Recent progress in the physics and engineering design study for themodification programme of JT-60 is presented. In order to achieve a steady state high-βplasmaoperation, which is the dominant issue of this programme...Recent progress in the physics and engineering design study for themodification programme of JT-60 is presented. In order to achieve a steady state high-βplasmaoperation, which is the dominant issue of this programme, physics design for the MHD control and thestability analysis is investigated. Engineering design and the R & D for the superconducting coils,irradiation shield are performed well towards the mission of programme.展开更多
There are many cracked concrete structures worldwide. Although there have been numerous efforts to eliminate cracks, some cracks are very harmful and should be repaired as soon as possible. On the other hand, some cra...There are many cracked concrete structures worldwide. Although there have been numerous efforts to eliminate cracks, some cracks are very harmful and should be repaired as soon as possible. On the other hand, some cracks are almost harmless. So, a good guideline regarding how to deal with cracks in concrete structures is needed. In this guideline, the practical investigation, repair and strengthening method of cracked concrete structures is discussed. And the detecting subjects are cracks generated immediately after casting and during the service time. This guideline targets on the owners （including managers） of concrete structure and the engineers working for the maintenance of concrete structure. JCI （Japan Concrete Institute） published first version of ＂Practical Guideline for Investigation and Repair of Cracked Concrete Structures＂ in 1980, and then the fourth version titled ＂Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures--2009＂ was published. This guideline is very practical when cracks are observed in existing concrete structures, in any other countries as well as in Japan. These three authors led the establishment of this guideline.展开更多
An innovative in-flight glass melting technology with induced thermal plasmas was developed for the purpose of energy conservation and environmental protection. Two-dimensional modeling was used to simulate the thermo...An innovative in-flight glass melting technology with induced thermal plasmas was developed for the purpose of energy conservation and environmental protection. Two-dimensional modeling was used to simulate the thermofluid fields in the plasma torch. The in-flight melting behavior of glass raw material was investigated by various analysis methods. Results showed that the plasma temperature was up to 10000 K with a maximum velocity over 30 m/s, which made it possible to melt the granulated glass raw material within milliseconds. The carbonates in the raw material decomposed completely and the compounds in the raw material attainted 100% vitrification during the in-flight time from the nozzle exit to substrate. The particle melting process is similar to the unreacted-core shrinking model.展开更多
Watershed management consists of multifunctional activities to manage and address the increasing water resource problems. Ever increasing water demand and rapidly depleting water resources, it has become necessary to ...Watershed management consists of multifunctional activities to manage and address the increasing water resource problems. Ever increasing water demand and rapidly depleting water resources, it has become necessary to develop the adaptation options to recharge groundwater resources. A watershed is a special kind of Common Pool Resources (CPRs);an area is defined by hydrological linkages where optimal management requires coordinating the use of natural resources by public participation. Watershed developments have shown significant positive impacts on water table, perennially of water in wells and water availability especially in semi-arid regions. This paper describes direct and indirect impacts of the watershed activities and benefits of hydrological services dealing with watershed management with future prediction of net irrigation water supply. In the present work, we have also discussed the multiple impacts of watershed of CPRs for improving groundwater and surface water resources.展开更多
Fecal incontinence(FI),which can arise from various pathogenic mechanisms,has attracted considerable attention worldwide.Despite its importance,the reproduction of the defecatory system to study the mechanisms of FI r...Fecal incontinence(FI),which can arise from various pathogenic mechanisms,has attracted considerable attention worldwide.Despite its importance,the reproduction of the defecatory system to study the mechanisms of FI remains limited,largely because of social stigma and being considered inappropriate.Inspired by the rectum’s functionalities,we developed a soft robotic system that includes a power supply,pressure sensors,data acquisition systems,a flushing mechanism,stages,and a rectal module.Specifically,the innovative soft rectal module includes actuators inspired by sphincter muscles,both soft and rigid covers,and a soft rectum mold.The rectal mold,which was fabricated from materials that mimic human rectal tissue,was produced using a mold replication fabrication method.Both the soft and rigid components of the mold were created using three-dimensional(3D)printing technology.In addition,the sphincter muscle-inspired actuators featured double-layer pouch structures that were modeled and optimized based on multilayer perceptron methods to obtain a high contraction ratio(100%),generate high pressure(9.8 kPa),and have a short recovery time(3 s).Upon assembly,this defecation robot could smoothly expel liquid feces,perform controlled solid fecal cutting,and defecate extremely solid long feces,thus closely replicating the functions of the human rectum and anal canal.This defecation robot has the potential to facilitate human understanding of the complex defecation system and contribute to the development of improved quality-of-life devices related to defecation.展开更多
Perfluoroalkyl and polyfluoroalkyl substances(PFASs)pollution with their toxicity,carcinogenicity,and persistence has been concerned worldwide.Research into novel materials for detecting and removing PFASs has increas...Perfluoroalkyl and polyfluoroalkyl substances(PFASs)pollution with their toxicity,carcinogenicity,and persistence has been concerned worldwide.Research into novel materials for detecting and removing PFASs has increased rapidly,particularly in regard to the emergence of well-characterized single-atom materials(SAMs).Owing to the high selectivity,high atom utilization,and abundant active sites of SAMs,these materials exhibit remarkable efficacy in the detection and removal of PFASs.In this work,recent advances in the synthesis of SAMs for the detection and removal PFASs are reviewed.In-depth discussions of the structure-activity relationship and reaction mechanisms have demonstrated the high efficiency,activity,and selectivity of SAMs for the detection,adsorption,and degradation of PFASs.To optimize the application of SAMs in PFASs remediation,this review comprehensively surveys SAMs applications for PFASs and analyzes potential design strategies based on synthesis methods and corresponding properties.Synthesis strategies such as wet-chemistry,which offer ease of operation and high potential for large-scale production,are recommended for the further exploration of specific SAMs for the detection and removal of PFASs.Finally,this review identifies the challenges and opportunities for development of SAMs for the detection and remediation of PFASs,providing an outlook on strategic goals for a green economy and sustainable development.展开更多
