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Numerical simulation of damage in high arch dam due to earthquake

Hong ZHONG , Gao LIN , Hongjun LI

《结构与土木工程前沿(英文)》 2009年 第3卷 第3期   页码 316-322 doi: 10.1007/s11709-009-0039-9

摘要: Based on the assumption that concrete is macroscopic homogeneous, the cracking evolution process and damage mode of high arch dams are studied in consideration of the heterogeneity of concrete in mesoscale. The bilinear damage evolution model and the damage evolution model expressed in power function with descending section are adopted to combine with the Mohr-Coulomb criterion to investigate the crack development and fracture mode of high arch dams under the action of an earthquake. The analysis result of a high arch dam in China under design shows that cracks that take place in concrete are caused by excessive tensile stress. The cracks initiate at the middle of the dam top and distribute at the upper half of the dam while the rest of the parts remain intact. This conclusion agrees with the model test result.

关键词: mesoscopic heterogeneity     damage simulation in earthquakes     arch dam    

Heterogeneity of the tumor immune microenvironment and clinical interventions

《医学前沿(英文)》 2023年 第17卷 第4期   页码 617-648 doi: 10.1007/s11684-023-1015-9

摘要: Heterogeneity of the tumor immune microenvironment and clinical interventions

关键词: Heterogeneity tumor immune    

用于介观模拟电子束选区熔化的数据挖掘技术 Article

钱亚, 闫文韬, 林峰

《工程(英文)》 2019年 第5卷 第4期   页码 746-754 doi: 10.1016/j.eng.2019.06.006

摘要:

 在电子束选区熔化技术(EBSM)工艺中,制造部件的性质受到每一道熔道沉积质量的影响。然而,熔道的形成受到各种物理现象和工艺参数的支配,这些参数之间的相关性十分复杂,难以通过实验得出。近来,介观建模技术已成为模拟电子束(EB)熔化过程以及揭示特定熔道形貌的形成机制的手段。尽管如此,人们对工艺参数与熔道特征之间的相关性尚未有定量的理解。本文从介观模拟的结果出发,研究了熔道的形态特征,同时引入了熔道宽度和高度等关键性描述指标,以便从数值上评估沉积质量。本文还定量研究了各种工艺参数的影响,从而导出了工艺条件和熔道特征之间的相关性。最后,本文提出了一种由介观建模和数据挖掘技术组成的仿真驱动优化框架,并讨论了框架的潜力和局限性。

关键词: 电子束选区熔化     介观模型     数据挖掘    

bottleneck of phosphonic acid anchoring groups aiming toward enhancing the stability and efficiency of mesoscopic

《化学科学与工程前沿(英文)》 2022年 第16卷 第7期   页码 1060-1078 doi: 10.1007/s11705-021-2117-z

摘要: Novel near-infrared sensitizers with different anchoring groups aiming toward improved stability and efficiency of dye-sensitized solar cells were synthesized. Adsorption of these dyes on the mesoporous TiO2 surface revealed the dye adsorption rate of –CH=CH–COOH (SQ-139)>–CH=C(CN)COOH (SQ-140)>–PO3H2 (SQ-143)>–CH=C(CN)PO3H2 (SQ-148)>–CH=C(CN)PO3H–C2H5 (SQ-157)>–PO3H–C2H5 (SQ-151)>–CH=CH–COOH(–PO3H2) (SQ-162). The binding strength of these dyes on mesoporous TiO2 as investigated by dye desorption studies follows SQ-162>SQ-143>SQ-148>SQ-139>SQ-157~SQ-151>SQ-140 order. The acrylic acid anchoring group was demonstrated to be an optimum functional group owing to its fast dye adsorption rate and better binding strength on TiO2 along with good photoconversion efficiency. Results of dye binding on TiO2 surface demonstrated that SQ-162 bearing double anchoring groups of phosphonic and acrylic acid exhibited>550 times stronger binding as compared to dye SQ-140 having cyanoacrylic acid anchoring group. SQ-140 exhibited the best photovoltaic performance with photon harvesting mainly in the far-red to near-infrared wavelength region having short circuit current density, open-circuit voltage and fill factor of 14.28 mA·cm–2, 0.64 V and 0.65, respectively, giving the power conversion efficiency of 5.95%. Thus, dye SQ-162 not only solved the problem of very poor efficiency of dye bearing only phosphonic acid while maintaining the extremely high binding strength opening the path for the design and development of novel near-infrared dyes with improved efficiency and stability by further increasing the π-conjugation.

关键词: anchoring groups     adsorption behaviour     dye-binding strength     squaraine dyes     dye-sensitized solar cells    

Intratumor heterogeneity, microenvironment, and mechanisms of drug resistance in glioma recurrence and

Zhaoshi Bao, Yongzhi Wang, Qiangwei Wang, Shengyu Fang, Xia Shan, Jiguang Wang, Tao Jiang

《医学前沿(英文)》 2021年 第15卷 第4期   页码 551-561 doi: 10.1007/s11684-020-0760-2

摘要: Glioma is the most common lethal tumor of the human brain. The median survival of patients with primary World Health Organization grade IV glioma is only 14.6 months. The World Health Organization classification of tumors of the central nervous system categorized gliomas into lower-grade gliomas and glioblastomas. Unlike primary glioblastoma that usually develop in the elderly, secondary glioblastoma enriched with an isocitrate dehydrogenase mutant typically progresses from lower-grade glioma within 5–10 years from the time of diagnosis. Based on various evolutional trajectories brought on by clonal and subclonal alterations, the evolution patterns of glioma vary according to different theories. Some important features distinguish the normal brain from other tissues, e.g., the composition of the microenvironment around the tumor cells, the presence of the blood-brain barrier, and others. The underlying mechanism of glioma recurrence and evolution patterns of glioma are different from those of other types of cancer. Several studies correlated tumor recurrence with tumor heterogeneity and the immune microenvironment. However, the detailed reasons for the progression and recurrence of glioma remain controversial. In this review, we introduce the different mechanisms involved in glioma progression, including tumor heterogeneity, the tumor microenvironment and drug resistance, and their pre-clinical implements in clinical trials. This review aimed to provide new insights into further clinical strategies for the treatment of patients with recurrent and secondary glioma.

