The demand for high-energy-density sodium-ion batteries has driven research to increase the hard carbon(HC)plateau capacity(<0.1 V),but the plateau capacity-rate capability trade-off limits performance.We report a ...The demand for high-energy-density sodium-ion batteries has driven research to increase the hard carbon(HC)plateau capacity(<0.1 V),but the plateau capacity-rate capability trade-off limits performance.We report a way to regulate the closed pore structure and improve the rate capability of HC by the addition of graphene oxide using an emulsification process.In a non-emulsion system,graphene oxide not only shortens ion diffusion paths by inducing the formation of flakelike HC but also significantly improves the rate performance by serving as conductive bridges within the carbon matrix.The prepared graphene/phenolic resin carbon composite has reversible capacities of 362,340,319,274,119,86,69 and 48 mAh g^(−1)at current densities of 0.02,0.05,0.1,0.2,0.5,1,2 and 5 A g^(−1),respectively.When emulsification is introduced,the graphene oxide acts as a nano-confinement template,guiding the cross-linking of phenolic resin to form uniformly sized closed pores.This composite electrode material has the highest plateau capacity of 268 mAh g^(−1)at 20 mA g^(−1).展开更多
Pitch is an excellent precursor for the production of hard carbon,with pre-oxidation crucial process in the fabrication.The structural changes in the different molecular components of pitch during thermochemical treat...Pitch is an excellent precursor for the production of hard carbon,with pre-oxidation crucial process in the fabrication.The structural changes in the different molecular components of pitch during thermochemical treatment are a key factor in determining the sodium-ion storage of pitchbased hard carbon anodes.We investigated the effects of the different molecular structures in the asphaltene precursor,including aromatic rings and aliphatic chains,on the sodiumion storage behavior of the resulting carbon.We found that polar oxygen functional groups limit the steric hindrance caused by the aromatic rings in pitch,and thus facilitate the introduction of cross-linked structures.During high-temperature carbonization,aromatic rings form a rigid carbon framework that prevents the rearrangement of ordered carbon layers,leading to a short-range disordered carbon structure and promotes the production of closed pores.For example,a material prepared from asphaltene,which contains a large number of oxygen-containing functional groups and macromolecular aromatic rings,using pre-oxidation at 300℃ and carbonization at 1200℃ had a reversible capacity of 316.7 mAh g^(−1) when used as the anode for sodium ion batteries.Our research provides a theoretical basis for the selection of raw materials for the development of high-quality pitch-based hard carbons.展开更多
To address the challenges of rapid bit failure and high drilling costs associated with hard limestone in Sichuan Basin of China,we conducted rock-breaking experiments and simulations of shaped(cylindrical,ridge,and ch...To address the challenges of rapid bit failure and high drilling costs associated with hard limestone in Sichuan Basin of China,we conducted rock-breaking experiments and simulations of shaped(cylindrical,ridge,and chopper)cutters.Rock mechanics,drillability,and acoustic emission indentation tests revealed the drilling resistance characteristics of the limestone:average uniaxial compressive strength of 202.472 MPa,tensile strength of 7.092 MPa,and drillability of 7.866.We evaluated the performance differences between the shaped cutters before introducing an efficient and innovative finite-discrete-infinite element method(FDIEM)to establish an interaction model between the shaped cutters and limestone.The simulation results indicated the following:(1)The shaped cutters demonstrated superior rock-breaking performance compared to the traditional cylindrical cutter.(2)Compared with the cylindrical cutter,the ridge cutter yielded the lowest peak indentation force and mechanical specific energy,with reductions of 8.71%and 33.83%,respectively.This confirmed that the ridge cutter had the optimal tooth profile for the target formation.Its rock-breaking mechanism relied on the convex edges to induce localized high stress in the rock,which enabled efficient rock fragmentation via a plowing mode while mitigating frictional resistance from cuttings.(3)The novel chopper cutter with its secondary step surface exerted a buffering effect on the cuttings,thereby achieving high cutting stability.This study provides theoretical and technical support for the design of personalized drill bits and the acceleration of the rate of penetration(ROP)in deep hard rock formations.展开更多
This work presents a systematic analysis of proton-induced total ionizing dose(TID)effects in 1.2 k V silicon carbide(SiC)power devices with various edge termination structures.Three edge terminations including ring-a...This work presents a systematic analysis of proton-induced total ionizing dose(TID)effects in 1.2 k V silicon carbide(SiC)power devices with various edge termination structures.Three edge terminations including ring-assisted junction termination extension(RA-JTE),multiple floating zone JTE(MFZ-JTE),and field limiting rings(FLR)were fabricated and irradiated with45 Me V protons at fluences ranging from 1×10^(12) to 1×10^(14) cm^(-2).Experimental results,supported by TCAD simulations,show that the RA-JTE structure maintained stable breakdown performance with less than 1%variation due to its effective electric field redistribution by multiple P+rings.In contrast,MFZ-JTE and FLR exhibit breakdown voltage shifts of 6.1%and 15.2%,respectively,under the highest fluence.These results demonstrate the superior radiation tolerance of the RA-JTE structure under TID conditions and provide practical design guidance for radiation-hardened Si C power devices in space and other highradiation environments.展开更多
Coal-derived hard carbon(HC)represents a promising anode material for sodium-ion batteries owing to its cost-effectiveness and high carbon yield.However,conventional carbonization induces excessive graphitization,yiel...Coal-derived hard carbon(HC)represents a promising anode material for sodium-ion batteries owing to its cost-effectiveness and high carbon yield.However,conventional carbonization induces excessive graphitization,yielding insufficient interlayer spacing(d_(002)<0.37 nm)and underdeveloped closed pores.Herein,we propose a dynamic crystallization control strategy through carbothermal shock treatment(1300°C,30 s)that decouples thermodynamic and kinetic constraints.This method precisely modulates graphite domain ordering kinetics,producing short-range ordered structures with expanded interlayer spacing(d_(002)=0.385 nm)and homogeneously distributed closed nanopores.Through combined in situ characterization and first-principles calculations,we elucidate a three-stage crystallization mechanism:(i)amorphous carbon transformation,(ii)open-pore collapse,and(iii)pseudo-graphitic ordering.The optimized HC achieves record performance with 88.6%initial Coulombic efficiency and 204 mA h g^(−1)plateau capacity,while its optimal interlayer spacing lowers Na+diffusion barriers to enable exceptional rate capability(221 mA h g^(−1)at 0.5C after 300 cycles).Practical pouch cells maintain 85%capacity retention after 100 cycles at−20°C and deliver 284 Wh kg^(−1)energy density.This work establishes a kinetic regulation paradigm for graphitization-prone precursors,advancing the rational design of high-performance HC anodes.展开更多
