain to eliminate the radiation damping effect. When the static equilibrium under gravity load is obtained, dynamic calculation begins under excitation of the seismic wave input from the continuum model bottom. In this way, responses to the earthquake of a slope covered by deposits are analyzed dynamically. Combined with field monitoring data, deformation and stability of the slope are discussed. The effects of the relevant parameters of spectrum characteristic, duration, andpeak acceleration of seismic waves are further investigated and explained from the simulations.

Dynamics of Ore-Forming Processesof the Stratabound Skarn Copper Depositsof Tongling, Anhui Province

The skarn and ore bodies of the stratabound skarn copper deposits of Tongling, Anhui Province, are both controlled by definite stratigraphic horizons, and they are concordant with the strata. They occur as layers and layer-like bodies in permeable carbonate rocks of the Middle-Upper Carboniferous Huanglong and Chuanshan Formations which are underlain by impermeable shale or siliceous rocks of the Upper Devonian Wutong Formation. The authors study the dynamics of ore-forming processes of the ore deposits with the dynamic model of coupled transport and reaction, and the following results are obtained: The salinity gradient and flow rate of the ore-forming fluids can both promote the mixing and reaction of juvenile water and formation water, and the permeable strata are favourable sites for the intense transport-reaction of mixing and the formation of deposits. (2) As isothermal transport-reaction took place along the bedding of strata, the moving transport-reaction front formed at the contact between the ore-forming fluids and the rocks advanced slowly along the permeable strata, and then stratiform skarn and ore bodies concordant with the strata were formed. (3) The gradient transport-reaction taking place across the isotherms in the cross-bedding direction caused the mineralogical composition to alter gradually from magnesian skarn to sulphide ore bodies.

Coupling mechanism of mineralization and hydrocarbon-forming in hydrothermal convection system: An example from Longtoushan Sn-polymetal deposit, Dachang

Longtoushan Sn-polymetal deposit is a large-scale deposit of high-tenor. The ore-bodies occur in reef limestone of middle Devonian. There is much anthraxolite in reef limestone and ore-bodies. The anthraxolite is the postmature result of oil-gas' thermal metamorphism. The close relationship of anthraxolite and Sn-polymetal deposit reveals the space-time relation between oil-gas evolution and Sn-polymetal mineralization. Sulfur isotope of Longtoushan deposit is close to oil's sulfur in Devonian, which indicates obvious relationship between the sulfur's source of deposit and oil-gas' activity. The forming of Longtoushan deposit relates to exhalative-sedimentary mineralization in Devonian. Because of the favorable hydrocarbon-forming condition of Longtoushan reef and surrounding basin facies' black shale and peat, coupling of ore-formation and hydrocarbon-forming occurs in seabed's hydrothermal convection. The distributing of ore-forming elements indicates the presence of hydrothermal convection system. The thermal fluid containing organic matters conduces to Sn-polymetal elements' activation and transfer, and provides catalyzing condition to the transforming from SO42- to S2-. The erosion action of brine containing organic acid to reef limestone induces the growing of crannies and karst's caverns, which provides advantageous space to Sn-polymetal mineralization. The heat source of mineralization provides thermocatalysis condition to hydrocarbon-forming. When the circulatory fluid containing oil-gas enters the high-temperature region(＞150 ℃ ), the oil-gas is decomposed and anthraxolite comes into being.

A Study on the Geological-Geochemical Dynamicsof Hydrothermal Ore Deposition as Exemplified by the Muping-Rushan Gold Deposit Belt,Eastern Shandong, China

This paper presents a method of establishing a hydrothermal ore-forming reaction system. On the basis of the study of four typical hydrothermal deposits, the folowing conclusions concerning geochemical dynamic controlling during hydrothermal mineralization have been drawn: (1 ) The regional tectonic activities control the concentration and dispersion of elements in the ore-forming process in terms of their effects on the thermodynamic nature and conditions of the ore-forming reaction system. (2) During hydrothermal mineralization the activities of ore-bearing faults can be divided into two stages: the brittle splitting stage and the brirtle-tough tensing stage, which would create characteristically different geodynamic conditions for the geochemical thermodynamic ore-forming system. (3) The hydrothermal ore-forming reaction system is an open dynamic system. At the brittle splitting stage the system was so strongly supersaturated and unequilibrated as to speed up and enhance the crystallization and differentiation of ore-forming fluids. And at the brittle-tough tensing stage, the ore-forming system was in a weak supersaturated state; with decreasing temperature and pressure the crystallization of oreforming material would slow down, and it can be regarded as an equilibrated state. (4) In the later stages of hydrothermal evolution, gold would be concentrated in the residual ore-forming solution. The pulsating fracture activity in this stage led to the crush of pyrite ore and it was then filled with gold-enriched solution, forming high-grade "fissure" gold ore. This ore-forming process could be called the coupling mechanism of ore formation.

