Kinetic Monte Carlo （KMC） is a widely used method for studying the evolution of materials at the microcosmic level. At present, while there are many simulation software programs based on this algorithm, most focus o...Kinetic Monte Carlo （KMC） is a widely used method for studying the evolution of materials at the microcosmic level. At present, while there are many simulation software programs based on this algorithm, most focus on the verification of a certain phenomenon and have no analog-scale requirement, so many are serial in nature. The dynamic Monte Carlo algorithm is implemented using a parallel framework called SPPARKS, but Jt does not support the Embedded Atom Method （EAM） potential, which is commonly used in the dynamic simulation of metal materials. Metal material - the preferred material for most containers and components -- plays an important role in many fields, including construction engineering and transportation. In this paper, we propose and describe the development of a parallel software program called CrystaI-KMC, which is specifically used to simulate the lattice dynamics of metallic materials. This software uses MPI to achieve a parallel multiprocessing mode, which avoid the limitations of serial software in the analog scale. Finally, we describe the use of the paralleI-KMC simulation software CrystaI-KMC in simulating the diffusion of vacancies in iron, and analyze the experimental results. In addition, we tested the performance of CrystaI-KMC in ＂meta -Era＂ supercomputing clusters, and the results show the CrystaI-KMC parallel software to have good parallel speedup and scalability.展开更多
The liquid droplet evaporation character is important for not only combustion chamber design process but also high-accuracy spray combustion simulation. In this paper, the suspended droplets＇ evaporation character wa...The liquid droplet evaporation character is important for not only combustion chamber design process but also high-accuracy spray combustion simulation. In this paper, the suspended droplets＇ evaporation character was measured in a quiescent high-temperature environment by micro high-speed camera system. The gasoline and kerosene experimental results are consistent with the reference data. Methanol, common kerosene and aviation kerosene droplet evaporation characteristics, as well as their evaporation rate changing with temperature, were obtained. The evaporation rate experimental data were compared with the prediction result of Ranz-Marshall boiling temperature model（RMB）, Ranz-Marshall low-temperature model（RML）, drift flux model（DFM）, mass analogy model（MAM）, and stagnant film model（SFM）. The disparity between the experimental data and the model prediction results was mainly caused by the neglect of the natural convection effect, which was never introduced into the droplet evaporation concept. A new droplet evaporation model with consideration of natural convection buoyancy force effect was proposed in this paper. Under the experimental conditions in this paper, the calculation results of the new droplet evaporation model were agreed with the experimental data for kerosene, methanol and other fuels, with less than 20% relative deviations. The relative deviations between the new evaporation model predictions for kerosene and the experimental data from the references were within 10%.展开更多
Background:Intracranial supratentorial neuroenteric cysts are very rare lesions in the central nervous system.We described a neuroenteric cyst of the left lateral ventricle in a 38-year old male,which had been confirm...Background:Intracranial supratentorial neuroenteric cysts are very rare lesions in the central nervous system.We described a neuroenteric cyst of the left lateral ventricle in a 38-year old male,which had been confirmed by using immunohistochemistry.To date,this was the first reported case in which the neuroenteric cyst was located in the lateral ventricle.Case presentation:The patient had paroxysmal headache for half a year which exacerbated in the recent two months.MRI showed a 3cm*3cm*2.Scm cyst in the left lateral ventricle.We reported the first case,where the NC in the lateral ventricle was partly resected,provided new evidence to develop the hypothesis on NC etiology.The cyst was left partly due to the strong adherence to the surrounding structures.The final diagnosis was confirmed on histopathological and immunohistochemical analysis of the cyst.Conclusion:Lacking in characterization of the specific imaging features,neuroenteric cyst may be misdiagnosed as other types of cysts preoperatively.At present,surgical excision is the only effective treatment for neuroenteric cysts.Early diagnosis and more treatment options may be available in the future with more cases of neuroenteric cyst being reported and its pathogenesis being understood further,we hope the first reporting of the lateral ventricle NC by now can provide new evidence to NC etiology.展开更多
基金supported by the Innovation Team and Talents Cultivation Program of National Administration of Traditional Chinese Medicine(ZYYCXTD-C-202006)Gansu Cheezheng Tibetan Medicine(BUCM-2021-JS-FW-087,Beijing,China).