Hard carbon(HC)remains a leading anode candidate for sodium-ion storage,yet its application is hindered by low initial Coulombic efficiency(ICE)and limited plateau capacity due to uncontrolled defect density and open ...Hard carbon(HC)remains a leading anode candidate for sodium-ion storage,yet its application is hindered by low initial Coulombic efficiency(ICE)and limited plateau capacity due to uncontrolled defect density and open porosity.Here,we propose a scalable dual-regulation strategy that simultaneously tunes pore mouth size and defect chemistry to enhance sodium storage performance.Using phenol-formaldehyde resin as the carbon precursor and phosphorus pentoxide(P_(2)O_(5))as a bifunctional sacrificial template and dopant source,we synthesize phosphorus-functionalized hard carbon(PF-PHC)featuring a high density of closed pores with well-confined sub-nanometer pore entrances.The in-situ sublimation of P_(2)O_(5) during pyrolysis promotes the formation of closed-pore architectures,while residual phosphorus atoms effectively passivate vacancy-type defects,thereby reducing irreversible Na+adsorption and mitigating excessive solid electrolyte interphase(SEI)formation.As a result,PF-PHC achieves an ICE of 89.3%and a plateau capacity of 289 mAh g^(−1).In-situ characterizations reveal that regulating pore mouth dimensions decouples Na+and solvent access,enabling highly selective ion transport and stable interfacial chemistry.Sodium-ion hybrid capacitors(SIHCs)assembled based on PF-PHC deliver exceptional rate performance and outstanding long-term cycling stability,retaining 98.2%after 10,000 cycles at 2 A g^(−1).This study establishes pore mouth engineering as a robust and scalable design principle for advancing next-generation HC-based sodium storage materials.展开更多
There are limitations to using hard carbon(HC)in K^(+)storage due to its insufficient high-current reversible capacity and plateau potential,which result from the lack of effective active sites and low intercalation c...There are limitations to using hard carbon(HC)in K^(+)storage due to its insufficient high-current reversible capacity and plateau potential,which result from the lack of effective active sites and low intercalation capabilities.The construction of HC cathodes with more available functional groups and ordered carbon nanocrystal structures is essential for improving K^(+)storage efficiency.Herein,a new perspective is proposed for synthesizing hard carbon nanosheets(HCNS)with abundant hydroxyl groups(O-H)/carboxylic groups(O-C=O)and rational carbon nanocrystals by interfacial assembly and carbonization.Systematic in ex-situ observations,dynamic analysis and theory calculations elucidate that the superior electrochemical capability of HCNS is ascribed to the synergistic effect of abundant available functional groups and ordered graphitic microcrystalline.Consequently,the HCNS exhibits outstanding K^(+)storage capabilities in terms of superb energy density(146.2 Wh/kg),high power density(1,7800 Wh/kg),and ultralong lifespan(102.9%capacity retention after 10,000 cycles).It was also found that the HC structure correlates with the discharge/charge plateau,confirming the'adsorption-insertion'charge storage mechanism.Furthermore,the proposed work provides a theoretical basis for making high-performance HC anodes by understanding the effect of their microstructure on K^(+)storage.展开更多
Hard carbon is a vital anode material for sodium-ion batteries;however,the nonuniform growth of solid electrolyte interphase(SEI)film substantially diminishes its initial coulombic efficiency(ICE)and cycle life.The ch...Hard carbon is a vital anode material for sodium-ion batteries;however,the nonuniform growth of solid electrolyte interphase(SEI)film substantially diminishes its initial coulombic efficiency(ICE)and cycle life.The chemical and morphological properties of surface highly influence the electrode/electrolyte interfacial reactions.In this study,we have tuned orbital hybridization states forming an interface enriched with sp^(2) hybridized carbon(sp^(2)-C),which decreases the binding energy to solvent molecules and inhibits excessive solvent decomposition during SEI formation.Benefiting from successfully constructed inorganic-rich SEI,the ICE increased to 91%and sodium storage capacity reached 346 mAh/g.Besides,the capacity retention rate was 90.7%after 700 cycles at 1 A/g higher than pristine electrode(83.8%).展开更多
[目的]探讨Mako机器人辅助经改良Harding入路全髋关节置换术(total hip arthroplasty,THA)的治疗效果及安全性。[方法]回顾性分析本院2021年4月—2023年5月行THA的48例患者的资料。根据手术前医患沟通结果,24例采用Mako机器人辅助下THA...[目的]探讨Mako机器人辅助经改良Harding入路全髋关节置换术(total hip arthroplasty,THA)的治疗效果及安全性。[方法]回顾性分析本院2021年4月—2023年5月行THA的48例患者的资料。根据手术前医患沟通结果,24例采用Mako机器人辅助下THA(机器人组),另外24例采用经改良Harding入路常规徒手THA(徒手组)。比较两组患者围手术期、随访结果及影像评估资料。[结果]两组患者均顺利完成改良Harding入路THA,机器人组的手术时间[min,(102.6±15.7)vs(83.7±16.8),P<0.001]和术中出血量[mL,(279.7±35.1)vs(212.5±29.6),P<0.001]均显著大于徒手组,两组患者术后引流量、住院天数的差异无统计学意义(P>0.05)。术后平均随访(20.8±8.5)个月。随时间推移,两组患者VAS评分、Harris评分、最大伸髋和最大屈髋活动度(range of motion,ROM)、最大内收和最大外展ROM均显著改善(P<0.05)。术后1周机器人组的VAS评分[分,M(P25,P75),2.0(2.0,4.0)vs 3.5(3.0,5.0),P<0.001]、最大屈髋[°,(74.5±9.0)vs(66.5±10.4),P=0.006]、最大内收[°,(18.5±6.2)vs(7.0±1.6),P<0.001]显著优于徒手组;术后1周和术后3个月机器人组的Harris评分[分,(75.1±4.9)vs(68.3±5.1),P<0.001;(84.8±4.9)vs(78.3±4.5),P<0.001]、最大伸髋[°,(20.5±5.3)vs(12.5±5.6),P<0.001;(31.0±3.6)vs(24.1±4.5),P<0.001]、最大外展[°,(26.2±3.3)vs(21.5±4.8),P<0.001;(33.4±3.8)vs(27.8±4.3),P<0.001]显著优于徒手组,但是,末次随访时两组间上述指标的差异均已无统计学意义(P>0.05)。影像方面,机器人组的术后双下肢长度差异(leg length discrepancy,LLD)[mm,(4.9±1.0)vs(8.1±1.4),P<0.001]和双侧联合偏心距(combined offset,CO)差值(■CO)的绝对值[mm,(1.5±0.5)vs(3.5±0.6),P<0.001]、髋臼假体外展角[°,(40.3±1.7)vs(45.3±4.1),P<0.001]和前倾角[°,(15.9±1.2)vs(18.8±3.6),P<0.001]均显著小于徒手组。[结论]与常规徒手THA相比,Mako机器人辅助下改良Harding入路THA假体置放更精准,早期治疗效果更优,但机器人技术的手术时间较长且术中失血量更大。展开更多
This study introduces a test system for microwave-induced fracturing of hard rocks under true triaxial stress.The test system comprises a true triaxial stress loading system,an open-ended microwaveinduced fracturing s...This study introduces a test system for microwave-induced fracturing of hard rocks under true triaxial stress.The test system comprises a true triaxial stress loading system,an open-ended microwaveinduced fracturing system,a data acquisition system,an acoustic emission(AE)monitoring system,and an auxiliary specimen loading system.Microwave-induced surface and borehole fracturing tests under true triaxial stress were fulfilled for the first time,which overcomes the problem of microwave leakage in the coupling loading of true triaxial stress and microwave.By developing the dynamic monitoring system,the thermal response and fracture evolution were obtained during microwave irradiation.The monitoring system includes the infrared thermometry technique for monitoring rock surface temperature,the distributed optic fiber sensing technique for monitoring temperature in borehole in rock,the AE technique and two-dimensional digital speckle correlation technique for monitoring the evolution of thermal damage and the rock fracturing process.To validate the advantages of the test system and investigate the characteristics of microwave-induced fracturing of hard rocks,the study demonstrates the experimental methods and results for microwave-induced surface and borehole fracturing under true triaxial stress.The results show that thermal cracking presented intermittent characteristics(calm eactiveecalm)during microwave-induced surface and borehole fracturing of basalt.In addition,true triaxial stress can inhibit the development and distribution of thermal cracks during microwave-induced surface fracturing.When microwave-induced borehole fracturing occurs,it promotes the distribution of thermal cracks in rock,but inhibits the width of cracks.The results also prove the reliability of the test system.展开更多
