基于D-S证据理论的岩爆预测方法研究

为了有效预测岩爆,提出基于D-S证据理论的岩爆预测方法.首先,选取与岩爆发生相关的6个指标因素作为证据体,并通过模糊物元框架和正态型隶属度函数构建证据体的基本概率分配.然后,利用K均值将证据体分类,并提出簇内证据用传统方式融合而簇间证据用权重方式融合的组合融合规则,以减轻高冲突证据融合的不利影响.最后,将模型应用在秦岭终南山公路隧道2号竖井工程,且与经验方法对比.为了分析预测过程的不确定性和估计岩爆发生概率,采用蒙特卡洛模拟进行抽样仿真,并通过Spearman秩相关系数衡量输入指标的全局敏感性.研究结果表明:输入指标在不同的岩爆案例的影响程度差异较大且方向不同;5个岩爆案例的发生概率在40.8%~70.1%之间.该模型表现出优异的预测分类性能,可为深埋地下工程岩爆预测提供参考.

基于S-R和分解定理的二维几何非线性问题的虚单元法求解

应变-旋转(Strain-Rotation,S-R)和分解定理为分析几何非线性问题提供了合理可靠的理论基础,但用有限元求解时会遇到大变形发生后的网格畸变问题。近年提出的虚单元法(Virtual element method,VEM)适用于一般的多边形网格,因此,该文尝试使用一阶虚单元求解基于S-R和分解定理的二维几何非线性问题,以克服网格畸变的影响。基于重新定义的多项式位移空间基函数,推演获得一阶虚单元分析线弹性力学问题时允许位移空间向多项式位移空间的投影表达式;按照虚单元法双线性格式的计算规则,分析处理基于更新拖带坐标法和势能率原理的增量变分方程;进而建立离散系统方程及其矩阵表达形式,并编制MATLAB求解程序;采用常规多边形网格和畸变网格,应用该文算法分析均布荷载下的悬臂梁和均匀内压下的厚壁圆筒变形。结果与已有文献和ANSYS软件的对比表明:该文算法在两种网格中均可有效执行且具备足够数值精度。总体该文算法为基于S-R和分解定理的二维几何非线性问题求解提供了一种鲁棒方法。

四川康定偏岩子造山型金矿床成因:石英微量元素和硫化物S同位素证据

大渡河金矿带是中国重要的金矿化富集区,发育一系列造山型金矿床。偏岩子金矿床位于大渡河南段的康定地区,矿体赋存于震旦系灯影组白云岩中。金成矿过程分为金-黄铁矿-石英阶段、金-氟镁石阶段、金-硫化物-氟镁石-石英阶段和黄铁矿-白云石-白云母阶段4个成矿阶段。通过石英中微量元素和硫化物S同位素的原位分析,旨在约束成矿流体性质、成矿物质来源和矿床成因。石英中Li,B,Na,Al,P和K相对富集,主要以Al^(3+)^(+)(Li^(+),Na^(+),K^(+),H^(+))Si^(4+)和Al^(3+)^(+)P 5^(+)2Si^(4+)的替换机制进入石英晶格。石英中Al与Li呈明显正相关关系,指示其形成温度较低。围岩中硫化物的δ^(34) S值介于-22.3‰~-13.1‰之间,表明S来源于海相硫酸盐的细菌还原作用;矿石中硫化物的δ^(34) S值范围为5.4‰~7.0‰,与交代岩石圈地幔的硫同位素值一致。综合矿床地质特征、石英微量元素和硫化物硫同位素组成,研究认为偏岩子属于造山型金矿床。成矿流体在上升过程中与赋矿白云岩接触,发生水-岩反应,导致自然金、含金硫化物、氟镁石和萤石的沉淀结晶。

