Granite deformation and behavior of acoustic emission sequence under the temperature and pressure condition at different crust depths

Results of triaxial compression experiment results show that granite rock strength increases with the depth until 30 km. In shallow crust, rock failure exhibits abrupt or quasi-abrupt instability under lower pressure. Acoustic Emission (AE for short) distributed almost uniformly before and after failure. Go through downwards into the depth range with progressive failure feature, there are no or only a few number of AE before and after failure. In deeper range, rock failure shows some feature of quasi-abrupt instability under high pressure. There are still few AE before failure, but with the stick-slip, much more An events were detected after failure. Under the temperature and pressure condition of more deep crust (about 26 km), rock failure takes abrupt instability under high pressure as main feature, there are dense AE activities before failure and cumulated frequency of AE increases exponentially before the failure. In about 35 km depth range, rock strength decreases quickly with the depth and sample exhibits semi-ductile or ductile progressive fails, there are no AE being detected before and after failure. The b value of AE sequence before failure seems a little smaller than that after failure, and b value roughly decreased with depth. The numerical range of index α is the widest in about 18 km depth and becomes narrow in the condition of more shallow or more deep crust. So, when the temperature and pressure condition simulating the real environment of focal depth changes from shallow to deep in the crust, the range of a of microfracture sequence would undergo such an evolvement process that a changes from narrow to wide and then to narrow again.

Experiments of Brittle-Plastic Transition and Instability Modes of Juyongguan Granite at Different Temperatures and Pressures

Three groups of experiments on brittle-plastic transition and instability modes of granite were performed in a triaxial vessel with solid pressure medium at high temperature and high pressure. The results of experiments show that brittle faulting is the major failure mode at temperature <300℃, but crystal-plastic deformation is dominate at temperature >800℃, and there is a transition with increasing temperature from semi-brittle faulting to cataclastic flow and semi-brittle flow at temperatures of 300～800℃. So, temperature is the most influential factor in brittle-plastic transition of granite and confining pressure is the second factor. The results also show that progressive failure of granite occurs at lower pressure or high temperature where there is crystal plasticity, and sudden instability occurs at room temperature and high pressure (>300MPa) or high temperature and great pressure(550℃600MPa ～650℃700MPa), and a broad regime of quasi-sudden instability exists between the T-P condition of progressive failure and sudden instability. So, instability modes of granite depend simultaneously on the pressure and temperature.

A two-dimensional air streamer discharge model based on the improved Helmholtz equation at low temperature and sub-atmospheric pressure

In this paper,an efficient boundary condition is applied to solve the photoionization rate,and a two-dimensional numerical simulation is carried out for the development and propagation of an air streamer at low temperature and sub-atmospheric pressure.The results show that the new boundary condition improves the calculation accuracy,but the influence of photoionization on the streamer discharge process is not obvious.The discharge current in the development of streamer discharge is defined,and the corresponding expression of the positive and negative streamer discharge current is given.The influence of the electric field exceeding the threshold value on the discharge process is preliminarily introduced.In the process of discharge,only the propagation velocity of the streamer is obviously higher than that of normal temperature and pressure,and the trend of the other parameters is basically the same as that described in the previous paper.The above results give us a deeper understanding of the discharge characteristics under low temperature and sub-atmospheric pressure,which has certain significance for the development of aviation and high voltage engineering.

Chemical transformations of n-hexane and cyclohexane under the upper mantle conditions

Alkanes are an important part of petroleum,the stability of alkanes under extreme conditions is of great significance to explore the origin of petroleum and the carbon cycle in the deep Earth.Here,we performed Raman and infrared(IR)spectroscopy studies of n-hexane and cyclohexane under high pressure up to~42 GPa at room temperature(RT)and high temperature(HT).n-Hexane and cyclohexane undergo several phase transitions at RT around 1.8,8.5,18 GPa and 1.1,2.1,4.6,13,30 GPa,respectively,without any chemical reaction.By using resistive heating combined with diamond anvil cell at pressure up to 20 GPa and temperature up to 1000 K,both n-hexane and cyclohexane decompose to hydrogenated graphitic carbon and n-hexane exhibits higher stability than cyclohexane.Our results indicate that hydrocarbons tend to dehydrogenate in the upper mantle,and the extension of carbon chains may lead to the formation of some unsaturated compounds and eventually transfer into graphitic products.

