层状非均质性对CO_2在盖层中迁移泄漏规律的影响

盖层密封性能对CO_2地质封存工程的容量、经济性、安全性具有重要影响。盖层岩石具有明显的层状非均质特点,而这种层状非均质特点直接影响CO_2在盖层中的迁移与泄漏过程,从而影响盖层的密封性能。现有研究考虑了各向同性的非均质性对盖层密封性能的影响,但并未针对层状非均质性盖层展开相应的研究。建立了考虑孔隙度、渗透率和毛管压力参数变化关系的均质、非层状非均质和层状非均质3种盖层地质模型,并采用TOUGH2对统一边界条件的不同地质模型开展了数值模拟对比研究,分析了CO_2进入盖层、盖层内迁移和穿透盖层而形成缓慢泄漏的全过程。模拟结果表明:3种模型中,自由态CO_2饱和度分布与孔隙度、渗透率的分布基本一致;与均值模型相比,非层状非均质性会加速CO_2在盖层中的迁移,而层状非均质性将会阻碍CO_2在盖层中的迁移,增加穿透时间;与均质模型和非层状非均质模型相比,层状非均质模型将会大大降低CO_2的穿透盖层以后的泄漏速率和泄漏总量。针对建模和数值模拟过程中遇到的问题,提出了盖层地质建模过程中的一些局限性。其结果为更加客观和定量地评价CO_2在盖层内迁移规律及泄漏量奠定了一定的基础。

多岩性组合层状储层一体化压裂裂缝扩展试验研究

多岩性组合层状储层在纵向上交替发育多类含气产层,储层纵向岩性复杂多变、岩石力学性质及地应力条件差异大,采用纵向一体化穿层压裂改造时,水力裂缝垂向扩展形态复杂及延伸穿层规律不清。鉴于此,基于实际典型多岩性组合层状储层特征,通过室内浇筑灰岩、页岩与煤岩组合的大尺寸分层压裂试样,开展真三轴水力压裂物理模拟试验,研究垂直井与水平井2种井型条件下,多因素对水力裂缝垂向扩展行为的影响,并分析泵压曲线响应特征。试验结果表明:水力裂缝在纵向上呈现非对称、非平面扩展特征;依据水力裂缝与岩性界面不同的作用方式,具有停止、转向、分叉、穿透等多种复杂扩展模式;直井压裂时,主水力裂缝呈“十”字型,水力裂缝先后在水平和纵向上发生转向,充分沟通煤层割理;水平井压裂时,扩展至弱结构面时易发生分叉、转向扩展;垂向应力系数越大,水力裂缝越容易穿透岩性界面而沟通相邻产层;试样内部天然裂缝系统增加了水力裂缝转向、分叉概率及水平展布范围,但亦可耗散水力能量,限制缝高延伸;水力裂缝穿透岩性界面时,泵压曲线呈现增-降-增特征,沟通煤岩割理时曲线持续小幅度波动。建议一体化穿层压裂时避免选择在天然弱面发育的页岩层与煤层实施压裂作业,适当提高压裂液排量可增加穿层扩展概率以及提高水力裂缝分叉扩展的可能性。研究结果可为认识多岩性组合层状储层一体化压裂水力裂缝形态与优化施工参数提供指导。

层状非均质结构包气带入渗过程单相流与两相流数值模拟对比研究

包气带水分入渗过程受多种因素的影响。定量研究层状非均质岩性结构和入渗速率对其影响,有助于解决根据不同条件选择单相流模型或水气二相流模型模拟包气带水分入渗过程的问题。结合填埋场等场地地层条件及污废水入渗特征,分别建立了“上细下粗”和“上粗下细”包气带层状非均质岩性结构水分入渗单相流和水气二相流模型,探讨不同层状非均质岩性结构条件下模型的适用性。在“上粗下细”岩性结构模型基础上,进一步探究入渗速率对水气两相运移结果的影响。基于论文模型研究表明:(1)在包气带岩性结构为“上细下粗”的条件下,气相的影响基本可以忽略,可直接采用单相流模型对包气带水分运移进行模拟;在“上粗下细”岩性结构和本次模型设定的底部压力保持不变及污废水泄漏前场地未接受降水入渗补给等条件下,当包气带上下层介质渗透率比值大于16倍时,气相会对水相运移产生明显影响,且下层介质渗透率越小、上下层介质渗透率比值越大,单相流与两相流的运移结果差别越大,需要采用水气二相流模型模拟包气带水分运移。(2)在包气带“上粗下细”岩性结构条件下,入渗速率越大,气相对水流入渗的阻滞作用越明显,此时包气带水分运移模拟应采用水气二相流模型。

