The selection of chemical reactions is directly related to the quality of synthesis pathways,so a reasonable reaction evaluation metric plays a crucial role in the design and planning of synthesis pathways.Since react...The selection of chemical reactions is directly related to the quality of synthesis pathways,so a reasonable reaction evaluation metric plays a crucial role in the design and planning of synthesis pathways.Since reaction conditions also need to be considered in synthesis pathway design,a reaction metric that combines reaction time,temperature,and yield is required for chemical reactions of different reaction agents.In this study,a chemical reaction graph descriptor which includes the atom-atom mapping relationship is proposed to effectively describe reactions.Then,through pre-training using graph contrastive learning and fine-tuning through supervised learning,we establish a model for generating the probability of reaction superiority(RSscore).Finally,to validate the effectiveness of the current evaluation index,RSscore is applied in two applications,namely reaction evaluation and synthesis routes analysis,which proves that the RSscore provides an important agents-considered evaluation criterion for computer-aided synthesis planning(CASP).展开更多
Gastric cancer is one of the most common malignant tumors,for patients with advanced gastric cancer,the traditional treatment is mainly chemotherapy or combined targeted therapy;however,these have not achieved ideal e...Gastric cancer is one of the most common malignant tumors,for patients with advanced gastric cancer,the traditional treatment is mainly chemotherapy or combined targeted therapy;however,these have not achieved ideal efficacy.However,with the continuous deepening of research on molecular targeted drugs and immunosuppressants,the treatment of advanced gastric cancer patients has made new progress,and some new technologies have also been continuously emerged and applied,which brings hope for the treatment of advanced gastric cancer.Recently,several multicenter randomized controlled phase III studies on immunotherapy for advanced gastric cancer yielded encouraging results,demonstrating its superior efficacy in the treatment of advanced gastric cancer.However,prospective data to support the acceptance of surgery and the R0 removal rate following conversion therapy with immune checkpoint inhibitors are lacking.In this study,a 58-year-old woman with advanced gastric cancer and positive PD-L1 expression,negative HER-2 expression,and microsatellite stable status received immunochemotherapy combined with traditional Chinese medicine to achieve R0 resection and satisfactory efficacy.展开更多
Aqueous ammonia(NH3) is a promising alternative solvent for the capture of industrial CO_2 emissions, given its high chemical stability and CO_2 removal capacity, and low material costs and regeneration energy. NH3 al...Aqueous ammonia(NH3) is a promising alternative solvent for the capture of industrial CO_2 emissions, given its high chemical stability and CO_2 removal capacity, and low material costs and regeneration energy. NH3 also has potential for capturing multiple flue gas components, including NOx, SOxand CO_2, and producing value-added chemicals. However, its high volatility and low reactivity towards CO_2 limit its economic viability. Considerable efforts have been made to advance aqueous NH3-based post-combustion capture technologies in the last few years: in particular, General Electric's chilled NH3 process, CSIRO's mild-temperature aqueous NH3 process and SRI International's mixed-salts(NH3 and potassium carbonate) technology. Here, we review these research activities and other developments in the field, and outline future research needed to further improve aqueous NH3-based CO_2 capture technologies.展开更多
The value of form factor k at different drafts is important in predicting full-scale total resistance and speed for different types of ships. In the ITTC community, most organizations predict form factor k using a low...The value of form factor k at different drafts is important in predicting full-scale total resistance and speed for different types of ships. In the ITTC community, most organizations predict form factor k using a low-speed model test. However, this method is problematic for ships with bulbous bows and transom. In this article, a Computational Fluid Dynamics(CFD)-based method is introduced to obtain k for different type of ships at different drafts, and a comparison is made between the CFD method and the model test. The results show that the CFD method produces reasonable k values. A grid generating method and turbulence model are briefly discussed in the context of obtaining a consistent k using CFD.展开更多