Prediction Research of Deformation Modulus of Weak Rock Zone under In-situ Conditions

Weak rock zone (soft interlayer, fault zone and soft rock) is the highlight of large-scale geological engineering research. It is an important boundary for analysis of rock mass stability. Weak rock zone has been formed in a long geological period, and in this period, various rocks have undergone long-term consolidation of geostatic stress and tectonic stress; therefore, under in-situ conditions, their density and modulus of deformation are relatively high. Due to its fragmentary nature, once being exposed to the earth's surface, the structure of weak rock zone will soon be loosened, its density will be reduced, and its modulus of deformation will also be reduced significantly. Generally, weak rock zone can be found in large construction projects, especially in the dam foundation rocks of hydropower stations. These rocks cannot be eliminated completely by excavation. Furthermore, all tests nowadays are carried out after the exposure of weak rock zone, modulus of deformation under in-situ conditions cannot be revealed. In this paper, a test method explored by the authors has been introduced. This method is a whole multilayered medium deformation method. It is unnecessary to eliminate the relatively complete rocks covering on weak rock zone. A theoretical formula to obtain the modulus of deformation in various mediums has also been introduced. On-site comparative trials and indoor deformation modulus tests under equivalent density conditions have been carried out. We adopted several methods for the prediction researches of the deformation modulus of weak rock zone under in-situ conditions, and revealed a fact that under in-situ conditions, the deformation modulus of weak rock zone are several times higher than the test results obtained after the exposure. In a perspective of geological engineering, the research findings have fundamentally changed peoples' concepts on the deformation modulus of weak rock zone, provided important theories and methods for precise definition of deformation modulus of deep weak rock zone under cap rock conditions, as well as for reasonable engineering applications.

Geochemistry of Ore Fluids and Rb-Sr Isotopic Dating for the Wulong Gold Deposit in Liaoning, China

On the basis of detailed geological studies of the Wulong gold deposit, three metallogenic stages can be identified. With quartz fluid inclusions as an object of study, the authors investigated phase characteristics, compositional variations, temperature and pressure changes, fluid evolution, Pb isotope tracing and Rb-Sr isotopic dating of fluid inclusions entrapped in the above three metallogenic stages. The results show that Na+ is decreased obviously with metallogenic evolution, while K+ and other cations and gas compositions (H2, CO, CH4 and CO2) are increased slightly, and that the temperature and salinity vary in a pulsating manner along with the metallogenic evolution. Inverse calculation of hydrogen and oxygen isotopes indicate that at the first metallogenic stage the fluids were magmatic water, at the second stage they were dominated by magmatic water with a minor amount of meteoric water involved, and at the third stage, i.e., the final stage of metallogenesis, the fluids were composed completely of meteoric water. Its Pb isotopic composition implicates that the ore lead has some affinities with the lead in the Sanguliu granite, but the linear array of the ore-lead isotopic data reflects a mixing source of two end members. It can be deduced that the ore-forming materials and magma were both derived mainly from the same magma source region at depths. The Rb-Sr isotopic ages of the fluid inclusions are 112.2±3.2 Ma, indicating that the Wulong gold deposit was formed during the Yanshanian period.