Rate and Cycling Performance of Ti and Cu Dopedβ-NaMnO_(2) as Cathode of Sodium-ion Battery

Sodium-ion batteries are economical and environmentally sustainable energy storage batteries.Among them,β-NaMnO_(2),a promising sodium-ion cathode material,is a manganese-based oxide with a corrugated laminar structure,which has attracted significant attention due to its structural robustness and relatively high specific capacity.However,it has short cycle life and poor rate capability.To address these issues,Ti atoms,known for enhancing structural stability,and Cu atoms,which facilitate desodiation,were doped intoβ-NaMnO_(2) by first-principles calculation and crystal orbital Hamilton population(COHP)analysis.β-NaMn_(0.8)Ti_(0.1)Cu_(0.1)O_(2) exhibits a notable increase in reversible specific capacity and remarkable rate properties.Operating at a current density of 0.2C(1C=219 mA·g^(–1))and within a voltage range of 1.8–4.0 V,the modified material delivers an initial discharge capacity of 132 mAh·g^(–1).After charge/discharge testing at current densities of 0.2C,0.5C,1C,3C,and 0.2C,the material still maintains a capacity of 110 mA h·g^(–1).The doping of Ti atoms slows down the changes in the crystal structure,resulting in only minimal variation in the lattice constant c/a during the desodiation process.Mn and Cu engage in reversible redox reactions at voltages below 3.0 V and around 3.5 V,respectively.The extended plateau observed in the discharge curve below 3.0 V signifies that Mn significantly contributes to the overall battery capacity.This study provides insights into modifyingβ-NaMnO_(2) as a cathode material,offering experimental evidence and theoretical guidance for enhancing battery performance in Na-ion batteries.

2010—2012年山西省降水地面雨滴谱特征对比

利用2010—2012年OTTParsivel激光降水粒子谱仪在山西汾阳和方山两个站点观测的雨滴谱资料，分析了两地区对流性和层状性降水滴谱特征。结果表明：两地层状性降水发生的频率较大，对流性降水在方山的发生频率大于汾阳。对两类降水而言，不同地区的雨滴谱特征有所不同，方山地区降水的雨滴数浓度、液态含水量、平均雨强、雷达反射率均高于汾阳地区，汾阳和方山雨滴平均谱分布均呈单峰型，Gamma分布对层状性降水拟合效果优于对流性降水。两地对流性降水的μ-λ关系相差较小。

海洋平台用钢EH40-Z35的开发

通过向钢中添加Nb、V、Ti等微合金元素和采用TMCP工艺,开发出符合ABS、CCS、DNV等九国船级社认证规范的海洋平台用钢EH40-Z35。产品具有良好的抗层状撕裂性、低冷裂纹敏感性以及良好的焊接性能和低温韧性。

鞍钢大厚度集装箱船用止裂钢的研制

鞍钢通过采用低碳+微合金化、复合添加Cr、Mo、V等合金的成分设计,结合高质量钢冶炼、多阶段TMCP轧制及超快速冷却工艺,同时按照CCS、DNVGL等多国船级社认证规范要求,成功开发出90 mm厚度EH47BCACOD集装箱船用止裂钢板。钢板从表面至心部组织均匀,晶粒度达到10.5级,具有优异的抗层状撕裂性、低冷裂纹敏感性、良好的可焊性、合适的低温韧性及止裂性能。