Achieving more meaningful N2 conversion by reducing the energy input and carbon footprint is now being investigated through a method of N2 fixation instead of the Haber-Bosch process.Unfortunately,the electrochemical ...Achieving more meaningful N2 conversion by reducing the energy input and carbon footprint is now being investigated through a method of N2 fixation instead of the Haber-Bosch process.Unfortunately,the electrochemical N2 reduction reaction(NRR)method as a rising approach currently still shows low selectivity(Faradaic efficiency<10%)and high-energy consumption[applied potential at least-0.2 V versus the reversible hydrogen electrode(RHE)].Here,the role of molybdenum aluminum boride single crystals,belonging to a family of ternary transition metal aluminum borides known as MAB phases,is reported for the electrochemical NRR for the first time,at a low applied potential(-0.05 V versus RHE)under ambient conditions and in alkaline media.Due to the unique nano-laminated crystal structure of the MAB phase,these inexpensive materials have been found to exhibit excellent electrocatalytic performances(NH3 yield:9.2μg h^-1cm^-2mgcat^-1.,Faradaic efficiency:30.1%)at the low overpotential,and to display a high chemical stability and sustained catalytic performance.In conjunction,further mechanism studies indicate B and Al as main-group metals show a highly selective affinity to N2 due to the strong interaction between the B 2p/Al 3p band and the N 2p orbitals,while Mo exhibits specific catalytic activity toward the subsequent reduction reaction.Overall,the MAB-phase catalyst under the synergy of the elements within ternary compound can suppress the hydrogen evolution reaction and achieve enhanced NRR performance.The significance of this work is to provide a promising candidate in the future synthesis of ammonia.展开更多
Molecular simulation plays an increasingly important role in studying the properties of complex fluid systems containing charges,such as ions,piezoelectric materials,ionic liquids,ionic surfactants,polyelectrolytes,zw...Molecular simulation plays an increasingly important role in studying the properties of complex fluid systems containing charges,such as ions,piezoelectric materials,ionic liquids,ionic surfactants,polyelectrolytes,zwitterionic materials,nucleic acids,proteins,biomembranes and etc.,where the electrostatic interactions are of special significance.Several methods have been available for treating the electrostatic interactions in explicit and implicit solvent models.Accurate and efficient treatment of such interactions has therefore always been one of the most challenging issues in classical molecular dynamics simulations due to their inhomogeneity and long-range characteristics.Currently,two major challenges remain in the application field of electrostatic interactions in molecular simulations;(i)improving the representation of electrostatic interactions while reducing the computational costs in molecular simulations;(ii)revealing the role of electrostatic interactions in regulating the specific properties of complex fluids.In this review,the calculation methods of electrostatic interactions,including basic principles,applicable conditions,advantages and disadvantages are summarized and compared.Subsequently,the specific role of electrostatic interactions in governing the properties and behaviors of different complex fluids is emphasized and explained.Finally,challenges and perspective on the computational study of charged systems are given.展开更多
概述:老年抑郁症患者伴有躯体化症状在临床上非常常见。本病例报告了一例反复住院治疗,伴躯体症状的老年抑郁症患者。虽然在首次住院治疗获得了临床痊愈,但一年后病情复发,经过随访以及神经内科诊治,我们发现这其实是一例多系统萎缩(mul...概述:老年抑郁症患者伴有躯体化症状在临床上非常常见。本病例报告了一例反复住院治疗,伴躯体症状的老年抑郁症患者。虽然在首次住院治疗获得了临床痊愈,但一年后病情复发,经过随访以及神经内科诊治,我们发现这其实是一例多系统萎缩(multiple system atrophy,MSA)。这个病例的诊治过程提示我们对于一些反复治疗、疗效欠佳的老年抑郁症患者,尤其对于"躯体化症状"突出的病例,临床医生需要考虑是否存在躯体疾病,仔细寻找器质性病因。而快速动眼睡眠行为障碍(rapid eye movement sleep behavior disorder,RBD)展开更多
