Three-dimensional spatial structure of the macro-pores and flow simulation in anthracite coal based on X-ray μ-CT scanning data

The three-dimensional(3 D) structures of pores directly affect the CH4 flow.Therefore,it is very important to analyze the3 D spatial structure of pores and to simulate the CH4 flow with the connected pores as the carrier.The result shows that the equivalent radius of pores and throats are 1-16 μm and 1.03-8.9 μm,respectively,and the throat length is 3.28-231.25 μm.The coordination number of pores concentrates around three,and the intersection point between the connectivity function and the X-axis is 3-4 μm,which indicate the macro-pores have good connectivity.During the single-channel flow,the pressure decreases along the direction of CH4 flow,and the flow velocity of CH4 decreases from the pore center to the wall.Under the dual-channel and the multi-channel flows,the pressure also decreases along the CH4 flow direction,while the velocity increases.The mean flow pressure gradually decreases with the increase of the distance from the inlet slice.The change of mean flow pressure is relatively stable in the direction horizontal to the bedding plane,while it is relatively large in the direction perpendicular to the bedding plane.The mean flow velocity in the direction horizontal to the bedding plane(Y-axis) is the largest,followed by that in the direction horizontal to the bedding plane(X-axis),and the mean flow velocity in the direction perpendicular to the bedding plane is the smallest.

Three Phase Composite Cylinder Assemblage Model for Analyzing the Elastic Behavior of MWCNT-Reinforced Polymers

Evolution of computational modeling and simulation has given more emphasis on the research activities related to carbon nanotube(CNT)reinforced polymer composites recently.This paper presents the composite cylinder assemblage(CCA)approach based on continuum mechanics for investigating the elastic properties of a polymer resin reinforced by multi-walled carbon nanotubes(MWCNTs).A three-phase cylindrical representative volume element(RVE)model is employed based on CCA technique to elucidate the effects of inter layers,chirality,interspacing,volume fraction of MWCNT,interphase properties and temperature conditions on the elastic modulus of the composite.The interface region between CNT and polymer matrix is modeled as the third phase with varying material properties.The constitutive relations for each material system have been derived based on solid mechanics and proper interfacial traction continuity conditions are imposed.The predicted results from the CCA approach are in well agreement with RVE-based finite element model.The outcomes reveal that temperature softening effect becomes more pronounced at higher volume fractions of CNTs.

COADJOINT ORBITS FOR THE CENTRAL EXTENSION OF Diff^+(S^1) AND THEIR REPRESENTATIVES

According to Kirillov's idea, the irreducible unitary representations of a Lie group G roughly correspond to the coadjoint orbits (?).In the forward direction one applies the methods of geometric quantization to produce a representation, and in the reverse direction one computes a transform of the character of a representation, to obtain a coadjoint orbit. The method of orbits in the representations of Lie groups suggests the detailed study of coadjoint orbits of a Lie group G in the space (?)~* dual to the Lie algebra (?) of G. In this paper, two primary goals are achieved: one is to completely classify the smooth coadjoint orbits of Virasoro group for nonzero central charge c; the other is to find representatives for coadjoint orbits. These questions have been considered previously by Segal, Kirillov, and Witten, but their results are not quite complete. To accomplish this, the authors start by describing the coadjoint action of D-the Lie group of all orientation preserving diffeomorphisms on the circle S^1, and its central extension (?), then the authors will give a complete classification of smooth coadjoint orbits. In fact, they can be parameterized by a subspace Of conjugacy classes of (?)(1,1). Finally, the authors will show how to find representatives f coadjoint orbits by analyzing the vector fields stabilizing the orbits, and describe the amazing connection between the characteristic (trace) of conjugacy classes of (?)(1, 1) and that of vector fields stabilizing orbits.

