Polyhydroxyl-aluminum pillaring improved adsorption capacities of Pb^(2+) and Cd^(2+) onto diatomite

In order to greatly improve adsorption capacity, the diatomite was pillared by polyhydroxyl-aluminum.A series of adsorption tests were conducted to obtain the optimum condition for pillared diatomite synthesis. The scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR）, surface area and porosity analyzer and micro-electrophoresis were used to determine pore structure and surface property.The pillared diatomite attaining the optimal adsorption densities （qe） of Pb^2＋ and Cd^2＋ was synthesized with the following conditions： Addition of pillaring solution containing Al3＋-oligomers with a concentration range of 0.1-0.2 mol/L to a suspension containing Na＋-diatomite to obtain the required Al/diatomite ratio of 10 mmol/g; synthesis temperature of 80 ℃ for 120 min; aging at a temperature of 105 ℃ for 16 h. The adsorption capacities of Pb^2＋ and Cd^2＋ on pillared diatomite increase by 23.79% and 27.36% compared with natural diatomite, respectively. The surface property of pillared diatomite is more favorable for ion adsorption than natural diatomite. The result suggests that diatomite can be modified by pillaring with polyhydroxyl-aluminum to improve its adsorption properties greatly.

Depillaring of total thickness of a thick coal seam in single lift using cable bolts：A case study

Explaining fundamentals of application of cable bolting for a thick seam depillaring,this paper summarizes the results of field studies conducted during adoption of this approach in more than fifteen panels of Madhusudanpur 7 pit and incline mine.Nearly 7.0 m thick Kajora top coal seam of this mine is developed on pillars along the floor horizon to an average height of 3.0 m,leaving a coal band of around 4.0 m along the roof.Analysis of procured core samples showed that roof strata are easily caveable with a caveability index value of around 2000 only.Easily caveable overlying strata and shallow depth of cover alleviated most of the expected strata mechanics problems of the thick seam mining.However,extraction of total thickness at shallow cover caused differential-subsidence and cracks on the surface.These manifestations were immediately tackled to avoid creation of a breathing path for spontaneous heating in the extracted area.

Estimating shear strength of high-level pillars supported with cemented backfilling using the HoekeBrown strength criterion

Deep metal mines are often mined using the high-level pillars with subsequent cementation backfilling(HLSCB)mining method.At the design stage,it is therefore important to have a reasonable method for determining the shear strength of the high-level pillars(i.e.cohesion and internal friction angle)when they are supported by cemented backfilling.In this study,a formula was derived for the upper limit of the confining pressure σ3max on a high-level pillar supported by cemented backfilling in a deep metal mine.A new method of estimating the shear strength of such pillars was then proposed based on the Hoek eBrown failure criterion.Our analysis indicates that the horizontal stress σhh acting on the cemented backfill pillar can be simplified by expressing it as a constant value.A reasonable and effective value for σ3max can then be determined.The value of s3max predicted using the proposed method is generally less than 3 MPa.Within this range,the shear strength of the high-level pillar is accurately calculated using the equivalent MohreCoulomb theory.The proposed method can effectively avoid the calculation of inaccurate shear strength values for the high-level pillars when the original HoekeBrown criterion is used in the presence of large confining pressures,i.e.the situation in which the cohesion value is too large and the friction angle is too small can effectively be avoided.The proposed method is applied to a deep metal mine in China that is being excavated using the HLSCB method.The shear strength parameters of the high-level pillars obtained using the proposed method were input in the numerical simulations.The numerical results show that the recommended level heights and sizes of the high-level pillars and rooms in the mine are rational.