基于流固耦合的正压呼吸面罩抗变形分析

随着正压呼吸防护装备的设计向轻量化方向发展,面罩的厚度逐渐降低,在实际的使用过程中,送风系统产生的进气流量导致面罩存在变形的问题。为研究不同材质的呼吸防护面罩的抗变形能力,采用流固耦合数值模拟及实验验证的方法,分析PP、PET、PVC 3种材质对进气流量的抗变形能力,并且,结合不同环境温度对面罩变形量的影响进行综合分析。结果表明,进气量对PP材料的影响较大,PVC次之,PET变形程度最小;在380 L/min的进气流量下,PP变形量约为3.7 mm,PET变形量约为1.6 mm;除此以外,在不同环境温度下,对3种材料进行变形分析发现,环境温度对PVC的影响较大,PP次之,PET变形程度最小。综合以上分析结果,选择PET材料作为正压呼吸面罩材料。

轴向柱塞泵热特性及热力学建模实验研究

针对轴向柱塞泵在高压和高速工况下发热过快的问题,对柱塞泵热特性和热力学建模进行了仿真分析与实验研究。首先,在摩擦副发热理论基础上,考虑了泵内油液搅动摩擦与轴承摩擦发热源,研究了柱塞泵内发热机理和传热分析的热特性理论;然后,根据柱塞泵部件复杂和固流态域区分度高的特点,阐述了所采用的控制体积法原理,将泵划分为5个控制体积后,建立了以各个控制体温度变化为导向的热力学模型;最后,采用光纤光栅温度传感器和蓝牙无线温度传感器,针对不同的控制体节点设计了传感器封装结构和布置方法,共同组成了轴向柱塞泵在线热监测系统,并进行了在不同压力条件下的对照实验,对理论模型进行了有效性验证与分析。研究结果表明:对比实验和仿真结果,模型温度变化与实际误差值在5%左右,验证了该模型能准确地反映和预测泵热力学变化过程。该结果为柱塞泵热力学状态监测提供了故障诊断基础,并为液压系统热管理系统设计提供了理论基础和设计依据。

花岗岩类锂矿床中锂辉石和锂云母共生性的实验模拟研究

锂是一种稀有金属元素,锂辉石和锂云母是最重要的硬岩型锂矿矿石矿物,探究二者的共生性及条件,对揭示锂元素在不同锂矿石矿物中的赋存机制以及花岗岩类锂矿床的形成机制具有重要意义。本文应用热液金刚石压腔开展了锂辉石-锂云母-H_(2)O体系的原位观测结晶实验,10组实验产物均为锂辉石和白云母,锂辉石结晶集中在500~780℃、350~1300MPa的温压条件下,白云母结晶集中在440~710℃、180~1100MPa的温压条件下。结合前人实验得到的锂云母结晶条件(500~650℃、100~450MPa),以及实验产物云母的激光拉曼线扫结果,可以得到以下认识:锂辉石与白云母结晶温压条件具有较高的重叠度,与二者可在伟晶岩中广泛共生的现象一致;锂辉石和锂云母的结晶主要受到压力影响,温度和体系F含量的影响居于次要地位;透锂长石和锂云母形成于相似的温压条件,但体系F含量的高低分别促进锂云母和透锂长石的产出;在富Li体系中,随着压力的降低可以发生白云母到锂云母的转化,指示出自然界中白云母的锂云母边可能形成于熔体或热液结晶过程中,不一定是热液蚀变的结果。

多相混输泵用超高压机械密封性能研究

针对超高压混输泵机械密封易磨损失效的问题,介绍了端面槽加工和涂层应用两种策略,用热流固耦合分析方法,分析了浅槽微接触式机械密封在实际应用中的温度分布和端面变形情况,阐述了表面涂层技术的应用,进行了一系列机械密封性能的试验研究。研究结果不仅证实了这些技术在提高机械密封寿命和可靠性方面的有效性,还证实了端面开槽和涂层技术在降低摩擦、改善耐磨性能方面的显著效果。为超高压混输泵机械密封系统的设计和优化提供了重要的理论依据及实践指导。

蝶阀在高温时受力与变形的仿真分析

高温蝶阀是目前在航空航天试验、现代化工等领域最需要的控制设备之一。本文介绍了一种DN500的高温蝶阀在高温816℃、压力为1 MPa、阀杆施加8978 N·m的关闭扭矩时受力与变形的仿真分析,通过对蝶阀建立三维模型并用有限元计算方法获得的仿真分析数据使得产品设计在高温条件下更加安全可靠。