Recently,Problem-Based Learning(PBL)has been regarded as a possible way towards effective educational changes in Chinese universities.However,problems have been exposed in the adoption of PBL,such as choosing effectiv...Recently,Problem-Based Learning(PBL)has been regarded as a possible way towards effective educational changes in Chinese universities.However,problems have been exposed in the adoption of PBL,such as choosing effective PBL problems.The purpose of this paper is to provide a possible solution to the formulation of PBL problems for computer science courses,which is to reimplement open-source projects(ROSP).A case is demonstrated by showing how ROSP was adopted in a practical intercourse-level PBL course module.This paper contributes to a new PBL problem formulation method for promoting PBL in a practical way for Chinese universities.展开更多
Recently,InE has been regarded as a popular education strategy in Chinese universities.However,problems have been exposed in the adoption of InE,for example,in InE courses and competitions.The purpose of this paper is...Recently,InE has been regarded as a popular education strategy in Chinese universities.However,problems have been exposed in the adoption of InE,for example,in InE courses and competitions.The purpose of this paper is to provide a possible solution to the problems,which is to organize effective InE courses by integrating InE with Inter-Course-level Problem-Based Learning(ICPBL).A detailed case is demonstrated by an ICPBL elective course design with deep integration of InE in the teaching,learning,and assessments.This paper contributes to a new curriculum design for promoting InE education in practically for Chinese universities.展开更多
The heat transfer of hydrocarbon refrigerant across tube bundles have been widely used in refrigeration.Three-dimensional simulation model using volume of fluid(VOF) was presented to study the effects of tube shapes o...The heat transfer of hydrocarbon refrigerant across tube bundles have been widely used in refrigeration.Three-dimensional simulation model using volume of fluid(VOF) was presented to study the effects of tube shapes on flow pattern, film thickness and heat transfer of n-pentane across tube bundles, including circle, ellipse-shaped, egg-shaped and cam-shaped tube bundles. Simulation results agree well with experimental data in the literature. The liquid film thickness of sheet flow and heat transfer for different tube shapes were obtained numerically. The flow pattern transition occurs lower vapor quality for ellipse-shaped tube than other tube shapes. For sheet flow, the liquid film on circle tube and ellipseshaped tube is symmetrically distributed along the circumferential direction. However, the liquid film on egg-shaped tube at circumferential angles(θ) = 15°–60° is thicker than θ = 135°–165°. The liquid film on cam tube at θ = 15°–60° is slightly thinner than θ = 135°–165°. The liquid film thickness varies from thinner to thicker for ellipse-shaped, cam-shaped, egg-shape and circle within θ = 15°–60°. The effect of tube shape is insignificant on thin liquid film thickness. Ellipse-shaped tube has largest heat transfer coefficient for sheet flow. In practical engineering, the tube shape could be designed as ellipse to promote heat transfer.展开更多
基金the financial support of the National Natural Science Foundation of China(22078041,22278053)Dalian High-level Talents Innovation Support Program(2021RQ105)the Fundamental Research Funds for China Central Universities(DUT22QN209,DUT22LAB608).
文摘The selection of chemical reactions is directly related to the quality of synthesis pathways,so a reasonable reaction evaluation metric plays a crucial role in the design and planning of synthesis pathways.Since reaction conditions also need to be considered in synthesis pathway design,a reaction metric that combines reaction time,temperature,and yield is required for chemical reactions of different reaction agents.In this study,a chemical reaction graph descriptor which includes the atom-atom mapping relationship is proposed to effectively describe reactions.Then,through pre-training using graph contrastive learning and fine-tuning through supervised learning,we establish a model for generating the probability of reaction superiority(RSscore).Finally,to validate the effectiveness of the current evaluation index,RSscore is applied in two applications,namely reaction evaluation and synthesis routes analysis,which proves that the RSscore provides an important agents-considered evaluation criterion for computer-aided synthesis planning(CASP).