Investigation of stress-induced progressive failure of mine pillars using a Voronoi grain-based breakable block model

The Voronoi grain-based breakable block model(VGBBM)based on the combined finite-discrete element method(FDEM)was proposed to explicitly characterize the failure mechanism and predict the deformation behavior of hard-rock mine pillars.The influence of the microscopic parameters on the macroscopic mechanical behavior was investigated using laboratory-scale models.The field-scale pillar models(width-to-height,W/H=1,2 and 3)were calibrated based on the empirically predicted stress-strain curves of Creighton mine pillars.The results indicated that as the W/H ratios increased,the VGBBM effectively predicted the transition from strain-softening to pseudo-ductile behavior in pillars,and explicitly captured the separated rock slabs and the V-shaped damage zones on both sides of pillars and conjugate shear bands in core zones of pillars.The volumetric strain field revealed significant compressional deformation in core zones of pillars.While the peak strains of W/H=1 and 2 pillars were relatively consistent,there were significant differences in the strain energy storage and release mechanism.W/H was the primary factor influencing the deformation and strain energy in the pillar core.The friction coefficient of the structural plane was also an important factor affecting the pillar strength and the weakest discontinuity angle.The fracture surface was controlled by the discontinuity angle and the friction coefficient.This study demonstrated the capability of the VGBBM in predicting the strengths and deformation behavior of hard-rock pillars in deep mine design.

Pillar effect induced by ultrahigh phosphorous/nitrogen doping enables graphene/MXene film with excellent cycling stability for alkali metal ion storage

Graphene's large theoretical surface area and high conductivity make it an attractive anode material for potassium-ion batteries(PIBs).However,its practical application is hindered by small interlayer distance and long ion transfer distance.Herein,this paper aims to address the issue by introducing MXene through a simple and scalable method for assembling graphene and realizing ultrahigh P doping content.The findings reveal that MXene and P-C bonds have a "pillar effect" on the structure of graphene,and the P-C bond plays a primary role.In addition,N/P co-doping introduces abundant defects,providing more active sites for K^(+) storage and facilitating K^(+) adsorption.As expected,the developed ultrahigh phosphorous/nitrogen co-doped flexible reduced graphene oxide/MXene(NPrGM) electrode exhibits remarkable reversible discharge capacity(554 mA hg^(-1) at 0.05 A g^(-1)),impressive rate capability(178 mA h g^(-1) at 2 A g^(-1)),and robust cyclic stability(0.0005% decay per cycle after 10,000 cycles at 2 A g^(-1)).Furthermore,the assembled activated carbon‖NPrGM potassium-ion hybrid capacitor(PIHC) can deliver an impressive energy density of 131 W h kg^(-1) and stable cycling performance with 98.1% capacitance retention after5000 cycles at 1 A g^(-1).Such a new strategy will effectively promote the practical application of graphene materials in PIBs/PIHCs and open new avenues for the scalable development of flexible films based on two-dimensional materials for potential applications in energy storage,thermal interface,and electromagnetic shielding.

Numerical and theoretical study of load transfer behavior during cascading pillar failure

To further study the load transfer mechanism of roofemulti-pillarefloor system during cascading pillar failure(CPF),numerical simulation and theoretical analysis were carried out to study the three CPF modes according to the previous experimental study on treble-pillar specimens,e.g.successive failure mode(SFM),domino failure mode(DFM)and compound failure mode(CFM).Based on the finite element code rock failure process analysis(RFPA^(2D)),numerical models of treble-pillar specimen with different mechanical properties were established to reproduce and verify the experimental results of the three CPF modes.Numerical results show that the elastic rebound of roofefloor system induced by pillar instability causes dynamic disturbance to adjacent pillars,resulting in sudden load increases and sudden jump displacement of adjacent pillars.The phenomena of load transfer in the roofemulti-pillarefloor system,as well as the induced accelerated damage behavior in adjacent pillars,were discovered and studied.In addition,based on the catastrophe theory and the proposed mechanical model of treble-pillar specimen edisc spring group system,a potential function that characterizes the evolution characteristics of roof emulti-pillarefloor system was established.The analytical expressions of sudden jump and energy release of treble-pillar specimenedisc spring group system of the three CPF modes were derived according to the potential function.The numerical and theoretical results show good agreement with the experimental results.This study further reveals the physical essence of load transfer during CPF of roof emulti-pillarefloor system,which provides references for mine design,construction and disaster prevention.

