Electronic structure and flotation behavior of monoclinic and hexagonal pyrrhotite

Electronic structures of monoclinic and hexagonal pyrrhotite were studied using density functional theory method,together with their flotation behavior. The main contribution of monoclinic pyrrhotite is mainly from Fe 3d, while that of hexagonal pyrrhotite is from Fe 3d, Fe 3p and S 3s. The hexagonal pyrrhotite is more reactive than monoclinic pyrrhotite because of large density of states near the Fermi level. The hexagonal pyrrhotite shows antiferromagnetism. S—Fe bonds mainly exist in monoclinic pyrrhotite as the covalent bonds, while hexagonal pyrrhotite has no covalency. The main contributions of higest occupied molecular orbital(HOMO) and lowest unoccupied molecular obital(LUMO) for monoclinic pyrrhotite come from S and Fe. The main contribution of HOMO for hexagonal pyrrhotite comes from Fe, while that of LUMO comes from S. The coefficient of Fe atom is much larger than that of S atom of HOMO for hexagonal pyrrhotite, which contributes to the adsorption of Ca OH+ on the surface of hexagonal pyrrhotite when there is lime. As a result, lime has the inhibitory effect on the floatation of hexagonal pyrrhotite and the coefficient of Fe is very close to that of S for monoclinic pyrrhotite. Therefore, the existence of S prevents the adsorption of Ca OH+on the surface of monoclinic pyrrhotite, which leads to less inhibitory effect on the flotation of monoclinic pyrrhotite.

Effects of Oxygen Vacancy on the Electronic Structure of Monoclinic HfO_2 and Its Defect Energy States by the First Principles Calculation

The structural relaxation, electronic structures, formation energies and transition energy levels of monoclinic HfO2 with neutral and charged oxygen vacancies have been studied using the first principles calculation based on density-functional theory and generalized gradient approximation. The results show that oxygen vacancies with different charge states can be formed in m-HfO2 under both oxygen-rich and oxygen-poor conditions. Especially, lower formation energy is obtained in poor oxygen environment. In the presence of oxygen vacancies with different charge states, extra levels can be observed at different positions in the band gap. And the most stable charge states are obtained for varying Fermi levels in the HfO2 band gap. It is found that oxygen vacancy in m-HfO2 has a negative-U behavior.

Delft Molecular Mechanics Study on the Structures of Monoclinic MF Iand H[ Al] ZSM-5

Delft molecular mechanics minimization has been performed for the study on the structures of monoclinic MFI and H[Al]ZSM 5. The results were compared with those from quantum chemistry and other force field calculations. For the minimization of H[Al]ZSM 5, significant geometric rearrangements have been investigated in the local environments of Brnsted acidic sites, which resulted from the isomorphous substitution of Al for Si atoms in MFI framework.

Tectonic evolution of structures in Southern Sindh Monocline,Indus Basin,Pakistan formed in multi-extensional tectonic episodes of Indian Plate

There are a number of structures and structural styles found in extensional tectonic settings of the world,and it is a big challenge to study the evolution of these structures. Evolution of structures formed in extensional tectonic settings have been studied by researchers on different extensional basins of the world. Southern Sindh Monocline lies on the western corner of Indian Plate and the tectonic history of Indian plate has also experienced different extensional episodes, and its journey rifted from Gondwanaland to its final welding to Asia. The aim of this study is to figure out the evolution of structures in the subsurface of Southern Sindh Monocline, Pakistan using the seismic data interpretation and flattening of horizons approach. Structures within the subsurface of Southern Sindh Monocline have been characterized by different tectonic episodes of Indian plate while rifting from Gondwanaland, rifting from other plates at different geological times and to its collision with the Asia. Basic structures within study area are classified into nine types while the structural styles have been classified into six types as horst and grabens, dominos, crotch, synthetic and antithetic, negative and flashlight structural style. The structures within the study area revealed evidence for three major structural episodes which can be characterized as Episode 1: Structures associated with rifting of Indian plate from Gondwanaland during Late Jurassic to Early Cretaceous, Episode 2: Modification and reactivation of previous structures while Madagascar rifted from Indian Plate during the Middle Cretaceous and during Episode 3: Inversion and reactivation of structures occurred when Indian Plate collided with Asia during Early Eocene.