Pseudobinary Ti 1 x Al x N films were synthesized on Si (100) wafer by DC magnetron sputtering method using Ti 1 x Al x alloy targets with different Al contents. The composition of the Ti 1 x Al x N films was determin...Pseudobinary Ti 1 x Al x N films were synthesized on Si (100) wafer by DC magnetron sputtering method using Ti 1 x Al x alloy targets with different Al contents. The composition of the Ti 1 x Al x N films was determined by electron probe microanalysis (EPMA). Structural characteristic was performed by X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution TEM (HRTEM). First principles virtual crystal calculations for the Ti 1 x Al x N disordered alloys were used for the XRD simulations. The crystalline structure of the Ti 0.61 Al 0.39 N film was found to be a metastable single phase with NaCl (B1) structure. Its lattice constant, determined by XRD, was less than that of pure TiN. With the increase of Al content, the lattice constant of B1 phase was continually decreased, while würtzite (B4) structure was observed in the Ti 0.40 Al 0.60 N film. When x reached 0.75, the B1 phase disappeared, and only B4 phase was remained. The critical Al content for the phase transition from NaCl to würtzite structure in this paper was about 0.60, which could be explained by both the thermodynamic model and the electron theory. As-deposited Ti 1 x Al x N films exhibited excellent mechanical properties. Hardness measurements of Ti 1 x Al x N films showed a high value of 45GPa for x=0.39 and was decreased to value of 27 GPa with increasing Al at x=0.60.展开更多
A multichannel low-noise electronic prototype system was designed for a pixelated CdZnTe detector. This system is the result of preliminary work on a solar hard X-ray imager, which is one of the three payloads for fut...A multichannel low-noise electronic prototype system was designed for a pixelated CdZnTe detector. This system is the result of preliminary work on a solar hard X-ray imager, which is one of the three payloads for future solar observations satellite-Advanced Space-based Solar Observatory(ASO-S). A new charge-sensitive amplifier application-specific integrated circuit, VATA450.3, with an on-chip analog-to-digital converter, is used to read out 8×8 anode pixel signals. Two CdZnTe detectors with a thickness of 2 mm and 5 mm were tested. The 2-mm-thick detector achieved energy resolution better than 5%(fullwidth at half-maximum, FWHM) at 59.5 keV, and the 5-mm-thick detector had better resolution than 1.2%(FWHM) at 662 keV. The design and test results of the prototype system are discussed in this paper.展开更多
In the present paper,the hardness and Young's modulus of film-substrate systems are determined by means of nanoindentation experiments and modified models.Aluminum film and two kinds of substrates,i.e.glass and si...In the present paper,the hardness and Young's modulus of film-substrate systems are determined by means of nanoindentation experiments and modified models.Aluminum film and two kinds of substrates,i.e.glass and silicon,are studied.Nanoindentation XP Ⅱ and continuous stiffness mode are used during the experiments.In order to avoid the influence of the Oliver and Pharr method used in the experiments,the experiment data are analyzed with the constant Young's modulus assumption and the equal hardness assumption.The volume fraction model(CZ model)proposed by Fabes et al.(1992)is used and modified to analyze the measured hardness.The method proposed by Doerner and Nix(DN formula)(1986)is modified to analyze the measured Young's modulus.Two kinds of modified empirical formula are used to predict the present experiment results and those in the literature,which include the results of two kinds of systems,i.e.,a soft film on a hard substrate and a hard film on a soft substrate.In the modified CZ model,the indentation influence angle,(?), is considered as a relevant physical parameter,which embodies the effects of the indenter tip radius, pile-up or sink-in phenomena and deformation of film and substrate.展开更多
With the wide application of coating materials in aerospace and other fields, their safety under fatigue conditions in service is important.However, research on the fatigue properties of ceramic hard coatings started ...With the wide application of coating materials in aerospace and other fields, their safety under fatigue conditions in service is important.However, research on the fatigue properties of ceramic hard coatings started late, and a unified standard is yet to be established to evaluate the fatigue life of hard coating–ductile substrate systems.Studies also present different opinions on whether coatings can improve or reduce the fatigue life of substrates.In this paper, the influence of the properties of ceramic coatings on fatigue performance is reviewed, and the effects of coating on the mechanism of fatigue crack initiation in substrates are discussed, aiming to help readers understand the fatigue behavior of hard coating–ductile substrate systems.展开更多
Microwave pre-treatment is considered as a promising technique for alleviating cutter wear. This paper introduces a high-power microwave-induced fracturing system for hard rock. The test system consists of a high-powe...Microwave pre-treatment is considered as a promising technique for alleviating cutter wear. This paper introduces a high-power microwave-induced fracturing system for hard rock. The test system consists of a high-power microwave subsystem (100 kW), a true triaxial testing machine, a dynamic monitoring subsystem, and an electromagnetic shielding subsystem. It can realize rapid microwave-induced fracturing, intelligent tuning of impedance, dynamic feedback under strong microwave fields, and active control of microwave parameters by addressing the following issues: the instability and insecurity of the system, the discharge breakdown between coaxial lines during high-power microwave output, and a lack of feedback of rock-microwave response. In this study, microwave-induced surface and borehole fracturing tests under true triaxial stress were carried out. Experimental comparisons imply that high-power microwave irradiation can reduce the fracturing time of hard rock and that the fracture range (160 mm) of a 915-MHz microwave source is about three times that of 2.45 GHz. After microwave-induced borehole fracturing, many tensile cracks occur on the rock surface and in the borehole: the maximum reduction of the P-wave velocity is 12.8%. The test results show that a high-power microwave source of 915 MHz is more conducive to assisting mechanical rock breaking and destressing. The system can promote the development of microwave-assisted rock breaking equipment.展开更多
The microstructures and Vickers hardness at room temperature of arc-meltingprocessed intermetallics of Mo_5Si_3-MoSi_2 hypoeutectic alloy and hypereutectic alloy annealed at1200℃ for different time were investigated....The microstructures and Vickers hardness at room temperature of arc-meltingprocessed intermetallics of Mo_5Si_3-MoSi_2 hypoeutectic alloy and hypereutectic alloy annealed at1200℃ for different time were investigated. Lamellar structure consisted of Mo_5Si_3 (D8m) phaseand MoSi_2 (C11_b) phase was observed in all the alloys. For Mo_5Si_3-MoSi_2 hypoeutectic alloy, thelamellar structure was found only after annealing and developed well with fine spacing on the orderof hundred nanometers after annealing at 1200℃ for 48 h. But when the annealing time was up to 96h, the well-developed lamellar structure was destroyed. For Mo_5Si_3-MoSi_2 hypereutectic alloy, thelamellar structure was found both before and after annealing. However the volume fraction andspacing of the lamellar structure did not change significantly before and after annealing. Theeffects of the formation, development and destruction of lamellar structure on Vickers hardness ofalloys were also investigated. When Mo_5Si_3-MoSi_2 hypoeutectic alloy annealed at 1200℃ for 48 h,the Vickers hardness was improved about 19% compared with that without annealing and formation oflamellar structure. The highest Vickers hardness of Mo5Si3-MoSi_2 hypereutectic was increasing about18% when annealing at 1200℃ for 48 h.展开更多