This study delves into the pivotal role of sulfur vulcanization in defining the mechanical characteristics of natural rubber(NR)latex-dipped products.Utilizing sulfur vulcanization,known for its operational simplicity...This study delves into the pivotal role of sulfur vulcanization in defining the mechanical characteristics of natural rubber(NR)latex-dipped products.Utilizing sulfur vulcanization,known for its operational simplicity and cost-effectiveness,we examine its ability to enhance product elasticity and mechanical strength through various sulfidic bond formations such as mono-,di-,and polysulfidic bonds.Different vulcanization systems and sulfur contents were evaluated for their influence on the mechanical attributes of latex films,employing three types of NR latex,namely concentrated NR(CNR),deproteinized NR(DPNR),and small rubber particle NR(SRP),each representing distinct non-rubber components(NRCs).The study utilized advanced atomic force microscopy(AFM)equipped with PeakForce Quantitative Nanomechanical Mapping(QNM)to visualize and measure Young’s modulus distribution across the film of pre-vulcanized latex.Our findings reveal that films by CNR processed using the conventional vulcanization(CV)system exhibited enhanced tensile strength and elongation at break.It even showed a lower crosslink density than those processed using the efficient vulcanization(EV)system.Interestingly,DPNR films showed a more uniform distribution of Young’s modulus,correlating well with their superior mechanical strength.In contrast,SRP films showed excessive network structure formation in the particles due to accelerated vulcanization rates,hampering subsequent post-vulcanization interparticle crosslinking in film formation and remaining more rigid.The overall results Illustrate clearly that the ultimate mechanical properties of the latex films are strongly dependent on the type of sulfidic bonds formed.This research reveals further the very intricate relationship between the vulcanization methods,sulfur content,and latex type in optimizing the mechanical performance of NR latex products.It provides valuable insights for industry practices aimed at improving the quality and performance of latex-dipped goods.展开更多
ITR zeolite could be potentially used as catalysts in methanol to propylene(MTP),where their performance is strongly related to its Al distribution.However,the control of Al distribution in ITR zeolite poses a signifi...ITR zeolite could be potentially used as catalysts in methanol to propylene(MTP),where their performance is strongly related to its Al distribution.However,the control of Al distribution in ITR zeolite poses a significant synthetic challenge.Herein,we demonstrate the possibility to control the Al distribution in ITR zeolites using zeolite A as an aluminum source(A-ITR).The A-ITR exhibited similar crystallinity,nanosheet morphology,textual parameters,and acidic concentration with those of conventional ITR made zeolites using aluminum isopropoxide as an aluminum source(C-ITR).Characterizations of the zeolite product with^(27)Al MQ.MAS NMR spectra,^(27)Al MAS NMR spectra,and 1-hexene cracking reveal that the A-ITR zeolites have more Al species distributed in T6 and T8 sites located in relatively smaller micropores of the framework than C-ITR.As a result,the A-ITR gave enhanced catalyst lifetime and propylene selectivity due to the suppression of the aromatic cycle in the MTP reaction,compared with the C-ITR.This work provides an alternative approach to prepare efficient ITR zeolites for MTP reaction.展开更多
Type 2 diabetes(T2D)presents a significant health challenge,underscoring the need for functional foods and nutraceutical hypoglycemic bioactive peptides for its prevention.This study investigates the potential of prot...Type 2 diabetes(T2D)presents a significant health challenge,underscoring the need for functional foods and nutraceutical hypoglycemic bioactive peptides for its prevention.This study investigates the potential of proteolytic hydrolysate from artificially cultivated Chinese giant salamander(CGS)meat,a rich protein source,as a preventive strategy for T2D.We produced a CGS meat hydrolysate(CGSh)and demonstrated its ability to inhibit the T2D drug target dipeptidyl peptidaseⅣ(DPP-Ⅳ)through in vitro assays.We identified 5 peptides(WRPPDH,WAPPSKD,IPDSPF,IPEMIF,and VPIAVPT)with high DPP-Ⅳinhibitory activity in CGSh,suggesting its potential antidiabetic effects.In vivo experiments showed that CGSh effectively reduced insulin resistance in mice induced with a high-fat diet,as evidenced by a slower increase in blood glucose levels and a decreased HOMA-IR index.16S rRNA sequencing analysis revealed that CGSh improved gut microbial homeostasis,promoting beneficial microorganisms and reducing harmful bacteria.Metabolomic analyses identified an increase in valeric acid levels and highlighted nine potential biomarker metabolites.By inhibiting metabolic pathways such as AGE-RAGE,CGSh might also prevent diabetic complications and reduce inflammation.These findings suggest that CGSh has a promising hypoglycemic effect,making it a potential functional food ingredient for T2D prevention and treatment.展开更多
To improve the wettability of Al metal matrix composites（Al-MMCs） by common filler metals,Al-12Si-xTi（x=0.1,0.5,1,3.0;mass fraction,%） system active ternary filler metals were prepared.It was demonstrated that alt...To improve the wettability of Al metal matrix composites（Al-MMCs） by common filler metals,Al-12Si-xTi（x=0.1,0.5,1,3.0;mass fraction,%） system active ternary filler metals were prepared.It was demonstrated that although the added Ti existed within Ti（Al1-xSix）3（0≤x≤0.15） phase,the shear strength and shear fracture surface of the developed Al-12Si-xTi brazes were quite similar to those of traditional Al-12Si braze due to the presence of similar microstructure of Al-Si eutectic microstructure with large volume fraction.So,small Ti addition（～1%） did not make the active brazes brittle and hard compared with the conventional Al-12Si braze.The measured melting range of each Al-12Si-xTi foil was very similar,i.e.,580-590 ℃,because the composition was close to that of eutectic.For wettability improvement,with increasing Ti content,the interfacial gap between the Al2O3 reinforcement and filler metal（R/M） could be eliminated,and the amount of the remainder of the active fillers on the composite substrate decreased after sessile drop test at 610 ℃ for 30 min.So,the wettability improvement became easy to observe repeatedly with increasing Ti content.Additionally,the amount and size of Ti（AlSi）3 phase were sensitive to the Ti content（before brazing） and Si content（after brazing）.展开更多
