Port structures constitute the main link in the maritime transport chain of coastal countries and therefore contribute to their economic development. But it should be noted that the installation of said works is not w...Port structures constitute the main link in the maritime transport chain of coastal countries and therefore contribute to their economic development. But it should be noted that the installation of said works is not without consequences for the countries concerned. Benin, a country in the Gulf of Guinea, is no exception to this phenomenon because, due to its maritime history, it has a heritage of port structures. These structures, built on its coastline, cause a wide variety of environmental problems such as silting and erosion on either side of them. The general objective of this article is to contribute to the proper functionality of port facilities while minimizing environmental problems that may arise. It aims to provide managers with a tool allowing them to fully understand the state of their assets in order to rationalize maintenance actions. In order to achieve this objective, an assessment of the state of the structure, and then a structural diagnosis are necessary and recommendations can be established to restore the level of service of the latter. As a result, two examples were presented: the wharf of the Sèmè-Podji pipeline project and the maritime piles project of the Wasco de Gama bridge (control project), and recommendations adapted to this objective were established. The comparative analysis of the two examples, both maritime works, revealed an under-sizing at the level of the spans of the wharf bridge of the Sèmè-Podji pipeline project (spans of 7 m in length), while these spans vary on average by 45 m to 62 m for the Wasco da Gama bridge. Bringing the piles closer together at the Sèmè-Podji wharf reduces the energy of the current which promotes the accumulation of sediment. The structure no longer experiences a flow capable of setting in motion the sands accumulated since at least 2022. This element appears to be a fundamental characteristic explaining the erosion observed to the east of the structure.展开更多
γ-Secretase,called“the proteasome of the membrane,”is a membrane-embedded protease complex that cleaves 150+peptide substrates with central roles in biology and medicine,including amyloid precursor protein and the ...γ-Secretase,called“the proteasome of the membrane,”is a membrane-embedded protease complex that cleaves 150+peptide substrates with central roles in biology and medicine,including amyloid precursor protein and the Notch family of cell-surface receptors.Mutations inγ-secretase and amyloid precursor protein lead to early-onset familial Alzheimer’s disease.γ-Secretase has thus served as a critical drug target for treating familial Alzheimer’s disease and the more common late-onset Alzheimer’s disease as well.However,critical gaps remain in understanding the mechanisms of processive proteolysis of substrates,the effects of familial Alzheimer’s disease mutations,and allosteric modulation of substrate cleavage byγ-secretase.In this review,we focus on recent studies of structural dynamic mechanisms ofγ-secretase.Different mechanisms,including the“Fit-Stay-Trim,”“Sliding-Unwinding,”and“Tilting-Unwinding,”have been proposed for substrate proteolysis of amyloid precursor protein byγ-secretase based on all-atom molecular dynamics simulations.While an incorrect registry of the Notch1 substrate was identified in the cryo-electron microscopy structure of Notch1-boundγ-secretase,molecular dynamics simulations on a resolved model of Notch1-boundγ-secretase that was reconstructed using the amyloid precursor protein-boundγ-secretase as a template successfully capturedγ-secretase activation for proper cleavages of both wildtype and mutant Notch,being consistent with biochemical experimental findings.The approach could be potentially applied to decipher the processing mechanisms of various substrates byγ-secretase.In addition,controversy over the effects of familial Alzheimer’s disease mutations,particularly the issue of whether they stabilize or destabilizeγ-secretase-substrate complexes,is discussed.Finally,an outlook is provided for future studies ofγ-secretase,including pathways of substrate binding and product release,effects of modulators on familial Alzheimer’s disease mutations of theγ-secretase-substrate complexes.Comprehensive understanding of the functional mechanisms ofγ-secretase will greatly facilitate the rational design of effective drug molecules for treating familial Alzheimer’s disease and perhaps Alzheimer’s disease in general.展开更多
In this study,the casting process is used to fabricate modified polyvinyl alcohol(PVA),starch(S),and carboxymethyl cellulose(CMC)polymer blend films(PVA/S/CMC)loaded with various concentrations of irondoped carbon qua...In this study,the casting process is used to fabricate modified polyvinyl alcohol(PVA),starch(S),and carboxymethyl cellulose(CMC)polymer blend films(PVA/S/CMC)loaded with various concentrations of irondoped carbon quantum dots(Fe-CQDs)and denoted as(PVA/S/CMC@Fe-CQDs).A one-step microwave strategy was employed as a facile method to prepare Fe-CQDs.Through a series of characterization techniques,fourier-transform infrared(FTIR)spectroscopy,x-ray diffraction(XRD)analysis,and scanning electron microscopy(SEM)have been used to show the successful integration of Fe-CQDs into the PVA/S/CMCmatrix.Loading the synthesized Fe-CQDs to the polymeric matrix significantly enhanced the mechanical properties of the films represented in the tensile strength,Young’s modulus,and hardness.However,the elongation decreased noticeably upon increasing the iron-doped carbon dots.The surface wettability was also studied by measuring the contact angle of the prepared films.The findings showed a noticeable elevation in these measurements by increasing the Fe-CQDs content,declaring the role of a hydrophobic character in these nanoparticles when introduced into a hydrophilic polymeric system.The dielectric characteristics of the reinforced polymer composite films were evaluated.These results revealed that the ac-conductivity of the investigated films was boosted with increasing Fe-CQDs’ratio and frequency.The PVA/S/CMC@Fe-CQDs films possess substantial potential for efficient energy storage applications.展开更多
