Effect of strata properties and panel widths on chock performance

The selection of optimum chock (support) capacity is very crucial for a successful longwall mining. The selection of chock capacity depends on the site-specific geotechnical parameters, constraints and longwall panel geometry, which are generally not known in detail in priority. Hence, based on the field and laboratory data, various possible combinations should be analyzed to cater for the unforeseeable mining conditions. This paper discusses the use of numerical model for selecting an appropriate chock capacity based on the site-specific geological and geotechnical information and longwall panel geometry. The fracture mechanisms of immediate and main roofs are also discussed for various panel widths and support capacities. For the models considered, the chock convergence is predicted to increase by about 33% due to the increase in face width from 100 to 260 m. Similarly, the massive roof strata are found to yield higher chock convergence compared to bedded strata.

Monitoring and engineering interface coupling between monolayer WS_(2)and substrate through controllably introducing interfacial strain

The interface properties in two-dimensional(2D)layered materials and their van der Waals(vdW)homo-/heterostructures are of importance in both uncovering novel physical phenomena and optimizing device performance.Despite considerable research interest and enthusiasm direct toward the interlayer coupling in 2D homo-and heterostructures,there is limited research on the coupling at the 2D layered material-substrate interface.This limitation is due to the challenges in achieving direct detection.Currently,the coupling mechanisms at the 2D layered material-substrate interface is ambiguous,which needs greater attention.In this study,we have systematically investigated the interface coupling between monolayer WS_(2)and its supported substrates using high-temperature and high-vacuum in-situ Raman spectroscopy through monitoring the low-frequency Raman mode of monolayer WS_(2).Our findings reveal that both interfacial spacing and strain can significantly affect the coupling strength between the monolayer WS_(2)and the supported substrate.More notably,we found that the strategic introduction of appropriate interfacial strain can effectively enhance the interface coupling.Consequently,we have succeeded in achieving effective regulation of the sample-substrate coupling via a convenient way of controlling the cooling process during annealing.Our findings contribute to a deeper understanding of the coupling correlation between 2D layered materials and substrates,which is of great significance for the design and optimization of high-performance devices based on 2D layered semiconductors.

Recent advances and opportunities in MXene-based liquid crystals

The recent progress on the liquid crystalline(LC)dispersion of two-dimensional(2D)transition metal carbides(MXenes)has propelled this unique nanomaterial into a realm of high-performance architectures,such as films and fibers.Additionally,compared to architectures made from typical non-LC dispersions,those derived from LC MXene possess tunable ion transport routes and enhanced conductivity and physical properties,demonstrating great potential for a wide range of applications,such as electronic displays,smart glasses,and thermal camouflage devices.This review provides an overview of the progress achieved in the production and processing of LC MXenes,including critical discussions on satisfying the required conditions for LC formation.It also highlights how acquiring LC MXenes has broadened the current solution-based manufacturing paradigm of MXene-based architectures,resulting in unprecedented performances in their conventional applications(e.g.,energy storage and strain sensing)and in their emerging uses(e.g.,tribology).Opportunities for innovation and foreseen challenges are also discussed,offering future research directions on how to further benefit from the exciting potential of LC MXenes with the aim of promoting their widespread use in designing and manufacturing advanced materials and applications.

Horizontal borehole azimuth optimization for enhanced stability and coal seam gas production

Horizontal boreholes have been widely used to extract natural gas from coal seams.However,these boreholes can encounter severe instability issues leading to production interruption.Optimizing drilling azimuth is a potential solution for enhancing borehole stability while considering gas production.In this work,we improved and implemented a dual-porosity,fully coupled geomechanical-hydraulic numerical model into COMSOL Multiphysics to investigate into this factor.The sophisticated numerical model incorporates various critical factors,including desorption-induced matrix shrinkage,stress-dependent anisotropic fracture permeability,and the interactions of gas flow and reservoir deformation in matrices and fractures.A suite of simulation scenarios(e.g.,varying coal strength)was carried out to quantify the impact of drilling azimuth on coal permeability evolution,cumulative gas production,and the borehole break-out width for Goonyella Middle Seam of Bowen Basin,Australia.The model was calibrated against both theoretical permeability values and field gas production data.Due to the lack of directly measured matrix permeability data,the actual gas production was used to back calculate the best-matched matrix permeability,which is 0.65μD for this particular work.Moreover,based on the breakout shape and induced volumetric strains around the borehole,drilling along the maximum horizontal stress does not necessarily lead to the best stability of the borehole,as generally believed.A drilling azimuth between 0and 60results in similar breakout width,whereas a drilling azimuth between 60and 90achieves the most efficient gas production.By considering both gas production efficiency and borehole stability,for this particular reservoir condition,the optimum drilling azimuth is determined to be between 45and 60.This study presents a practical approach for determining the optimum drilling azimuth in coal seam gas extraction through in seam boreholes.

