To further improve the microstructure and mechanical properties of gas tungsten arc welded(GTAW)welded joints for ZC63 magnesium alloy,post-weld heat treatment is carried out.It is found that the majority of the MgZnC...To further improve the microstructure and mechanical properties of gas tungsten arc welded(GTAW)welded joints for ZC63 magnesium alloy,post-weld heat treatment is carried out.It is found that the majority of the MgZnCu phase in the fusion zone(FZ)is dissolved in theα-Mg matrix under suitable heat treatment conditions.The remainder is diffusely distributed as rods or granules at the grain bound-aries.The excessive heat treatment temperature(460℃)leads to abnormal grain growth(AGG)in the FZ.The substructure gradient between the abnormally grown grains and the surrounding small grains pro-vides the driving force for AGG.Meanwhile,the dissolution of the MgZnCu phase weakens the hindering effect of the second phase on grain boundary migration,setting the stage for AGG.In addition,the detri-mental impact of the continuous MgZnCu phase on the mechanical properties of the welded joint is also lessened by its dissolution.The ultimate tensile strength(UTS),yield strength(YS)and elongation(EL)of the welded joints are 255 MPa,119 MPa and 27.0%,respectively,under the post-weld heat treatment process of 440℃×12 h.The welding coefficient of the welded joint reaches 97.0%,satisfying the service criteria set forth by the mechanical properties of the welded joints.展开更多
Identification of carriers of fragile X syndrome(FXS) with the subsequent prenatal diagnosis and knowledge of FXS-associated genetic profiles are essential for intervention in specific populations. We report the resul...Identification of carriers of fragile X syndrome(FXS) with the subsequent prenatal diagnosis and knowledge of FXS-associated genetic profiles are essential for intervention in specific populations. We report the results of carrier screening of 39,458 East Asian adult women and prenatal diagnosis from 87 FXS carriers.The prevalence of FXS carriers and full mutation fetuses was estimated to be 1/581 and 1/3124 in East Asian populations, respectively. We confirmed the validity of the current threshold of CGG trinucleotide repeats for FMR1 categorization;the integral risks of full mutation expansion were approximately 6.0%,43.8%, and 100% for premutation alleles with 55—74, 75—89, and ≥ 90 CGG repeats, respectively. The protective effect of AGG(adenine-guanine-guanine nucleotides) interruption in East Asian populations was validated, which is important in protecting premutation alleles with 75—89 CGG repeats from full mutation expansion. Finally, family history was shown not an effective indicator for FXS carrier screening in East Asian populations, and population-based screening was more cost-effective. This study provides an insight into the largest carrier screening and prenatal diagnosis for FXS in East Asian populations to date. The FXSassociated genetic profiles of East Asian populations are delineated, and population-based carrier screening is shown to be promising for FXS intervention.展开更多
On October 11th, 2010, Dr. Karl-LudwigKley, Chairman of the Merck Executive Board, announced in Shanghai that Merck KGaA, the global pharmaceutical and chemical company, has successfully completed its acquisition of M...On October 11th, 2010, Dr. Karl-LudwigKley, Chairman of the Merck Executive Board, announced in Shanghai that Merck KGaA, the global pharmaceutical and chemical company, has successfully completed its acquisition of Millipore Corporation, a leading Life Science company based in Billerica, Massachusetts, USA, for an aggregate purchase price including debt and cash of approximately EUR 5.2 billion (US$ 7.0 billion). Merck agreed to acquire Millipore on February 28th, 2010 for US$107 in cash per share of Millipore common stock.展开更多
Graph transformation systems have become a general formal modeling language to describe many models in software development process.Behavioral modeling of dynamic systems and model-to-model transformations are only a ...Graph transformation systems have become a general formal modeling language to describe many models in software development process.Behavioral modeling of dynamic systems and model-to-model transformations are only a few examples in which graphs have been used to software development.But even the perfect graph transformation system must be equipped with automated analysis capabilities to let users understand whether such a formal specification fulfills their requirements.In this paper,we present a new solution to verify graph transformation systems using the Bogor model checker.The attributed graph grammars(AGG)-like graph transformation systems are translated to Bandera intermediate representation(BIR),the input language of Bogor,and Bogor verifies the model against some interesting properties defined by combining linear temporal logic(LTL) and special-purpose graph rules.Experimental results are encouraging,showing that in most cases our solution improves existing approaches in terms of both performance and expressiveness.展开更多