NLLoc is a nonlinear search positioning method.In this study,we use simulated arrival time data to quantitatively evaluate the NLLoc method from three aspects:arrival time picking accuracy,station distribution,and vel...NLLoc is a nonlinear search positioning method.In this study,we use simulated arrival time data to quantitatively evaluate the NLLoc method from three aspects:arrival time picking accuracy,station distribution,and velocity model.The results show that the NLLoc method exhibits high positioning accuracy and stability in terms of arrival time picking accuracy and station distribution;however,it is sensitive to the velocity model.The positioning accuracy is higher when the velocity model is smaller than the true velocity.We combined absolute and relative positioning methods.First,we use the NLLoc method for absolute positioning of seismic data and then the double difference positioning method for relative positioning to obtain a more accurate relocation result.Furthermore,we used the combined method to locate the earthquake sequence after collecting dense seismic array data on the Luanzhou M_(S)4.3 earthquake that occurred on April 16,2021,in Hebei Province.By fitting the fault plane with the relocated earthquake sequences,the results show that the strike and dip angles of the seismogenic fault of the Luanzhou M_(S)4.3 earthquake are 208.5°and 85.6°,respectively.This indicates a high-dip angle fault with North-North-East strike and North-West dip directions.Furthermore,we infer that the seismogenic fault of the Luanzhou M_(S)4.3 earthquake is the Lulong fault.展开更多
According to specifications for Welding Procedure Qualification of ASME IX Section and Chinese code, JB 4708 2000, a software package for managing welding documents has been rebuilt. Consequently, the new software pa...According to specifications for Welding Procedure Qualification of ASME IX Section and Chinese code, JB 4708 2000, a software package for managing welding documents has been rebuilt. Consequently, the new software package can be used in a Limited Area Network (LAN) with 4 different levels of authorities for different users. Therefore, the welding documents, including DWPS (Design for Welding Procedure Specifications), PQRs (Procedure Qualification Records) and WPS (Welding Procedure Specifications) can be shared within a company. At the same time, the system provides users various functions such as browsing, copying, editing, searching and printing records, and helps users to make decision of whether a new PQR test is necessary or not according to the codes above as well. Furthermore, super users can also browse the history of record modification and retrieve the records when needed.展开更多
Inoculation with efficient microbes had been proved to be the most important way for the bioremediation of polluted environments. For the treatment of abandoned site of Beijing Coking Chemical Plant contaminated with ...Inoculation with efficient microbes had been proved to be the most important way for the bioremediation of polluted environments. For the treatment of abandoned site of Beijing Coking Chemical Plant contaminated with high level of high-molecular-weight polycyclic aromatic hydrocarbons （HMW-PAHs）, a bacterial consortium capable of degrading HMW-PAHs, designated 1-18-1, was enriched and screened from HMW-PAHs contaminated soil. Its degrading ability was analyzed by high performance liquid chromatography （HPLC）, and the community structure was investigated by construction and analyses of the 16S rRNA gene clone libraries （A, B and F） at different transfers. The results indicated that 1-18-1 was able to utilize pyrene, fluoranthene and benzo[a]pyrene as sole carbon and energy source for growth. The degradation rate of pyrene and fluoranthene reached 82.8% and 96.2% after incubation for 8 days at 30℃, respectively; while the degradation rate of benzo[a]pyrene was only 65.1% after incubation for 28 days at 30℃. Totally, 108, 100 and 100 valid clones were randomly selected and sequenced from the libraries A, B, and E Phylogenetic analyses showed that all the clones could be divided into 5 groups, Bacteroidetes, ct-Proteobacteria, Actinobacteria, β-Proteobacteda and γ- Proteobacteria. Sequence similarity analyses showed total 39 operational taxonomic units （OTUs） in the libraries. The predominant bacterial groups were α-Proteobacteria （19 OTUs, 48.7%）, γ-Proteobacteria （90TUs, 23.1%） and β-Proteobacteria （80TUs, 20.5%）. During the transfer process, the proportions of α-Proteobacteria and β-Proteobacteria increased greatly （from 47% to 93%）, while γ-Proteobacteda decreased from 32% （library A） to 6% （library F）; and Bacteroidetes group disappeared in libraries B and F.展开更多
This study investigated differences in the community structure and environmental responses of the bacterial community in sediments of the Bohai Sea.Illumina high-throughput sequencing technology and real-time PCR were...This study investigated differences in the community structure and environmental responses of the bacterial community in sediments of the Bohai Sea.Illumina high-throughput sequencing technology and real-time PCR were used to assay the bacterial 16S rRNA genes in the surface sediments of 13 sampling stations in the Bohai Sea.The results showed that sediments at the majority of the 13 sampling stations were contaminated by heavy metal mercury.The main phyla of bacteria recorded included Proteobacteria(52.92%),Bacteroidetes(11.76%),Planctomycetes(7.39%),Acidobacteria(6.53%)and Chloroflexi(4.97%).The genus with the highest relative abundance was Desulfobulbus(4.99%),which was the dominant genus at most sampling stations,followed by Lutimonas and Halioglobus.The main factors influencing bacterial community structure were total organic carbon,followed by depth and total phosphorus.The content of lead,cadmium,chromium,copper and zinc had a consistent effect on community structure.Arsenic showed a negative correlation with bacterial community structure in most samples,while the impact of mercury on community structure was not significant.The bacterial community in sediment samples from the Bohai Sea was rich in diversity and displayed an increase in diversity from high to low latitudes.The data indicated that the Bohai Sea had abundant microbial resources and was rich in bacteria with the potential to metabolize many types of pollutants.展开更多