塔里木盆地典型砂岩油气储层自生伊利石K-Ar同位素测年研究与成藏年代探讨

塔里木盆地共发现 8套砂岩油气储层 ,对其中的 5套典型砂岩油气储层进行了自生伊利石K Ar同位素测年分析与研究。利用该项技术对其成藏史进行初步探讨是本次研究的主要目的。中央隆起下志留统沥青砂岩的自生伊利石年龄为 383.4 5～ 2 35 .17Ma ,表明志留系古油藏形成于加里东晚期—海西晚期 ;上泥盆统东河砂岩的自生伊利石年龄为 2 6 3.82～ 2 31.34Ma ,表明东河砂岩油气藏主要形成于海西晚期 ;库车坳陷依南 2气田 (依南 2井 )下侏罗统阳霞组砂岩的自生伊利石年龄为 2 8.0 8～ 2 3.85Ma ,表明油气充注发生在中新世以来 ;喀什凹陷阿克莫木气田 (阿克 1井 )下白垩统砂岩的自生伊利石年龄为 2 2 .6 0～ 18.79Ma ,表明中新世可能有古油气运移或古油藏形成 ;库车坳陷迪那 2气藏 (迪那 2 0 1井 )古近系砂岩中的伊利石主要为碎屑成因 ,不能用于进行油气成藏史研究 ,但该气藏白垩系砂岩的自生伊利石年龄为 2 5 .4 9～ 15 .4 7Ma ,表明可能为中新世成藏。本次研究表明 ,该项技术在塔里木盆地初步显示出较好的应用效果 ,具有较为广阔的应用前景。

塔中隆起志留系沥青砂岩油气储层自生伊利石K-Ar同位素测年研究与成藏年代探讨

据自生伊利石K—Ar同位素测年技术对塔中隆起志留系沥青砂岩油藏成藏年代的测定，并与孔雀河地区进行对比。塔中隆起及孔雀河地区志留系沥青砂岩的自生伊利石年龄为383．45—203．96Ma，表明主要为晚加里东-早海西期和晚海西期成藏，位于盆地边部的乔1井、孔雀1井及龙口1井、英南2井相对较早（383．45—271．20Ma），主要为晚加里东-早海西期成藏，位于盆地中心的塔中37井、塔中67井、塔中12井及塔中32井相对较晚（203．96—235．17Ma），主要为晚海西期成藏，部分井如塔中23井、塔中30井相对较早（293．54和296．31Ma），为早海西期成藏。自生伊利石年龄与沥青砂岩厚度具有较好的对应关系，说明古构造格局可能是主要的成藏控制因素之一，位于沉降中心及其周围的古油藏如乔1井、孔雀1井成藏较早。测年结果不仅与油气系统等常规油气成藏史研究成果基本一致，而且还进一步反映了油藏形成时间上的差异。

超分子荧光探针用于环境水样中百草枯的测定

基于七元瓜环可使中性红的荧光增强从而设计荧光探针,当在荧光探针中加入百草枯后荧光强度又逐渐降低,利用此种超分子配合物的荧光"开-关"效应,从而建立了一种新颖的检测百草枯的荧光方法。当百草枯浓度在(1~8)×10^(-6 )mol·L^(-1)范围内,百草枯浓度与探针的荧光强度具有良好的线性关系,且检出限为1.4×10^(-8 )mol·L^(-1),加标回收率为104%~108%,可在河水样品中检测百草枯的含量。