Singularity-free Green's function for EM sources embedded in a stratified medium

We present a method to unify the calculation of Green＇s functions for an electromagnetic（EM） transmitting source embedded in a homogeneous stratified medium.A virtual interface parallel to layer interfaces is introduced through the source location.The potentials for Green＇s function are derived by decomposing the partial wave solutions to Helmholtz＇s equations into upward and downward within boundaries.The amplitudes of the potentials in each stratum are obtained recursively from the initial amplitudes at the source level.The initial amplitudes are derived by coupling with the transmitting sources and following the discontinuity of the tangential electric and magnetic fields at the source interface.Only the initial terms are related to the transmitting sources and thus need to be modified for different transmitters,whereas the kernel connected with the stratified media stays unchanged.Hence,the present method can be easily applied to EM transmitting sources with little modification.The application of the proposed method to the marine controlled-source electromagnetic method（MCSEM） demonstrates its simplicity and flexibility.

海拉尔盆地贝中次凹油藏特征

贝中次凹位于海拉尔盆地贝尔凹陷南部，主要含油层为南屯组，其次为布达特群和铜钵庙组，是一个复式油气聚集带。构造上东西向受边界断裂控制形成不对称双断式结构，有利相带为浅湖一半深湖背景下的扇三角洲前缘及辫状三角洲前缘沉积。由于不同构造部位、不同时期受构造和储层控制程度不同，因此可以形成不同的油藏类型。贝中次凹油藏主要受构造和沉积相带双重控制，具有分带性，分析认为油藏类型主要有3种：西部构造带的岩性-构造层状油藏；中部低凸起构造带为复式油气聚集带，主要为南屯组的岩性-构造层状油藏、构造～岩性油藏和布达特群潜山构造油藏；东部构造带主要为构造-岩性油藏和岩性油藏。

疏松砂岩浅层气含气饱和度解释方法研究——黑帝庙油藏为例

含气饱和度是储量计算中的重要参数。黑帝庙油藏属于层状岩性构造气藏,储层孔隙度、渗透率高,电阻率相对偏低,而且没有进行密闭取心,如何确定一个合理的含气饱和度是储层测井评价的难题。通过分析黑帝庙油藏的特征,分别应用压汞和测井资料,选用沃尔法、孔喉半径法、气柱高度法以及印度尼西亚方程,对储层含气饱和度进行解释,并应用研究区的试气资料采用统计的方法对不同方法解释结果进行分析表明,由于难以确定合理的喉道半径和没有考虑储层电性的影响使得孔喉半径法解释结果偏低,受气藏类型的影响和难以确定层状构造气藏的气水界面使得气柱高度法解释结果偏低,沃尔法与印度尼西亚方程解释结果相当,且与储层采气强度符合较好,以此确定了储层的原始含气饱和度,满足储量提交需求。

Corrosion resistance of Mg−Al LDH/Mg(OH)2/silane−Ce hybrid coating on magnesium alloy AZ31

An environmentally-friendly hybrid coating on AZ31 magnesium alloy substrates was reported.The synergic effect was studied on Mg−Al-layered double hydroxide Mg−Al LDH/Mg(OH)2-coated AZ31 magnesium alloy via an in-situ steam coating process and a subsequent combined surface modification of bis-[triethoxysilylpropyl]tetrasulfide(BTESPT)silane and Ce(NO3)3.The microstructure and composition characteristics of the hybrid coatings were investigated by means of X-ray diffraction(XRD),scanning electronic microscopy(SEM),Fourier transform infrared spectrophotometry(FT-IR)and X-ray photoelectron spectroscopy(XPS).The corrosion resistance of the coated samples was evaluated by potentiodynamic polarization(PDP),electrochemical impedance spectrum(EIS)and hydrogen evolution rate during immersion in 3.5 wt.%NaCl solution.The results show an improved corrosion resistance of the alloy in the presence of BTESPT silane and Ce(NO3)3.This is most likely due to the synergistic effect of steam coating and silane coating to enhance the barrier properties of hybrid coating.In addition,the formation mechanism and anti-corrosion mechanism of coatings were discussed.