Numerical simulation of direct shear tests on mechanical properties of talus deposits based on self-adaptive PCNN digital image processing

The macro mechanical properties of materials with characteristics of large scale and complicated structural composition can be analyzed through its reconstructed meso-structures.In this work,the meso-structures of talus deposits that widely exist in the hydro-power engineering in the southwest of China were first reconstructed by small particles according to the in-situ photographs based on the self-adaptive PCNN digital image processing,and then numerical direct shear tests were carried out for studying the mechanical properties of talus deposits.Results indicate that the reconstructed meso-structures of talus deposits are more consistent with the actual situation because the self-adaptive PCNN digital image processing has a higher discrimination in the details of soil-rock segmentation.The existence and random distribution of rock blocks make the initial shear stiffness,the peak strength and the residual strength higher than those of the "pure soil" with particle size less than 1.25 cm apparently,but reduce the displacements required for the talus deposits reaching its peak shear strength.The increase of rock proportion causes a significant improvement in the internal friction angle of talus deposit,which to a certain degree leads to the characteristics of shear stress-displacement curves having a changing trend from the plastic strain softening deformation to the nonlinear strain hardening deformation,while an unconspicuous increase in cohesion.The uncertainty and heterogeneity of rock distributions cause the differences of rock proportion within shear zone,leading to a relatively strong fluctuation in peak strengths during the shear process,while movement features of rock blocks,such as translation,rotation and crossing,expand the scope of shear zone,increase the required shear force,and also directly lead to the misjudgment that the lower shear strength is obtained from the samples with high rock proportion.That,however,just explains the reason why the shear strength gained from a small amount of indoor test data is not consistent with engineering practice.

“Structure-Lithologic-Fluid” Metallogenic Coupling of the Wuzhishan Lead-Zinc Deposit in Puding, Guizhou Province

1 Introduction The Wuzhishan lead-zinc ore-concentrated area in Puding is located in the east of the Sichuan,Guizhou and Yunnan lead-zinc metallogenic domain,with the Youjiang-Nanpan River metallogenic province to the

Effect of hydrogen content on dielectric strength of the silicon nitride film deposited by ICP-CVD

The inductively coupled plasma chemical vapor deposition(ICP-CVD) deposited silicon nitride(SiN_(x)) thin film was evaluated for its application as the electrical insulating film for a capacitor device.In order to achieve highest possible dielectric strength of SiN_(x),the process parameters of ICP-CVD were carefully tuned to control hydrogen in SiN_(x) films by means of tuning N_(2)/SiH_(4) ratio and radio frequency(RF) power.Besides electrical measurements,the hydrogen content in the films was measured by dynamic secondary ion mass spectrometry(D-SIMS).Fourier transform infrared spectroscopy(FTIR) and micro Raman spectroscopy were used to characterize the SiN_(x) films by measuring Si-H and N-H bonds’ intensities.It was found that the more Si-H bonds lead to the higher dielectric strength.

The effect of discharge conditions of ICP etching reactor on plasma parameters

This study investigated the inductively coupled plasma etching reactor and RF coils developed by North Microelectronic Corporation. Full three dimensional simulations were made at different discharge conditions. The simulations examined and compared the distribution and non-uniformity of several plasma parameters at a fixed position upon the wafer at different pressures and coil currents. These parameters included electron density, electron temperature and power deposition. The results demonstrate that the electron density, power deposition and uniformity increase with either higher pressure or stronger coil currents, while the electron temperature decreases at this condition. Coil number increase can reduce the non-uniformity of parameters in the spatial distribution. The linear relationship between power deposition and electron density does not always exist. The comparison between simulation results and experiment results is also presented in the paper.