八元瓜环与吲哚乙酸及甲基紫精的超分子相互作用研究

利用紫外吸收光谱法、荧光光谱法、等温量热滴定法、氢核磁共振技术等研究了八元瓜环(Q[8])与富电子客体吲哚乙酸(IAA)及缺电子客体甲基紫精(MV2+)在水溶液中的超分子相互作用,探讨了主客体作用体系的作用机制,作用位点,作用模式及热力学等性质。紫外吸收光谱及荧光发射光谱研究结果表明Q[8]与IAA及Q[8]与MV2+在水溶液中均形成了包结计量比为1∶1的主客体配合物,等温量热滴定法研究结果显示Q[8]/IAA及Q[8]/MV2+体系的ΔH<0,ΔG<0,表明上述超分子体系是发进行且是放热反应。当在Q[8]/IAA二元体系中加入MV2+时,MV2+能与Q[8]/IAA体系在水溶液中形成1∶1∶1型三元主客体配合物,IAA的吲哚环及亚甲基部位受到了瓜环的屏蔽作用进入了Q[8]的空腔,MV2+吡啶环部位也进入Q[8]的空腔,也即IAA及MV2+均相互协同进入Q[8]空腔而与Q[8]形成了主客体配合物,原因可能是由于富电子客体IAA与缺电子客体MV2+之间的电荷相互转移诱导作用引起的。上述研究结果为瓜环在富电子客体及缺电子客体超分子自组装方面的应用提供了一定的理论依据。

The role of functional materials to produce high areal capacity lithium sulfur battery

The lithium sulfur batteries(LSBs) are considered as one of the promising next generation energy storage devices due to the high theoretical specific capacity of sulfur(1675 m Ah g-1), naturally available, low cost.However, the practical LSBs are impeded by the well-known "shuttle effect" combined with other technical drawbacks. The "shuttle effect" causes rapid capacity decay, severe self-discharging and low active material utilization. The polysulfide(PS) which has lone pair electrons in each sulfur atom is considered as Lewis base and shows strong affinity to various polar, Lewis acid and catenation interactive materials but very weakly interacts with the non-polar conductive carbons. The "shuttle effect" occurs due to the diffusion of high order PS from the cathode to the anode and then low-order PS back to the cathode. The PS is polar and, due to a lone pair of electrons associated with the sulfur atom, is considered a Lewis base. As such, the PS shows a strong affinity with various polar and Lewis acid materials. In addition, a more novel trapping can be performance through a catenation reaction. For LSBs to compete with the state-of-the-art lithium ion batteries(LIBs), the LSB areal capacity need to be ~6 m Ah cm-2(which is proportional to sulfur loading). To achieve this target the PS shuttling needs to mitigate, which can be achieved through using functional materials. This review addresses the aforementioned phenomena by considering the PS phase interacts with the various functional materials and how this impacts areal capacity and cycling stability of LSBs.

Electrolyte/Structure‑Dependent Cocktail Mediation Enabling High‑Rate/Low‑Plateau Metal Sulfide Anodes for Sodium Storage

As promising anodes for sodium-ion batteries,metal sulfides ubiquitously suffer from low-rate and high-plateau issues,greatly hindering their application in full-cells.Herein,exemplifying carbon nanotubes(CNTs)-stringed metal sulfides superstructure(CSC)assembled by nano-dispersed SnS_(2) and CoS_(2) phases,cocktail mediation effect similar to that of high-entropy materials is initially studied in ether-based electrolyte to solve the challenges.The high nano-dispersity of metal sulfides in CSC anode underlies the cocktail-like mediation effect,enabling the circumvention of intrinsic drawbacks of different metal sulfides.By utilizing ether-based electrolyte,the reversibility of metal sulfides is greatly improved,sustaining a long-life effectivity of cocktail-like mediation.As such,CSC effectively overcomes low-rate flaw of SnS_(2) and highplateau demerit of CoS_(2),simultaneously realizes a high rate and a low plateau.In half-cells,CSC delivers an ultrahigh-rate capability of 327.6 mAh g^(−1) anode at 20 A g^(−1),far outperforming those of monometallic sulfides(SnS_(2),CoS_(2))and their mixtures.Compared with CoS_(2) phase and SnS_(2)/CoS_(2) mixture,CSC shows remarkably lowered average charge voltage up to ca.0.62 V.As-assembled CSC//Na1.5VPO4.8F0.7 full-cell shows a good rate capability(0.05~1.0 A g^(−1),120.3 mAh g^(−1) electrode at 0.05 A g^(−1))and a high average discharge voltage up to 2.57 V,comparable to full-cells with alloy-type anodes.Kinetics analysis verifies that the cocktail-like mediation effect largely boosts the charge transfer and ionic diffusion in CSC,compared with single phase and mixed phases.Further mechanism study reveals that alternative and complementary electrochemical processes between nano-dispersed SnS_(2) and CoS_(2) phases are responsible for the lowered charge voltage of CSC.This electrolyte/structure-dependent cocktail-like mediation effect effectively enhances the practicability of metal sulfide anodes,which will boost the development of high-rate/-voltage sodium-ion full batteries.