小红石砬子铅锌(银)矿床成因:来自S-Pb同位素和元素特征的证据

小红石砬子铅锌(银)矿床是吉中-延边铜镍多金属成矿带中具有代表性的中型矿床,前人关于该矿床类型划分的观点有火山成因块状硫化物型(Volcanogenic Massive Sulfide,VMS)、中-低温热液脉型、喷流沉积-热液叠加改造型,这三种观点的争论严重制约了对该矿区及区域成矿和找矿的认识。本文选取该矿床中金属硫化物开展原位微量和S-Pb同位素分析,赋矿围岩开展全岩S同位素分析。闪锌矿Fe-Zn含量(4.48%~10.33%、53.67%~62.12%)与中温热液矿床一致(3.00%~10.00%、50.00%~60.00%,成矿温度约200℃),Zn/Cd比值(53.68~76.75)同样指示中低温成矿作用(高温:Zn/Cd>500;低温:Zn/Cd<250),Ga/Ge比值在lg(Ga/Ge)-T图解中,对应温度约为100~180℃,上述温度范围与前人测定的流体包裹体均一温度基本吻合(90~250℃)。闪锌矿Zn/Cd的比值(53.68~76.75)与Cd含量(7577×10-6~11266×10-6)特征与密西西比河谷型(Mississippi Valley-Type,MVT)矿床一致;黄铁矿Fe/S比值(0.76~1.29,平均值为0.89)接近典型MVT矿床的理论值(0.88)。金属硫化物δ34 S V-CDT值介于-9.6‰~-0.5‰之间,总体偏负;赋矿围岩δ34 S V-CDT值介于-8.5‰~4.2‰之间,两者重叠范围较大(主要集中于-9.0‰~-2.0‰),说明围岩提供了主要的还原硫,而古老基底可能提供了部分较轻的硫。金属硫化物Pb同位素比值为206 Pb/204 Pb=18.30~18.39、207 Pb/204 Pb=15.61~15.63、208 Pb/204 Pb=38.38~38.44,指示铅为混合来源,成矿物质可能主要来自上地壳和造山带,模式年龄计算显示上太古界乌拉山群变质岩可能为铅的初始来源。综上所述,小红石砬子铅锌(银)矿床地球化学特征与MVT型矿床基本一致,地质特征略有差别,因此推测其为类MVT型矿床。

ESD保护电路在HDMI板级信号完整性中的影响分析及其布局优化研究

为了解决HDMI接入ESD保护电路后信号完整性受破坏等问题,从器件的空间布局对HDMI信号完整性影响进行研究分析,同时考虑了瞬态电压抑制(TVS)高频寄生参数的影响,搭建了ESD放电模型和TVS高频等效电路模型,并对其可靠性进行了验证。从差分器件接入信号线旋转角度和彼此间错开距离研究其对信号完整性的影响,设计了25套不同夹角和4套不同错开距离的板级模型,在不同特性的传输频率下进行S参数仿真,并从中选取出垂直型、水平型、错开型三种具有代表性的空间布局模型,利用有限元仿真得到差分信号线的S参数和眼图。仿真结果表明,垂直型排布相比于其他两种典型空间布局,回波损耗平均降低了248.1%,插入损耗平均降低了20.6%,眼图的眼宽和眼高在三种空间布局中最大。研究成果为PCB静电放电保护电路分析与设计提供了布局优化指导。

S对铸造高温合金K417G凝固行为的影响

在1340~1230℃采用等温凝固实验,研究了w[S]分别为0.0001%、0.0018%和0.0037%对K417G合金凝固特性的影响。结果表明,S降低合金的固相线温度,扩大固液两相区,当w[S]从0.0001%增加到0.0037%时,合金的固相线温度由1255℃降低至1245℃。在凝固过程中S元素偏析于液相,并在终凝区析出Y相,且S促进Al、Cr元素在固液界面处的富集。在相同等温温度下,S元素对MC碳化物和γ+γ’共晶的析出温度与形貌无明显影响,但S含量的增加促使MC碳化物、γ+γ’共晶和Y相数量的增加,且Y相的析出温度从1230℃提升至1240℃。

S形钢丝初辊压工艺的数值分析

根据主缆S形钢丝的技术指标要求,利用有限元分析和试验测试等手段,在保持总变形不变的条件下,对10#钢分别进行4道、6道、8道初辊压测试试验。试验结果表明S形钢丝应力的集中区域存在于变形过渡区和辊缝中心线的主要变形区,随着辊压道次的增加,拉长的晶粒也更多。数值分析的预测结果与实验表征的结果具有良好的一致性。