文摘Gastric cancer is one of the most common malignant tumors,for patients with advanced gastric cancer,the traditional treatment is mainly chemotherapy or combined targeted therapy;however,these have not achieved ideal efficacy.However,with the continuous deepening of research on molecular targeted drugs and immunosuppressants,the treatment of advanced gastric cancer patients has made new progress,and some new technologies have also been continuously emerged and applied,which brings hope for the treatment of advanced gastric cancer.Recently,several multicenter randomized controlled phase III studies on immunotherapy for advanced gastric cancer yielded encouraging results,demonstrating its superior efficacy in the treatment of advanced gastric cancer.However,prospective data to support the acceptance of surgery and the R0 removal rate following conversion therapy with immune checkpoint inhibitors are lacking.In this study,a 58-year-old woman with advanced gastric cancer and positive PD-L1 expression,negative HER-2 expression,and microsatellite stable status received immunochemotherapy combined with traditional Chinese medicine to achieve R0 resection and satisfactory efficacy.
文摘Aqueous ammonia(NH3) is a promising alternative solvent for the capture of industrial CO_2 emissions, given its high chemical stability and CO_2 removal capacity, and low material costs and regeneration energy. NH3 also has potential for capturing multiple flue gas components, including NOx, SOxand CO_2, and producing value-added chemicals. However, its high volatility and low reactivity towards CO_2 limit its economic viability. Considerable efforts have been made to advance aqueous NH3-based post-combustion capture technologies in the last few years: in particular, General Electric's chilled NH3 process, CSIRO's mild-temperature aqueous NH3 process and SRI International's mixed-salts(NH3 and potassium carbonate) technology. Here, we review these research activities and other developments in the field, and outline future research needed to further improve aqueous NH3-based CO_2 capture technologies.
基金Supported by Ministry of Industry and Information(No.K24097)
文摘The value of form factor k at different drafts is important in predicting full-scale total resistance and speed for different types of ships. In the ITTC community, most organizations predict form factor k using a low-speed model test. However, this method is problematic for ships with bulbous bows and transom. In this article, a Computational Fluid Dynamics(CFD)-based method is introduced to obtain k for different type of ships at different drafts, and a comparison is made between the CFD method and the model test. The results show that the CFD method produces reasonable k values. A grid generating method and turbulence model are briefly discussed in the context of obtaining a consistent k using CFD.
文摘Achieving more meaningful N2 conversion by reducing the energy input and carbon footprint is now being investigated through a method of N2 fixation instead of the Haber-Bosch process.Unfortunately,the electrochemical N2 reduction reaction(NRR)method as a rising approach currently still shows low selectivity(Faradaic efficiency<10%)and high-energy consumption[applied potential at least-0.2 V versus the reversible hydrogen electrode(RHE)].Here,the role of molybdenum aluminum boride single crystals,belonging to a family of ternary transition metal aluminum borides known as MAB phases,is reported for the electrochemical NRR for the first time,at a low applied potential(-0.05 V versus RHE)under ambient conditions and in alkaline media.Due to the unique nano-laminated crystal structure of the MAB phase,these inexpensive materials have been found to exhibit excellent electrocatalytic performances(NH3 yield:9.2μg h^-1cm^-2mgcat^-1.,Faradaic efficiency:30.1%)at the low overpotential,and to display a high chemical stability and sustained catalytic performance.In conjunction,further mechanism studies indicate B and Al as main-group metals show a highly selective affinity to N2 due to the strong interaction between the B 2p/Al 3p band and the N 2p orbitals,while Mo exhibits specific catalytic activity toward the subsequent reduction reaction.Overall,the MAB-phase catalyst under the synergy of the elements within ternary compound can suppress the hydrogen evolution reaction and achieve enhanced NRR performance.The significance of this work is to provide a promising candidate in the future synthesis of ammonia.
基金supported by the National Natural Science Foundation of China(21776093,21376089,41976203,21506178,21908066)。
文摘Molecular simulation plays an increasingly important role in studying the properties of complex fluid systems containing charges,such as ions,piezoelectric materials,ionic liquids,ionic surfactants,polyelectrolytes,zwitterionic materials,nucleic acids,proteins,biomembranes and etc.,where the electrostatic interactions are of special significance.Several methods have been available for treating the electrostatic interactions in explicit and implicit solvent models.Accurate and efficient treatment of such interactions has therefore always been one of the most challenging issues in classical molecular dynamics simulations due to their inhomogeneity and long-range characteristics.Currently,two major challenges remain in the application field of electrostatic interactions in molecular simulations;(i)improving the representation of electrostatic interactions while reducing the computational costs in molecular simulations;(ii)revealing the role of electrostatic interactions in regulating the specific properties of complex fluids.In this review,the calculation methods of electrostatic interactions,including basic principles,applicable conditions,advantages and disadvantages are summarized and compared.Subsequently,the specific role of electrostatic interactions in governing the properties and behaviors of different complex fluids is emphasized and explained.Finally,challenges and perspective on the computational study of charged systems are given.