The generalized inversion of S-wave amplitude spectra from the free-field strong motion recordings of the China National Strong Motion Observation Network System （NSMONS） are used to evaluate the site effects in the...The generalized inversion of S-wave amplitude spectra from the free-field strong motion recordings of the China National Strong Motion Observation Network System （NSMONS） are used to evaluate the site effects in the Wenchuan area. In this regard, a total of 602 recordings from 96 aftershocks of the Wenchuan earthquake with magnitudes of M3.7-M6.5 were selected as a dataset. These recordings were obtained from 28 stations at a hypocenter distance ranging from 30 km to 150 km. The inversion results have been verified as reliable by comparing the site response at station 62WUD using the Generalized Inversion Technique （GIT） and the Standard Spectral Ratio method （SSR）. For all 28 stations, the site predominant frequency F and the average site amplification in different frequency bands of 1.0-5.0 Hz, 5.0-10.0 Hz and 1.0-10.0 Hz have been calculated based on the inversion results. Compared with the results from the horizontal-to-vertical spectral ratio （HVSR） method, it shows that the HVSR method can reasonably estimate the site predominant frequency but underestimates the site amplification. The linear fitting between the average site amplification for each frequency band and the V20 （the average uppermost-20 m shear wave velocity） shows good correlation. A distance measurement called the asperity distance DAspt is proposed to reasonably characterize the source-to-site distance for large earthquakes. Finally, the inversed site response is used to identify the soil nonlinearity in the main shock and aftershocks of Wenchuan earthquake. In ten of the 28 stations analyzed in the main shock, the soil behaved nonlinearly, where the ground motion level is apparently beyond a threshold ofPGA 〉 300 cm/s^2 or PGV 〉 20 cm/s, and only one station coded 51SFB has evidence of soil nonlinear behavior in the aftershocks.展开更多
This study aims to investigate the possibility of using biopolymer(environmental friendly material) to enhance the mechanical behaviors of collapsible soil.Two types of biopolymers were(xanthan gum and guar gum) used ...This study aims to investigate the possibility of using biopolymer(environmental friendly material) to enhance the mechanical behaviors of collapsible soil.Two types of biopolymers were(xanthan gum and guar gum) used in this study due to their stable behaviors under severe conditions and their availability with reasonable prices.The experimental program focused on three major soil properties,i.e.compaction characterizations,collapsible potential and shear parameters.These three properties are essential in process of soil improvement.Different biopolymer concentrations were used in this study and the experimental program was performed at two curing periods(soon after mixing the soil with the biopolymer and after one week curing time).Shear parameters were measured for the treated specimens under both soaked and unsoaked conditions,while a collapsible potential test was performed under different mixing conditions(wet mix and dry mix).A numerical model was built to predict the behavior of the treated collapsible soil after and before water immersing.The results indicated that the ability of both xanthan gum and guar gum can be used as improvement materials for collapsible soil treatment.The collapsible potential has been reduced from 9%to 1%after mixing the soil with 2%biopolymer concentration in the wet case.After one week curing,the cohesion has been increased from 8.5 kPa to105 kPa by increasing the xanthan gum concentration from zero to 2%,leading to an overall improvement in soil shear strength.It also proves that the guar gum is superior to the xanthan gum.The shear strength of soil can be increased by about 30%when using the guar gum in comparison with the xanthan gum at the same conditions;however,the collapsible potential of soil material will be reduced by about 20%.展开更多
This paper reports on an investigation of the seismic response of base-isolated reinforced concrete buildings, which considers various isolation system parameters under bidirectional near-fault and far-fault motions. ...This paper reports on an investigation of the seismic response of base-isolated reinforced concrete buildings, which considers various isolation system parameters under bidirectional near-fault and far-fault motions. Three-dimensional models of 4-, 8-, and 12-story base-isolated buildings with nonlinear effects in the isolation system and the superstructure are investigated, and nonlinear response history analysis is carried out. The bounding values of isolation system properties that incorporate the aging effect of isolators are also taken into account, as is the current state of practice in the design and analysis of base-isolated buildings. The response indicators of the buildings are studied for near-fault and far-fault motions weight-scaled to represent the design earthquake （DE） level and the risk-targeted maximum considered earthquake （MCER） level. Results of the nonlinear response history analyses indicate no structural damage under DE-level motions for near-fault and far-fault motions and for MCER-level far-fault motions, whereas minor structural damage is observed under MCER- level near-fault motions. Results of the base-isolated buildings are compared with their fixed-base counterparts. Significant reduction of the superstructure response of the 12-story base-isolated building compared to the fixed-base condition indicates that base isolation can be effectively used in taller buildings to enhance performance. Additionally, the applicability of a rigid superstructure to predict the isolator displacement demand is also investigated. It is found that the isolator displacements can be estimated accurately using a rigid body model for the superstructure for the buildings considered.展开更多
One purpose of this paper is to give a brief overview on the research status of deformation,fracture and toughening mechanisms of polymers,including experimental,theoretical and numerical studies.Emphasis is on the mo...One purpose of this paper is to give a brief overview on the research status of deformation,fracture and toughening mechanisms of polymers,including experimental,theoretical and numerical studies.Emphasis is on the more recent progresses of micromechanics of rubber particle cavitation and crazing,and the de- velopment of fracture criteria for ductile polymers. The other purpose is to study the effect of triaxial stress constraint on the deforma- tion and fracture behavior of polymers.Polycarbonate(PC),acrylonitrile-butadiene- styrene(ABS)and PC/ABS alloy are considered in this investigation.A series of circumferentially blunt-notched bars are used to experimentally generate different tri- axial stress fields.The fracture surfaces of specimens with different notch radius are examined by scanning electron microscope(SEM)to study the fracture and tough- ening mechanisms of polymer alloy.It is shown that the triaxial stress constraint has a significant effect on the deformation,fracture and toughening of PC,ABS and PC/ABS alloy.We will also discuss the extent to which a micromechanies criterion proposed by the first author can serve as a fracture criterion for ductile polymers. A new ductile fracture parameter is emphasized,which can be employed to evaluate the fracture ductility of polymers.Stress state independence of the parameter for the PC,ABS and PC/ABS alloy has been experimentally verified.展开更多