SP700钛合金热变形行为及组织演变

采用Gleeble3800热模拟试验机对SP700钛合金进行热压缩试验,研究合金在变形温度为800~880℃、应变速率为1~10 s–1、压缩变形量为30%和50%条件下的流变行为及显微组织演变.结果表明,随着变形温度升高和应变速率降低,SP700钛合金热压缩变形的峰值流变应力降低.合金在800℃压缩变形时,流变应力曲线呈明显的动态软化,其显微组织中α片层逐渐破碎球化,部分α片层发生动态再结晶.随变形温度升高,合金压缩真应力–应变曲线呈稳态流变状态.在相同变形温度下,随应变速率和压缩变形量增加,α片层球化程度增加.热变形过程中,平行于压缩轴的α片层在压应力作用下弯曲扭折,片层内取向差不连续存在,并于不连续处存在新α/α界面.垂直于压缩轴的α片层在压应力作用下界面发生起伏,片层内部存在累积取向差.在界面起伏处β相楔入α片层,最终导致α片层的破碎球化.

环渤中凹陷挥发性原油特征及其主控因素

为研究环渤中凹陷挥发性原油特征、成藏主控因素和有利区带,利用原油族组分、原油物性、PVT高压物性实验分析等技术手段,对渤中凹陷及围区多个油田和含油气构造的原油组分和物性特征进行了统计分析,明确了渤中凹陷挥发性原油“五高三低”的特征以及各特征的数值范围。基于多组分相态变化的机理分析认为,渤中凹陷易于发育挥发性原油油藏的主控条件有3个:①优质烃源岩经过较高的热演化能够为挥发性原油提供轻质烃类组分;②渤中凹陷埋深较大,高温高压能够满足挥发性原油赋存的条件;③渤中凹陷快速沉降形成的区域泥岩盖层是挥发性原油能够保存的有利条件。基于渤中凹陷的温压梯度,推测渤中凹陷及围区埋深在2.5~4.3 km且有区域泥岩封盖的地层中易于发现挥发性油藏。

超超临界1 050 MW机组中压缸超温原因分析与处理

文章介绍了超超临界1050MW机组中压缸进汽室超温情况,以及发电厂利用机组A级检修机会,对中压缸解体检修,发现内缸、隔板套、隔板多处变形,通流部件有碰磨痕迹,随后将第1级隔板返厂增加切向旋流冷却孔,对隔板套、隔板等进行加工,对通流间隙进行调整。机组检修结束启动后,中压缸超温问题顺利解决,中压缸效率也得到恢复。

Stony Brook’s High-Pressure Laboratory Collaborations with French Scientists

For more than a half century, my colleagues and I in the Stony Brook High Pressure Laboratory have profited from collaborations with French scientists in their laboratories in Orsay, Paris, Toulouse, Lille, Lyon, Strasbourg and Rennes. These interactions have included postdoctoral appointments of French colleagues in our laboratory as well as two année sabbatique by me;in 1983-84, in the Laboratoire de Géophysique et Géodynamique Interne at the Université Paris XI in Orsay and in 2020-2003 in the Laboratoire des Méchanismes et Transfert en Géologie at the Université Paul Sabatier in Toulouse. The objective of this report is to relate this history and to illustrate the scientific advances which resulted from these collaborations.

Study on the Elman Neural Network Operation Control Strategy of the Central Air Conditioning Chilled Water System

The stable operation of the central air conditioning water system always is a major difficulty for the control profession. Paper focus on the water system with multi variable, strong coupling, nonlinear, large time delay characteristics, presented use feed forward coupling compensation method, to eliminate the coupling effect between temperature and pressure. In this paper, the Elman neural network controller is designed for the first time, and the simulation results show that the response time of Elman neural network controller is shorter, the system is more stable and the overshoot is small.

