Short process forming techniques for brazing and soldering materials can shorten the process,improve product quality,and increase production efficiency,which has received much attention from welding researchers.This r...Short process forming techniques for brazing and soldering materials can shorten the process,improve product quality,and increase production efficiency,which has received much attention from welding researchers.This review mainly summarized the research reports on short process forming techniques for brazing and soldering materials.Firstly,the traditional process and its shortcomings were presented.Secondly,the latest research of short process forming technologies,such as continuous casting technique,atomization powder technique,solder ball forming technique,and rapid solidification technique,was summarized,and the traditional forming performance of several brazing and soldering materials was introduced.Finally,the current restrictions and research trends of short process forming technique for brazing and solder materials were put forward,providing theoretical guidance and reference for related research and technique development in brazing and soldering field.展开更多
Al-Mg-Si(AA6xxx)series alloys have been used widely in automotive industry for lightweight purpose.This work focuses on developing a short process for manufacturing Al-0.5Mg-1.3Si(wt.%)alloy sheets with good mechanica...Al-Mg-Si(AA6xxx)series alloys have been used widely in automotive industry for lightweight purpose.This work focuses on developing a short process for manufacturing Al-0.5Mg-1.3Si(wt.%)alloy sheets with good mechanical properties.Hereinto,a preparation route without homogenization was proposed on the basis of sub-rapid solidification(SRS)technique.The sample under SRS has fine microstructure and higher average partition coefficients of solute atoms,leading to weaker microsegregation owing to the higher cooling rate(160℃/s)than conventional solidification(CS,30℃/s).Besides,Mg atoms tend to be trapped in Al matrix under SRS,inducing suppression of Mg2Si,and promoting generation of Al Fe Si phase.After being solution heat treated(T4 state),samples following the SRS route have lower yield strength compared with that by CS route,indicating better formability in SRS sample.After undergoing pre-strain and artificial aging(T6 state),the SRS samples have comparable yield strength to CS samples,satisfying the service requirements.This work provides technological support to industrially manufacture high performance AA6xxx series alloys with competitive advantage by a novel,short and low-cost process,and open a door for the further development of twin-roll casting based on SRS technique in industries.展开更多
As an important intermediate product, short-chain fatty acids（SCFAs） can be generated after hydrolysis and acidification from waste activated sludge, and then can be transformed to methane during anaerobic digestion...As an important intermediate product, short-chain fatty acids（SCFAs） can be generated after hydrolysis and acidification from waste activated sludge, and then can be transformed to methane during anaerobic digestion process. In order to obtain more SCFA and methane,most studies in literatures were centered on enhancing the hydrolysis of sludge anaerobic digestion which was proved as un-efficient. Though the alkaline pretreatment in our previous study increased both the hydrolysis and acidification processes, it had a vast chemical cost which was considered uneconomical. In this paper, a low energy consumption pretreatment method, i.e. enhanced the whole three stages of the anaerobic fermentation processes at the same time, was reported, by which hydrolysis and acidification were both enhanced, and the SCFA and methane generation can be significantly improved with a small quantity of chemical input. Firstly, the effect of different pretreated temperatures and pretreatment time on sludge hydrolyzation was compared. It was found that sludge pretreated at 100°C for 60 min can achieve the maximal hydrolyzation. Further, effects of different initial p Hs on acidification of the thermal pretreated sludge were investigated and the highest SCFA was observed at initial p H 9.0with fermentation time of 6 d, the production of which was 348.63 mg COD/g VSS（6.8 times higher than the blank test） and the acetic acid was dominant acid. Then, the mechanisms for this new pretreatment significantly improving SCFA production were discussed. Finally,the effect of this low energy consumption pretreatment on methane generation was investigated.展开更多
In several stress responsive gene loci of monocot cereal crops,we have previously identified an unusual posttranscriptional processing mediated by paired presence of short direct repeated （SDR） sequences at 5＇ and ...In several stress responsive gene loci of monocot cereal crops,we have previously identified an unusual posttranscriptional processing mediated by paired presence of short direct repeated （SDR） sequences at 5＇ and 3＇ splicing junctions that are distinct from conventional （U2/U12-type） splicing boundaries.By using the known SDR-containing sequences as probes,24 plant candidate genes involved in diverse functional pathways from both monocots and dicots that potentially possess SDR-mediated posttranscriptional processing were predicted in the GenBank database.The SDRs-mediated posttranscriptional processing events including cis-and trans-actions were experimentally detected in majority of the predicted candidates.Extensive sequence analysis demonstrates several types of SDR-associated splicing peculiarities including partial exon deletion,exon fragment repetition,exon fragment scrambling and trans-splicing that result in either loss of partial exon or unusual exonic sequence rearrangements within or between RNA molecules.In addition,we show that the paired presence of SDR is necessary but not sufficient in SDR-mediated splicing in transient expression and stable transformation systems.We also show prokaryote is incapable of SDR-mediated premRNA splicing.展开更多