District Partisan Homogeneity, Communications, and the Electoral Motive: An Analysis of the Facebook Posts of Members of the U.S. House of Representatives

The research examines the way in which members of the U.S. House of Representative represent themselves on the social network site Facebook. Each member’s activity is observed on seven different occasions and the frequency and substantive character of posts made during the second half of 2013 are established. The focus is on position-taking posts versus posts which mention the district the member serves in. Our expectation is that members from electorally safe districts will be more likely to advertise their policy positions while members from marginal districts will be more inclined to advertise their district connections. We control for minority party status, gender, and ideological extremism among other concerns and learn electoral safety is a good predictor of both “position-taking” and “district mentions”. Consistent with an electoral motive, we also find members from the minority party less likely to take positions on the issues of the day and more likely to mention the district they serve in.

The Three Cs:China,Culture and Civilization

Steeped in a civilization featuring inclusivity and peaceful nature,China seeks exchanges and mutual learning among civilizations rather than cultural hegemony.WHILE claiming its preeminent global economic status,China has also come to assert its equivalent position in world politics and diplomacy,typically representing the interests of the developing world.

North American Association Put Manufacturers and Representatives Together

For more than half a centurymanufacturers in search of independentrepresentatives to sell their products innew markets and to establishrelationships with prospective customershave relied upon the services of theManufacturers’ Agents NationalAssociation (MANA).

Editorial for the Special Issue on Natural Medicine

As the world continues to search for innovative therapeutic solutions,the field of natural medicines has emerged as a vibrant area of research.The potential of natural products to treat a wide range of diseases,coupled with the relatively low sideeffects of such products,has captured the attention of scientists,clinicians,and the general public alike.This Special Issue on Natural Medicine aims to present the latest advancements in this exciting field,highlighting both fundamental research and clinical applications.The collection of articles in this Special Issue covers a broad spectrum of topics,ranging from medicinal chemistry to biological mechanisms,and from the study of single botanic compounds to complex plant formulas.We are particularly pleased to include a comprehensive review by Yi Wang et al.on the bioactivities,mechanisms,production,and potential application of bile acids in preventing and treating infectious diseases.This review not only summarizes the current landscape of bile acids research but also highlights several promising compounds for future investigations,such as the recent interest in ursodeoxycholic acid.In a related topic,Shishan Yu’s team has developed artificial bear bile using synthetic chemistry and enzyme engineering,providing a sustainable substitute for natural bear bile.This innovation meets medical needs while addressing animal welfare issues,representing a notable progression in the field.

Speech by Mr.Lawrence Fortun,Congressman of the Philippine House of Representatives

Greetings…Allow me to begin by extending,on behalf of the Philippine delegation,our heartfelt gratitude to the Chinese Association for International Understanding(CAFIU)for this excellent opportunity for greater understanding of China and its relations to the Philippines,the ASEAN and the rest of the world.This exchange has likewise been an important occasion for us to share our insights on these relations in the light of our common interests and aspirations

From Major-Countries Coordination to Global Mechanisms:an Analysis of the Global Governance of Large AI Models

The global governance of large artificial intelligence(AI)models calls for urgent actions.Large models,representing a type of technological innovation,is advancing global technological progress and is also compelling the international community’s attention to the role of global governance system in coordinating the development of AI.In building a global governance mechanism for large models,both traditional governance system and new international system should be explored to construct Regime Complexes for the governance of large models.

Assessing the impact of climate change on agricultural production in central Afghanistan