Mapping of hard rock aquifer system and artificial recharge zonation were carried out in an area of 325 km^2 in parts of the Perambalur District,Tamil Nadu,India.This district has been declared as one of the over-expl...Mapping of hard rock aquifer system and artificial recharge zonation were carried out in an area of 325 km^2 in parts of the Perambalur District,Tamil Nadu,India.This district has been declared as one of the over-exploited regions in Tamil Nadu by the Central Groundwater Board.To raise the groundwater level,suitable recharge zones were identified and artificial recharge structures are suggested using geomatics technology in the present study.To this end,various thematic maps concerning lithology,soil,geomorphology,land use,land cover,slope,lineament,lineament density,drainage,drainage density and groundwater depth level were prepared.Fissile hornblende gneiss(244 km^2)covered most of the study area followed by charnockites(68 km^2).Structural hills and rocky pediments characterize the major geomorphological features in the targeted area,and are followed by deep moderated pediments.The area is mostly used as crop and fallow land,followed by scrub land and deciduous forest.In the study area,the slopes are predominantly very gentle(142 km^2)and nearly level(66 km^2)ones.Besides,Groundwater level data of 58 wells have been generated,in which the minimum and maximum depth were 3 and 28 m respectively.Integration under the GIS environment has been carried out using all the thematic layers to identify the groundwater prospect zone through the introduction of weight and rank methods.Integrated output performances were classified into very poor,poor,moderate,good and excellent categories.All these classes were further divided into two groups as suitable and non-suitable area for the selection of recharge sites.Hard rock fractures were mapped as lineaments from satellite images,and besides that,rose diagram was also generated to find out the trend of the fracture.Furthermore,fracture data of 146 numbers have been collected using Brunton compass to generate rose diagram and were correlated with the rose diagram derived from lineaments.The present study significantly brought up a few areas such as Ammapalayam,Melapuliyur,Senjeri and around Siruvachur for artificial recharge.展开更多
A new hard X-ray pulse-height analysis （PHA） system has been established on HT-7 tokamak for long pulse steady-state operation. This PHA system consists of hard X-ray diagnostics and multi-channel analysers （MCA）....A new hard X-ray pulse-height analysis （PHA） system has been established on HT-7 tokamak for long pulse steady-state operation. This PHA system consists of hard X-ray diagnostics and multi-channel analysers （MCA）. The hard X-ray diagnostics consists of a vertical X-ray detector array （CdTe） and a horizontal X-ray detector array （NaI）. The hard X-ray diagnostics can provide the profile of power deposition and the distribution function of fast electron during radio frequency （RF） current drive. The MCA system is the electronic part of the PHA system, which has been modularized and linked to PC through LAN. Each module of MCA can connect with 8 X-ray detectors. The embedded Ethernet adapter in the MCA module makes the data communication between PC and MCA very convenient. A computer can control several modules of MCA through certain software and a hub. The RAM in MCA can store 1024 or more spectra for each detector and therefore the PHA system can be applied in the long pulse discharge of several minutes.展开更多
Water is an essential natural resource without which life wouldn’t exist.The study aims to identify groundwater potential areas in Vepapanthattai taluk of Perambalur district,Tamil Nadu,India,using analytic hierarchy...Water is an essential natural resource without which life wouldn’t exist.The study aims to identify groundwater potential areas in Vepapanthattai taluk of Perambalur district,Tamil Nadu,India,using analytic hierarchy process(AHP)model.Remote sensing and magnetic parameters have been used to determine the evaluation indicators for groundwater occurrence under the ArcGIS environment.Groundwater occurrence is linked to structural porosity and permeability over the predominantly hard rock terrain,making magnetic data more relevant for locating groundwater potential zones in the research area.NE-SW and NW-SE trending magnetic breaks derived from reduction to pole map are found to be more significant for groundwater exploration.The lineaments rose diagram indicates the general trend of the fracture to be in the NE-SW direction.Assigned normalised criteria weights acquired using the AHP model was used to reclassify the thematic layers.As a result,the taluk’s low,moderate,and high potential zones cover 25.08%,25.68%and 49.24%of the study area,respectively.The high potential zones exhibit characteristics favourable for groundwater infiltration and storage,with factors as gentle slope of<3°,high lineament densities,magnetic breaks,magnetic low zones as indicative of dykes and cracks,lithology as colluvial deposits and land surface with dense vegetation.The depth of the fracture zones was estimated using power spectrum and Euler Deconvolution method.The groundwater potential mapping results were validated using groundwater level data measured from the wells,which indicated that the groundwater potential zoning results are consistent with the data derived from the real world.展开更多
This paper presents theoretical computations of magnetic force bearings made of new type hard magnetic materials neodymium iron boron. A set of devices capable of simultaneously measuring magnetic eccentricity, ...This paper presents theoretical computations of magnetic force bearings made of new type hard magnetic materials neodymium iron boron. A set of devices capable of simultaneously measuring magnetic eccentricity, crosswise stiffness and magnetic pulling force is designed.展开更多
文摘The demand for high-energy-density sodium-ion batteries has driven research to increase the hard carbon(HC)plateau capacity(<0.1 V),but the plateau capacity-rate capability trade-off limits performance.We report a way to regulate the closed pore structure and improve the rate capability of HC by the addition of graphene oxide using an emulsification process.In a non-emulsion system,graphene oxide not only shortens ion diffusion paths by inducing the formation of flakelike HC but also significantly improves the rate performance by serving as conductive bridges within the carbon matrix.The prepared graphene/phenolic resin carbon composite has reversible capacities of 362,340,319,274,119,86,69 and 48 mAh g^(−1)at current densities of 0.02,0.05,0.1,0.2,0.5,1,2 and 5 A g^(−1),respectively.When emulsification is introduced,the graphene oxide acts as a nano-confinement template,guiding the cross-linking of phenolic resin to form uniformly sized closed pores.This composite electrode material has the highest plateau capacity of 268 mAh g^(−1)at 20 mA g^(−1).