In order to detecting and tracking along the weld seam with rotating arc sensor in underwater welding,the highpressure water environment rotating arc welding hardware platform is established and welding experiments us...In order to detecting and tracking along the weld seam with rotating arc sensor in underwater welding,the highpressure water environment rotating arc welding hardware platform is established and welding experiments using rotating arc sensor is done. Different radius of rotating arc sensor is used. And the corresponding welding current and voltage is obtained,which is compared with the results of rotating arc sensor short-circuit process simulation model under high-pressure water environment established in this article. The results show that under high-pressure water environment,rotating arc radius should be optimized,otherwise the short-circuit-arcing cycle will transit to a short-circuit-arcing-abruption cycle,making the welding quality poor. At last the critical radius between the short-circuit-arcing cycle and short-circuit-arcing-abruption cycle under high-pressure water environment is obtained.展开更多
The effects of Reactive Black 5 utilized to cotton fabrics by short wet-steam process on the dyeing properties were investigated. This study will provide a theoretical reference for short wet-steam process of cotton f...The effects of Reactive Black 5 utilized to cotton fabrics by short wet-steam process on the dyeing properties were investigated. This study will provide a theoretical reference for short wet-steam process of cotton fabrics with bifunctional reactive dyes. The optimal amount of Selilao agent was 20 g/L, while the soaping and rubbing fastness of the dyed cotton fabrics were both reached to 4-5 rating.展开更多
An intelligent fuzzy c-means system for process monitoring and recognition of process disturbances during short- circuiting gas metal arc welding （GMAW） is introduced in this paper. The raw measured and statisticall...An intelligent fuzzy c-means system for process monitoring and recognition of process disturbances during short- circuiting gas metal arc welding （GMAW） is introduced in this paper. The raw measured and statistically test data of probability density distribution （ PDD ） and class frequency distribution （ CFD ） of welding electrical parameters are further processed into a 7-dimensional array which is designed to describe various welding conditions, and is employed as input vector of the intelligent fuzzy c-means system. The fuzzy c-means system is used to conduct process monitoring and automatic recognition. The correct recognition rate of 24 test data under 8 kinds of welding condition is 92%.展开更多
The modeling of the term structure of interest rates is one of primary topics for researches in financial economics. Here we consider models of the short interest rate in discrete processes. Our methodology of analysi...The modeling of the term structure of interest rates is one of primary topics for researches in financial economics. Here we consider models of the short interest rate in discrete processes. Our methodology of analysis follows the framework of discrete stochastic calculus.展开更多
The effect of tramp elements in the steel was intensively studied. It was found that the solubility of tramp elements decreased as the temperature decreased under normal cooling conditions. The tramp elements （Cu, Pb...The effect of tramp elements in the steel was intensively studied. It was found that the solubility of tramp elements decreased as the temperature decreased under normal cooling conditions. The tramp elements （Cu, Pb, and Sn） diffused toward the grain boundaries, and intermetallic compounds or rich phases which have low melting points were formed, causing reduction in ductility and failure during the bending test. Rebars with Cu content which were left to air cooling after the last step showed drop in elongation, up to 32 %. On contrast, the samples with high per- centage of tramp elements （Cu, Pb, and Sn） in the billet, which were rolled and subjected to Tempcore process, did not show drop in elongation or failure in bending test （especially for rebar with diameter less than 32 mm）; however, copper must be less than 0.35 mass% to prevent the precipitation of Cu-rich zones of critical size in 32 mm. When quench- ing was applied, the tramp elements remained in the interstitial supersaturated solid solution positions inside the grains and would not have the chance to diffuse and form precipitates, hindering the copper precipitates from reac- hing the critical size necessary for impairing the properties. This would hinder the occurrence of the harmful effect of the tramp elements on the elongation or the hot shortness after rolling.展开更多
Probability criterion has its practical significance, and its investment decision-making is determined by the expected discounted wealth. In a complete, standard financial market with short-selling allowed, this paper...Probability criterion has its practical significance, and its investment decision-making is determined by the expected discounted wealth. In a complete, standard financial market with short-selling allowed, this paper probes into the investment decision-making with probability criterion. The upper limit of criterion function is obtained. The corresponding discounted wealth process and hedging portfolio process are provided. Finally, an illustrative example of one-dimensional constant-coefficient financial market is given.展开更多
基金National Key Research and Development Program(2021YFB3401101)。
文摘Short process forming techniques for brazing and soldering materials can shorten the process,improve product quality,and increase production efficiency,which has received much attention from welding researchers.This review mainly summarized the research reports on short process forming techniques for brazing and soldering materials.Firstly,the traditional process and its shortcomings were presented.Secondly,the latest research of short process forming technologies,such as continuous casting technique,atomization powder technique,solder ball forming technique,and rapid solidification technique,was summarized,and the traditional forming performance of several brazing and soldering materials was introduced.Finally,the current restrictions and research trends of short process forming technique for brazing and solder materials were put forward,providing theoretical guidance and reference for related research and technique development in brazing and soldering field.