When plate tectonics began on the Earth has been long debated and here we argue this topic based on the records of Earth-Moon geology and asteroid belt to conclude that the onset of plate tectonics was during the midd...When plate tectonics began on the Earth has been long debated and here we argue this topic based on the records of Earth-Moon geology and asteroid belt to conclude that the onset of plate tectonics was during the middle Hadean（4.37-4.20 Ga）. The trigger of the initiation of plate tectonics is the ABEL Bombardment, which delivered oceanic and atmospheric components on a completely dry reductive Earth, originally comprised of enstatite chondrite-like materials. Through the accretion of volatiles, shock metamorphism processed with vaporization of both CI chondrite and supracrustal rocks at the bombarded location, and significant recrystallization went through under wet conditions, caused considerable eclogitization in the primordial continents composed of felsic upper crust of 21 km thick anorthosite, and 50 km or even thicker KREEP lower crust. Eclogitization must have yielded a powerful slab-pull force to initiate plate tectonics in the middle Hadean. Another important factor is the size of the bombardment. By creating Pacific Ocean class crater by 1000 km across impactor, rigid plate operating stagnant lid tectonics since the early Hadean was severely destroyed, and oceanic lithosphere was generated to have bi-modal lithosphere on the Earth to enable the operation of plate tectonics.Considering the importance of the ABEL Bombardment event which initiated plate tectonics including the appearance of ocean and atmosphere, we propose that the Hadean Eon can be subdivided into three periods：（1） early Hadean（4.57-4.37 Ga）,（2） middle Hadean（4.37-4.20 Ga）, and（3） late Hadean（4.20-4.00 Ga）.展开更多
U-Pb ages of detrital zircons were newly dated for 4 Archean sandstones from the Pilbara craton in Australia, Wyoming craton in North America, and Kaapvaal craton in Africa. By using the present results with previousl...U-Pb ages of detrital zircons were newly dated for 4 Archean sandstones from the Pilbara craton in Australia, Wyoming craton in North America, and Kaapvaal craton in Africa. By using the present results with previously published data, we compiled the age spectra of detrital zircons for 2.9, 2.6, 2.3,1.0, and0.6 Ga sandstones and modern river sands in order to document the secular change in age structure of continental crusts through time. The results demonstrated the following episodes in the history of continental crust：（1） low growth rate of the continents due to the short cycle in production/destruction of granitic crust during the Neoarchean to Paleoproterozoic（2.9-23 Ga）,（2） net increase in volume of the continents during Paleo-to Mesoproterozoic（2.3-1.0 Ga）, and（3） net decrease in volume of the continents during the Neoproterozoic and Phanerozoic（after 1.0 Ga）. In the Archean and Paleoproterozoic, the embryonic continents were smaller than the modern continents, probably owing to the relatively rapid production and destruction of continental crust. This is indeed reflected in the heterogeneous crustal age structure of modern continents that usually have relatively small amount of Archean crusts with respect to the post-Archean ones. During the Mesoproterozoic, plural continents amalgamated into larger ones comparable to modern continental blocks in size. Relatively older crusts were preserved in continental interiors, whereas younger crusts were accreted along continental peripheries.In addition to continental arc magmatism, the direct accretion of intra-oceanic island arc around continental peripheries also became important for net continental growth. Since 1.0 Ga, total volume of continents has decreased, and this appears consistent with on-going phenomena along modern active arc-trench system with dominant tectonic erosion and/or arc subduction. Subduction of a huge amount of granitic crusts into the mantle through time is suggested, and this requires re-consideration of the mantle composition and heterogeneity.展开更多
Oxide-Zeolite(OX-ZEO) bifunctional catalyst design concept has been exemplified in several processes to direct conversion syngas to value-added chemicals and fuels such as mixed light olefins, ethylene, aromatics and ...Oxide-Zeolite(OX-ZEO) bifunctional catalyst design concept has been exemplified in several processes to direct conversion syngas to value-added chemicals and fuels such as mixed light olefins, ethylene, aromatics and gasoline.Herein we demonstrate that the product can be steered toward liquefied petroleum gas(LPG) with a selectivity up to 89% in hydrocarbons especially propane selectivity reaching 80% at CO conversion of 63% using ZnCrOx-H-SSZ-39 catalyst.Interestingly, the quantity of the acid sites of SSZ-39 does not influence obviously the hydrocarbon distribution but the strength is crucial for selective formation of propane.This finding provides an alternative route of LPG synthesis from a variety of carbon resources via syngas.展开更多
Diamond/metal composites are widely used in aerospace and electronic packaging fields due to their outstanding high thermal conductivity and low expansion.However,the difference in chemical properties leads to interfa...Diamond/metal composites are widely used in aerospace and electronic packaging fields due to their outstanding high thermal conductivity and low expansion.However,the difference in chemical properties leads to interface incompatibility between diamond and metal,which has a considerable impact on the performance of the composites.To improve the interface compatibility between diamond and metal,it is necessary to modify the interface of composites.This paper reviews the experimental research on interface modification and the application of computational simulation in diamond/metal composites.Combining computational simulation with experimental methods is a promising way to promote diamond/metal composite interface modification research.展开更多
In China, combustion of fossil fuels and biomass has produced serious air pollution that does harm to human health. Based on dose-response relationships derived from epidemiological studies, the authors calculated the...In China, combustion of fossil fuels and biomass has produced serious air pollution that does harm to human health. Based on dose-response relationships derived from epidemiological studies, the authors calculated the number of deaths and people with health problems which were thought to be attributable to China＇s air pollution in the year of 2000. In order to estimate the corresponding economic impacts from the national point of view, the general equilibrium approach was selected as an analysis tool for this study. A computable general equilibrium （CGE） model was constructed involving 39 sectors and 32 commodities. The human capital approach （HCA） was also used for comparison. The economic burden of disease for people estimated by HCA was equivalent to 1.26‰ （ranging from 0.44‰ to 1.84‰） of China＇s gross domestic product （GDP）. China＇s GDP loss estimated by the general equilibrium approach reached 0.38‰ （ranging from 0.16‰ to 0.51‰）. The difference between the two approaches and the implications of the results were discussed.展开更多
文摘Recent progress in the physics and engineering design study for themodification programme of JT-60 is presented. In order to achieve a steady state high-βplasmaoperation, which is the dominant issue of this programme, physics design for the MHD control and thestability analysis is investigated. Engineering design and the R & D for the superconducting coils,irradiation shield are performed well towards the mission of programme.