南翼山浅油藏储层特征

南翼山浅油藏的主要储油层系为上第三系上新统下油砂山组(N2^1)上部及上新统上油砂山组(N2^2)下部，为背斜构造控制的岩性层状油藏．南翼山浅油藏储层岩性主要包括：(含粉砂)藻灰岩、粉砂质(泥质)泥晶灰岩和灰质(泥质)粉砂岩．各油层一般都包括这3类储层岩性．其中以粉砂质(泥质)泥晶灰岩为主．其次为(含粉砂)藻灰岩和灰质(泥质)粉砂岩．南翼山浅油藏储集空间类型主要有：溶孔、成岩缝、粒间孔、微孔隙．各油层一般都包括这四类储集空间类型，其中溶孔是最主要的储集空间类型．南翼山浅油藏储层物性最好的为(含粉砂)藻灰岩，其次为粉砂质(泥质)泥晶灰岩和灰质(泥质)粉砂岩．(含粉砂)藻灰岩储层的排驱压力大多小于10Mpa，最大连通孔喉半径大多为0．04～0．5μm，平均孔隙半径大多大于10μm，面孔率大于2％．粉砂质(泥质)泥晶灰岩和灰质(泥质)粉砂岩储层的排驱压力大多大于10Mpa，最大连通孔喉半径大多小于0．04μm，平均孔隙半径大多为5～10μm．面孔率小于2％．储层的主要控制因素包括：沉积徽相；断裂作用；晚期沿断裂带大气淡水的溶解作用；有机酸的溶解作用．

Experimental study of motion characteristics of rock slopes with weak intercalation under seismic excitation

In order to investigate the effect of a weak intercalation on slope stability, a large-scale shaking table model test was conducted to study the dynamic response of rock slope models with weak intercalation.The dynamic response of the prototype slopes were studied in laboratory with the consideration of law of similitude. The initiation failure was observed in the rock slope model with a counter-tilt thin-weak intercalation firstly, not in the slope model with a horizontal thin-weak intercalation. Furthermore, it was interesting that the fracture site is shifted from crest top to the slope surface near the weak intercalation, which is different with the location of failure position in a normal layered slope. We also discussed the effect of the dip angle and the thickness of weak intercalation on the failure mechanism and instability mode of the layered rock slope. From the experimental result, it was noted that the stability of the slope with a counter-tilt weak intercalation could be worse than that of the other slopes under seismic excitation. The findings showed the difference of failure in slopes with a horizontal and counter weak intercalation, and implicated the further evaluation of failure of layered slopes caused by seismic loads.

Failure mode and strength anisotropic characteristic of stratified rock mass under uniaxial compressive situation

A stratified rock mass model was founded by FLAC^3D. The failure mode and anisotropic characteristic of strength for stratified rock mass were analyzed. The analysis results show that the numerical simulation can visually reflect the failure modes of rock samples under different inclination angles β of structural plane. The stiffness of rock sample before peak strength changes in the compressive procedure. With the increase of β, the compressive strength σc of rock sample decreases firstly and then increases; when β is in the range of 20°-30° and 80°-90°, σc has the largest sensitivity to r; while β falls in the range of 30°-70°, σc varies little. When φj〈β〈90° （ φj is friction angle of structure plane）, the results obtained from numerical simulation and theoretical analysis are in almost the same values; while β〈 φj or β=90°, they are in great different values. The results obtained from theoretical analysis are obvious larger than those from numerical simulation; and the results from numerical simulation can reflect the difference of compressive strength of rock samples for the two situations of β≥φj and β=90°, which is in more accordance with the real situation.

Stability of Stratified Gas-Liquid Flow in Horizontal and Near Horizontal Pipes

A viscous Kelvin-Helmholtz criterion of the interfacial wave instability is proposed in this paper based on the linear stability analysis of a transient one-dimensional two-fluid model. In thismodel, the pressure is evaluated using the local momentum balance rather than the hydrostatic approximation. The criterion predicts well the stability limit of stratified flow in horizontal and nearly horizontal pipes. The experimental and theoretical investigation on the effect of pipe inclination on the interfacial instability are carded out. It is found that the critical liquid height at the onset of interfacial wave instability is insensitive to the pipe inclination. However, the pipe inclination significantly affects critical superficial liquid velocity and wave velocity especially lor low gas velocities.