Afghanistan has faced extreme climatic crises such as drought,rising temperature,and scarce precipitation,and these crises will likely worsen in the future.Reduction in crop yield can affect food security in Afghanistan,where the majority of population and economy are completely dependent on agriculture.This study assessed the interaction between climate change and crop yield in Kabul of Afghanistan during the reference(1990–2020)and future(2025–2100)periods.Climate data(1990–2020)were collected from four meteorological stations and three local organizations,and wheat yield data(1990–2020)were acquired from the United States Agriculture Department.Data during the reference period(1990–2020)were used for the validation and calibration of the statistical downscaling models such as the Statistical Downscaling Model(SDSM)and Long Ashton Research Station Weather Generator(LARS-WG).Furthermore,the auto-regression model was used for trend analysis.The results showed that an increase in the average annual temperature of 2.15℃,2.89℃,and 4.13℃will lead to a reduction in the wheat yield of 9.14%,10.20%,and 12.00%under Representative Concentration Pathway(RCP)2.6,RCP4.5,and RCP8.5 during the future period(2025–2100),respectively.Moreover,an increase in the annual maximum temperature of 1.79℃,2.48℃,and 3.74℃also causes a significant reduction in the wheat yield of 2.60%,3.60%,and 10.50%under RCP2.6,RCP4.5,and RCP8.5,respectively.Furthermore,an increase in the annual minimum temperature of 2.98℃,2.23℃,and 4.30℃can result in an increase in the wheat yield of 6.50%,4.80%,and 9.30%under RCP2.6,RCP4.5,and RCP8.5,respectively.According to the SDSM,the decrease of the average monthly precipitation of 4.34%,4.10%,and 5.13%results in a decrease in the wheat yield of 2.60%,2.36%,and 3.18%under RCP2.6,RCP4.5,and RCP8.5,respectively.This study suggests that adaptation strategies can be applied to minimize the consequences of climate change on agricultural production.

Data-driven methods for predicting the representative temperature of bridge cable based on limited measured data

Cable-stayed bridges have been widely used in high-speed railway infrastructure.The accurate determination of cable’s representative temperatures is vital during the intricate processes of design,construction,and maintenance of cable-stayed bridges.However,the representative temperatures of stayed cables are not specified in the existing design codes.To address this issue,this study investigates the distribution of the cable temperature and determinates its representative temperature.First,an experimental investigation,spanning over a period of one year,was carried out near the bridge site to obtain the temperature data.According to the statistical analysis of the measured data,it reveals that the temperature distribution is generally uniform along the cable cross-section without significant temperature gradient.Then,based on the limited data,the Monte Carlo,the gradient boosted regression trees(GBRT),and univariate linear regression(ULR)methods are employed to predict the cable’s representative temperature throughout the service life.These methods effectively overcome the limitations of insufficient monitoring data and accurately predict the representative temperature of the cables.However,each method has its own advantages and limitations in terms of applicability and accuracy.A comprehensive evaluation of the performance of these methods is conducted,and practical recommendations are provided for their application.The proposed methods and representative temperatures provide a good basis for the operation and maintenance of in-service long-span cable-stayed bridges.

Three working groups on commercial aerospace established

In order to implement the spirits of the Central Economic Work Conference and systematically promote the standardization work of commercial aerospace,SAC/TC 425,Space technology and operation,recently established three working groups for emerging fields and strategic emerging industries related to commercial aerospace.The work scope of WG 1 on commercial aircraft launching covers the standards research,development and revision for operation support,process,industrial chains,and other fields of launching.It is also responsible for the updating of standards documents published by correspondent international standardization organizations for further analysis and adoption.WG 2 on the application of satellite internet is responsible for the research,development and revision of standards in areas such as the application scenarios and demands,functions and process,interfaces and data forms of satellite internet.Its first batch of members consists of 29 service providers,operators,equipment manufacturers,and parties representing public interests in this field.

Fast mapping of a chlorophyll b synthesis-deficiency gene in barley(Hordeum vulgare L.) via bulked-segregant analysis with reduced-representation sequencing

Bulked-segregant analysis coupled with next-generation sequencing(BSA-seq) has emerged as an efficient tool for genetic mapping of single genes or major quantitative trait loci controlling(agronomic) traits of interest. However, such a mapping-by-sequencing approach usually relies on deep sequencing and advanced statistical methods. Application of BSA-Seq based on construction of reduced-representation libraries and allele frequency analysis permitted anchoring the barley pale-green(pg) gene on chromosome 3 HL. With further marker-assisted validation, pg was mapped to a 3.9 Mb physical-map interval. In the pg mutant a complete deletion of chlorophyllide a oxygenase(HvCAO) gene was identified.Because the product of this gene converts Chl a to Chl b, the pg mutant is deficient in Chl b.An independent Chl b-less mutant line M4437_2 carried a nonsynonymous substitution(F263 L) in the C domain of HvCAO. The study demonstrates an optimized pooling strategy for fast mapping of agronomically important genes using a segregating population.