The increasing number of photovoltaic(PV)generation and electric vehicles(EVs)on the load side has necessitated an aggregator(Agg)in power system operation.In this paper,an Agg is used to manage the energy profiles of...The increasing number of photovoltaic(PV)generation and electric vehicles(EVs)on the load side has necessitated an aggregator(Agg)in power system operation.In this paper,an Agg is used to manage the energy profiles of PV generation and EVs.However,the daily management of the Agg is challenged by uncertain PV fluctuations.To address this problem,a robust multi-time scale energy management strategy for the Agg is proposed.In a day-ahead phase,robust optimization is developed to determine the power schedule.In a real-time phase,a rolling horizon-based convex optimization model is established to track the day-ahead power schedule based on the flexibilities of the EVs.A case study indicates a good scheduling performance under an uncertain PV output.Through the convexification,the solving efficiency of the real-time operation model is improved,and the over-charging and over-discharging problems of EVs can be suppressed to a certain extent.Moreover,the power deviation between day-ahead and real-time scheduling is controllable when the EV dispatching capacity is sufficient.The strategy can ensure the flexibility of the Agg for real-time operation.展开更多
We report on a global cropland extent product at 30-m spatial resolution developed with two 30-m global land cover maps(i.e.FROM-GLC,Finer Resolution Observation and Monitoring,Global Land Cover;FROM-GLC=agg)and a 250...We report on a global cropland extent product at 30-m spatial resolution developed with two 30-m global land cover maps(i.e.FROM-GLC,Finer Resolution Observation and Monitoring,Global Land Cover;FROM-GLC=agg)and a 250-m cropland probability map.A common land cover validation sample database was used to determine optimal thresholds of cropland probability in different parts of the world to generate a cropland/noncropland mask according to the classification accuracies for cropland samples.A decision tree was then applied to combine two 250-m cropland masks:one existing mask from the literature and the other produced in this study,with the 30-m global land cover map FROM-GLC-agg.For the smallest difference with country-level cropland area in Food and Agriculture Organization Corporate Statistical(FAOSTAT)database,a final global cropland extent map was composited from the FROM-GLC,FROM-GLC-agg,and two masked crop=land layers.From this map FROM-GC(Global Cropland),we estimated the global cropland areas to be 1533.83 million hectares(Mha)in 2010,which is 6.95 Mha(0.45%)less than the area reported by the Food and Agriculture Organization(FAO)of the United Nations for the year 2010.A country-by=country comparison between the map and the FAOSTAT data showed a linear relationship(FROM-GC=1.05*FAOSTAT-1.2(Mha)with R^(2)=0.97).Africa,South America,Southeastern Asia,and Oceania are the regions with large discrepancies with the FAO survey.展开更多
基金supported by the National Natural Science Foundation of China(No.51974082)the Fundamental Research Funds for the Central Universities(No.N2209001)the Programme of Introducing Talents of Discipline Innovation to Universities 2.0(the 111 Project 2.0 of China,No.BP0719037).
文摘To further improve the microstructure and mechanical properties of gas tungsten arc welded(GTAW)welded joints for ZC63 magnesium alloy,post-weld heat treatment is carried out.It is found that the majority of the MgZnCu phase in the fusion zone(FZ)is dissolved in theα-Mg matrix under suitable heat treatment conditions.The remainder is diffusely distributed as rods or granules at the grain bound-aries.The excessive heat treatment temperature(460℃)leads to abnormal grain growth(AGG)in the FZ.The substructure gradient between the abnormally grown grains and the surrounding small grains pro-vides the driving force for AGG.Meanwhile,the dissolution of the MgZnCu phase weakens the hindering effect of the second phase on grain boundary migration,setting the stage for AGG.In addition,the detri-mental impact of the continuous MgZnCu phase on the mechanical properties of the welded joint is also lessened by its dissolution.The ultimate tensile strength(UTS),yield strength(YS)and elongation(EL)of the welded joints are 255 MPa,119 MPa and 27.0%,respectively,under the post-weld heat treatment process of 440℃×12 h.The welding coefficient of the welded joint reaches 97.0%,satisfying the service criteria set forth by the mechanical properties of the welded joints.