文摘There are many cracked concrete structures worldwide. Although there have been numerous efforts to eliminate cracks, some cracks are very harmful and should be repaired as soon as possible. On the other hand, some cracks are almost harmless. So, a good guideline regarding how to deal with cracks in concrete structures is needed. In this guideline, the practical investigation, repair and strengthening method of cracked concrete structures is discussed. And the detecting subjects are cracks generated immediately after casting and during the service time. This guideline targets on the owners （including managers） of concrete structure and the engineers working for the maintenance of concrete structure. JCI （Japan Concrete Institute） published first version of ＂Practical Guideline for Investigation and Repair of Cracked Concrete Structures＂ in 1980, and then the fourth version titled ＂Practical Guideline for Investigation, Repair and Strengthening of Cracked Concrete Structures--2009＂ was published. This guideline is very practical when cracks are observed in existing concrete structures, in any other countries as well as in Japan. These three authors led the establishment of this guideline.
基金the New Energy and Industrial Technology Development Organization of Japan(No.A0006)
文摘An innovative in-flight glass melting technology with induced thermal plasmas was developed for the purpose of energy conservation and environmental protection. Two-dimensional modeling was used to simulate the thermofluid fields in the plasma torch. The in-flight melting behavior of glass raw material was investigated by various analysis methods. Results showed that the plasma temperature was up to 10000 K with a maximum velocity over 30 m/s, which made it possible to melt the granulated glass raw material within milliseconds. The carbonates in the raw material decomposed completely and the compounds in the raw material attainted 100% vitrification during the in-flight time from the nozzle exit to substrate. The particle melting process is similar to the unreacted-core shrinking model.
文摘Watershed management consists of multifunctional activities to manage and address the increasing water resource problems. Ever increasing water demand and rapidly depleting water resources, it has become necessary to develop the adaptation options to recharge groundwater resources. A watershed is a special kind of Common Pool Resources (CPRs);an area is defined by hydrological linkages where optimal management requires coordinating the use of natural resources by public participation. Watershed developments have shown significant positive impacts on water table, perennially of water in wells and water availability especially in semi-arid regions. This paper describes direct and indirect impacts of the watershed activities and benefits of hydrological services dealing with watershed management with future prediction of net irrigation water supply. In the present work, we have also discussed the multiple impacts of watershed of CPRs for improving groundwater and surface water resources.
基金supported by Grant-in-Aid for Scientific Research on Innovative Areas from the Japan Society for the Promotion of Science(Nos.18H05473 and 23K13290).
文摘Fecal incontinence(FI),which can arise from various pathogenic mechanisms,has attracted considerable attention worldwide.Despite its importance,the reproduction of the defecatory system to study the mechanisms of FI remains limited,largely because of social stigma and being considered inappropriate.Inspired by the rectum’s functionalities,we developed a soft robotic system that includes a power supply,pressure sensors,data acquisition systems,a flushing mechanism,stages,and a rectal module.Specifically,the innovative soft rectal module includes actuators inspired by sphincter muscles,both soft and rigid covers,and a soft rectum mold.The rectal mold,which was fabricated from materials that mimic human rectal tissue,was produced using a mold replication fabrication method.Both the soft and rigid components of the mold were created using three-dimensional(3D)printing technology.In addition,the sphincter muscle-inspired actuators featured double-layer pouch structures that were modeled and optimized based on multilayer perceptron methods to obtain a high contraction ratio(100%),generate high pressure(9.8 kPa),and have a short recovery time(3 s).Upon assembly,this defecation robot could smoothly expel liquid feces,perform controlled solid fecal cutting,and defecate extremely solid long feces,thus closely replicating the functions of the human rectum and anal canal.This defecation robot has the potential to facilitate human understanding of the complex defecation system and contribute to the development of improved quality-of-life devices related to defecation.
基金supported by Shenzhen Science and Technology Program(NO.JCYJ20210324094000001).
文摘Perfluoroalkyl and polyfluoroalkyl substances(PFASs)pollution with their toxicity,carcinogenicity,and persistence has been concerned worldwide.Research into novel materials for detecting and removing PFASs has increased rapidly,particularly in regard to the emergence of well-characterized single-atom materials(SAMs).Owing to the high selectivity,high atom utilization,and abundant active sites of SAMs,these materials exhibit remarkable efficacy in the detection and removal of PFASs.In this work,recent advances in the synthesis of SAMs for the detection and removal PFASs are reviewed.In-depth discussions of the structure-activity relationship and reaction mechanisms have demonstrated the high efficiency,activity,and selectivity of SAMs for the detection,adsorption,and degradation of PFASs.To optimize the application of SAMs in PFASs remediation,this review comprehensively surveys SAMs applications for PFASs and analyzes potential design strategies based on synthesis methods and corresponding properties.Synthesis strategies such as wet-chemistry,which offer ease of operation and high potential for large-scale production,are recommended for the further exploration of specific SAMs for the detection and removal of PFASs.Finally,this review identifies the challenges and opportunities for development of SAMs for the detection and remediation of PFASs,providing an outlook on strategic goals for a green economy and sustainable development.