THEORETICAL PREDICTION OF TOOL-CHIP CONTACT LENGTH IN ORTHOGONAL METAL MACHINING BY COMPUTER SIMULATION

A method for determination of tool-chip contact length is theoreticallypresented in orthogonal metal machining. By using computer simulation and based on the analyses ofthe elastro-plastic deformation with lagrangian finite element method in the deformation zone, theaccumulated representative length of the low layer, the tool-chip contact length of the chipcontacting the tool rake are calculated, experimental studies are also carried out with 0.2 percentcarbon steel. It is shown that the tool-chip contact lengths obtained from computer simulation havea good agreement with those of measured values.

Determination of Trace Elements in Edible Nuts in the Beijing Market by ICP-MS

Nuts have received increased attention from the public in recent years as important sources of some essential elements, and information on the levels of elements in edible nuts is useful to consumers. Determination of the elemental distributions in nuts is not only necessary in evaluating the total dietary intake of the essential elements, but also useful in detecting heavy metal contamination in food. The aim of this study was to determine the mineral contents in edible nuts, and to assess the food safety of nuts in the Beijing market. Levels of Li, Cr, Mn, Co, Cu, Zn, As, Se, Rb, Sr, Mo, Cd, Cs, Ba, Pb, Th, and U in 11 types of edible nuts and seeds （macadamia nuts, lotus nuts, pistachios, sunflower seeds, pine nuts, almonds, walnuts, chestnuts, hazelnuts, cashews, and ginkgo nuts） as well as raisins were determined by inductively coupled plasma mass spectrometry （ICP-MS）. The accuracy of the method was validated using standard reference materials GBWlO014 （cabbage） and GBWlO016 （tea）. Our results provide useful information for evaluating the levels of trace elements in edible nuts in the Beijing market, will be helpful for improving food safety, and will aid in better protecting consumer interests.

A local homogenization approach for simulating the reinforcement effect of the fully grouted bolt in deep underground openings

Fully grouted bolts are a key component of the support system for underground openings.Although considerable effort has been made in the simulation of the reinforcement effect of the fully grouted bolts on the rock masses surrounding underground openings,most of the work has limited significance since the structural element approach is used.This study proposes a local homogenization approach(L-H approach)that integrates elastoplastic mechanics,composite mechanics,and analytical approaches with numerical simulation to effectively simulate the reinforcement effect of the fully grouted bolt on deep surrounding rock masses.In the L-H approach,the representative volume of bolted rock mass(RVBRM)with a fully grouted bolt is established based on the original mesh model utilized in the rockbolt element approach.The RVBRM is a regular quadrangular prism with a cross-sectional size equal to the bolt spacing and a length equal to the bolt length.The RVBRM is homogenized by the L-H approach from a unidirectional bolt-reinforced composite into a homogeneous transversely isotropic medium whose mechanical properties are described by a new transversely isotropic elastoplastic model.The L-H parameters for the RVBRM are obtained using analytical approaches,composite mechanics,and known parameters of the rock mass and bolt.Using the L-H approach,the reinforcement effect of the fully grouted bolt on the bolted rock specimen and the surrounding rock mass in Jinping II Diversion Tunnel#2 with a depth greater than 2000 m is simulated.The results show that the predictions of the L-H approach are more in agreement with the physical model results of bolted rock specimen and provide a more realistic response of the bolted surrounding rock mass.The L-H approach demonstrates that fully grouted bolts with common bolt spacings and diameters substantially enhance the elastic modulus,shear strength,and tensile strength of the rock mass in the direction of the bolt axis.