Supramolecular Macrocycle Regulated Single-Atom MoS_(2)@Co Catalysts for Enhanced Oxygen Evolution Reaction

The development of active water oxidation catalysts for water splitting has stimulated considerable interest.Herein,the design and building of single atom Co sites using a supramolecular tailoring strategy are reported,that is,the introduction of pillar[4]arene[1]quinone(P4A1Q)permits mononuclear Co species stereoelectronically assembled on MoS_(2)matrix to construct an atomically dispersed MoS_(2)@Co catalyst with modulated local electronic structure,definite chemical environment and enhanced oxygen evolution reaction performance.Theoretical calculations indicate that immsobilized single-Co sites exhibit an optimized adsorption capability of oxygen-containing intermediates,endowing the catalyst an excellent electrocatalytic oxygen evolution reaction activity,with a low overpotential of 370 mV at 10 mA cm^(-2)and a small Tafel slope of 90 mV dec^(-1).The extendable potential of this strategy to other electrocatalysts such as MoS_(2)@Ni and MoS_(2)@Zn,and other applications such as the hydrogen evolution reaction was also demonstrated.This study affords new insights into the rational design of single metal atom systems with enhanced electrocatalytic performance.

三维复杂断层网建模方法及应用

针对复杂断层网,提出一种新的路径切割算法,能够处理各种复杂的断层相交情况,如Y型、λ型、X型、半Y型、半λ型等削截关系;避免了Pillar方法和二叉树等传统方法的限制,提高了断层建模的灵活性和精确度。该方法提高了断面之间接触关系的半自动处理程度,方便断层网的快速更新。通过实际模型的验证,解决了复杂断层网的快速构建问题,提高了建模效率。

Experimental studies on pillar failure characteristics based on acoustic emission location technique

Acoustic emission （AE） technique is a useful tool for investigating rock damage mechanism, and is used to study the temporal-spatial evolution process of microcracks during the similar pillar material experiment. A combined AE location algorithm was developed based on the Least square algorithm and Geiger location algorithm. The pencil break test results show that the location precision can meet the demand of microcrack monitoring. The 3D location of AE events can directly reflect the process of initiation, propagation and evolutionary of microcracks. During the loading process, stress is much likely concentrated on the area between pillar and roof of the specimen, where belongs to danger zone of macroscopic failure. When rock reaches its plastic deformation stage, AE events begin to decrease, which indicates that AE quiet period can be seen as precursor characteristic of rock failure.

Predicting pillar stability for underground mine using Fisher discriminant analysis and SVM methods

The purpose of this study is to apply some statistical and soft computing methods such as Fisher discriminant analysis （FDA） and support vector machines （SVMs） methodology to the determination of pillar stability for underground mines selected from various coal and stone mines by using some index and mechanical properties, including the width, the height, the ratio of the pillar width to its height, the uniaxial compressive strength of the rock and pillar stress. The study includes four main stages： sampling, testing, modeling and assessment of the model performances. During the modeling stage, two pillar stability prediction models were investigated with FDA and SVMs methodology based on the statistical learning theory. After using 40 sets of measured data in various mines in the world for training and testing, the model was applied to other 6 data for validating the trained proposed models. The prediction results of SVMs were compared with those of FDA as well as the measured field values. The general performance of models developed in this study is close; however, the SVMs exhibit the best performance considering the performance index with the correct classification rate Prs by re-substitution method and Pcv by cross validation method. The results show that the SVMs approach has the potential to be a reliable and practical tool for determination of pillar stability for underground mines.