基金supported by Mahidol University(Fundamental Fund:fiscal year 2024 by the National Science Research and Innovation Fund(NSRF),FF-078/2567)Academy of Tropical Agricultural Sciences for Science and Technology Innovation Team of National Tropical Agricultural Science Center(No.CATASCXTD202401)the National Research Council of Thailand(NRCT)via the Royal Golden Jubilee Ph.D.Program(No.PHD/0150/2560)。
文摘This study delves into the pivotal role of sulfur vulcanization in defining the mechanical characteristics of natural rubber(NR)latex-dipped products.Utilizing sulfur vulcanization,known for its operational simplicity and cost-effectiveness,we examine its ability to enhance product elasticity and mechanical strength through various sulfidic bond formations such as mono-,di-,and polysulfidic bonds.Different vulcanization systems and sulfur contents were evaluated for their influence on the mechanical attributes of latex films,employing three types of NR latex,namely concentrated NR(CNR),deproteinized NR(DPNR),and small rubber particle NR(SRP),each representing distinct non-rubber components(NRCs).The study utilized advanced atomic force microscopy(AFM)equipped with PeakForce Quantitative Nanomechanical Mapping(QNM)to visualize and measure Young’s modulus distribution across the film of pre-vulcanized latex.Our findings reveal that films by CNR processed using the conventional vulcanization(CV)system exhibited enhanced tensile strength and elongation at break.It even showed a lower crosslink density than those processed using the efficient vulcanization(EV)system.Interestingly,DPNR films showed a more uniform distribution of Young’s modulus,correlating well with their superior mechanical strength.In contrast,SRP films showed excessive network structure formation in the particles due to accelerated vulcanization rates,hampering subsequent post-vulcanization interparticle crosslinking in film formation and remaining more rigid.The overall results Illustrate clearly that the ultimate mechanical properties of the latex films are strongly dependent on the type of sulfidic bonds formed.This research reveals further the very intricate relationship between the vulcanization methods,sulfur content,and latex type in optimizing the mechanical performance of NR latex products.It provides valuable insights for industry practices aimed at improving the quality and performance of latex-dipped goods.
基金supported by the National Key Research and Development Program of China(2022YFA1503602)the National Natural Science Foundation of China(22288101,U21B20101 and 22172141)+1 种基金the BASF International Network of Centers of Excellence projectthe Zhejiang Provincial Natural Science Foundation of China(LR24B030001)。
文摘ITR zeolite could be potentially used as catalysts in methanol to propylene(MTP),where their performance is strongly related to its Al distribution.However,the control of Al distribution in ITR zeolite poses a significant synthetic challenge.Herein,we demonstrate the possibility to control the Al distribution in ITR zeolites using zeolite A as an aluminum source(A-ITR).The A-ITR exhibited similar crystallinity,nanosheet morphology,textual parameters,and acidic concentration with those of conventional ITR made zeolites using aluminum isopropoxide as an aluminum source(C-ITR).Characterizations of the zeolite product with^(27)Al MQ.MAS NMR spectra,^(27)Al MAS NMR spectra,and 1-hexene cracking reveal that the A-ITR zeolites have more Al species distributed in T6 and T8 sites located in relatively smaller micropores of the framework than C-ITR.As a result,the A-ITR gave enhanced catalyst lifetime and propylene selectivity due to the suppression of the aromatic cycle in the MTP reaction,compared with the C-ITR.This work provides an alternative approach to prepare efficient ITR zeolites for MTP reaction.
基金funded by the Shenzhen Agricultural Development Special Fund(Fishery)Agricultural High-tech Project([2021]735)SAMR technical guarantee project(2023YJ22 and 2023YJ37)。
文摘Type 2 diabetes(T2D)presents a significant health challenge,underscoring the need for functional foods and nutraceutical hypoglycemic bioactive peptides for its prevention.This study investigates the potential of proteolytic hydrolysate from artificially cultivated Chinese giant salamander(CGS)meat,a rich protein source,as a preventive strategy for T2D.We produced a CGS meat hydrolysate(CGSh)and demonstrated its ability to inhibit the T2D drug target dipeptidyl peptidaseⅣ(DPP-Ⅳ)through in vitro assays.We identified 5 peptides(WRPPDH,WAPPSKD,IPDSPF,IPEMIF,and VPIAVPT)with high DPP-Ⅳinhibitory activity in CGSh,suggesting its potential antidiabetic effects.In vivo experiments showed that CGSh effectively reduced insulin resistance in mice induced with a high-fat diet,as evidenced by a slower increase in blood glucose levels and a decreased HOMA-IR index.16S rRNA sequencing analysis revealed that CGSh improved gut microbial homeostasis,promoting beneficial microorganisms and reducing harmful bacteria.Metabolomic analyses identified an increase in valeric acid levels and highlighted nine potential biomarker metabolites.By inhibiting metabolic pathways such as AGE-RAGE,CGSh might also prevent diabetic complications and reduce inflammation.These findings suggest that CGSh has a promising hypoglycemic effect,making it a potential functional food ingredient for T2D prevention and treatment.
基金Project(50875199) supported by the National Natural Science Foundation of ChinaProject supported by State Key Laboratory of Advanced Welding and Joining,China
文摘To improve the wettability of Al metal matrix composites（Al-MMCs） by common filler metals,Al-12Si-xTi（x=0.1,0.5,1,3.0;mass fraction,%） system active ternary filler metals were prepared.It was demonstrated that although the added Ti existed within Ti（Al1-xSix）3（0≤x≤0.15） phase,the shear strength and shear fracture surface of the developed Al-12Si-xTi brazes were quite similar to those of traditional Al-12Si braze due to the presence of similar microstructure of Al-Si eutectic microstructure with large volume fraction.So,small Ti addition（～1%） did not make the active brazes brittle and hard compared with the conventional Al-12Si braze.The measured melting range of each Al-12Si-xTi foil was very similar,i.e.,580-590 ℃,because the composition was close to that of eutectic.For wettability improvement,with increasing Ti content,the interfacial gap between the Al2O3 reinforcement and filler metal（R/M） could be eliminated,and the amount of the remainder of the active fillers on the composite substrate decreased after sessile drop test at 610 ℃ for 30 min.So,the wettability improvement became easy to observe repeatedly with increasing Ti content.Additionally,the amount and size of Ti（AlSi）3 phase were sensitive to the Ti content（before brazing） and Si content（after brazing）.