Projection of the Zhujiang(Pearl) River Delta's potential submerged area due to sea level rise during the 21st century based on CMIP5 simulations

Projections of potential submerged area due to sea level rise are helpful for improving understanding of the influence of ongoing global warming on coastal areas. The Ensemble Empirical Mode Decomposition method is used to adaptively decompose the sea level time series in order to extract the secular trend component. Then the linear relationship between the global mean sea level （GMSL） change and the Zhujiang （Pearl） River Delta （PRD） sea level change is calculated： an increase of 1.0 m in the GMSL corresponds to a 1.3 m （uncertainty interval from 1.25 to 1.46 m） increase in the PRD. Based on this relationship and the GMSL rise projected by the Coupled Model Intercomparison Project Phase 5 under three greenhouse gas emission scenarios （representative concentration pathways, or RCPs, from low to high emission scenarios RCP2.6, RCP4.5, and RCP8.5）, the PRD sea level is calculated and projected for the period 2006-2100. By around the year 2050, the PRD sea level will rise 0.29 （0.21 to 0.40） m under RCP2.6, 0.31 （0.22 to 0.42） m under RCP4.5, and 0.34 （0.25 to 0.46） m under RCP8.5, respectively. By 2100, it will rise 0.59 （0.36 to 0.88） m, 0.71 （0.47 to 1.02） m, and 1.0 （0.68 to 1.41） m, respectively. In addition, considering the extreme value of relative sea level due to land subsidence （i.e., 0.20 m） and that obtained from intermonthly variability （i.e., 0.33 m）, the PRD sea level will rise 1.94 m by the year 2100 under the RCP8.5 scenario with the upper uncertainty level （i.e., 1.41 m）. Accordingly, the potential submerged area is 8.57x103 km2 for the PRD, about 1.3 times its present area.

Micromechanical Analysis of Thermal Expansion Coefficients

Thermal expansion coefficients play an important role in the design and analysis of composite structures. A detailed analysis of thermo-mechanical distortion can be performed on microscopic level of a structure. However, for a design and analysis of large structures, the knowledge of effective material properties is essential. Thus, either a theoretical prediction or a numerical estimation of the effective properties is indispensable. In some simple cases, exact analytical solutions for the effective properties can be derived. Moreover, bounds on the effective values exist. However, in dealing with complex heterogeneous composites, numerical methods are becoming increasingly important and more widely used, because of the limiting applicability of the existing (semi-)analytical approaches. In this study, finite-element methods for the calculation of effective thermal expansion coefficients of composites with arbitrary geometrical inclusion configurations are discussed and applied to a heterogeneous lightning protection coating made from Dexmet&#174 copper foil 3CU7-100FA and HexPly&#174 epoxy resin M21. A short overview of some often used (semi-)analytical formulas for effective thermal expansion coefficients of heterogeneous composites is given in addition.

First record of disk-footed bat Eudiscopus denticulus(Chiroptera,Vespertilionidae)from China and resolution of phylogenetic position of the genus

DEAR EDITOR,The disk-footed bat Eudiscopus denticulus(Osgood,1932)is a rare species in Southeast Asia.During two chiropteran surveys in the summer of 1981 and 2019,eight and three small Myotis-like bats with distinct disk-like hindfeet were collected from Yunnan Province,China,respectively.External,craniodental,and phylogenetic evidence confirmed these specimens as E.denticulus,representing a new genus in China.The complete mitochondrial genome consistently showed robust support for E.denticulus as a basal lineage within Myotinae.The coding patterns and characteristics of its mitochondrial genome were similar to that of other published genomes from Myotis.The echolocation signals of the newly collected individuals were analyzed.The potential distribution range of Eudiscopus in Southeast Asia inferred using the MaxEnt model indicated its potential occurrence along the southern border region of Yunnan,China.