文摘Pitch is an excellent precursor for the production of hard carbon,with pre-oxidation crucial process in the fabrication.The structural changes in the different molecular components of pitch during thermochemical treatment are a key factor in determining the sodium-ion storage of pitchbased hard carbon anodes.We investigated the effects of the different molecular structures in the asphaltene precursor,including aromatic rings and aliphatic chains,on the sodiumion storage behavior of the resulting carbon.We found that polar oxygen functional groups limit the steric hindrance caused by the aromatic rings in pitch,and thus facilitate the introduction of cross-linked structures.During high-temperature carbonization,aromatic rings form a rigid carbon framework that prevents the rearrangement of ordered carbon layers,leading to a short-range disordered carbon structure and promotes the production of closed pores.For example,a material prepared from asphaltene,which contains a large number of oxygen-containing functional groups and macromolecular aromatic rings,using pre-oxidation at 300℃ and carbonization at 1200℃ had a reversible capacity of 316.7 mAh g^(−1) when used as the anode for sodium ion batteries.Our research provides a theoretical basis for the selection of raw materials for the development of high-quality pitch-based hard carbons.
基金the National Science and Technology Major Project(Grant No.2025ZD1008300)the Major Scientific Research Instrument Development Project of the National Natural Science Foundation of China(Grant No.52327803).
文摘To address the challenges of rapid bit failure and high drilling costs associated with hard limestone in Sichuan Basin of China,we conducted rock-breaking experiments and simulations of shaped(cylindrical,ridge,and chopper)cutters.Rock mechanics,drillability,and acoustic emission indentation tests revealed the drilling resistance characteristics of the limestone:average uniaxial compressive strength of 202.472 MPa,tensile strength of 7.092 MPa,and drillability of 7.866.We evaluated the performance differences between the shaped cutters before introducing an efficient and innovative finite-discrete-infinite element method(FDIEM)to establish an interaction model between the shaped cutters and limestone.The simulation results indicated the following:(1)The shaped cutters demonstrated superior rock-breaking performance compared to the traditional cylindrical cutter.(2)Compared with the cylindrical cutter,the ridge cutter yielded the lowest peak indentation force and mechanical specific energy,with reductions of 8.71%and 33.83%,respectively.This confirmed that the ridge cutter had the optimal tooth profile for the target formation.Its rock-breaking mechanism relied on the convex edges to induce localized high stress in the rock,which enabled efficient rock fragmentation via a plowing mode while mitigating frictional resistance from cuttings.(3)The novel chopper cutter with its secondary step surface exerted a buffering effect on the cuttings,thereby achieving high cutting stability.This study provides theoretical and technical support for the design of personalized drill bits and the acceleration of the rate of penetration(ROP)in deep hard rock formations.
基金supported by the IITP(Institute for Information&Communications Technology Planning&Evaluation)under the ITRC(Information Technology Research Center)support program(IITP-2025-RS-2024-00438288)grant funded by the Korea government(MSIT)+1 种基金National Research Council of Science&Technology(NST)grant by the MSIT(Aerospace Semiconductor Strategy Research Project No.GTL25051-000)supported by the IC Design Education Center(IDEC),Korea。
文摘This work presents a systematic analysis of proton-induced total ionizing dose(TID)effects in 1.2 k V silicon carbide(SiC)power devices with various edge termination structures.Three edge terminations including ring-assisted junction termination extension(RA-JTE),multiple floating zone JTE(MFZ-JTE),and field limiting rings(FLR)were fabricated and irradiated with45 Me V protons at fluences ranging from 1×10^(12) to 1×10^(14) cm^(-2).Experimental results,supported by TCAD simulations,show that the RA-JTE structure maintained stable breakdown performance with less than 1%variation due to its effective electric field redistribution by multiple P+rings.In contrast,MFZ-JTE and FLR exhibit breakdown voltage shifts of 6.1%and 15.2%,respectively,under the highest fluence.These results demonstrate the superior radiation tolerance of the RA-JTE structure under TID conditions and provide practical design guidance for radiation-hardened Si C power devices in space and other highradiation environments.
基金supported by the Key Laboratory of Sichuan Province for Lithium Resources Comprehensive Utilization and New Lithium Based Materials for Advanced Battery Technology(LRMKF202405)the National Natural Science Foundation of China(52402226)the Natural Science Foundation of Sichuan Province(2024NSFSC1016).
文摘Coal-derived hard carbon(HC)represents a promising anode material for sodium-ion batteries owing to its cost-effectiveness and high carbon yield.However,conventional carbonization induces excessive graphitization,yielding insufficient interlayer spacing(d_(002)<0.37 nm)and underdeveloped closed pores.Herein,we propose a dynamic crystallization control strategy through carbothermal shock treatment(1300°C,30 s)that decouples thermodynamic and kinetic constraints.This method precisely modulates graphite domain ordering kinetics,producing short-range ordered structures with expanded interlayer spacing(d_(002)=0.385 nm)and homogeneously distributed closed nanopores.Through combined in situ characterization and first-principles calculations,we elucidate a three-stage crystallization mechanism:(i)amorphous carbon transformation,(ii)open-pore collapse,and(iii)pseudo-graphitic ordering.The optimized HC achieves record performance with 88.6%initial Coulombic efficiency and 204 mA h g^(−1)plateau capacity,while its optimal interlayer spacing lowers Na+diffusion barriers to enable exceptional rate capability(221 mA h g^(−1)at 0.5C after 300 cycles).Practical pouch cells maintain 85%capacity retention after 100 cycles at−20°C and deliver 284 Wh kg^(−1)energy density.This work establishes a kinetic regulation paradigm for graphitization-prone precursors,advancing the rational design of high-performance HC anodes.