Li–S battery is one of the most promising candidates for next-generation energy storage technology.However, the rapid capacity fading and low-energy-density limit its large-scale applications. Scholars invest a lot o...Li–S battery is one of the most promising candidates for next-generation energy storage technology.However, the rapid capacity fading and low-energy-density limit its large-scale applications. Scholars invest a lot of effort to introduce new materials. A neglected problem is that reasonable structure is as important as new material. In this review, four kinds of cathode structures were analyzed through morphology and electrochemical properties. The relationship between structures and properties was elaborated through reaction mechanism. The advantages and disadvantages of each structure were discussed. We hope the summary and discussion provide inspiration for structure design in Li–S battery cathode materials.展开更多
A dinuclear copper（Ⅱ） complex,[Cu2（HL）2（H2O）6] 1（H3L = 2,4,6-tri（3-carboxy-phenylthio）-1,3,5-triazine）,was synthesized hydrothermally and characterized by single-crystal X-ray diffraction,IR and thermal ana...A dinuclear copper（Ⅱ） complex,[Cu2（HL）2（H2O）6] 1（H3L = 2,4,6-tri（3-carboxy-phenylthio）-1,3,5-triazine）,was synthesized hydrothermally and characterized by single-crystal X-ray diffraction,IR and thermal analysis.Single-crystal X-ray diffraction reveals that complex 1 is a dinuclear copper（Ⅱ） complex,which is further extended to a 3D network by weak interactions such as O…H-O hydrogen bonds and noncovalent S...S interactions.The crystal of compound 1 belongs to monoclinic,space group C2/c,with a = 50.15（2）,b = 6.789（3）,c =15.667（8） ,β = 90.588（9）o,V = 5334（4） 3,Z = 4,C48H38Cu2N6O18S6,Mr = 1306.28,Dc = 1.627 g/cm3,F（000） = 2664,Rint = 0.0631,T = 293（2） K,μ = 1.112 mm-1,the final R = 0.0661 and wR = 0.1850 for 3782 observed reflections with I 2σ（I）.展开更多
We apply ambient noise tomography to continuous three-component broadband seismic data between January 1,2008 and December 31,2008 from the regional networks of 76 stations de-ployed by China Earthquake Administration...We apply ambient noise tomography to continuous three-component broadband seismic data between January 1,2008 and December 31,2008 from the regional networks of 76 stations de-ployed by China Earthquake Administration.Ambient noise cross-correlations were performed to produce the Green＇s functions of each station-pair.Within the period from 6 to 50 s,Rayleigh and Love wave dispersion curves were measured using the multiple filter analysis method.Then three-dimensional（3-D） S-wave velocity structures from the surface down to 70 km are inverted from both Rayleigh and Love wave dispersion results.The obtained S-wave velocity maps show strong lateral variations and correlate well with the distinct geological and tectonic features in the study area.The Sichuan basin displays low velocity in shallow depth due to thick sedimentary deposits but high velocity in the mid-lower crust;the eastern Tibetan plateau is clearly featured with a low-velocity zone in its mid-to-lower crust which is consistent with the crustal flow model proposed to explain the mechanism of uplift and pattern of deformation for the Tibetan plateau.Meanwhile,our results also exhibit that the crustal thickness decreased from the eastern Tibetan plateau to the Sichuan basin.展开更多
The success of the tuned mass damper (TMD) in reducing wind-induced structural vibrations has been well established. However, from most of the recent numerical studies, it appears that for a structure situated on very...The success of the tuned mass damper (TMD) in reducing wind-induced structural vibrations has been well established. However, from most of the recent numerical studies, it appears that for a structure situated on very soft soil, soil-structure interaction (SSI) could render a damper on the structure totally ineffective. In order to experimentally verify the SSI effect on the seismic performance of TMD, a series of shaking table model tests have been conducted and the results are presented in this paper. It has been shown that the TMD is not as effective in controlling the seismic responses of structures built on soft soil sites due to the SSI effect. Some test results also show that a TMD device might have a negative impact if the SSI effect is neglected and the structure is built on a soft soil site. For structures constructed on a soil foundation, this research verifies that the SSI effect must be carefully understood before a TMD control system is designed to determine if the control is necessary and if the SSI effect must be considered when choosing the optimal parameters of the TMD device.展开更多