“地质网格”技术在复杂断块油藏地质建模中的应用

符合客观实际的三维地质模型是油藏地质研究的最终成果,而目前常用的建模软件及其数学算法在构建复杂构造模型和强非均质储集层模型时存在局限性。本文以大港油田C区Z断块为例,利用"地质网格"技术避免了常规PILLAR网格系统在建立构造模型时遇到的网格扭曲现象,确保了构造的完整性和准确性;应用相控多变差函数分析技术弥补了单一变差函数无法准确表征储层空间分布状况及物性变化特征的缺憾,较好地解决了沉积微相变化快、储层非均质性强等问题,为油田勘探开发部署提供了更符合客观实际的精细地质模型。

应用Petrel进行构造建模的研究

采用Petrel软件进行构造建模能更准确直观反映地下构造情况。以某油田工区为例,在地质资料分析的基础上,以地震资料解释及合成地震记录标定结果为约束条件,采用构造特征分析技术研究了分析断层间的接触关系及其延展趋势,建立该研究区的构造模型,并针对建模过程中出现的问题,提出了相应的解决方法。该研究方法提高了构造解释的精度,为后续的油藏地质建模奠定了基础。

微创经椎弓根Pillar植入治疗胸腰椎压缩性骨折疗效及相关并发症分析

目的 ：探讨经椎弓根pillar植入治疗胸腰椎压缩性骨折的临床效果及相关并发症。方法 ：回顾分析2010年1月～2013年4月采用微创经椎弓根pillar置入治疗胸腰椎压缩性骨折患者27例的临床疗效。手术前后进行疼痛强度视觉模拟评分（visual analogue scale,VAS）、Oswestry功能障碍指数（Oswestry disability index,ODI）、伤椎前缘高度比值、矢状面指数（伤椎前缘高度/伤椎后缘高度×100%）、伤椎Cobb′s角。结果：27例患者共植入54枚椎体支柱块,均获得6～26个月的随访,平均手术时间为（47.6±8.5）min,平均术中失血量（28.4±12.3）ml。术后CT证实17例患者椎弓根皮质有破裂,其中外侧皮质破裂15例,内侧皮质破裂2例,其中1例患者因内侧壁破裂引起下肢神经症状,经治疗后缓解。术后1周及末次随访时VAS评分、ODI值、椎体前缘高度比值、矢状面指数值及伤椎Cobb′s角与术前比较差异均具有统计学意义（P〈0.05）,而术后1周与末次随访时比较差异无统计学意义（P〉0.05）,椎体支柱块未发生移位或塌陷。结论：微创经椎弓根pillar置入是治疗胸腰椎压缩骨折一种安全、有效、可行的方法,严格掌握手术适应证、术中规范操作可降低并发症的发生。

Pillar植入系统联合鼻部手术治疗OSAHS 38例疗效分析

目的探讨Pillar植入系统联合鼻部手术治疗阻塞性睡眠呼吸暂停低通气综合征(OSAHS)的效果。方法选取2006年7至2008年11月本科OSAHS患者38例,38例均同期行Pillar植入系统治疗和鼻部手术,术前及术后6个月均行多导睡眠呼吸监测(polysomnography,PSG),对术前及术后的PSG结果(包括AHI、LSaO2)进行统计学分析。结果术后6个月进行PSG监测,治愈10例,好转17例,减轻7例,无效4例,总有效率达89.5%;所有患者无手术并发症发生。结论Pillar植入系统联合鼻部手术治疗单纯型鼾症(primary snoring,PS)及轻-中度OSAHS可取得良好效果。

平行束孔爆破模型试验及其机理探讨

本文介绍了垂直密集束状平行炮孔(简称平行束孔)落矿有底柱崩落采矿法的实质和结构,并分析了它的特点和优点。由于平行束孔落矿是核心的关键技术,本文为此做了爆破模型试验,对其爆破机理进行了研究和探讨。该项研究在国内尚属首次。