Corrosion Study of Two-step Deposition Coatings on Copper Foil

To improve corrosion inhibition performance of copper foil with a novel two-step electrochemical modification processes,the surface of 35μm copper foils was coated with graphene oxide(GO)via electrochemical method at first step,then was further coated with 3-aminopropyltrimethoxysilane(APTS)at the second step.For the first step the copper foil acted as anode,and as cathode for the second one(we labeled it as E-GO).Optimum coating parameters for the preparation of E-GO coating are 5 V and 1 min with ratio of APTS/deionized water(DI)1.5/98.5(v/v).The physicochemical properties of modified coating were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM)and hydrophilicity test.Electrochemical behavior of different samples were also investigated.The experimental results indicate that anti-corrosion performance is significantly improved with two-step modified coating.And E-GO coating shows more positive corrosion potential and the highest corrosion resistance rate than others according to the Tafel curve.It is also found that surface hydrophobicity of E-GO coating is significantly improved.

热液成矿系统构造控矿理论

构造对成矿的控制是热液成矿系统的典型特征之一,系统剖析多重尺度控矿构造的几何学、运动学、动力学、流变学和热力学对认识矿床成因和预测找矿至关重要;而如何实现控矿构造格架、渗透性结构、成矿流体通道和矿化变形网络由静态到多尺度时-空四维动态的转变,查明流体通道和矿床增量生长过程与控制因素,揭示热液成矿系统的构造-流体耦合成矿机制和定位规律是亟待解决的关键科学难题。为此,我们在对已有相关成果系统梳理的基础上,提出了科学构建热液成矿系统构造控矿理论的基本要点与对应方法及应用范畴:(1)流体而非构造是构造控矿理论的中心,热液系统的流体流动与成矿作用受控于断裂带格架及其渗透性结构,其中渗透率是将流体流动与流体压力变化联系起来理解控矿构造的核心;(2)不同控矿构造组合的关键控制是构造差应力和流体压力的大小,而矿化类型的变化可能是由于构造应力场引起的容矿构造方位的不同和赋矿围岩之间的强度差异所致;(3)流体通道的生长始于超压流体储库上游围岩中孤立的微裂隙沿流体压力梯度最大的方向、随裂隙发育且相互连结而形成新的长裂隙,并最终连通形成断裂网络内的流体通道,矿床的增量生长发生在高流体通量的短爆发期,断层反复滑动驱动其内流体压力、流速和应力快速变化,当由此诱发的流体通道生长破坏了流体系统的动态平衡时,随之而来的流体快速降压就成为金属沉淀成矿的关键驱动因素;(4)以热液裂隙-脉系统野外地质观测和构造-蚀变-矿化网络三维填图为基础,通过宏观与微观各级控矿构造相结合、地质历史与构造应力分析相结合、局部与区域点-线-面相结合、浅部与深部相结合、时间与空间相结合、定性和定量相结合,对各种控矿因素开展多学科、多尺度、多层次、全方位综合研究,是应遵循的基本原则;(5)通过构造-蚀变-矿化网络填图,将蚀变-矿化体与控矿构造的类型、形态、规模、产状和间距等几何学特征联系起来,利用热液裂隙-脉系统和断裂网络拓扑学及矿体三维几何结构分析等定量方法查明控矿构造格架和渗透性结构并揭示矿化变形网络的连通性与成矿潜力;(6)合理构建地质模型,选取合适的热力学参数和动力学边界条件,利用HCh和COMSOL等方法,定量模拟成矿过程中的流体流动、热-质传递、应力变形和化学反应等的时-空变化,是揭示构造-流体耦合成矿机理和定位规律、预测矿化中心和确定找矿目标的有效途径。进而提出了构造控矿理论的研究流程:聚焦构造-流体耦合成矿机制和定位规律这一关键科学问题,选择热液裂隙-脉系统和构造-蚀变-矿化网络为重点研究对象;通过几何学描述、运动学判断、流变学分析、动力学解析和热力学综合,厘定控矿构造格架,定位矿化中心,示踪成矿流体通道和多种矿化样式的增量生长过程及其关键控制,揭示渗透性结构的时-空演变规律及构造再活化与成矿定位的成因关联,建立构造-流体耦合成矿模式,服务新一轮战略找矿突破。以胶东焦家金矿田为例,开展控矿构造理论研究和成矿预测应用实践,证实了其科学性和有效性。

我国大气环境模式的研究进展和未来展望

本文针对我国大气环境模式的发展历史和主要特点开展系统综述,并对大气环境模式的研究进行展望,提出未来可能的发展方向.我国自20世纪60年代开始大气环境模式方面的发展和应用研究,历经输送扩散模式、酸沉降模式、空气质量模式、气候-化学耦合模式、地球系统模式等不同阶段,自主发展了具有中国特色的大气环境模式,改进完善了国际先进的大气环境模式,在大气污染防治与管控、重大活动环境保障和气候变化应对等方面发挥了重要作用.未来需要进一步加强大气污染形成机理在模式的应用研究、排放清单反演和动态源排放模式研发、多源观测资料与大气环境模式融合、集合预报技术研发、非结构网格系统研发、基于人工智能的环境大模型研发,全面提升我国大气环境模式的整体性能,积极推进我国大气环境模式的开源化和国际化.