Three Epimedium species,E.pubescens Maxim.,E.sagittatum(Sieb.&Zucc.)Maxim.,and E.wushanense T.S.Ying,which are sympatrically distributed in the western Hubei Province,have been used in traditional Chinese medicine...Three Epimedium species,E.pubescens Maxim.,E.sagittatum(Sieb.&Zucc.)Maxim.,and E.wushanense T.S.Ying,which are sympatrically distributed in the western Hubei Province,have been used in traditional Chinese medicine(TCM)for about 2,000 years.Genetic variability and population genetic structure of 11 natural populations of these Epimedium species were investigated using isoelectric focusing in thin-layer polyacrylamide slab gels.Of the 22 enzyme systems prescreened,six coding for 13 loci and 45 alleles were resolved,which were used for analyzing genetic diversity and population structure at both intraspecific and interspecific levels.The results showed that:l)high levels of genetic diversity were observed in all three species(A=2.6-3.2,P=69.2%-84.6%,Ho=0.274-0.377,HE=0.282-0.369),which were higher than that of other herbaceous and aulmal-pollinated species with similar life-history characteristics;2)there was significant deviation from Hardy-Weinberg Equilibrium,with one half of the loci showing heterozygote excess and the other homozygote excess,in all populations,suggesting the complicated breeding system of Epimedium species;3)the low level of intraspecific and interspecific genetic differentiation(GST=0.0246-0.0409 and 0.0495-0.1213,respectively)indicated a high level of gene flow among populations and close genetic relationship among the three species;and 4)UPGMA cluster analysis further showed that E.pubescens was more closely related to E.sagittatum than to E.wushanense,which was in good agreement with the morphological characters and the recent phylogenetic analysis of these species.On the basis of these results,it was concluded that the mixed breeding system,long-lived perennial life form,ancient evolutionary history,and seed dispersal by ants in Epimedium are responsible for the genetic variation and population structure of these species.展开更多
Based on S wave records of deep teleseisms on Digital Seismic Network of Shanxi Province, shear wave velocity structures beneath 6 stations were obtained by means of S wave waveform fitting. The result shows that the ...Based on S wave records of deep teleseisms on Digital Seismic Network of Shanxi Province, shear wave velocity structures beneath 6 stations were obtained by means of S wave waveform fitting. The result shows that the crust is thick in the studied region, reaching 40 km in thickness under 4 stations. The crust all alternatives high velocity layer with low velocity one. There appear varied velocity structures for different stations, and the stations around the same tectonic region exhibit similar structure characteristics. Combined with dominant depth distribution of many small-moderate earthquakes, the correlation between seismogenic layers and crustal structures of high and low velocity layers has been discussed.展开更多
Based on the biological prototype characteristics of shark’s gill jet orifice,the flexible driving characteristics of ionic exchange polymer metal composites(IPMC)artificial muscle materials and the use of sleeve fle...Based on the biological prototype characteristics of shark’s gill jet orifice,the flexible driving characteristics of ionic exchange polymer metal composites(IPMC)artificial muscle materials and the use of sleeve flexible connector,the IPMC linear driving unit simulation model is built and the IPMC material-driving dynamic control structure of bionic gill unit is developed.Meanwhile,through the stress analysis of bionic gill plate and the motion simulation of bionic gill unit,it is verified that various dynamic control and active control of the jet orifice under the condition of different mainstream field velocities will be taken by using IPMC material-driving.Moreover,the large-deflection deformation of bionic gill plate under dynamic pressure and the comparative analysis with that of a rigid gill plate is studied,leading to the achievement of approximate revised modifier from real value to theoretical value of the displacement control of IPMC.展开更多
Impurity formation energy, electronic structure, and photocatalytic properties of C-, N-, or S-doped BiOCl are investigated by density-functional theory plus U calculations(DFT + U). Results show that the doping effec...Impurity formation energy, electronic structure, and photocatalytic properties of C-, N-, or S-doped BiOCl are investigated by density-functional theory plus U calculations(DFT + U). Results show that the doping effect of S is better than that of C or N on the tunable photocatalytic activities of BiOCl. At low concentration, S-doped BiOCl systems are the most stable under Bi-rich growth conditions because of their lower impurity-formation energy. Compared with the electronic structures of S-doped BiOCl, C-or N-doped BiOCl have relatively deeper impurity energy levels appearing in their band gap(except Bi_(36)O_(35)NCl_(36)), which may act as photogenerated carrier-recombination centers and reduce photocatalytic activity. At high concentration, S is substituted on the O lattice site system, whereas some S 3p states mix with the valence band; this mixture leads to an obvious band-gap decrease and continuum-state formation above the valence-band edge of BiOCl. Such activity is advantageous to photochemical catalysis response. Compared with pure Bi OCl and a low-concentration S-doped system, a high-concentration S-doped system shows an obvious redshift on the absorption edge and has better photocatalytic O_2 evolution performance.展开更多
The title compound 9S,9aS-neotuberostemonine （1） was isolated from the 95%ethanol extract of the roots of Stemona tuberosa. The crystal structure of 1, C22H33NO4, wasdetermined by single-crystal X-ray diffraction an...The title compound 9S,9aS-neotuberostemonine （1） was isolated from the 95%ethanol extract of the roots of Stemona tuberosa. The crystal structure of 1, C22H33NO4, wasdetermined by single-crystal X-ray diffraction analysis. The crystal belongs to orthorhombicsystem, space group P212121, with a-9.0115（11）, b = 10.612（4）, c = 22.074（3） A, V= 2110.9（8）S^3, Z= 4, Mr= 375.49, Dc= 1.182 g/cm3, λ= 0.71079 A,μ= 0.080 cm^-1, F（000） = 816, S = 1.019,R = 0.0579 and wR = 0.1358. A total of 3109 unique reflections were collected, of which 2902were observed （I〉 2σ（I））. The absolute configuration of 1 could be assigned by referring to theconserved configuration of the methyl groups at C（13） and C（20）. In the solid state, the moleculeswere linked into a chain along the a-axis through weak hydrogen bond C（ll）-H（11A）…O（2）.Compound 1 shows significant inhibition of cough by 24%, 44% and 65% at doses of 50, 100 and150 mg/kg, respectively.展开更多