基金supported by the National Natural Science Foundation of China(22269020,U23A20582,42167068)the Gansu Province Higher Education Industry Support Plan Project(2023CYZC-17)+1 种基金2024 Major Cultivation Project for University Research and Innovation Platforms(2024CXPT-10)the Key Project of the Natural Science Foundation of Gansu Province(25JRRA004).
文摘Hard carbon(HC)remains a leading anode candidate for sodium-ion storage,yet its application is hindered by low initial Coulombic efficiency(ICE)and limited plateau capacity due to uncontrolled defect density and open porosity.Here,we propose a scalable dual-regulation strategy that simultaneously tunes pore mouth size and defect chemistry to enhance sodium storage performance.Using phenol-formaldehyde resin as the carbon precursor and phosphorus pentoxide(P_(2)O_(5))as a bifunctional sacrificial template and dopant source,we synthesize phosphorus-functionalized hard carbon(PF-PHC)featuring a high density of closed pores with well-confined sub-nanometer pore entrances.The in-situ sublimation of P_(2)O_(5) during pyrolysis promotes the formation of closed-pore architectures,while residual phosphorus atoms effectively passivate vacancy-type defects,thereby reducing irreversible Na+adsorption and mitigating excessive solid electrolyte interphase(SEI)formation.As a result,PF-PHC achieves an ICE of 89.3%and a plateau capacity of 289 mAh g^(−1).In-situ characterizations reveal that regulating pore mouth dimensions decouples Na+and solvent access,enabling highly selective ion transport and stable interfacial chemistry.Sodium-ion hybrid capacitors(SIHCs)assembled based on PF-PHC deliver exceptional rate performance and outstanding long-term cycling stability,retaining 98.2%after 10,000 cycles at 2 A g^(−1).This study establishes pore mouth engineering as a robust and scalable design principle for advancing next-generation HC-based sodium storage materials.
基金supported by the National Natural Science Foundation of China(Nos.22269020,42167068,U23A20582)Gansu Province Higher Education Industry Support Plan Project(No.2023CYZC-17)2024 Major Cultivation Projectfor University Research and Innovation Platforms(No.2024CXPT-10).
文摘There are limitations to using hard carbon(HC)in K^(+)storage due to its insufficient high-current reversible capacity and plateau potential,which result from the lack of effective active sites and low intercalation capabilities.The construction of HC cathodes with more available functional groups and ordered carbon nanocrystal structures is essential for improving K^(+)storage efficiency.Herein,a new perspective is proposed for synthesizing hard carbon nanosheets(HCNS)with abundant hydroxyl groups(O-H)/carboxylic groups(O-C=O)and rational carbon nanocrystals by interfacial assembly and carbonization.Systematic in ex-situ observations,dynamic analysis and theory calculations elucidate that the superior electrochemical capability of HCNS is ascribed to the synergistic effect of abundant available functional groups and ordered graphitic microcrystalline.Consequently,the HCNS exhibits outstanding K^(+)storage capabilities in terms of superb energy density(146.2 Wh/kg),high power density(1,7800 Wh/kg),and ultralong lifespan(102.9%capacity retention after 10,000 cycles).It was also found that the HC structure correlates with the discharge/charge plateau,confirming the'adsorption-insertion'charge storage mechanism.Furthermore,the proposed work provides a theoretical basis for making high-performance HC anodes by understanding the effect of their microstructure on K^(+)storage.
基金support from the Heilongjiang Province"Double First Class"Discipline Collaborative Innovation Project(No.LJGXCG2023-061).
文摘Hard carbon is a vital anode material for sodium-ion batteries;however,the nonuniform growth of solid electrolyte interphase(SEI)film substantially diminishes its initial coulombic efficiency(ICE)and cycle life.The chemical and morphological properties of surface highly influence the electrode/electrolyte interfacial reactions.In this study,we have tuned orbital hybridization states forming an interface enriched with sp^(2) hybridized carbon(sp^(2)-C),which decreases the binding energy to solvent molecules and inhibits excessive solvent decomposition during SEI formation.Benefiting from successfully constructed inorganic-rich SEI,the ICE increased to 91%and sodium storage capacity reached 346 mAh/g.Besides,the capacity retention rate was 90.7%after 700 cycles at 1 A/g higher than pristine electrode(83.8%).
文摘[目的]探讨Mako机器人辅助经改良Harding入路全髋关节置换术(total hip arthroplasty,THA)的治疗效果及安全性。[方法]回顾性分析本院2021年4月—2023年5月行THA的48例患者的资料。根据手术前医患沟通结果,24例采用Mako机器人辅助下THA(机器人组),另外24例采用经改良Harding入路常规徒手THA(徒手组)。比较两组患者围手术期、随访结果及影像评估资料。[结果]两组患者均顺利完成改良Harding入路THA,机器人组的手术时间[min,(102.6±15.7)vs(83.7±16.8),P<0.001]和术中出血量[mL,(279.7±35.1)vs(212.5±29.6),P<0.001]均显著大于徒手组,两组患者术后引流量、住院天数的差异无统计学意义(P>0.05)。术后平均随访(20.8±8.5)个月。随时间推移,两组患者VAS评分、Harris评分、最大伸髋和最大屈髋活动度(range of motion,ROM)、最大内收和最大外展ROM均显著改善(P<0.05)。术后1周机器人组的VAS评分[分,M(P25,P75),2.0(2.0,4.0)vs 3.5(3.0,5.0),P<0.001]、最大屈髋[°,(74.5±9.0)vs(66.5±10.4),P=0.006]、最大内收[°,(18.5±6.2)vs(7.0±1.6),P<0.001]显著优于徒手组;术后1周和术后3个月机器人组的Harris评分[分,(75.1±4.9)vs(68.3±5.1),P<0.001;(84.8±4.9)vs(78.3±4.5),P<0.001]、最大伸髋[°,(20.5±5.3)vs(12.5±5.6),P<0.001;(31.0±3.6)vs(24.1±4.5),P<0.001]、最大外展[°,(26.2±3.3)vs(21.5±4.8),P<0.001;(33.4±3.8)vs(27.8±4.3),P<0.001]显著优于徒手组,但是,末次随访时两组间上述指标的差异均已无统计学意义(P>0.05)。影像方面,机器人组的术后双下肢长度差异(leg length discrepancy,LLD)[mm,(4.9±1.0)vs(8.1±1.4),P<0.001]和双侧联合偏心距(combined offset,CO)差值(■CO)的绝对值[mm,(1.5±0.5)vs(3.5±0.6),P<0.001]、髋臼假体外展角[°,(40.3±1.7)vs(45.3±4.1),P<0.001]和前倾角[°,(15.9±1.2)vs(18.8±3.6),P<0.001]均显著小于徒手组。[结论]与常规徒手THA相比,Mako机器人辅助下改良Harding入路THA假体置放更精准,早期治疗效果更优,但机器人技术的手术时间较长且术中失血量更大。
基金the National Natural Science Foundation of China(Grant No.41827806)and the Liaoning Revitalization Talent Program(Grant No.XLYC1801002).