基金Financial supports from The National key research and development program(No.2016YFE0115300)The Natural Science Foundation of China(Nos.51790483,51625402,51790485 and 51801069)are greatly acknowledged+2 种基金Partial financial support came from The science and technology development program of Jilin Province(No.20190901010JC)The Changjiang Scholars Program(T2017035)the Program for JLU Science and Technology Innovative Research Team(JLUSTIRT,2017TD-09).
文摘Al-Mg-Si(AA6xxx)series alloys have been used widely in automotive industry for lightweight purpose.This work focuses on developing a short process for manufacturing Al-0.5Mg-1.3Si(wt.%)alloy sheets with good mechanical properties.Hereinto,a preparation route without homogenization was proposed on the basis of sub-rapid solidification(SRS)technique.The sample under SRS has fine microstructure and higher average partition coefficients of solute atoms,leading to weaker microsegregation owing to the higher cooling rate(160℃/s)than conventional solidification(CS,30℃/s).Besides,Mg atoms tend to be trapped in Al matrix under SRS,inducing suppression of Mg2Si,and promoting generation of Al Fe Si phase.After being solution heat treated(T4 state),samples following the SRS route have lower yield strength compared with that by CS route,indicating better formability in SRS sample.After undergoing pre-strain and artificial aging(T6 state),the SRS samples have comparable yield strength to CS samples,satisfying the service requirements.This work provides technological support to industrially manufacture high performance AA6xxx series alloys with competitive advantage by a novel,short and low-cost process,and open a door for the further development of twin-roll casting based on SRS technique in industries.
基金supported by the National Science Foundation of China (Grant no. 51408419)the National Key Technology Research and Development Program of China (Grant nos. 2014BAL02B02-03 and 2014BAC29B01)the Key Program for International S&T Cooperation Projects of China (Grant no. 2012DFG91380)
文摘As an important intermediate product, short-chain fatty acids（SCFAs） can be generated after hydrolysis and acidification from waste activated sludge, and then can be transformed to methane during anaerobic digestion process. In order to obtain more SCFA and methane,most studies in literatures were centered on enhancing the hydrolysis of sludge anaerobic digestion which was proved as un-efficient. Though the alkaline pretreatment in our previous study increased both the hydrolysis and acidification processes, it had a vast chemical cost which was considered uneconomical. In this paper, a low energy consumption pretreatment method, i.e. enhanced the whole three stages of the anaerobic fermentation processes at the same time, was reported, by which hydrolysis and acidification were both enhanced, and the SCFA and methane generation can be significantly improved with a small quantity of chemical input. Firstly, the effect of different pretreated temperatures and pretreatment time on sludge hydrolyzation was compared. It was found that sludge pretreated at 100°C for 60 min can achieve the maximal hydrolyzation. Further, effects of different initial p Hs on acidification of the thermal pretreated sludge were investigated and the highest SCFA was observed at initial p H 9.0with fermentation time of 6 d, the production of which was 348.63 mg COD/g VSS（6.8 times higher than the blank test） and the acetic acid was dominant acid. Then, the mechanisms for this new pretreatment significantly improving SCFA production were discussed. Finally,the effect of this low energy consumption pretreatment on methane generation was investigated.