The Structure and Properties of Multi-cations Doped KNN-based Piezoelectric Ceramics

The piezoelectric strain of K_(0.5)Na_(0.5)NbO_(3)-based lead-free ceramic at different temperatures was studied.The Rayleigh analysis shows that the intrinsic and extrinsic contributions are increased at temperature from 173 to 298 K.In addition,a monoclinic phase structure was observed at 83 K.The results of phase field simulation show that the temperature dependent microstructure evolution is a function of the local structure size.This work contributes to understanding the structure and properties relationship of the multi-cations doped KNN-based piezoelectric ceramics as a function of temperature.

Synthesis,Crystal Structure and Thermal Decomposition of a New Energetic Dipotassium 3,3'-Dinitro-5,5'-bis-1,2,4-triazole-1,1'-diolate

A new energetic dipotassium 3,3-dinitro-5,5-bis-1,2,4-triazole-1,1-diolate [K2（DNOBT）] was synthesized, and structurally characterized by elemental analysis, IR spectra, 13 C NMR and single-crystal X-ray diffraction. K2（DNOBT）·2H2O crystallizes in monoclinic system, space group P21/n with a=6.0446（10）, b=15.999（3）, c=6.4169（11） , β=99.421（2）°, V=612.21（18） 3, Z=4, Dc=2.009 g·cm（-3）, F（000）=372, μ=0.838 mm（-1）, S=1.012, the final R=0.0248 and w R（I 〉 2σ（I））=0.0604. Thermal decomposition of the title compound was studied by using DSC and TG-DTG, and there is primarily one exothermic decomposition process at 371.5 ℃.

The Structure of Trichosanthin with Space Group C2 at 1. 9 Resolution

The crystal structure of trichosanthin (TCS) in space group C2 hasbeen refined by PROLSQ and XPLOR to an R-factor of 0. 204 for 33, 531 reflectionswith F。≥2-σ(F。) between 6 to 1. 9 A resolution. The root mean square(r. m. s. ) devi-ations of bond lengths and bond angles from the standard values are 0. 015 A and 2.77°, respectively. The overall fold of the molecule of TCS is, in general, similar to oth-er RIPs, but there are some differences in secondary structure and in the active sitecleft. An overlay of the two molecules (shown by Mol. A and Mol. B), which are notrelated by symmetry in an asymmetric unit, results in an r. m. s. deviation of 0. 850Afor the main chain atoms. The backbones of the C-terminus of the two molecules arequite different. The structures of the water in two molecules are not completely analo-gous. In the active site cleft of Mol. B, the bonding sites of three water molecules toprotein are similar to those of N atoms of formycin ring in the structure of pokeweedantiviral protein complexed with formycin 5-monophosphate, and the side chains of twoTyr70 in the two crystalline forms of TCS show a similar orientation, which is differentfrom that of the corresponding residue in ricin A-chain.

Synthesis of NiMoO_4 nanoparticles by sol-gel method and their structural,morphological,optical,magnetic and photocatlytic properties

Nickel molybdate(NiMoO4)nanoparticles(NPs)were synthesized by sol-gel method.Utilizing water as solvent providescrystalline nanostructures.These nanocrystals were structurally characterized by X-ray diffraction,energy dispersive X-ray analysis(EDX),and Fourier transform infrared spectra.Compositional stoichiometry was confirmed by EDX technique.The size and shapewere observed by scanning electron microscopy(SEM)and transmission electron microscope(TEM).It was found that the obtainedNPs were pure and single phase crystalline with monoclinic structure.The optical properties were studied by ultraviolet-visiblediffuse reflectance spectroscopy(UV-Vis-DRS)and photoluminescence(PL)measurements at room temperature.The magneticproperties were studied by vibrating sample magnetometer(VSM)and results showed superparamagnetic behavior of the obtainednanoparticles.Photocatalytic activity of NiMoO4was studied.The photocatalytic activity of NiMoO4was enhanced with the additionof TiO2.The catalysts NiMoO4,TiO2and NiMoO4-TiO2nanocomposites(NC)were tested for photocatalytic degradation(PCD)of4-chlorophenol(4-CP).It was found that PCD efficiency of NiMoO4-TiO2NC was higher than that of pure NiMoO4and TiO2.