文摘Port structures constitute the main link in the maritime transport chain of coastal countries and therefore contribute to their economic development. But it should be noted that the installation of said works is not without consequences for the countries concerned. Benin, a country in the Gulf of Guinea, is no exception to this phenomenon because, due to its maritime history, it has a heritage of port structures. These structures, built on its coastline, cause a wide variety of environmental problems such as silting and erosion on either side of them. The general objective of this article is to contribute to the proper functionality of port facilities while minimizing environmental problems that may arise. It aims to provide managers with a tool allowing them to fully understand the state of their assets in order to rationalize maintenance actions. In order to achieve this objective, an assessment of the state of the structure, and then a structural diagnosis are necessary and recommendations can be established to restore the level of service of the latter. As a result, two examples were presented: the wharf of the Sèmè-Podji pipeline project and the maritime piles project of the Wasco de Gama bridge (control project), and recommendations adapted to this objective were established. The comparative analysis of the two examples, both maritime works, revealed an under-sizing at the level of the spans of the wharf bridge of the Sèmè-Podji pipeline project (spans of 7 m in length), while these spans vary on average by 45 m to 62 m for the Wasco da Gama bridge. Bringing the piles closer together at the Sèmè-Podji wharf reduces the energy of the current which promotes the accumulation of sediment. The structure no longer experiences a flow capable of setting in motion the sands accumulated since at least 2022. This element appears to be a fundamental characteristic explaining the erosion observed to the east of the structure.
基金supported in part by Award 2121063 from National Science Foundation(to YM)AG66986 from the National Institutes of Health(to MSW).
文摘γ-Secretase,called“the proteasome of the membrane,”is a membrane-embedded protease complex that cleaves 150+peptide substrates with central roles in biology and medicine,including amyloid precursor protein and the Notch family of cell-surface receptors.Mutations inγ-secretase and amyloid precursor protein lead to early-onset familial Alzheimer’s disease.γ-Secretase has thus served as a critical drug target for treating familial Alzheimer’s disease and the more common late-onset Alzheimer’s disease as well.However,critical gaps remain in understanding the mechanisms of processive proteolysis of substrates,the effects of familial Alzheimer’s disease mutations,and allosteric modulation of substrate cleavage byγ-secretase.In this review,we focus on recent studies of structural dynamic mechanisms ofγ-secretase.Different mechanisms,including the“Fit-Stay-Trim,”“Sliding-Unwinding,”and“Tilting-Unwinding,”have been proposed for substrate proteolysis of amyloid precursor protein byγ-secretase based on all-atom molecular dynamics simulations.While an incorrect registry of the Notch1 substrate was identified in the cryo-electron microscopy structure of Notch1-boundγ-secretase,molecular dynamics simulations on a resolved model of Notch1-boundγ-secretase that was reconstructed using the amyloid precursor protein-boundγ-secretase as a template successfully capturedγ-secretase activation for proper cleavages of both wildtype and mutant Notch,being consistent with biochemical experimental findings.The approach could be potentially applied to decipher the processing mechanisms of various substrates byγ-secretase.In addition,controversy over the effects of familial Alzheimer’s disease mutations,particularly the issue of whether they stabilize or destabilizeγ-secretase-substrate complexes,is discussed.Finally,an outlook is provided for future studies ofγ-secretase,including pathways of substrate binding and product release,effects of modulators on familial Alzheimer’s disease mutations of theγ-secretase-substrate complexes.Comprehensive understanding of the functional mechanisms ofγ-secretase will greatly facilitate the rational design of effective drug molecules for treating familial Alzheimer’s disease and perhaps Alzheimer’s disease in general.
文摘In this study,the casting process is used to fabricate modified polyvinyl alcohol(PVA),starch(S),and carboxymethyl cellulose(CMC)polymer blend films(PVA/S/CMC)loaded with various concentrations of irondoped carbon quantum dots(Fe-CQDs)and denoted as(PVA/S/CMC@Fe-CQDs).A one-step microwave strategy was employed as a facile method to prepare Fe-CQDs.Through a series of characterization techniques,fourier-transform infrared(FTIR)spectroscopy,x-ray diffraction(XRD)analysis,and scanning electron microscopy(SEM)have been used to show the successful integration of Fe-CQDs into the PVA/S/CMCmatrix.Loading the synthesized Fe-CQDs to the polymeric matrix significantly enhanced the mechanical properties of the films represented in the tensile strength,Young’s modulus,and hardness.However,the elongation decreased noticeably upon increasing the iron-doped carbon dots.The surface wettability was also studied by measuring the contact angle of the prepared films.The findings showed a noticeable elevation in these measurements by increasing the Fe-CQDs content,declaring the role of a hydrophobic character in these nanoparticles when introduced into a hydrophilic polymeric system.The dielectric characteristics of the reinforced polymer composite films were evaluated.These results revealed that the ac-conductivity of the investigated films was boosted with increasing Fe-CQDs’ratio and frequency.The PVA/S/CMC@Fe-CQDs films possess substantial potential for efficient energy storage applications.