文摘目的:评价白脉软膏在腰椎间盘突出症(lumbar disc herniation)患者中的疗效与安全性。方法:本研究设计了一项前瞻、随机、双盲、安慰剂对照的多中心临床试验方案。计划招募194例患者,按1:1的比例平均分配至试验组和对照组。患者将接受为期14天的白脉软膏或安慰剂的干预,随后进行为期1周的随访。通过视觉模拟评分法(visual analogue scale score)评估疼痛程度,日本骨科协会评估治疗分数(Japanese Orthopedic Association score)评估功能状态,Likert量表将用于评估麻木程度,此外还将记录应急处理的使用和对健康教育的依从情况。安全性评估将包括实验室检查和不良事件记录。讨论:这项试验将首次对白脉软膏在腰椎间盘突出症患者中进行临床疗效和安全性评价。使用安慰剂的优势在于排除因盲法不充分而导致的偏倚。为了避免由研究对象和研究者的主观因素引起的任何偏倚,对于结局评价者、数据管理人员、统计分析人员以及所有相关研究人员都将实施盲法。本试验结果将为腰椎间盘突出症的治疗以及白脉软膏的未来研究方向提供重要依据。
基金supported by the National Key R & D Program of China (Nos. 2017YFB0202003 and 2017YFB0202 104)
文摘Kinetic Monte Carlo （KMC） is a widely used method for studying the evolution of materials at the microcosmic level. At present, while there are many simulation software programs based on this algorithm, most focus on the verification of a certain phenomenon and have no analog-scale requirement, so many are serial in nature. The dynamic Monte Carlo algorithm is implemented using a parallel framework called SPPARKS, but Jt does not support the Embedded Atom Method （EAM） potential, which is commonly used in the dynamic simulation of metal materials. Metal material - the preferred material for most containers and components -- plays an important role in many fields, including construction engineering and transportation. In this paper, we propose and describe the development of a parallel software program called CrystaI-KMC, which is specifically used to simulate the lattice dynamics of metallic materials. This software uses MPI to achieve a parallel multiprocessing mode, which avoid the limitations of serial software in the analog scale. Finally, we describe the use of the paralleI-KMC simulation software CrystaI-KMC in simulating the diffusion of vacancies in iron, and analyze the experimental results. In addition, we tested the performance of CrystaI-KMC in ＂meta -Era＂ supercomputing clusters, and the results show the CrystaI-KMC parallel software to have good parallel speedup and scalability.
基金supported by the National Natural Science Foundation of China (No. 51106006)
文摘The liquid droplet evaporation character is important for not only combustion chamber design process but also high-accuracy spray combustion simulation. In this paper, the suspended droplets＇ evaporation character was measured in a quiescent high-temperature environment by micro high-speed camera system. The gasoline and kerosene experimental results are consistent with the reference data. Methanol, common kerosene and aviation kerosene droplet evaporation characteristics, as well as their evaporation rate changing with temperature, were obtained. The evaporation rate experimental data were compared with the prediction result of Ranz-Marshall boiling temperature model（RMB）, Ranz-Marshall low-temperature model（RML）, drift flux model（DFM）, mass analogy model（MAM）, and stagnant film model（SFM）. The disparity between the experimental data and the model prediction results was mainly caused by the neglect of the natural convection effect, which was never introduced into the droplet evaporation concept. A new droplet evaporation model with consideration of natural convection buoyancy force effect was proposed in this paper. Under the experimental conditions in this paper, the calculation results of the new droplet evaporation model were agreed with the experimental data for kerosene, methanol and other fuels, with less than 20% relative deviations. The relative deviations between the new evaporation model predictions for kerosene and the experimental data from the references were within 10%.
文摘Background:Intracranial supratentorial neuroenteric cysts are very rare lesions in the central nervous system.We described a neuroenteric cyst of the left lateral ventricle in a 38-year old male,which had been confirmed by using immunohistochemistry.To date,this was the first reported case in which the neuroenteric cyst was located in the lateral ventricle.Case presentation:The patient had paroxysmal headache for half a year which exacerbated in the recent two months.MRI showed a 3cm*3cm*2.Scm cyst in the left lateral ventricle.We reported the first case,where the NC in the lateral ventricle was partly resected,provided new evidence to develop the hypothesis on NC etiology.The cyst was left partly due to the strong adherence to the surrounding structures.The final diagnosis was confirmed on histopathological and immunohistochemical analysis of the cyst.Conclusion:Lacking in characterization of the specific imaging features,neuroenteric cyst may be misdiagnosed as other types of cysts preoperatively.At present,surgical excision is the only effective treatment for neuroenteric cysts.Early diagnosis and more treatment options may be available in the future with more cases of neuroenteric cyst being reported and its pathogenesis being understood further,we hope the first reporting of the lateral ventricle NC by now can provide new evidence to NC etiology.