基金Nonprofit Industry Research Project of CEA under Grant No. 201208014National Natural Science Fund No. 51278473Environmental Protection Research Fund for Public Interest No. 201209040
文摘The generalized inversion of S-wave amplitude spectra from the free-field strong motion recordings of the China National Strong Motion Observation Network System （NSMONS） are used to evaluate the site effects in the Wenchuan area. In this regard, a total of 602 recordings from 96 aftershocks of the Wenchuan earthquake with magnitudes of M3.7-M6.5 were selected as a dataset. These recordings were obtained from 28 stations at a hypocenter distance ranging from 30 km to 150 km. The inversion results have been verified as reliable by comparing the site response at station 62WUD using the Generalized Inversion Technique （GIT） and the Standard Spectral Ratio method （SSR）. For all 28 stations, the site predominant frequency F and the average site amplification in different frequency bands of 1.0-5.0 Hz, 5.0-10.0 Hz and 1.0-10.0 Hz have been calculated based on the inversion results. Compared with the results from the horizontal-to-vertical spectral ratio （HVSR） method, it shows that the HVSR method can reasonably estimate the site predominant frequency but underestimates the site amplification. The linear fitting between the average site amplification for each frequency band and the V20 （the average uppermost-20 m shear wave velocity） shows good correlation. A distance measurement called the asperity distance DAspt is proposed to reasonably characterize the source-to-site distance for large earthquakes. Finally, the inversed site response is used to identify the soil nonlinearity in the main shock and aftershocks of Wenchuan earthquake. In ten of the 28 stations analyzed in the main shock, the soil behaved nonlinearly, where the ground motion level is apparently beyond a threshold ofPGA 〉 300 cm/s^2 or PGV 〉 20 cm/s, and only one station coded 51SFB has evidence of soil nonlinear behavior in the aftershocks.
文摘This study aims to investigate the possibility of using biopolymer(environmental friendly material) to enhance the mechanical behaviors of collapsible soil.Two types of biopolymers were(xanthan gum and guar gum) used in this study due to their stable behaviors under severe conditions and their availability with reasonable prices.The experimental program focused on three major soil properties,i.e.compaction characterizations,collapsible potential and shear parameters.These three properties are essential in process of soil improvement.Different biopolymer concentrations were used in this study and the experimental program was performed at two curing periods(soon after mixing the soil with the biopolymer and after one week curing time).Shear parameters were measured for the treated specimens under both soaked and unsoaked conditions,while a collapsible potential test was performed under different mixing conditions(wet mix and dry mix).A numerical model was built to predict the behavior of the treated collapsible soil after and before water immersing.The results indicated that the ability of both xanthan gum and guar gum can be used as improvement materials for collapsible soil treatment.The collapsible potential has been reduced from 9%to 1%after mixing the soil with 2%biopolymer concentration in the wet case.After one week curing,the cohesion has been increased from 8.5 kPa to105 kPa by increasing the xanthan gum concentration from zero to 2%,leading to an overall improvement in soil shear strength.It also proves that the guar gum is superior to the xanthan gum.The shear strength of soil can be increased by about 30%when using the guar gum in comparison with the xanthan gum at the same conditions;however,the collapsible potential of soil material will be reduced by about 20%.
文摘This paper reports on an investigation of the seismic response of base-isolated reinforced concrete buildings, which considers various isolation system parameters under bidirectional near-fault and far-fault motions. Three-dimensional models of 4-, 8-, and 12-story base-isolated buildings with nonlinear effects in the isolation system and the superstructure are investigated, and nonlinear response history analysis is carried out. The bounding values of isolation system properties that incorporate the aging effect of isolators are also taken into account, as is the current state of practice in the design and analysis of base-isolated buildings. The response indicators of the buildings are studied for near-fault and far-fault motions weight-scaled to represent the design earthquake （DE） level and the risk-targeted maximum considered earthquake （MCER） level. Results of the nonlinear response history analyses indicate no structural damage under DE-level motions for near-fault and far-fault motions and for MCER-level far-fault motions, whereas minor structural damage is observed under MCER- level near-fault motions. Results of the base-isolated buildings are compared with their fixed-base counterparts. Significant reduction of the superstructure response of the 12-story base-isolated building compared to the fixed-base condition indicates that base isolation can be effectively used in taller buildings to enhance performance. Additionally, the applicability of a rigid superstructure to predict the isolator displacement demand is also investigated. It is found that the isolator displacements can be estimated accurately using a rigid body model for the superstructure for the buildings considered.
基金The project supported by the National Natural Science Foundation of China (10125212)the Trans-Century Training Program Foundation and the Key Research Fund of the Education Ministry of China (01159)
文摘One purpose of this paper is to give a brief overview on the research status of deformation,fracture and toughening mechanisms of polymers,including experimental,theoretical and numerical studies.Emphasis is on the more recent progresses of micromechanics of rubber particle cavitation and crazing,and the de- velopment of fracture criteria for ductile polymers. The other purpose is to study the effect of triaxial stress constraint on the deforma- tion and fracture behavior of polymers.Polycarbonate(PC),acrylonitrile-butadiene- styrene(ABS)and PC/ABS alloy are considered in this investigation.A series of circumferentially blunt-notched bars are used to experimentally generate different tri- axial stress fields.The fracture surfaces of specimens with different notch radius are examined by scanning electron microscope(SEM)to study the fracture and tough- ening mechanisms of polymer alloy.It is shown that the triaxial stress constraint has a significant effect on the deformation,fracture and toughening of PC,ABS and PC/ABS alloy.We will also discuss the extent to which a micromechanies criterion proposed by the first author can serve as a fracture criterion for ductile polymers. A new ductile fracture parameter is emphasized,which can be employed to evaluate the fracture ductility of polymers.Stress state independence of the parameter for the PC,ABS and PC/ABS alloy has been experimentally verified.