基金Supported by the Foundation:This research project is jointly supported by Hebei Provincial Science and Technology Program(No.22375406D)The Earthquake Science and Technology Program of Hebei Province(No.DZ2023120500009,DZ2024120500001).
文摘NLLoc is a nonlinear search positioning method.In this study,we use simulated arrival time data to quantitatively evaluate the NLLoc method from three aspects:arrival time picking accuracy,station distribution,and velocity model.The results show that the NLLoc method exhibits high positioning accuracy and stability in terms of arrival time picking accuracy and station distribution;however,it is sensitive to the velocity model.The positioning accuracy is higher when the velocity model is smaller than the true velocity.We combined absolute and relative positioning methods.First,we use the NLLoc method for absolute positioning of seismic data and then the double difference positioning method for relative positioning to obtain a more accurate relocation result.Furthermore,we used the combined method to locate the earthquake sequence after collecting dense seismic array data on the Luanzhou M_(S)4.3 earthquake that occurred on April 16,2021,in Hebei Province.By fitting the fault plane with the relocated earthquake sequences,the results show that the strike and dip angles of the seismogenic fault of the Luanzhou M_(S)4.3 earthquake are 208.5°and 85.6°,respectively.This indicates a high-dip angle fault with North-North-East strike and North-West dip directions.Furthermore,we infer that the seismogenic fault of the Luanzhou M_(S)4.3 earthquake is the Lulong fault.
文摘According to specifications for Welding Procedure Qualification of ASME IX Section and Chinese code, JB 4708 2000, a software package for managing welding documents has been rebuilt. Consequently, the new software package can be used in a Limited Area Network (LAN) with 4 different levels of authorities for different users. Therefore, the welding documents, including DWPS (Design for Welding Procedure Specifications), PQRs (Procedure Qualification Records) and WPS (Welding Procedure Specifications) can be shared within a company. At the same time, the system provides users various functions such as browsing, copying, editing, searching and printing records, and helps users to make decision of whether a new PQR test is necessary or not according to the codes above as well. Furthermore, super users can also browse the history of record modification and retrieve the records when needed.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(No. KSCS2-YW-G-055-01)the High-Tech Research and Development Program(863)of China(No.2006AA06Z316)the Program of Beijing Academy of Science Technology(No.IE012009610019-1)
文摘Inoculation with efficient microbes had been proved to be the most important way for the bioremediation of polluted environments. For the treatment of abandoned site of Beijing Coking Chemical Plant contaminated with high level of high-molecular-weight polycyclic aromatic hydrocarbons （HMW-PAHs）, a bacterial consortium capable of degrading HMW-PAHs, designated 1-18-1, was enriched and screened from HMW-PAHs contaminated soil. Its degrading ability was analyzed by high performance liquid chromatography （HPLC）, and the community structure was investigated by construction and analyses of the 16S rRNA gene clone libraries （A, B and F） at different transfers. The results indicated that 1-18-1 was able to utilize pyrene, fluoranthene and benzo[a]pyrene as sole carbon and energy source for growth. The degradation rate of pyrene and fluoranthene reached 82.8% and 96.2% after incubation for 8 days at 30℃, respectively; while the degradation rate of benzo[a]pyrene was only 65.1% after incubation for 28 days at 30℃. Totally, 108, 100 and 100 valid clones were randomly selected and sequenced from the libraries A, B, and E Phylogenetic analyses showed that all the clones could be divided into 5 groups, Bacteroidetes, ct-Proteobacteria, Actinobacteria, β-Proteobacteda and γ- Proteobacteria. Sequence similarity analyses showed total 39 operational taxonomic units （OTUs） in the libraries. The predominant bacterial groups were α-Proteobacteria （19 OTUs, 48.7%）, γ-Proteobacteria （90TUs, 23.1%） and β-Proteobacteria （80TUs, 20.5%）. During the transfer process, the proportions of α-Proteobacteria and β-Proteobacteria increased greatly （from 47% to 93%）, while γ-Proteobacteda decreased from 32% （library A） to 6% （library F）; and Bacteroidetes group disappeared in libraries B and F.
基金The National Key Basic Research Special Foundation of China under contract No.2017YFC1404500the National Natural Science Foundation of China under contract No.41676115
文摘This study investigated differences in the community structure and environmental responses of the bacterial community in sediments of the Bohai Sea.Illumina high-throughput sequencing technology and real-time PCR were used to assay the bacterial 16S rRNA genes in the surface sediments of 13 sampling stations in the Bohai Sea.The results showed that sediments at the majority of the 13 sampling stations were contaminated by heavy metal mercury.The main phyla of bacteria recorded included Proteobacteria(52.92%),Bacteroidetes(11.76%),Planctomycetes(7.39%),Acidobacteria(6.53%)and Chloroflexi(4.97%).The genus with the highest relative abundance was Desulfobulbus(4.99%),which was the dominant genus at most sampling stations,followed by Lutimonas and Halioglobus.The main factors influencing bacterial community structure were total organic carbon,followed by depth and total phosphorus.The content of lead,cadmium,chromium,copper and zinc had a consistent effect on community structure.Arsenic showed a negative correlation with bacterial community structure in most samples,while the impact of mercury on community structure was not significant.The bacterial community in sediment samples from the Bohai Sea was rich in diversity and displayed an increase in diversity from high to low latitudes.The data indicated that the Bohai Sea had abundant microbial resources and was rich in bacteria with the potential to metabolize many types of pollutants.