Pillar植入术治疗阻塞性睡眠呼吸暂停综合征病人的观察和护理

[目的]探讨Pillar植入术治疗阻塞性睡眠呼吸暂停综合征(OSAS)的护理及术后随访。[方法]46例鼾症病人经我导睡眠仪(PSG)监测分为轻至中度OSAS(28例)、重度OSAS(6例)和单纯鼾症(12例)3组,行Pillar植入术,并给予全面的身心护理和健康教育,术前及术后1个月和6个月均进行鼾声视觉类比量表(VAS)评分和PSG监测。[结果]术后随访6个月,Pillar植入系统对于轻至中度OSAS病人和单纯鼾症病人打鼾的改善显著,而对于重度OSAS病人疗效较差。28例轻至中度OSAS病人治愈4例,显效10例,有效5例,无效9例,总有效率达67.9%,呼吸紊乱指数(AHI)由术前的每小时17.03次±10.63次到术后6个月降至每小时11.17次±9.52次;6例重度OSAS病人有效1例(1/6),AHI由术前每小时62.93次±9.21次降至每小时55.42次±13.77次,46例病人术后无并发症。[结论]Pillar植入系统对于治疗鼾症可以有效地改善打鼾,对于睡眠呼吸暂停的改善轻至中度OSAS病人的疗效较好,而重度OSAS病人的疗效较差。而做好Pillar手术的护理,可帮助病人顺利完成手术治疗,减轻他们术前的忧虑和术后的痛苦,获得满意效果,提高生活质量。

油藏体数模综合展示技术研究

为扩展用户业务数据的展示,综合分析油藏体的地质结构以及油水分布情况,研究复杂三维地层油藏数值模拟可视化实现过程中的关键技术,先分析现有数模软件输出文件格式,结合用户特定业务数据,应用Pillar模型构建三维地层模型,再使用Open Inventor三维图像开发平台完成3D展示,在此基础上实现三维模型网格筛选、切片、色谱自定义等人机交互功能,提供油藏体数值模拟综合展示功能。

First Synthesis of Zirconia-pillared Layered Lanthanum Niobate

A zirconia-pillared layered lanthanum niobate was prepared by first preswelling layered HLaNb2O7 with n-hexadecylamine(n-C16H33NH2), then further reacting with zirconyl chloride aqueous solution, and finally calcining the resultant solid product in air. The obtained new material has an interlayer spacing of 1.36nm, and a high thermal stability above 700 degrees C.

Preparation and Microstructure of Al-pillared Interlayered Montmorillonite

Al-pillared interlayered montmorillonite (Al-PILM) was prepared using the artificial Na-montmorillonite from the Qingfengshan bentonite mine as a starting material mixed with Al-pillaring solutions.The microstructure of the materials was studied by an X-ray powder diffractometer and a Fourier transform infrared (FTIR) spectrometer.The results indicated that the basal spacing [d(001) value] of the materials was increased significantly to 1.9194 nm relative to Na-montmorillonite (1.2182 nm).After calcined for 2 h at 300℃,the basal spacing was stabilized at 1.8394 nm and the layered structure of the materials was not destroyed.Thermal analysis was conducted by a thermal gravimetry and differential thermal analysis (TG-DTA) instrument,it showed that Al-PILM lost physically adsorbed water below 230.6℃ and water formed by dehydroxylation of the pillars at around 497.1℃, with a peak of the phase transformation at 903.0℃.

应用轮廓变化信息的实验鼠行为识别

实验鼠行为分析数据是神经学、生理学、药物学等学科实验数据的重要部分。针对实验鼠缺少肢体运动信息的特点,提出一种实验鼠多行为分析方法。提取实验鼠轮廓的帧间变化信息,同时考虑变化信息与实验鼠本身的位置关系,对行为视频形成系列轮廓变化帧。在训练阶段,通过Pillar K-means聚类算法从系列帧中提取80个关键帧,并把每一个训练行为视频用对应关键帧频数的直方图表示。在测试阶段,测试视频用最近邻法确定每一帧对应的关键帧,形成相应的关键帧直方图,从而把分类问题变成一个直方图相似性问题,再应用卡方距离进行分类。实验结果表明,该方法对8种行为的分类准确率最高达到100%,最低达到95%。