Enhanced corrosion resistance of micro-arc oxidation coated magnesium alloy by superhydrophobic Mg-Al layered double hydroxide coating

To further enhance the corrosion resistance of the porous micro-arc oxidation(MAO) ceramic layers on AZ31 magnesium alloy, superhydrophobic Mg-Al layered double hydroxide(LDH) coating was fabricated on MAO-coated AZ31 alloy by using in-situ growth method followed by surface modification with stearic acid. The characteristics of different coatings were investigated by XRD, SEM and EDS. The effect of the hydrothermal treatment time on the formation of the LDH coatings was studied. The results demonstrated that the micro-pores and cracks of MAO coating were gradually sealed via in-situ growing LDH with prolonging hydrothermal treating time. Electrochemical measurement displayed that the lowest corrosion current density, the most positive corrosion potential and the highest impedance modulus were observed for superhydrophobic LDH/MAO coating compared with those of MAO coating and LDH/MAO coating. Immersion experiment proved that the superhydrophobic LDH/MAO coating with the active anti-corrosion capability significantly enhanced the long-term corrosion protection for MAO coated alloy.

Heat Transfer Characteristics of Dropwise Condensation of Steam on Vertical Polymer Coated Plates

The plasma polymerization method and dynamic ion-beam mixed implantation method were employed to coat ultra-thin polymer films on copper plates. Experiments indicated that steady dropwise condensation of steam at atmospheric pressure occurred. The condensation heat transfer coefficients increased by approximately 3 and 5－7 times for the polytrimethylvinylsilane film and polytetrafluoroethylene film respectively, compared with the value for film condensation under the same experimental conditions. The temperatures on the condensing surface and inside the test block were found to be rapidly and randomly fluctuated. The properties of the coated films and advantages of the methods used in this investigation were discussed briefly.

Imaging features of solid pseudopapillary tumor of the pancreas on multi-detector row computed tomography

AIM： To retrospectively analyze the imaging features of solid-pseudopapillary tumors （SPTs） of the pancreas on multi-detector row computed tomography （MDCT） and define the imaging findings suggestive of malignant potential. METHODS： A total of 24 consecutive cases with surgically and pathologically confirmed SPTs of the pancreas underwent preoperative abdominal MDCT studies in our hospital. All axial CT images, CT angiographic images, and coronally and sagittally reformed images were obtained. The images were retrospectively reviewed at interactive picture archiving and communication system workstations. RESULTS： Of the 24 cases of SPTs, 11 cases （45.8%） occurred in the pancreatic head and seven （29.1%） in the tail. Eighteen were pathologically diagnosed as benign and six as malignant. MDCT diagnosis of SPTs was well correlated with the surgical and pathological results （Kappa = 0.6, P 〈 0.05）. The size of SPTs ranged from 3 to 15 cm （mean, 5.8 cm）. When the size of the tumor was greater than 6 cm （including 6 cm）, the possibilities of vascular （8 vs 1） and capsular invasion （9 vs 0） increased significantly （P 〈 0.05）.Two pathologically benign cases with vascular invasion and disrupted capsule on MDCT presented with local recurrence and hepatic metastases during follow-up about 1 year after the resection of the primary tumors. CONCLUSION： Vascular and capsular invasion with superimposed spread into the adjacent pancreatic parenchyrna and nearby structures in SPTs of the pancreas can be accurately revealed by MDCT preoperatively. These imaging findings are predictive of the malignant potential associated with the aggressive behavior of the tumor, even in the pathologically benign cases.

Anisotropy of Critical Fields in MgB_2: Two-Band Ginzburg-Landau Theory for Layered Superconductors

The temperature dependence of the anisotropy parameter of upper critical field γHe2 （T） = Hc2^‖ （T） /Hc2^⊥ （T） and London penetration depth γλ （T） = λ‖（T）/λ⊥ （T） are calculated using two-band Ginzburg-Landau theory for layered superconductors. It is shown that, with decreasing temperature the anisotropy parameter γHc2 （T） is increased, while the London penetration depth anisotropy γλ（T） reveals an opposite behavior. Results of our calculations are in agreement with experimental data for single crystal MgB2 and with other calculations..Results of an analysis of magnetic field Hc1 in a single vortex between superconducting layers are also presented.