激光惯性约束聚变堆包层能量沉积特性

参考国内外聚变堆技术,建立了一种200 MW激光惯性约束聚变堆包层概念设计,包层采用超临界二氧化碳和锂铅双冷结构。研究构建了瞬态和稳态耦合模型计算包层温度分布及变化。靶丸内爆反应使用MULTI-IFE进行计算,核热耦合部分基于蒙特卡罗程序OpenMC和自编程换热模型对包层模型结构、冷却和产氚进行计算。研究结果表明,核热耦合模型能够完成对包层的初步计算分析,周期性的瞬态载荷会引起第一壁面温度的振荡,但包层内部的温度最终会收敛到稳态计算结果。堆腔尺寸对于降低温度以及震荡效果明显,但仍需氙展平辐射功率峰。包层产氚和能量导出同时受到堆腔尺寸和增殖区的影响,在200 MW工况下,3 m半径和0.25 m增殖区尺寸计算结果最能满足需求。

基于耦合马尔科夫链的砂岩型铀矿岩性模拟

为了更好地服务于砂岩型铀矿的找矿和开采,人们开始寻找能够揭露隐伏地质情况的方法,近年来,岩性模拟被越来越多的学者所关注。结合前人的研究,文章提出了一种基于耦合强度系数的改进耦合马尔科夫链模型岩性模拟的方法。基于砂岩型铀矿成矿原理,通过调节马尔科夫链模型耦合过程中的耦合强度系数,使模拟结果更接近真实地层状态。选取鄂尔多斯盆地塔然高勒矿床为例,应用改进的耦合马尔科夫链模型还原了研究区的部分地层岩性,验证该方法的可行性。结果显示,该方法不仅可以精确地模拟地层岩性的真实性,并且在一定程度上解决了以往方法对钻孔数量过度依赖的问题。

非岩浆后生热液矿床构造—流体耦合成矿作用研究现状综述

构造—流体耦合成矿作用是矿床学研究的核心问题之一。本文聚焦非岩浆后生热液矿床成矿系统的构造—流体耦合成矿作用研究成果,从构造对流体作用、流体对构造作用两个方面,总结了构造活动与流体作用同步进行且相互影响的机制。通过典型实例分析,认为构造—流体耦合成矿作用研究要从时间、空间、物质方面的耦合关系阐明构造与流体成矿作用过程及其“矿源—输运—聚集”过程,揭示构造活动与流体成矿作用机理。在此基础上,提出了构造—流体耦合成矿作用研究的主要方向及发展趋势。该研究对丰富热液矿床成因理论研究和成矿规律的认识具有重要意义。

松辽盆地砂岩型铀矿铀含量配分比例的半定量分析

钱家店铀矿是位于松辽盆地南部的复成因砂岩型铀矿,受表生淋滤、辉绿岩中低温热液和深部油气等多流体影响,目前铀矿物赋存状态尚有一定争议,铀在矿石内不同矿物中的配分尚不明确。为了进一步明确铀赋存状态和在不同矿物中的配分,计算钱家店矿石中不同矿物中铀的配分比例,本文运用岩矿鉴定、铀化学逐级提取、电子探针和激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)微区原位分析技术开展综合测试分析。明确了钱家店铀矿物的赋存状态,认为钱家店铀矿物以吸附态为主,约占总铀含量的80%,结合态铀矿物或含铀矿物约占比20%。其中吸附态铀矿物主要富集在方解石等碳酸盐矿物中,占总铀含量的47.86%,其次是在黏土矿物中占17.94%,在铁锰氧化物矿物中占12.21%。独立铀矿物是与黄铁矿密切共生的沥青铀矿为主,约占铀总含量的9.07%,另有少量含钛铀矿物和铀石约占5.08%。这种矿石中各碎屑组分中铀的占比量化研究,为矿床地浸开采及资源量计算提供依据。

Numerical Simulation of the Mass Movement Process of the 2018 Sedongpu Glacial Debris Flow by Using the Fluid-Solid Coupling Method