Electronic structures and optical properties of monoclinic ZrO2 studied by first-principles local density approximation plus U approach

The electronic structures and optical properties of the monoclinic ZrO2 (m-ZrO2) are investigated by means of first-principles local density approximation (LDA) + U approach.Without on-site Coulomb interactions,the band gap of m-ZrO2 is 3.60 eV,much lower than the experimental value (5.8 eV).By introducing the Coulomb interactions of 4d orbitals on Zr atom (Ud) and of 2p orbitals on O atom (Up),we can reproduce the experimental value of the band gap.The calculated dielectric function of m-ZrO2 exhibits a small shoulder at the edge of the band gap in its imaginary part,while in the tetragonal ZrO2 and cubic ZrO2 it is absent,which is consistent with the experimental observations.The origin of the shoulder is attributed to the difference of electronic structures near the edge of the valence and conduction bands.

塔西南齐姆根楔形构造与走滑构造叠加两阶段演化模式

塔里木盆地西南缘逆冲带由西部近东西方向的喀什逆冲构造带和东部近东西方向柯克亚—和田逆冲构造带以及中间喀什—叶城走滑断层系组成,而北西—南东走向的喀什—叶城走滑断层带及其东侧齐姆根构造则为呈北东方向凸出的弧形构造。齐姆根弧形构造在地表地质和地震剖面均表现为向盆地方向倾斜的单斜形态。而且在塔西南地区,该弧形构造上从白垩系到新近系地层厚度明显大于东西两侧逆冲带同时代地层厚度,表现为异常增厚的特征。为了探讨齐姆根弧形构造特征及地层厚度异常增厚等原因,依据前人的地表地质填图成果,以及塔里木盆地西南缘齐姆根地区及邻区完成的二维地震资料及钻井资料成果,对该区地震剖面资料进行详细的构造解释,提出齐姆根弧形构造单斜之下存在3个隐伏逆冲构造楔形体,即棋盘楔形构造、齐姆根楔形构造和英吉沙楔形构造。地震剖面解释的生长地层指出棋盘楔形构造形成最早,为上新世阿图什组沉积时期;其次发育齐姆根楔形构造,为更新世西域组底部沉积时期;最晚发育英吉沙楔形构造,时间大约在更新世西域组中-上段沉积时期,据此认为齐姆根中深层逆冲构造位移扩展方式为前展式。而且地震剖面解释上也揭示了白垩系到新近系地层厚度异常增厚发育的构造部位及发育规律,说明地层异常厚度变化受区域构造控制,其时间大约为更新世西域组沉积时期。该时期对应于喀什—叶城走滑断层系活动时期,据此我们推测由于走滑断层系区域侧向挤压作用以及东西两侧发育的逆冲构造带起到了限制阻挡作用,三者联合之下造成了齐姆根单斜上含软弱层的各时代地层被挤压屈曲形成弧形形态构造,在弧形构造发育期间岩层之间层间滑脱加厚可导致地层厚度异常增厚。综合前面认识,最后提出齐姆根弧形构造为叠加构造发育地区,经历了早、晚两期构造叠加变形:早期为逆冲楔形构造发育阶段,晚期为走滑作用改造及弧形构造形成阶段。而且沿着齐姆根弧形构造走向,弧形构造北西侧翼部单斜发生逆时针旋转,而弧形构造南东侧翼部单斜发生顺时针旋转,并得到已有古地磁数据支持,属于旋转弧构造类型。该认识支持了帕米尔东侧局部弧形构造是在早期发育的逆冲推覆构造基础上,逐渐叠加有晚期发育的左旋走滑断层而形成弧形构造。