基金supported by the National Key Basic Research Program (973 program) (No. 2006CB100205)the National Science Fund for Distinguished Young Scholars (No. 30825030)+2 种基金the National Natural Science Foundation of China (No. 30770466, 90717110, 30970260 and 30971752)the Earmarked Fund for Modern Agro-industry Technology Research System (No. nycytx-01)the National High Technology Research and Development Program of China (863 Program) (No. 2007AA10Z100)
文摘In several stress responsive gene loci of monocot cereal crops,we have previously identified an unusual posttranscriptional processing mediated by paired presence of short direct repeated （SDR） sequences at 5＇ and 3＇ splicing junctions that are distinct from conventional （U2/U12-type） splicing boundaries.By using the known SDR-containing sequences as probes,24 plant candidate genes involved in diverse functional pathways from both monocots and dicots that potentially possess SDR-mediated posttranscriptional processing were predicted in the GenBank database.The SDRs-mediated posttranscriptional processing events including cis-and trans-actions were experimentally detected in majority of the predicted candidates.Extensive sequence analysis demonstrates several types of SDR-associated splicing peculiarities including partial exon deletion,exon fragment repetition,exon fragment scrambling and trans-splicing that result in either loss of partial exon or unusual exonic sequence rearrangements within or between RNA molecules.In addition,we show that the paired presence of SDR is necessary but not sufficient in SDR-mediated splicing in transient expression and stable transformation systems.We also show prokaryote is incapable of SDR-mediated premRNA splicing.
基金supported by the National Natural Science Foundation of China(Grant No.51665016)founded by the China Scholarship Council(Grant No.201508360113)
文摘In order to detecting and tracking along the weld seam with rotating arc sensor in underwater welding,the highpressure water environment rotating arc welding hardware platform is established and welding experiments using rotating arc sensor is done. Different radius of rotating arc sensor is used. And the corresponding welding current and voltage is obtained,which is compared with the results of rotating arc sensor short-circuit process simulation model under high-pressure water environment established in this article. The results show that under high-pressure water environment,rotating arc radius should be optimized,otherwise the short-circuit-arcing cycle will transit to a short-circuit-arcing-abruption cycle,making the welding quality poor. At last the critical radius between the short-circuit-arcing cycle and short-circuit-arcing-abruption cycle under high-pressure water environment is obtained.
文摘The effects of Reactive Black 5 utilized to cotton fabrics by short wet-steam process on the dyeing properties were investigated. This study will provide a theoretical reference for short wet-steam process of cotton fabrics with bifunctional reactive dyes. The optimal amount of Selilao agent was 20 g/L, while the soaping and rubbing fastness of the dyed cotton fabrics were both reached to 4-5 rating.
基金The authors are grateful to the financial support provided by the National Natural Science Foundation of China under grant No. 51005106, Research Fund for the Doctoral Program of Jiangsu Uni- versity of Science and Technology under grant No. 35060902, A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘An intelligent fuzzy c-means system for process monitoring and recognition of process disturbances during short- circuiting gas metal arc welding （GMAW） is introduced in this paper. The raw measured and statistically test data of probability density distribution （ PDD ） and class frequency distribution （ CFD ） of welding electrical parameters are further processed into a 7-dimensional array which is designed to describe various welding conditions, and is employed as input vector of the intelligent fuzzy c-means system. The fuzzy c-means system is used to conduct process monitoring and automatic recognition. The correct recognition rate of 24 test data under 8 kinds of welding condition is 92%.
文摘The modeling of the term structure of interest rates is one of primary topics for researches in financial economics. Here we consider models of the short interest rate in discrete processes. Our methodology of analysis follows the framework of discrete stochastic calculus.
文摘The effect of tramp elements in the steel was intensively studied. It was found that the solubility of tramp elements decreased as the temperature decreased under normal cooling conditions. The tramp elements （Cu, Pb, and Sn） diffused toward the grain boundaries, and intermetallic compounds or rich phases which have low melting points were formed, causing reduction in ductility and failure during the bending test. Rebars with Cu content which were left to air cooling after the last step showed drop in elongation, up to 32 %. On contrast, the samples with high per- centage of tramp elements （Cu, Pb, and Sn） in the billet, which were rolled and subjected to Tempcore process, did not show drop in elongation or failure in bending test （especially for rebar with diameter less than 32 mm）; however, copper must be less than 0.35 mass% to prevent the precipitation of Cu-rich zones of critical size in 32 mm. When quench- ing was applied, the tramp elements remained in the interstitial supersaturated solid solution positions inside the grains and would not have the chance to diffuse and form precipitates, hindering the copper precipitates from reac- hing the critical size necessary for impairing the properties. This would hinder the occurrence of the harmful effect of the tramp elements on the elongation or the hot shortness after rolling.
基金This project was supported by the National Natural Science Foundation of China(70171004)Tianjin Natural Science Foundation(013602611).
文摘Probability criterion has its practical significance, and its investment decision-making is determined by the expected discounted wealth. In a complete, standard financial market with short-selling allowed, this paper probes into the investment decision-making with probability criterion. The upper limit of criterion function is obtained. The corresponding discounted wealth process and hedging portfolio process are provided. Finally, an illustrative example of one-dimensional constant-coefficient financial market is given.