In the context of global warming and intensified human activities,glacier instability in plateau regions has increased,and glacier debris flows have become active,which poses a significant threat to the lives and property of people and socioeconomic development.The mass movement process of glacier debris flows is extremely complex,so this paper uses the 2018 Sedongpu glacier debris flow event on the Qinghai-Tibet Plateau as an example and applies a numerical simulation method to invert the whole process of mass movement.In view of the interaction between phases in the process of motion,we use the fluid-solid coupling method to describe the mass movement.The granular-flow model and drift-flux model are employed in FLOW3D software to study the mass movement process of glacier debris flows and explore their dynamic characteristics.The results indicate that the glacier debris flow lasted for 700 s,and the movement process was roughly divided into four stages,including initiation,scraping,surging and deposition;the depositional characteristics calculated by the fluid-solid coupling model are consistent with the actual survey results and have good reliability;strong erosion occurs during the mass movement,the clear volume amplification effect,and the first wave climbs 17.8 m across the slope.The fluid-solid coupling method can better simulate glacier debris flows in plateau regions,which is helpful for the study of the mechanism and dynamic characteristics of such disasters.

电流体雾化双液滴电聚结行为研究

电流体喷印技术具有分辨率高,溶液参数适应性广等优点,是新型显示制造工艺创新突破的重要载体之一,可用于OLED微米厚度有机TFE膜高效制造。为深入探索电流体雾化技术制备微纳液膜过程,解决现阶段对液膜制备过程中各因素作用机理了解不清的问题,基于相场方法建立了液滴电聚结两相流耦合模型,分析了制备过程中“双液滴电聚结”单元。研究外加电压、基板接触角、液滴间隙和直径对液滴聚结的影响,并总结了液滴可聚结工艺参数相图。研究结果表明,外加电压越大、液滴隙径比越小,聚结后液滴高径比越大,聚结越快;基板接触角越大,聚结后高径比越大,聚结越慢,甚至可能使液滴无法聚结。在亲水基板上外加适当电压或增加液滴密度缩短液滴间隙有助于促成基板上液滴电聚结.该研究结论和工艺相图可应用与电流体雾化制膜时工艺参数调控。

Chemical vapor deposition synthesis and Raman scattering investigation of quasi-one-dimensional ZrS_(3)nanoflakes

Quasi-one-dimensional ZrS_(3)nanoflakes attract intense interest attributed to their superior electrical and optical anisotropy,stemming from the low symmetry in the crystal structure.However,the conventional chemical vapor transport method for synthesizing bulk ZrS_(3)is limited by morphology and size controllability.It is highly desirable to propose a facile way to precisely synthesize ZrS_(3)nanoflakes.In this work,the chemical vapor deposition method is proposed as a feasible way to synthesize ZrS_(3)nanoflakes.The effects of various substrates and temperatures on ZrS_(3)synthesis have been investigated.For the as-grown ZrS_(3),good crystallinity is confirmed with X-ray diffraction and transmission electron microscopy.The structure and interlayer coupling are investigated with Raman scattering spectroscopy.The strong in-plane anisotropy and interlayer coupling of the ZrS_(3)nanoflakes are illustrated with angle-resolved Raman spectroscopy and temperature-dependent Raman characterization,respectively.This study demonstrates a feasible way for the synthesis of transition metal trisulfides,which may shed new light on the research of other two-dimensional anisotropic transition metal materials.

床沙级配调整对黄河下游洪水演进的影响

小浪底水库运行以来,进入黄河下游的水沙条件出现了较大变化,受水库清水下泄影响,黄河下游床沙粒径出现了明显的粗化。为了探讨床沙级配粗化对黄河下游洪水演进的影响,本文首先建立了适用于黄河下游的一维水沙耦合数学模型,然后采用花园口至孙口河段2020年4—10月的实测洪水过程对模型进行了验证;其次根据河段床沙粗化特点,并以花园口床沙粗化过程为代表,设计了4组床沙级配作为模拟计算的初始床沙条件;最后采用验证后的模型进行了模拟计算,分析了床沙级配调整对洪水演进的影响。结果表明:床沙级配调整对黄河下游的流量、水位、含沙量、洪水演进时间以及河段冲淤量均有影响,但是对流量影响较小,而水位、含沙量、洪水演进时间与河段冲淤量对床沙级配的改变响应较为敏感。床沙中值粒径d_(50)由0.076 mm(级配1)增至0.242mm(级配4)时,夹河滩断面水位增高0.89 m,花园口至孙口河段冲淤量由冲刷0.679亿m^(3)转变为淤积0.059亿m^(3),冲刷量减幅为109%。研究结果可为新水沙情势下黄河下游河道治理提供借鉴与参考。