基金financially supported by the National Natural Science Foundation of China(Nos.21273058 and 21673064)Harbin Technological Achievements Transformation Projects(No.2016DB4AG023)Harbin Institute of Technology Environment and Ecology Innovation Special Funds(No.HSCJ201620)
文摘Li–S battery is one of the most promising candidates for next-generation energy storage technology.However, the rapid capacity fading and low-energy-density limit its large-scale applications. Scholars invest a lot of effort to introduce new materials. A neglected problem is that reasonable structure is as important as new material. In this review, four kinds of cathode structures were analyzed through morphology and electrochemical properties. The relationship between structures and properties was elaborated through reaction mechanism. The advantages and disadvantages of each structure were discussed. We hope the summary and discussion provide inspiration for structure design in Li–S battery cathode materials.
基金supported by grants from the 973 Program (2007CB815301)the National Science Foundation of China (21073192,20733003, 20871114 and 20801055)+1 种基金the Science Foundation of CAS (KJCX2-YW-H20)Fujian Province (2009HZ0006-1,2006L2005)
文摘A dinuclear copper（Ⅱ） complex,[Cu2（HL）2（H2O）6] 1（H3L = 2,4,6-tri（3-carboxy-phenylthio）-1,3,5-triazine）,was synthesized hydrothermally and characterized by single-crystal X-ray diffraction,IR and thermal analysis.Single-crystal X-ray diffraction reveals that complex 1 is a dinuclear copper（Ⅱ） complex,which is further extended to a 3D network by weak interactions such as O…H-O hydrogen bonds and noncovalent S...S interactions.The crystal of compound 1 belongs to monoclinic,space group C2/c,with a = 50.15（2）,b = 6.789（3）,c =15.667（8） ,β = 90.588（9）o,V = 5334（4） 3,Z = 4,C48H38Cu2N6O18S6,Mr = 1306.28,Dc = 1.627 g/cm3,F（000） = 2664,Rint = 0.0631,T = 293（2） K,μ = 1.112 mm-1,the final R = 0.0661 and wR = 0.1850 for 3782 observed reflections with I 2σ（I）.
基金supported by the National Natural ScienceFoundation of China (No. 40804007)the Fundamental Research Funds for the Central Universities (No. 2010ZD06)
文摘We apply ambient noise tomography to continuous three-component broadband seismic data between January 1,2008 and December 31,2008 from the regional networks of 76 stations de-ployed by China Earthquake Administration.Ambient noise cross-correlations were performed to produce the Green＇s functions of each station-pair.Within the period from 6 to 50 s,Rayleigh and Love wave dispersion curves were measured using the multiple filter analysis method.Then three-dimensional（3-D） S-wave velocity structures from the surface down to 70 km are inverted from both Rayleigh and Love wave dispersion results.The obtained S-wave velocity maps show strong lateral variations and correlate well with the distinct geological and tectonic features in the study area.The Sichuan basin displays low velocity in shallow depth due to thick sedimentary deposits but high velocity in the mid-lower crust;the eastern Tibetan plateau is clearly featured with a low-velocity zone in its mid-to-lower crust which is consistent with the crustal flow model proposed to explain the mechanism of uplift and pattern of deformation for the Tibetan plateau.Meanwhile,our results also exhibit that the crustal thickness decreased from the eastern Tibetan plateau to the Sichuan basin.
基金National Natural Science Foundation of China Under Grant No.59778027State Key Laboratory of Coastal Offshore EngineeringDalian University of Technology Under Grant No.9702
文摘The success of the tuned mass damper (TMD) in reducing wind-induced structural vibrations has been well established. However, from most of the recent numerical studies, it appears that for a structure situated on very soft soil, soil-structure interaction (SSI) could render a damper on the structure totally ineffective. In order to experimentally verify the SSI effect on the seismic performance of TMD, a series of shaking table model tests have been conducted and the results are presented in this paper. It has been shown that the TMD is not as effective in controlling the seismic responses of structures built on soft soil sites due to the SSI effect. Some test results also show that a TMD device might have a negative impact if the SSI effect is neglected and the structure is built on a soft soil site. For structures constructed on a soil foundation, this research verifies that the SSI effect must be carefully understood before a TMD control system is designed to determine if the control is necessary and if the SSI effect must be considered when choosing the optimal parameters of the TMD device.
基金This work was supported by the National Natural Science Foundation of China(No.30570171)100 Talents Program of Chinese Academy of Sciences(No.05045112)Wuhan Chenguang Project(No.20055003059-45).