基于滇中典型紧窄单斜岩溶水系统特征的隧洞涌水条件分析

中国西南地区分布着大面积的碳酸盐岩,地层和构造的空间组合结构差异形成了多种复杂而各具特色的岩溶水系统。当隧洞穿越岩溶水系统时,涌水问题表现各异,涌水条件难以识别,这一直是隧洞工程建设面临的重要挑战。滇中引水工程小扑隧洞隧址区发育线状延伸、紧密互层的可溶与非可溶岩地层,构成典型的紧窄单斜岩溶水系统。文章细致梳理研究区岩溶水系统特征的控制性因素,结合地下水监测信息和水化学特征识别小扑隧洞的涌水条件。结果表明:紧窄单斜构造影响了岩溶发育的空间格局和地下水的径流及转换方式,控制着含水层介质发育和地下水补径排分布的特征,进而可将研究区细分为4个特征各异的小尺度岩溶水系统。小扑隧洞不同段穿越的岩溶水系统特征差异较大,隧洞涌水经历的水文地球化学作用过程不尽相同,综合认为隧洞1#洞段涌水来源于暗河管道,2#洞段涌水为揭露岩溶裂隙所致,补给高程分别为2165.4 m和2234.69 m,并初步确定各自的充水水源补给范围。研究结果可为后续隧洞防排水工程方案设计以及突涌水灾害防治提供依据。

A new transition metal diphosphideα-MoP_(2) synthesized by a high-temperature and high-pressure technique

Monoclinicα-MoP_(2),with the OsGe2-type structure(space group C2/m,Z=4)and lattice parameters a=8.7248(11)Å,b=3.2322(4)Å,c=7.4724(9)Å,andβ=119.263°,was synthesized under a pressure of 4~GPa at a temperature between 1100℃and 1200℃.The structure ofα-MoP_(2) and its relationship to other transition metal diphosphides are discussed.Surprisingly,the ambient pressure phase orthorhombicβ-MoP_(2)(space group Cmc21)is denser in structure thanα-MoP_(2).Room-temperature high-pressure x-ray diffraction studies exclude the possibility of phase transition fromβ-MoP_(2) to α-MoP_(2),suggesting thatα-MoP_(2) is a stable phase at ambient conditions;this is also supported by the total energy and phonon calculations.

二维地震技术在新峰一矿煤层构造勘查中的应用研究

为了解新峰一矿煤层厚度和变化情况以及构造分布,采用二维地震技术,勘查了新峰一矿煤层构造,分析了二维地震技术参数,确定了井深、药量、检波器参数等,研究区布置二维地震测线13条,其中,主测线10条,联络测线3条,测线总长71 km,测线上物理点3 475个,井深12 m,药量3.0 kg。研究得出,研究区被第三、四地层所覆盖,覆盖层厚度50~900 m,由西北向东南厚度逐渐增大。研究区地层总体为一走向北西、倾向南西的单斜构造,倾角在20°~25°,并发现1个向斜,解释断点19个,组合断层7条。研究为后期煤炭的开采提供了技术支持。

北方岩溶地下水系统模式及特征

目前,有关北方岩溶地下水系统模式划分主要着眼于水资源或岩溶水系统本身,不能满足煤矿防治水和水资源利用的多重需求,且其系统性和实用性不足。文章在分析大量资料的基础上,对北方岩溶地下水系统的特征进行综合分析研究,提出了以结构特征、补给特征、强径流带与主构造(或地层)走向关系和排泄特征等为依据的北方岩溶地下水系统模式分类方案,将已知北方岩溶地下水系统划分为11种模式,对其中与华北型煤田有关的7种模式的煤矿床水文地质特征进行了概述。

任意分布形式煤层开采地表移动预计方法

地下开采煤层的分布形式多种多样，平面分布仅是曲面分布形式中的一种简单情况。根据概率积分法的基本原理及其预计参数的一般规律，将复杂的褶皱构造煤层按轴线划分为单斜构造煤层后，采用曲面积分法，推导出了开采曲面分布煤层时预计地表移动与变形值的计算公式，介绍了对任意形状工作面的处理方法及确定积分区间的方法。最后，用实测资料进行了验证，预计精度令人满意。