基金supported by the National Natural Science Foundation of China(82071662,to Q.G.)。
文摘Identification of carriers of fragile X syndrome(FXS) with the subsequent prenatal diagnosis and knowledge of FXS-associated genetic profiles are essential for intervention in specific populations. We report the results of carrier screening of 39,458 East Asian adult women and prenatal diagnosis from 87 FXS carriers.The prevalence of FXS carriers and full mutation fetuses was estimated to be 1/581 and 1/3124 in East Asian populations, respectively. We confirmed the validity of the current threshold of CGG trinucleotide repeats for FMR1 categorization;the integral risks of full mutation expansion were approximately 6.0%,43.8%, and 100% for premutation alleles with 55—74, 75—89, and ≥ 90 CGG repeats, respectively. The protective effect of AGG(adenine-guanine-guanine nucleotides) interruption in East Asian populations was validated, which is important in protecting premutation alleles with 75—89 CGG repeats from full mutation expansion. Finally, family history was shown not an effective indicator for FXS carrier screening in East Asian populations, and population-based screening was more cost-effective. This study provides an insight into the largest carrier screening and prenatal diagnosis for FXS in East Asian populations to date. The FXSassociated genetic profiles of East Asian populations are delineated, and population-based carrier screening is shown to be promising for FXS intervention.
文摘On October 11th, 2010, Dr. Karl-LudwigKley, Chairman of the Merck Executive Board, announced in Shanghai that Merck KGaA, the global pharmaceutical and chemical company, has successfully completed its acquisition of Millipore Corporation, a leading Life Science company based in Billerica, Massachusetts, USA, for an aggregate purchase price including debt and cash of approximately EUR 5.2 billion (US$ 7.0 billion). Merck agreed to acquire Millipore on February 28th, 2010 for US$107 in cash per share of Millipore common stock.
文摘Graph transformation systems have become a general formal modeling language to describe many models in software development process.Behavioral modeling of dynamic systems and model-to-model transformations are only a few examples in which graphs have been used to software development.But even the perfect graph transformation system must be equipped with automated analysis capabilities to let users understand whether such a formal specification fulfills their requirements.In this paper,we present a new solution to verify graph transformation systems using the Bogor model checker.The attributed graph grammars(AGG)-like graph transformation systems are translated to Bandera intermediate representation(BIR),the input language of Bogor,and Bogor verifies the model against some interesting properties defined by combining linear temporal logic(LTL) and special-purpose graph rules.Experimental results are encouraging,showing that in most cases our solution improves existing approaches in terms of both performance and expressiveness.
基金supported in part by the National Natural Science Foundation of China(No.51877078)the Fundamental Research Funds for the Central Universities(No.2018MS012)
文摘The increasing number of photovoltaic(PV)generation and electric vehicles(EVs)on the load side has necessitated an aggregator(Agg)in power system operation.In this paper,an Agg is used to manage the energy profiles of PV generation and EVs.However,the daily management of the Agg is challenged by uncertain PV fluctuations.To address this problem,a robust multi-time scale energy management strategy for the Agg is proposed.In a day-ahead phase,robust optimization is developed to determine the power schedule.In a real-time phase,a rolling horizon-based convex optimization model is established to track the day-ahead power schedule based on the flexibilities of the EVs.A case study indicates a good scheduling performance under an uncertain PV output.Through the convexification,the solving efficiency of the real-time operation model is improved,and the over-charging and over-discharging problems of EVs can be suppressed to a certain extent.Moreover,the power deviation between day-ahead and real-time scheduling is controllable when the EV dispatching capacity is sufficient.The strategy can ensure the flexibility of the Agg for real-time operation.
基金This research was partially supported by an Open Fund of State Key Laboratory of Remote Sensing Science(OFSLRSS201202)a National High Technology Grant from China(2009AA12200101).
文摘We report on a global cropland extent product at 30-m spatial resolution developed with two 30-m global land cover maps(i.e.FROM-GLC,Finer Resolution Observation and Monitoring,Global Land Cover;FROM-GLC=agg)and a 250-m cropland probability map.A common land cover validation sample database was used to determine optimal thresholds of cropland probability in different parts of the world to generate a cropland/noncropland mask according to the classification accuracies for cropland samples.A decision tree was then applied to combine two 250-m cropland masks:one existing mask from the literature and the other produced in this study,with the 30-m global land cover map FROM-GLC-agg.For the smallest difference with country-level cropland area in Food and Agriculture Organization Corporate Statistical(FAOSTAT)database,a final global cropland extent map was composited from the FROM-GLC,FROM-GLC-agg,and two masked crop=land layers.From this map FROM-GC(Global Cropland),we estimated the global cropland areas to be 1533.83 million hectares(Mha)in 2010,which is 6.95 Mha(0.45%)less than the area reported by the Food and Agriculture Organization(FAO)of the United Nations for the year 2010.A country-by=country comparison between the map and the FAOSTAT data showed a linear relationship(FROM-GC=1.05*FAOSTAT-1.2(Mha)with R^(2)=0.97).Africa,South America,Southeastern Asia,and Oceania are the regions with large discrepancies with the FAO survey.