文摘This study introduces a test system for microwave-induced fracturing of hard rocks under true triaxial stress.The test system comprises a true triaxial stress loading system,an open-ended microwaveinduced fracturing system,a data acquisition system,an acoustic emission(AE)monitoring system,and an auxiliary specimen loading system.Microwave-induced surface and borehole fracturing tests under true triaxial stress were fulfilled for the first time,which overcomes the problem of microwave leakage in the coupling loading of true triaxial stress and microwave.By developing the dynamic monitoring system,the thermal response and fracture evolution were obtained during microwave irradiation.The monitoring system includes the infrared thermometry technique for monitoring rock surface temperature,the distributed optic fiber sensing technique for monitoring temperature in borehole in rock,the AE technique and two-dimensional digital speckle correlation technique for monitoring the evolution of thermal damage and the rock fracturing process.To validate the advantages of the test system and investigate the characteristics of microwave-induced fracturing of hard rocks,the study demonstrates the experimental methods and results for microwave-induced surface and borehole fracturing under true triaxial stress.The results show that thermal cracking presented intermittent characteristics(calm eactiveecalm)during microwave-induced surface and borehole fracturing of basalt.In addition,true triaxial stress can inhibit the development and distribution of thermal cracks during microwave-induced surface fracturing.When microwave-induced borehole fracturing occurs,it promotes the distribution of thermal cracks in rock,but inhibits the width of cracks.The results also prove the reliability of the test system.
基金supported by "University Innovation and Research Training Program (China)" (No. 2009003)the Natural Science Foundation of Jiangsu Province (No.BK2011252)the Industry Science and Technology Supported Plan of Changzhou (No. CE20110012)
文摘Pseudobinary Ti 1 x Al x N films were synthesized on Si (100) wafer by DC magnetron sputtering method using Ti 1 x Al x alloy targets with different Al contents. The composition of the Ti 1 x Al x N films was determined by electron probe microanalysis (EPMA). Structural characteristic was performed by X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution TEM (HRTEM). First principles virtual crystal calculations for the Ti 1 x Al x N disordered alloys were used for the XRD simulations. The crystalline structure of the Ti 0.61 Al 0.39 N film was found to be a metastable single phase with NaCl (B1) structure. Its lattice constant, determined by XRD, was less than that of pure TiN. With the increase of Al content, the lattice constant of B1 phase was continually decreased, while würtzite (B4) structure was observed in the Ti 0.40 Al 0.60 N film. When x reached 0.75, the B1 phase disappeared, and only B4 phase was remained. The critical Al content for the phase transition from NaCl to würtzite structure in this paper was about 0.60, which could be explained by both the thermodynamic model and the electron theory. As-deposited Ti 1 x Al x N films exhibited excellent mechanical properties. Hardness measurements of Ti 1 x Al x N films showed a high value of 45GPa for x=0.39 and was decreased to value of 27 GPa with increasing Al at x=0.60.
基金supported by the National Natural Science Funds of China(Nos.11622327,11273070,11773087,U1631116)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2014275)the Strategic Pioneer Program on Space Science of the Chinese Academy of Sciences(No.XDA15010200)
文摘A multichannel low-noise electronic prototype system was designed for a pixelated CdZnTe detector. This system is the result of preliminary work on a solar hard X-ray imager, which is one of the three payloads for future solar observations satellite-Advanced Space-based Solar Observatory(ASO-S). A new charge-sensitive amplifier application-specific integrated circuit, VATA450.3, with an on-chip analog-to-digital converter, is used to read out 8×8 anode pixel signals. Two CdZnTe detectors with a thickness of 2 mm and 5 mm were tested. The 2-mm-thick detector achieved energy resolution better than 5%(fullwidth at half-maximum, FWHM) at 59.5 keV, and the 5-mm-thick detector had better resolution than 1.2%(FWHM) at 662 keV. The design and test results of the prototype system are discussed in this paper.
基金The project supported by the National Natural Science Foundation of China (10202023,10272103),the Excellent Post-doctoral Research-starting Fund of CAS and the Key Project from CAS (No.KJCX2-SW-L2)
文摘In the present paper,the hardness and Young's modulus of film-substrate systems are determined by means of nanoindentation experiments and modified models.Aluminum film and two kinds of substrates,i.e.glass and silicon,are studied.Nanoindentation XP Ⅱ and continuous stiffness mode are used during the experiments.In order to avoid the influence of the Oliver and Pharr method used in the experiments,the experiment data are analyzed with the constant Young's modulus assumption and the equal hardness assumption.The volume fraction model(CZ model)proposed by Fabes et al.(1992)is used and modified to analyze the measured hardness.The method proposed by Doerner and Nix(DN formula)(1986)is modified to analyze the measured Young's modulus.Two kinds of modified empirical formula are used to predict the present experiment results and those in the literature,which include the results of two kinds of systems,i.e.,a soft film on a hard substrate and a hard film on a soft substrate.In the modified CZ model,the indentation influence angle,(?), is considered as a relevant physical parameter,which embodies the effects of the indenter tip radius, pile-up or sink-in phenomena and deformation of film and substrate.
基金financially supported by the National Natural Science Foundation of China (Nos.51922002 and 51771025)the Fundamental Research Funds for the Central Universities (No.FRF-TP-17-19-003C1Z)。
文摘With the wide application of coating materials in aerospace and other fields, their safety under fatigue conditions in service is important.However, research on the fatigue properties of ceramic hard coatings started late, and a unified standard is yet to be established to evaluate the fatigue life of hard coating–ductile substrate systems.Studies also present different opinions on whether coatings can improve or reduce the fatigue life of substrates.In this paper, the influence of the properties of ceramic coatings on fatigue performance is reviewed, and the effects of coating on the mechanism of fatigue crack initiation in substrates are discussed, aiming to help readers understand the fatigue behavior of hard coating–ductile substrate systems.
基金support from the Na-tional Natural Science Foundation of China(Grant No.41827806)the liaoning Revitalization Talent Program of China(Grant No.XLYCYSZX1902).