济阳坳陷东营组沉积体系新认识

东营组作为济阳坳陷断陷末期沉积的重要层系,对其沉积体系认识不清导致对其储层分布、油藏类型、成藏规律不明确,从而制约了东营组的勘探。综合钻井、测井、地震等资料,依据沉积学基本原理和方法,通过断陷末期盆地地质构造特征及岩相古地理多因素分析表明,济阳坳陷东营组沉积时期在单斜式构造背景控制下形成了东部跨凹陷的大型辫状河三角洲沉积,东三段沉积时期是辫状河三角洲主要发育期,东二段湖盆收缩、沉积范围缩小,西部以滨浅湖沉积为主,伴有小型的近源扇三角洲及近岸水下扇沉积,东部演化为以河流相为主。东一段沉积时期湖盆萎缩,广泛发育河流相及滨浅湖沉积。平面上充填样式表现为由南部的东营凹陷辫状河三角洲平原亚相、前缘亚相向北部沾化—滩海地区的前三角洲亚相过渡,前三角洲发育一定规模的滑塌浊积扇。东营组沉积模式的建立不仅完善了济阳坳陷新生代沉积演化序列,对东营组储层预测起到了重要指导作用,而且也为今后东营组成藏条件的研究奠定了基础。

高氯酸·四氨·双(5-硝基四唑)合钴(Ⅲ)(BNCP)的晶体结构

制备了高氯酸.四氨.双(5-硝基四唑)合钴(Ⅲ)(BNCP)的单晶,用X-ray单晶面探衍射仪对其晶体进行了结构测定。证实该晶体属单斜晶系,空间群为P2(1)/n。晶胞参数为:a=10.0149(11);b=10.5387(11);c=14.8241(16)。V=1479.2(3)3,Z=4,DC=2.050 mg.mm-3,μ=1.421 mm-1,F(000)=928,并得到了BNCP的原子坐标、等效温度因子、键长、键角和扭转角等数据。根据测试参数,分析了BNCP的结构特点和分解机理。

单斜构造区岩溶倾斜洞穴发育趋势与岩层产状相关性识别

通过构建岩溶倾斜洞穴发育趋势面和岩层倾向面,探讨在单斜构造区岩溶倾斜洞发育趋势与岩层产状的相关性。首先,根据洞穴探测导线长度、方向、倾角等要素,以测量初始点为原点建立空间直角坐标系,将测量空间方位角转换为平面直角坐标系中的方向角,将测量数据投影在平面直角坐标系上,运用向量加法原理求出各测点平面向量及坐标,结合各测点的相对高差,运用趋势面分析方法进行一次拟合,构建洞道空间展布平面方程;其次,根据岩层产状信息在空间坐标系中构建平面方程;最后,通过计算两平面法向量的夹角,来判断洞穴空间展布平面和岩层产状平面的重合度,同时求出两平面与同一水平面的交线所成角来判断洞穴空间展布趋势面与岩层面的倾向关系。通过实例证明,该方法用于探讨单斜构造区岩层产状对倾斜洞穴发育趋势的影响识别具有一定的实用性。

VO_2晶体电子结构及其掺杂的第一性原理研究

运用密度泛函平面波赝势(PWP)和广义梯度近似(GGA)方法,对二氧化钒(VO2)两种不同晶体电子结构进行了计算.研究了低温单斜晶型和高温四方晶型结构的VO2电子态密度(DOS)和能带(energyband)结构,通过分析发现,四方晶的金属性比较明显,这是由于电子态密度和能带结构分析结果表明不同特性产生的原因是V原子的3d电子贡献不同导致的.本文中我们还将部分O原子替换为F原子后对单斜晶替位掺杂进行了的计算讨论,本文的计算结果都较好地符合实验结果,表明密度泛函平面波赝势和广义梯度近似方法可以用来描述VO2的结构和性质.我们认为,这种方法应用于描述氧化物的电子结构和性质是一种新的探索.

钙钛矿型YNiO_3电子能带结构的第一性原理

采用第一性原理计算了钙钛矿材料YNiO3正交相、单斜相的电子能带结构。计算结果表明:YNiO3正交相为直接带隙,带隙大小约为0.99 eV;单斜相低能导带向费米面移动进入带隙区,与费米面相交而部分填满,使其具有金属性而导电。同时发现,Ni在正交相中只存在一种组态Ni3+,而在单斜相中则存在Ni2+和Ni4+两种不同的组态,即存在电荷歧化2Ni3+→Ni2++Ni4+。