H_(2)S分压对SA387M Gr.11CL2(H)炼化管道用钢腐蚀行为的影响

为了探究H_(2)S分压对SA387M Gr.11CL2(H)炼化管道用钢腐蚀行为的影响,采用高压釜进行试验,通过SEM,EDS,XRD和EPMA分析了SA387M Gr.11CL2(H)钢腐蚀产物的形貌、成分和物相。结果表明,随着H_(2)S分压(PH_(2)S)的增加,SA387M Gr.11CL2(H)钢的腐蚀减薄量增大。PH_(2)S≤0.5 MPa时,以全面腐蚀为主;PH_(2)S=1.0 MPa时,钢发生全面腐蚀伴随局部腐蚀,应力促进了局部腐蚀。SA387M Gr.11CL2(H)钢耐硫化物应力腐蚀性能良好。PH_(2)S≤0.5 MPa时,腐蚀产物膜中Cr的化合物和具有保护性的硫铁化合物发挥协同作用,有效阻止介质中Cl-的侵入;PH_(2)S=1.0 MPa时,腐蚀产物膜中Cr的化合物含量少,生成的硫铁化合物不具有保护性。H_(2)S分压影响了腐蚀产物膜的生成;Cr的化合物和硫铁化合物的组成和结构的变化,是导致SA387M Gr.11CL2(H)钢发生全面腐蚀和局部腐蚀的主要原因。

Ore Genesis for Stratiform Ore Bodies of the Dongfengnanshan Copper Polymetallic Deposit in the Yanbian Area, NE China:Constraints from LA-ICP-MS in situ Trace Elements and Sulfide S–Pb Isotopes

The Dongfengnanshan Cu polymetallic deposit is one representative deposit of the Tianbaoshan ore district in the Yanbian area, northeast(NE) China. There occur two types of ore bodies in this deposit, the stratiform ore bodies and veintype ones, controlled by the Early Permian strata and the Late Hercynian diorite intrusion, respectively. Due to the ambiguous genetic type of the stratiform ore bodies, there has been controversy on the relationship between them and veintype ore bodies. To determine the genetic type of stratiform ore bodies, laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS) in situ trace elements and S–Pb isotope analysis have been carried on the sulfides in the stratiform ore bodies. Compared with that in skarn, Mississippi Valley-type(MVT), and epithermal deposits, sphalerite samples in the stratiform ore bodies of the Dongfengnanshan deposit are significantly enriched in Fe, Mn, and In, while depleted in Ga, Ge, and Cd, which is similar to the sphalerite in volcanic-associated massive sulfide(VMS) deposits. Co/Ni ratio of pyrrhotites in the stratiform ore bodies is similar to that in VMS-type deposits. The concentrations of Zn and Cd of chalcopyrites are similar to those of recrystallized VMS-type deposits. These characteristics also reflect the intermediate ore-forming temperature of the stratiform ore bodies in this deposit. Sulfur isotope compositions of sulfides are similar to those of VMS-type deposits, reflecting that sulfur originated from the Permian Miaoling Formation. Lead isotope compositions indicate mixed-source for lead. Moreover, the comparison of the Dongfengnanshan stratiform ore bodies with some VMStype deposits in China and abroad, on the trace elements and S–Pb isotope characteristics of the sulfides reveals that the stratiform ore bodies of the Dongfengnanshan deposit belong to the VMS-type, and have closely genetic relationship with the early Permian marine volcanic sedimentary rocks.

EXPLICIT ERROR ESTIMATE FOR THE NONCONFORMING WILSON'S ELEMENT

In this article, we study the explicit expressions of the constants in the error estimate of the nonconforming finite element method. We explicitly obtain the approximation error estimate and the consistency error estimate for the Wilson＇s element without the regular assumption, respectively, which implies the final finite element error estimate. Such explicit a priori error estimates can be used as computable error bounds.

On the Error Estimate of Adini's Element for the Second Order Problems

The main aim of this paper is to have an accurate analysis on the famous Adini＇s element for the second order problems under to the anisotropic meshes. We firstly show that the interpolation of Adini＇s element satisfy the anisotropic property. Then the optimal error estimate is obtained without the regularity assumption on the meshes.

Analysis of the geometrical dependence of auxetic behavior in reentrant structures by finite elements

Materials with a negative Poisson＇s ratio（PR）are called auxetics;they are characterized by expansion/contraction when tensioned/compressed.Given this counterintuitive behavior,they present very particular characteristics and mechanical behavior.Geometrical models have been developed to justify and artificiall reproduce such materials＇ auxetic behavior.The focus of this study is the exploration of a reentrant model by analyzing the variation in the PR of reentrant structures as a function of geometrical and base material parameters.It is shown that,even in the presence of protruding ribs,there may not be auxetic behavior,and this depends on the geometry of each reentrant structure.Values determined for these parameters can be helpful as approximate reference data in the design and fabrication of auxetic lattices using reentrant geometries.