Oxidation Kinetics of Aluminum Powders in a Gas Fluidized Bed Reactor in the Potential Application of Surge Arresting Materials

In this technical paper, the oxidation mechanism and kinetics of aluminum powders are discussed in great details. The potential applications of spherical aluminum powders after oxidation to be part of the surging arresting materials are discussed. Theoretical calculations of oxidation of spherical aluminum powders in a typical gas fluidization bed are demonstrated. Computer software written by the author is used to carry out the basic calculations of important parameters of a gas fluidization bed at different temperatures. A mathematical model of the dynamic system in a gas fluidization bed is developed and the analytical solution is obtained. The mathematical model can be used to estimate aluminum oxide thickness at a defined temperature. The mathematical model created in this study is evaluated and confirmed consistently with the experimental results on a gas fluidization bed. Detail technical discussion of the oxidation mechanism of aluminum is carried out. The mathematical deviations of the mathematical modeling have demonstrated in great details. This mathematical model developed in this study and validated with experimental results can bring a great value for the quantitative analysis of a gas fluidization bed in general from a theoretical point of view. It can be applied for the oxidation not only for aluminum spherical powders, but also for other spherical metal powders. The mathematical model developed can further enhance the applications of gas fluidization technology. In addition to the development of mathematical modeling of a gas fluidization bed reactor, the formation of oxide film through diffusion on both planar and spherical aluminum surfaces is analyzed through a thorough mathematical deviation using diffusion theory and Laplace transformation. The dominant defects and their impact to oxidation of aluminum are also discussed in detail. The well-controlled oxidation film on spherical metal powders such as aluminum and other metal spherical powders can potentially become an important part of switch devices of surge arresting materials, in general.

四川米易海塔地区康定群五马箐组变质作用温压条件及其对铀成矿的指示意义

康定群五马箐组是四川米易海塔地区混合岩型铀矿的赋矿地层。文章对五马箐组中的蚀变斜长角闪岩进行了系统的岩相学、矿物地球化学、变质温压条件估算研究,探讨了该地区变质作用与铀成矿的关系。研究结果表明:米易海塔地区的变质岩经历了1个变质作用阶段和2个后期流体蚀变阶段。峰期变质阶段的温压条件为523~608℃和0.18~0.40 GPa,后两期流体蚀变阶段的温度为264~334℃。海塔地区的早期铀矿化时代与区内的变质-混合岩化时代较为相近,峰期变质阶段的温压条件和后期流体蚀变阶段的温度条件与混合岩型铀矿的流体包裹体均一温度划分的两个大的成矿阶段基本一致,反映海塔地区的混合岩型铀矿经历了变质-混合岩化作用成矿和后期热液叠加改造作用成矿两个大的阶段。

基于热流固耦合的分级注水泥器失效分析

针对分级注水泥器在实际固井使用过程中出现的循环孔打不开、关不上等失效问题,基于热流固耦合分析理论和CFD数值模拟方法,结合某油井的实际固井数据,建立从井口到分级注水泥器位置处的完整三维有限元模型.运用流体计算软件得到不同流体在不同井深位置处产生的压力与温度,将流体域求得的压力与温度传递到固体域,对分级注水泥器变形进行分析.结果表明,固井过程中注入不同流体产生的压力不同,压力对分级注水泥器的变形量有较大影响,本体与滑套的变形是导致循环孔无法正常打开或关闭的主要原因.

藏东川西交通廊道波密至林芝段重大工程水文地质条件及问题研究

为研究藏东川西波密至林芝段重大工程的水文地质条件和存在的主要工程水文地质问题,在参考前人研究成果基础上,通过开展关键钻孔岩心地质编录和野外水文地质调查等研究工作,得出了相关研究结果。结果表明:沿线具有高寒、高陡、高地震烈度、高地应力、高地温、高水压等复杂的地质环境特征,主要存在深埋长大隧道高水压涌突水、断裂带基岩裂隙高压突水、高温热水热害、隧道排水对生态环境影响等四类水文地质问题。易贡隧道外水压力预测值在0.80~3.47 MPa之间,易贡隧道和色季拉山隧道预测涌水量最大值接近或超过10×10^(4)m^(3)/d,拉月隧道附近沿线25个钻孔实测孔底温度在12.5℃~93.5℃。