文摘Microwave pre-treatment is considered as a promising technique for alleviating cutter wear. This paper introduces a high-power microwave-induced fracturing system for hard rock. The test system consists of a high-power microwave subsystem (100 kW), a true triaxial testing machine, a dynamic monitoring subsystem, and an electromagnetic shielding subsystem. It can realize rapid microwave-induced fracturing, intelligent tuning of impedance, dynamic feedback under strong microwave fields, and active control of microwave parameters by addressing the following issues: the instability and insecurity of the system, the discharge breakdown between coaxial lines during high-power microwave output, and a lack of feedback of rock-microwave response. In this study, microwave-induced surface and borehole fracturing tests under true triaxial stress were carried out. Experimental comparisons imply that high-power microwave irradiation can reduce the fracturing time of hard rock and that the fracture range (160 mm) of a 915-MHz microwave source is about three times that of 2.45 GHz. After microwave-induced borehole fracturing, many tensile cracks occur on the rock surface and in the borehole: the maximum reduction of the P-wave velocity is 12.8%. The test results show that a high-power microwave source of 915 MHz is more conducive to assisting mechanical rock breaking and destressing. The system can promote the development of microwave-assisted rock breaking equipment.
文摘The microstructures and Vickers hardness at room temperature of arc-meltingprocessed intermetallics of Mo_5Si_3-MoSi_2 hypoeutectic alloy and hypereutectic alloy annealed at1200℃ for different time were investigated. Lamellar structure consisted of Mo_5Si_3 (D8m) phaseand MoSi_2 (C11_b) phase was observed in all the alloys. For Mo_5Si_3-MoSi_2 hypoeutectic alloy, thelamellar structure was found only after annealing and developed well with fine spacing on the orderof hundred nanometers after annealing at 1200℃ for 48 h. But when the annealing time was up to 96h, the well-developed lamellar structure was destroyed. For Mo_5Si_3-MoSi_2 hypereutectic alloy, thelamellar structure was found both before and after annealing. However the volume fraction andspacing of the lamellar structure did not change significantly before and after annealing. Theeffects of the formation, development and destruction of lamellar structure on Vickers hardness ofalloys were also investigated. When Mo_5Si_3-MoSi_2 hypoeutectic alloy annealed at 1200℃ for 48 h,the Vickers hardness was improved about 19% compared with that without annealing and formation oflamellar structure. The highest Vickers hardness of Mo5Si3-MoSi_2 hypereutectic was increasing about18% when annealing at 1200℃ for 48 h.
文摘Mapping of hard rock aquifer system and artificial recharge zonation were carried out in an area of 325 km^2 in parts of the Perambalur District,Tamil Nadu,India.This district has been declared as one of the over-exploited regions in Tamil Nadu by the Central Groundwater Board.To raise the groundwater level,suitable recharge zones were identified and artificial recharge structures are suggested using geomatics technology in the present study.To this end,various thematic maps concerning lithology,soil,geomorphology,land use,land cover,slope,lineament,lineament density,drainage,drainage density and groundwater depth level were prepared.Fissile hornblende gneiss(244 km^2)covered most of the study area followed by charnockites(68 km^2).Structural hills and rocky pediments characterize the major geomorphological features in the targeted area,and are followed by deep moderated pediments.The area is mostly used as crop and fallow land,followed by scrub land and deciduous forest.In the study area,the slopes are predominantly very gentle(142 km^2)and nearly level(66 km^2)ones.Besides,Groundwater level data of 58 wells have been generated,in which the minimum and maximum depth were 3 and 28 m respectively.Integration under the GIS environment has been carried out using all the thematic layers to identify the groundwater prospect zone through the introduction of weight and rank methods.Integrated output performances were classified into very poor,poor,moderate,good and excellent categories.All these classes were further divided into two groups as suitable and non-suitable area for the selection of recharge sites.Hard rock fractures were mapped as lineaments from satellite images,and besides that,rose diagram was also generated to find out the trend of the fracture.Furthermore,fracture data of 146 numbers have been collected using Brunton compass to generate rose diagram and were correlated with the rose diagram derived from lineaments.The present study significantly brought up a few areas such as Ammapalayam,Melapuliyur,Senjeri and around Siruvachur for artificial recharge.
基金supported by National Nature Science Foundation of China (No. 10235010)
文摘A new hard X-ray pulse-height analysis （PHA） system has been established on HT-7 tokamak for long pulse steady-state operation. This PHA system consists of hard X-ray diagnostics and multi-channel analysers （MCA）. The hard X-ray diagnostics consists of a vertical X-ray detector array （CdTe） and a horizontal X-ray detector array （NaI）. The hard X-ray diagnostics can provide the profile of power deposition and the distribution function of fast electron during radio frequency （RF） current drive. The MCA system is the electronic part of the PHA system, which has been modularized and linked to PC through LAN. Each module of MCA can connect with 8 X-ray detectors. The embedded Ethernet adapter in the MCA module makes the data communication between PC and MCA very convenient. A computer can control several modules of MCA through certain software and a hub. The RAM in MCA can store 1024 or more spectra for each detector and therefore the PHA system can be applied in the long pulse discharge of several minutes.
文摘Water is an essential natural resource without which life wouldn’t exist.The study aims to identify groundwater potential areas in Vepapanthattai taluk of Perambalur district,Tamil Nadu,India,using analytic hierarchy process(AHP)model.Remote sensing and magnetic parameters have been used to determine the evaluation indicators for groundwater occurrence under the ArcGIS environment.Groundwater occurrence is linked to structural porosity and permeability over the predominantly hard rock terrain,making magnetic data more relevant for locating groundwater potential zones in the research area.NE-SW and NW-SE trending magnetic breaks derived from reduction to pole map are found to be more significant for groundwater exploration.The lineaments rose diagram indicates the general trend of the fracture to be in the NE-SW direction.Assigned normalised criteria weights acquired using the AHP model was used to reclassify the thematic layers.As a result,the taluk’s low,moderate,and high potential zones cover 25.08%,25.68%and 49.24%of the study area,respectively.The high potential zones exhibit characteristics favourable for groundwater infiltration and storage,with factors as gentle slope of<3°,high lineament densities,magnetic breaks,magnetic low zones as indicative of dykes and cracks,lithology as colluvial deposits and land surface with dense vegetation.The depth of the fracture zones was estimated using power spectrum and Euler Deconvolution method.The groundwater potential mapping results were validated using groundwater level data measured from the wells,which indicated that the groundwater potential zoning results are consistent with the data derived from the real world.
文摘This paper presents theoretical computations of magnetic force bearings made of new type hard magnetic materials neodymium iron boron. A set of devices capable of simultaneously measuring magnetic eccentricity, crosswise stiffness and magnetic pulling force is designed.