A major quantitative trait locus controlling phosphorus utilization efficiency under different phytate-P conditions at vegetative stage in barley

Organic phosphorus（P） is an important component of the soil P pool, and it has been proven to be a potential source of P for plants. The phosphorus utilization efficiency（PUE） and PUE related traits（tiller number（TN）, shoot dry weight（DW）, and root dry weight） under different phytate-P conditions（low phytate-P, 0.05 mmol L^-1 and normal phytate-P, 0.5 mmol L^-1） were investigated using a population consisting of 128 recombinant inbred lines（RILs） at the vegetative stage in barley. The population was derived from a cross between a P-inefficient genotype（Baudin） and a P-efficient genotype（CN4027, a Hordeum spontaneum accession）. A major locus（designated Qpue.sau-3 H） conferring PUE was detected in shoots and roots from the RIL population. The quantitative trait locus（QTL） was mapped on chromosome 3 H and the allele from CN4027 confers high PUE. This locus explained up to 30.3 and 28.4% of the phenotypic variance in shoots under low and normal phytate-P conditions, respectively. It also explains 28.3 and 30.7% of the phenotypic variation in root under the low and normal phytate-P conditions, respectively. Results from this study also showed that TN was not correlated with PUE, and a QTL controlling TN was detected on chromosome 5 H. However, dry weight（DW） was significantly and positively correlated with PUE, and a QTL controlling DW was detected near the Qpue.sau-3 H locus. Based on a covariance analysis, existing data indicated that, although DW may affect PUE, different genes at this locus are likely involved in controlling these two traits.

Towards Privacy-Aware and Trustworthy Data Sharing Using Blockchain for Edge Intelligence

The popularization of intelligent healthcare devices and big data analytics significantly boosts the development of Smart Healthcare Networks(SHNs).To enhance the precision of diagnosis,different participants in SHNs share health data that contain sensitive information.Therefore,the data exchange process raises privacy concerns,especially when the integration of health data from multiple sources(linkage attack)results in further leakage.Linkage attack is a type of dominant attack in the privacy domain,which can leverage various data sources for private data mining.Furthermore,adversaries launch poisoning attacks to falsify the health data,which leads to misdiagnosing or even physical damage.To protect private health data,we propose a personalized differential privacy model based on the trust levels among users.The trust is evaluated by a defined community density,while the corresponding privacy protection level is mapped to controllable randomized noise constrained by differential privacy.To avoid linkage attacks in personalized differential privacy,we design a noise correlation decoupling mechanism using a Markov stochastic process.In addition,we build the community model on a blockchain,which can mitigate the risk of poisoning attacks during differentially private data transmission over SHNs.Extensive experiments and analysis on real-world datasets have testified the proposed model,and achieved better performance compared with existing research from perspectives of privacy protection and effectiveness.

基于生命周期评价的产品水足迹计算方法及案例分析

科学评价人类活动对水资源的影响是实现水资源可持续利用的前提。对比目前广泛应用的以虚拟水理论为基础的水足迹计算方法,详细介绍了基于生命周期评价(LCA)的产品水足迹计算方法,并以我国小麦生产为例进行实证研究。与虚拟水方法相比,LCA方法评价结果体现了水资源利用的环境影响,便于不同产品、不同生产阶段以及不同产地产品间水足迹的比较。实例研究表明:我国黄河、海河流域小麦水足迹平均为1 262 L H2Oe.kg-1,而长江流域仅为31 L H2Oe.kg-1;小麦生产对我国极度缺水的北方造成的压力远高于水资源较为丰富的南方地区。LCA方法能科学评价农产品生产对水资源的影响,为我国保障粮食安全和水资源可持续利用提供科学依据。