文摘概述:老年抑郁症患者伴有躯体化症状在临床上非常常见。本病例报告了一例反复住院治疗,伴躯体症状的老年抑郁症患者。虽然在首次住院治疗获得了临床痊愈,但一年后病情复发,经过随访以及神经内科诊治,我们发现这其实是一例多系统萎缩(multiple system atrophy,MSA)。这个病例的诊治过程提示我们对于一些反复治疗、疗效欠佳的老年抑郁症患者,尤其对于"躯体化症状"突出的病例,临床医生需要考虑是否存在躯体疾病,仔细寻找器质性病因。而快速动眼睡眠行为障碍(rapid eye movement sleep behavior disorder,RBD)
基金This research was financially supported by the PBL Research and Application Project of Northeastern University(Grant No.PBL-JX2021yb029,PBL-JX2021yb027).
文摘Recently,Problem-Based Learning(PBL)has been regarded as a possible way towards effective educational changes in Chinese universities.However,problems have been exposed in the adoption of PBL,such as choosing effective PBL problems.The purpose of this paper is to provide a possible solution to the formulation of PBL problems for computer science courses,which is to reimplement open-source projects(ROSP).A case is demonstrated by showing how ROSP was adopted in a practical intercourse-level PBL course module.This paper contributes to a new PBL problem formulation method for promoting PBL in a practical way for Chinese universities.
基金This research was financially supported by the PBL Research and Application Project of Northeastern University(Grant No.PBL-JX2021yb029,PBL-JX2021yb027).
文摘Recently,InE has been regarded as a popular education strategy in Chinese universities.However,problems have been exposed in the adoption of InE,for example,in InE courses and competitions.The purpose of this paper is to provide a possible solution to the problems,which is to organize effective InE courses by integrating InE with Inter-Course-level Problem-Based Learning(ICPBL).A detailed case is demonstrated by an ICPBL elective course design with deep integration of InE in the teaching,learning,and assessments.This paper contributes to a new curriculum design for promoting InE education in practically for Chinese universities.
基金supported by National Natural Science Foundation of China (52006242)National Natural Science Foundation of China (52192623)+1 种基金Science Foundation of China University of Petroleum,Beijing (ZX20200126)Science and technology program for strategic cooperation of CNPC–China University of Petroleum (ZLZX2020-05)。
文摘The heat transfer of hydrocarbon refrigerant across tube bundles have been widely used in refrigeration.Three-dimensional simulation model using volume of fluid(VOF) was presented to study the effects of tube shapes on flow pattern, film thickness and heat transfer of n-pentane across tube bundles, including circle, ellipse-shaped, egg-shaped and cam-shaped tube bundles. Simulation results agree well with experimental data in the literature. The liquid film thickness of sheet flow and heat transfer for different tube shapes were obtained numerically. The flow pattern transition occurs lower vapor quality for ellipse-shaped tube than other tube shapes. For sheet flow, the liquid film on circle tube and ellipseshaped tube is symmetrically distributed along the circumferential direction. However, the liquid film on egg-shaped tube at circumferential angles(θ) = 15°–60° is thicker than θ = 135°–165°. The liquid film on cam tube at θ = 15°–60° is slightly thinner than θ = 135°–165°. The liquid film thickness varies from thinner to thicker for ellipse-shaped, cam-shaped, egg-shape and circle within θ = 15°–60°. The effect of tube shape is insignificant on thin liquid film thickness. Ellipse-shaped tube has largest heat transfer coefficient for sheet flow. In practical engineering, the tube shape could be designed as ellipse to promote heat transfer.