文摘Three Epimedium species,E.pubescens Maxim.,E.sagittatum(Sieb.&Zucc.)Maxim.,and E.wushanense T.S.Ying,which are sympatrically distributed in the western Hubei Province,have been used in traditional Chinese medicine(TCM)for about 2,000 years.Genetic variability and population genetic structure of 11 natural populations of these Epimedium species were investigated using isoelectric focusing in thin-layer polyacrylamide slab gels.Of the 22 enzyme systems prescreened,six coding for 13 loci and 45 alleles were resolved,which were used for analyzing genetic diversity and population structure at both intraspecific and interspecific levels.The results showed that:l)high levels of genetic diversity were observed in all three species(A=2.6-3.2,P=69.2%-84.6%,Ho=0.274-0.377,HE=0.282-0.369),which were higher than that of other herbaceous and aulmal-pollinated species with similar life-history characteristics;2)there was significant deviation from Hardy-Weinberg Equilibrium,with one half of the loci showing heterozygote excess and the other homozygote excess,in all populations,suggesting the complicated breeding system of Epimedium species;3)the low level of intraspecific and interspecific genetic differentiation(GST=0.0246-0.0409 and 0.0495-0.1213,respectively)indicated a high level of gene flow among populations and close genetic relationship among the three species;and 4)UPGMA cluster analysis further showed that E.pubescens was more closely related to E.sagittatum than to E.wushanense,which was in good agreement with the morphological characters and the recent phylogenetic analysis of these species.On the basis of these results,it was concluded that the mixed breeding system,long-lived perennial life form,ancient evolutionary history,and seed dispersal by ants in Epimedium are responsible for the genetic variation and population structure of these species.
基金State Key Basic Development and Programming Project Mechanism and Prediction of Continental Strong Earthquakes (G1998040705).
文摘Based on S wave records of deep teleseisms on Digital Seismic Network of Shanxi Province, shear wave velocity structures beneath 6 stations were obtained by means of S wave waveform fitting. The result shows that the crust is thick in the studied region, reaching 40 km in thickness under 4 stations. The crust all alternatives high velocity layer with low velocity one. There appear varied velocity structures for different stations, and the stations around the same tectonic region exhibit similar structure characteristics. Combined with dominant depth distribution of many small-moderate earthquakes, the correlation between seismogenic layers and crustal structures of high and low velocity layers has been discussed.
基金Project(51275102)supported by the National Natural Science Foundation of ChinaProject(HEUCF140713)supported by the Fundamental Research Funds for the Central Universities,China
文摘Based on the biological prototype characteristics of shark’s gill jet orifice,the flexible driving characteristics of ionic exchange polymer metal composites(IPMC)artificial muscle materials and the use of sleeve flexible connector,the IPMC linear driving unit simulation model is built and the IPMC material-driving dynamic control structure of bionic gill unit is developed.Meanwhile,through the stress analysis of bionic gill plate and the motion simulation of bionic gill unit,it is verified that various dynamic control and active control of the jet orifice under the condition of different mainstream field velocities will be taken by using IPMC material-driving.Moreover,the large-deflection deformation of bionic gill plate under dynamic pressure and the comparative analysis with that of a rigid gill plate is studied,leading to the achievement of approximate revised modifier from real value to theoretical value of the displacement control of IPMC.
基金This project was supported by the China Postdoctoral Science Foundation,Henan Postdoctoral Science Foundation,NCWU 2017 Annual Teaching Teacher Training Object ProjectKey Research Projects of Higher Education in Henan Province(18B150010)+1 种基金the Key Scientific Research Project of Henan Higher Education(No.17A520011)the Science and Technology Research Project of Henan Province(182102110029)
文摘Impurity formation energy, electronic structure, and photocatalytic properties of C-, N-, or S-doped BiOCl are investigated by density-functional theory plus U calculations(DFT + U). Results show that the doping effect of S is better than that of C or N on the tunable photocatalytic activities of BiOCl. At low concentration, S-doped BiOCl systems are the most stable under Bi-rich growth conditions because of their lower impurity-formation energy. Compared with the electronic structures of S-doped BiOCl, C-or N-doped BiOCl have relatively deeper impurity energy levels appearing in their band gap(except Bi_(36)O_(35)NCl_(36)), which may act as photogenerated carrier-recombination centers and reduce photocatalytic activity. At high concentration, S is substituted on the O lattice site system, whereas some S 3p states mix with the valence band; this mixture leads to an obvious band-gap decrease and continuum-state formation above the valence-band edge of BiOCl. Such activity is advantageous to photochemical catalysis response. Compared with pure Bi OCl and a low-concentration S-doped system, a high-concentration S-doped system shows an obvious redshift on the absorption edge and has better photocatalytic O_2 evolution performance.
基金supported by Guangdong Key Scientific Project(2013A022100029)Zhongshan Scientific Scheme(2017B1134)
文摘The title compound 9S,9aS-neotuberostemonine （1） was isolated from the 95%ethanol extract of the roots of Stemona tuberosa. The crystal structure of 1, C22H33NO4, wasdetermined by single-crystal X-ray diffraction analysis. The crystal belongs to orthorhombicsystem, space group P212121, with a-9.0115（11）, b = 10.612（4）, c = 22.074（3） A, V= 2110.9（8）S^3, Z= 4, Mr= 375.49, Dc= 1.182 g/cm3, λ= 0.71079 A,μ= 0.080 cm^-1, F（000） = 816, S = 1.019,R = 0.0579 and wR = 0.1358. A total of 3109 unique reflections were collected, of which 2902were observed （I〉 2σ（I））. The absolute configuration of 1 could be assigned by referring to theconserved configuration of the methyl groups at C（13） and C（20）. In the solid state, the moleculeswere linked into a chain along the a-axis through weak hydrogen bond C（ll）-H（11A）…O（2）.Compound 1 shows significant inhibition of cough by 24%, 44% and 65% at doses of 50, 100 and150 mg/kg, respectively.