基金supported by Grant-in-Aid for Scientific Research on Innovative Areas Grant Number 26106002
文摘When plate tectonics began on the Earth has been long debated and here we argue this topic based on the records of Earth-Moon geology and asteroid belt to conclude that the onset of plate tectonics was during the middle Hadean（4.37-4.20 Ga）. The trigger of the initiation of plate tectonics is the ABEL Bombardment, which delivered oceanic and atmospheric components on a completely dry reductive Earth, originally comprised of enstatite chondrite-like materials. Through the accretion of volatiles, shock metamorphism processed with vaporization of both CI chondrite and supracrustal rocks at the bombarded location, and significant recrystallization went through under wet conditions, caused considerable eclogitization in the primordial continents composed of felsic upper crust of 21 km thick anorthosite, and 50 km or even thicker KREEP lower crust. Eclogitization must have yielded a powerful slab-pull force to initiate plate tectonics in the middle Hadean. Another important factor is the size of the bombardment. By creating Pacific Ocean class crater by 1000 km across impactor, rigid plate operating stagnant lid tectonics since the early Hadean was severely destroyed, and oceanic lithosphere was generated to have bi-modal lithosphere on the Earth to enable the operation of plate tectonics.Considering the importance of the ABEL Bombardment event which initiated plate tectonics including the appearance of ocean and atmosphere, we propose that the Hadean Eon can be subdivided into three periods：（1） early Hadean（4.57-4.37 Ga）,（2） middle Hadean（4.37-4.20 Ga）, and（3） late Hadean（4.20-4.00 Ga）.
基金supported by Japan Society of Promotion of Science (JSPS KAKENHI Grants-in-Aid for Scientific Research Grant Nos. 23224012, 26106002, and 26106005) from the Japanese Ministry of Education, Science, Sports, Technology, and Culture
文摘U-Pb ages of detrital zircons were newly dated for 4 Archean sandstones from the Pilbara craton in Australia, Wyoming craton in North America, and Kaapvaal craton in Africa. By using the present results with previously published data, we compiled the age spectra of detrital zircons for 2.9, 2.6, 2.3,1.0, and0.6 Ga sandstones and modern river sands in order to document the secular change in age structure of continental crusts through time. The results demonstrated the following episodes in the history of continental crust：（1） low growth rate of the continents due to the short cycle in production/destruction of granitic crust during the Neoarchean to Paleoproterozoic（2.9-23 Ga）,（2） net increase in volume of the continents during Paleo-to Mesoproterozoic（2.3-1.0 Ga）, and（3） net decrease in volume of the continents during the Neoproterozoic and Phanerozoic（after 1.0 Ga）. In the Archean and Paleoproterozoic, the embryonic continents were smaller than the modern continents, probably owing to the relatively rapid production and destruction of continental crust. This is indeed reflected in the heterogeneous crustal age structure of modern continents that usually have relatively small amount of Archean crusts with respect to the post-Archean ones. During the Mesoproterozoic, plural continents amalgamated into larger ones comparable to modern continental blocks in size. Relatively older crusts were preserved in continental interiors, whereas younger crusts were accreted along continental peripheries.In addition to continental arc magmatism, the direct accretion of intra-oceanic island arc around continental peripheries also became important for net continental growth. Since 1.0 Ga, total volume of continents has decreased, and this appears consistent with on-going phenomena along modern active arc-trench system with dominant tectonic erosion and/or arc subduction. Subduction of a huge amount of granitic crusts into the mantle through time is suggested, and this requires re-consideration of the mantle composition and heterogeneity.
基金supported by the Ministry of Science and Technology of China (No.2017YFB0602201)the Chinese Academy of Sciences (XDA21020400)+2 种基金the National Natural Science Foundation of China (Grant nos.91645204, 21425312 and 21621063)the Youth Innovation Promotion Association of Chinese Academy of Sciences (2019184)the INCOE (International Network of Centers of Excellence) project coordinated by BASF SE
文摘Oxide-Zeolite(OX-ZEO) bifunctional catalyst design concept has been exemplified in several processes to direct conversion syngas to value-added chemicals and fuels such as mixed light olefins, ethylene, aromatics and gasoline.Herein we demonstrate that the product can be steered toward liquefied petroleum gas(LPG) with a selectivity up to 89% in hydrocarbons especially propane selectivity reaching 80% at CO conversion of 63% using ZnCrOx-H-SSZ-39 catalyst.Interestingly, the quantity of the acid sites of SSZ-39 does not influence obviously the hydrocarbon distribution but the strength is crucial for selective formation of propane.This finding provides an alternative route of LPG synthesis from a variety of carbon resources via syngas.
基金financially supported by the National Natural Science Foundation of China(Nos.52071117 and 51771063)the Heilongjiang Provincial Science Fund for Distinguished Young Scholars(No.JQ2021E002)。
文摘Diamond/metal composites are widely used in aerospace and electronic packaging fields due to their outstanding high thermal conductivity and low expansion.However,the difference in chemical properties leads to interface incompatibility between diamond and metal,which has a considerable impact on the performance of the composites.To improve the interface compatibility between diamond and metal,it is necessary to modify the interface of composites.This paper reviews the experimental research on interface modification and the application of computational simulation in diamond/metal composites.Combining computational simulation with experimental methods is a promising way to promote diamond/metal composite interface modification research.
文摘In China, combustion of fossil fuels and biomass has produced serious air pollution that does harm to human health. Based on dose-response relationships derived from epidemiological studies, the authors calculated the number of deaths and people with health problems which were thought to be attributable to China＇s air pollution in the year of 2000. In order to estimate the corresponding economic impacts from the national point of view, the general equilibrium approach was selected as an analysis tool for this study. A computable general equilibrium （CGE） model was constructed involving 39 sectors and 32 commodities. The human capital approach （HCA） was also used for comparison. The economic burden of disease for people estimated by HCA was equivalent to 1.26‰ （ranging from 0.44‰ to 1.84‰） of China＇s gross domestic product （GDP）. China＇s GDP loss estimated by the general equilibrium approach reached 0.38‰ （ranging from 0.16‰ to 0.51‰）. The difference between the two approaches and the implications of the results were discussed.