MYC2： The Master in Action

Jasmonates （JAs） are plant hormones with essential roles in plant defense and development. The basic- helix-loop-helix （bHLH） transcription factor （TF） MYC2 has recently emerged as a master regulator of most aspects of the jasmonate （JA） signaling pathway in Arabidopsis. MYC2 coordinates JA-mediated defense responses by antagonistically regulating two different branches of the JA signaling pathway that determine resistance to pests and pathogens, respectively. MYC2 is required for induced systemic resistance （ISR） triggered by beneficial soil microbes while MYC2 function is targeted by pathogens during effector-mediated suppression of innate immunity in roots. Another notable function of MYC2 is the regulation of crosstalk between the signaling pathways of JA and those of other phytohormones such as abscisic acid （ABA）, salicylic acid （SA）, gibberellins （GAs）, and auxin （IAA）. MYC2 also regulates interactions between JA signaling and light, phytochrome signaling, and the circadian clock, MYC2 is involved in JA-regulated plant development, lateral and adventitious root formation, flowering time, and shade avoidance syndrome. Related bHLH TFs MYC3 and MYC4 also regulate both overlapping and distinct MYC2-regulated functions in Arabidopsis while MYC2 orthologs act as ＇master switches＇ that regulate JA-mediated biosynthesis of secondary metabolites. Here, we briefly review recent studies that revealed mechanistic new insights into the mode of action of this versatile TF.

Stabilizing the Extrinsic Porosity in Metal-Organic Cages-Based Supramolecular Framework by In Situ Catalytic Polymerization

Porous supramolecular frameworks based on metal-organic cages(MOCs)usually have poor structural stability after activation.This issue narrows the scope of their potential applications,particularly for the inclusion of guest molecules that demand high porosity.Herein,the authors have reported the stabilization of a mesoporous zirconium MOC-based supramolecular framework with an in situ catalytic polymerization strategy.Due to the passivation effect imparted by this strategy,the introduced polymer is primarily distributed on the surface of the crystals,which results in the hybrid material retaining its crystallinity and permanent porosity.A preliminary application of this type of stabilized mesoporous supramolecular framework shows that among MOC-based supramolecular frameworks,it has the highest high-pressure methane uptake.Such a facile strategy may provide a general way to stabilize fragile porous materials and facilitate exploration of their potential applications.

System bias correction of short-term hub-height wind forecasts using the Kalman filter

Wind energy is a fluctuating source for power systems, which poses challenges to grid planning for the wind power industry. To improve the short-term wind forecasts at turbine height, the bias correction approach Kalman filter (KF) is applied to 72-h wind speed forecasts from the WRF model in Zhangbei wind farm for a period over two years. The KF approach shows a remarkable ability in improving the raw forecasts by decreasing the root-mean-square error by 16% from 3.58 to 3.01 m s−1, the mean absolute error by 14% from 2.71 to 2.34 m s−1, the bias from 0.22 to − 0.19 m s−1, and improving the correlation from 0.58 to 0.66. The KF significantly reduces random errors of the model, showing the capability to deal with the forecast errors associated with physical processes which cannot be accurately handled by the numerical model. In addition, the improvement of the bias correction is larger for wind speeds sensitive to wind power generation. So the KF approach is suitable for short-term wind power prediction.

Effectiveness of seed dispersal by ants in a Neotropical tree

Seed dispersal and subsequent recruitment is the template on which forest regeneration takes place.Hence,considering the scale over which ecological processes occur is key for understanding the overall impact of various dispersal agents.To explore leafcutter ant(Atta colombica)dispersal effectiveness in space and time,seed movement and subsequent recruitment of a large-seeded predominately vertebrate-dispersed tree,Simarouba amara(Aubl.Simaroubaceae),was investigated on Barro Colorado Island,Panama.At each of 218 reproductive-sized adults(>20 cm diameter at breast height),presence or absence of a leafcutter ant colony was noted,with extensive checks for Atta activity taking place at or in close proximity to seed and seedling transects,which extended 4 cardinal directions for 30 m from each reproductive female tree(n=74).Only at 2 S.amara trees were nests observed,and in these areas a dense S.amara seedling carpet was observed.Although nearby nest and dump sites might increase local S.amara recruitment in the short term,mortality at these sites is complete or nearly so.Hence,the seed dispersal effectiveness by leafcutter ants appears to be ephemeral and likely contributes inconsequentially to the long-term recruitment and distribution patterns of the species.This finding highlights the importance of evaluating disperser effectiveness at ecologically relevant spatiotemporal scales.