Finite Element Analysis of Diamond Saw Blades to Prevent Steel Base Wear

The FEM analysis of stress and deformation of steel base of the special diamond saw blades are carried out.The small carbide round segments are welded on the side of blades in order to increase the side wear re sistance of blade.Comparing with conventional saw blade,the maximum stress val ues of reasonable special saw blade are reduced respectively about 17%20% 33%,and the maximum deformation values are reduced respectively about 26%22 %44.7%in thetangential(X),radial(Y)and axial(Z)direction.The stress conce ntration zone is decreased for the special structure diamond saw blade.The stru ctures of diamond saw blade with different number of hard material pellet are an alyzed and optimized.

基于S-A模型的覆冰输电线绕流数值分析

基于Spalart-Allmaras湍流模型(S-A模型)封闭的雷诺平均N-S方程,采用沿均匀流线的三阶Runge-Kutta法和Galerkin法分别进行时间和空间离散,得到了湍流方程的有限元格式。采用自编Matlab程序,数值模拟了不同风攻角下覆冰输电线绕流问题,得到了覆冰输电线绕流瞬态和时均流场、气动力系数时程曲线和平均气动力系数随风攻角的变化关系,并与试验结果进行对比,验证了该算法的有效性。基于流场演化和平均压力分布,分析表明风攻角变化引起的边界层分离点转移是产生升力系数尖峰突跳现象的主要原因。

滇西兰坪金顶铅锌矿床精细刻画矿化过程:来自硫化物原位微量元素和S-Pb同位素的证据

金顶铅锌矿床位于中国西南中新生代兰坪盆地,是亚洲第二大铅锌矿床,其巨大的储量和复杂的地质成矿史吸引了众多学者的研究,但在矿床成因和矿化过程的精细描述等方面仍存在较大争议。本文通过详细的野外地质调查并结合硫化物的LA-(MC)ICP-MS微量元素和硫、铅同位素分析对该矿床进行了详细解剖。金顶铅锌矿床的含矿地层为景星组砂岩、云龙组含砾砂岩及灰岩角砾岩。成矿过程可分为2个主要阶段:第Ⅰ阶段早期为浸染状的黄铁矿-白铁矿-闪锌矿-方铅矿,晚期硫化物呈块状且出现天青石;第Ⅱ阶段为闪锌矿-方铅矿-黄铁矿-天青石-重晶石-方解石-石膏阶段。成矿过程中硫化物的原位微量元素和S-Pb同位素表现出规律演化特征。主要金属元素除了以简单的类质同象形式赋存于闪锌矿中,Zn^(2+)与微量元素存在4Zn^(2+)→2Fe^(2+)→Ge^(4+)、2Zn^(2+)→Fe2+→Mn^(2+)、3Zn^(2+)→In^(3+)→Sn^(3+)等复杂的替代关系。综合微量元素和S-Pb同位素演化规律,本文认为金顶铅锌矿的成矿流体早阶段与富含金属的盆地卤水和富含H2S的流体有关,晚阶段则与大气水的混入有关。在后一过程中,大气水萃取了区域上富含Fe、Mn、Tl的红层碎屑岩,进而导致Fe、Mn、Tl等元素含量的升高,同时闪锌矿也表现出更宽范围的微量元素特征和更窄范围的^(208)Pb/^(204)Pb、^(207)Pb/^(204)Pb和δ^(34)S值的特征。由此推断,超大型金顶铅锌矿床是由多来源流体相互叠加而形成,其成矿物质主要来源于兰坪盆地沉积地层。此外,BSR作用在硫酸盐还原过程中起着重要作用,西部矿段还原硫可能还有少量TSR作用的贡献。最后,本文讨论了金顶铅锌矿床的矿床成因和精细矿化过程,综合分析认为它是一个受层间构造控制的、富Cd和Ge等多种分散元素的后生碎屑岩容矿型MVT铅锌矿床。

Anisotropic Interpolation Error Estimates of a Nonconforming Element

The main aim of this paper is to study the local anisotropic interpolation error estimates. We show that the interpolation of a nonconforming element satisfy the anisotropic property for both the second and fourth order problems.

Are spatial distributions of major elements in soil influenced by human landscapes?

The present study attempted to evaluate the influence of human activity on major elements （Na2O, MgO, A1203, SiO2, K2O, CaO, Fe203）, and to find a method to explore correlations between major elements and human disturbances, according to geospatial theories and methods. The study results indicate that landscapes influence major elements in diverse ways： Al2O3 is closely related to road and mine landscapes; strong relationships exist between MgO, Fe2O3, CaO, and SiO2 and roads; Na2O, SiO2, and Fe2O3 are unrelated to city landscapes; and Na2O is unrelated to road and mine landscapes.

Feasibility of a New Granular Rapid Release Elemental S Fertilizer in Preventing S Deficiency of Canola on a S-Deficient Soil

Our previous research has indicated that granular elemental S (ES) fertilizers are not effective in the year of application and also are not consistently as effective as sulphate-S in increasing seed yield of canola in subsequent years, especially when applied at seeding in spring, because of slow dispersion of elemental S particles from granules for subsequent oxidation of ES to sulphate-S. A field experiment was established in autumn 2010 to determine the relative effectiveness of a new rapid release elemental S (RRES, now called Vitasul) fertilizer, in comparison to sulphate-S fertilizer, with various combinations of application times and placement methods (applied at 20 kg&middotS&middotha-1) on seed yield, straw yield, oil and protein concentration in seed, N and S uptake, partial factor productivity (PFP—kg&middotseed&middotkg-1 applied N&middotha-1—blanket application of 120 kg&middotN&middotha-1), S use efficiency (SUE—increase in kg&middotseed&middotkg-1 applied S&middotha-1) and percent recovery of applied S in seed + straw (%) of canola in 2011, 2012 and 2013 growing seasons on a S-deficient Gray Luvisol loam soil at Star City, Saskatchewan. The 11 treatments included two granular S sources (RRES and potassium sulphate) and five application time/placement method combinations (broadcast in autumn and incorporated in spring, broadcast in spring pre-tillage [broadcast and incorporated], broadcast in spring pre-emergence, sideband in spring and seedrow-placed in spring), plus a zero-S control. There was a significant response of seed yield of canola to applied S in all 3 years, but the responses varied with S source and with application time-placement combinations in different years. Seed yield increased considerably with all sulphate-S treatments compared to the zero-S control, although seed yield tended to be slightly lower in some spring and/or autumn broadcast treatments than the other sulphate-S treatments. Compared to the zero-S control, seed yield also increased significantly with all RRES treatments, but the increase was greater with autumn applied RRES than the spring applied RRES in many cases. Autumn applied RRES produced only slightly lower seed yield but spring applied RRES produced much lower seed yield than the highest yielding spring applied sulphate-S treatments. In 2011, straw yields increased significantly with applied S in some S treatments, but there was no significant effect of S fertilization on straw yield in 2012 and 2013. Oil concentration in canola seed increased only with sulphate-S fertilizer treatments in 2011, and it increased with both sulphate-S and ES sources in 2012 and 2013. There was no effect of any S treatment on the protein concentration in canola seed. The response trends of total N uptake and PFP were usually similar to seed yield for both S sources, but total S uptake, SUE and % recovery of applied S were lower with RRES than sulphate-S in many/most cases. In conclusion, the findings suggested the potential of spring broadcast pre-emergence RRES or autumn broadcast RRES in preventing S deficiency in hybrid canola, although seed yields were still slightly lower than the ideal highest yielding spring broadcast/incorporated sulphate-S treatment.

A simplified two-dimensional boundary element method with arbitrary uniform mean flow

To reduce computational costs, an improved form of the frequency domain boundary element method（BEM） is proposed for two-dimensional radiation and propagation acoustic problems in a subsonic uniform flow with arbitrary orientation. The boundary integral equation（BIE） representation solves the two-dimensional convected Helmholtz equation（CHE） and its fundamental solution, which must satisfy a new Sommerfeld radiation condition（SRC） in the physical space. In order to facilitate conventional formulations, the variables of the advanced form are expressed only in terms of the acoustic pressure as well as its normal and tangential derivatives, and their multiplication operators are based on the convected Green＇s kernel and its modified derivative. The proposed approach significantly reduces the CPU times of classical computational codes for modeling acoustic domains with arbitrary mean flow. It is validated by a comparison with the analytical solutions for the sound radiation problems of monopole,dipole and quadrupole sources in the presence of a subsonic uniform flow with arbitrary orientation.

SWRCH35K自冲铆接的失效分析与疲劳寿命预测

针对某车机械离合器SWRCH35K铆接结构在做耐久台架试验时发生断裂问题,通过疲劳寿命预测分析其影响因素;建立离合器铆钉有限元模型,对其施加边界条件,进行有限元分析,根据分析结果进行结构优化设计。结果表明:直径φ4的铆钉CAE疲劳寿命在65万次左右,不满足100万次的要求;优化设计后,直径φ5的铆钉CAE疲劳寿命达到200万次左右,满足设计要求,与台架试验结论一致。由此说明,采用有限元技术预测铆钉疲劳寿命可行,可为离合器铆接设计提供参考。