关键词: glioma     evolution mechanism     strategies     tumor heterogeneity     secondary glioma    

Heterogeneity of chronic obstructive pulmonary disease: from phenotype to genotype

null

《医学前沿(英文)》 2013年 第7卷 第4期   页码 425-432 doi: 10.1007/s11684-013-0295-x

摘要:

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality throughout the world and is mainly characterized by persistent airflow limitation. Given that multiple systems other than the lung can be impaired in COPD patients, the traditional FEV1/FVC ratio shows many limitations in COPD diagnosis and assessment. Certain heterogeneities are found in terms of clinical manifestations, physiology, imaging findings, and inflammatory reactions in COPD patients; thus, phenotyping can provide effective information for the prognosis and treatment. However, phenotypes are often based on symptoms or pathophysiological impairments in late-stage COPD, and the role of phenotypes in COPD prevention and early diagnosis remains unclear. This shortcoming may be overcome by the potential genotypes defined by the heterogeneities in certain genes. This review briefly describes the heterogeneity of COPD, with focus on recent advances in the correlations between genotypes and phenotypes. The potential roles of these genotypes and phenotypes in the molecular mechanisms and management of COPD are also elucidated.

关键词: chronic obstructive pulmonary disease     heterogeneity     phenotype     genotype     prediction    

Effect of catalyst layer mesoscopic pore-morphology on cold start process of PEM fuel cells

Ahmed Mohmed DAFALLA, Fangming JIANG

《能源前沿(英文)》 2021年 第15卷 第2期   页码 460-472 doi: 10.1007/s11708-021-0733-4

摘要: Water transport is of paramount importance to the cold start of proton exchange membrane fuel cells (PEMFCs). Analysis of water transport in cathode catalyst layer (CCL) during cold start reveals the distinct characteristics from the normal temperature operation. This work studies the effect of CCL mesoscopic pore-morphology on PEMFC cold start. The CCL mesoscale morphology is characterized by two tortuosity factors of the ionomer network and pore structure, respectively. The simulation results demonstrate that the mesoscale morphology of CCL has a significant influence on the performance of PEMFC cold start. It was found that cold-starting of a cell with a CCL of less tortuous mesoscale morphology can succeed, whereas starting up a cell with a CCL of more tortuous mesoscale morphology may fail. The CCL of less tortuous pore structure reduces the water back diffusion resistance from the CCL to proton exchange membrane (PEM), thus enhancing the water storage in PEM, while reducing the tortuosity in ionomer network of CCL is found to enhance the water transport in and the water removal from CCL. For the sake of better cold start performance, novel preparation methods, which can create catalyst layers of larger size primary pores and less tortuous pore structure and ionomer network, are desirable.

关键词: cold start     energy conversion     fuel cells     mesoscale morphology     tortuosity     water management    

Computational modeling of fracture in concrete: A review

Luthfi Muhammad Mauludin, Chahmi Oucif

《结构与土木工程前沿(英文)》 2020年 第14卷 第3期   页码 586-598 doi: 10.1007/s11709-020-0573-z

摘要: This paper presents a review of fracture modeling of concrete. The complex material, such as concrete, has been widely used in construction industries and become trending issue in the last decades. Based on comprehensive literature review, there are two main approaches considered to-date of concrete fracture modeling, such as macroscopic and micromechanical models. The purpose of this review is to provide insight comparison from different techniques in modeling of fracture in concrete which are available. In the first section, an overview of fracture modeling in general is highlighted. Two different approaches both of macroscopic and micromechanical models will be reviewed. As heterogeneity of concrete material is major concern in micromechanical-based concrete modeling, one section will discuss this approach. Finally, the summary from all of reviewed techniques will be pointed out before the future perspective is given.

关键词: concrete fracture     macroscopic     micromechanical     heterogeneity    

Analysis of stress and failure in rock specimens with closed and open flaws on the surface

《结构与土木工程前沿(英文)》 2021年 第15卷 第5期   页码 1222-1237 doi: 10.1007/s11709-021-0773-1

摘要: The influence of closed and open surface flaws on the stress distribution and failure in rock specimens is investigated. Heterogeneous finite element models are developed to simulate the compression tests on flawed rock specimens. The simulated specimens include those with closed flaws and those with open flaws on the surface. Systematic analyses are conducted to investigate the influences of the flaw inclination, friction coefficient and the confining stress on failure behavior. Numerical results show significant differences in the stress, displacement, and failure behavior of the closed and open flaws when they are subjected to pure compression; however, their behaviors under shear and tensile loads are similar. According to the results, when compression is the dominant mode of stress applied to the flaw surface, an open flaw may play a destressing role in the rock and relocate the stress concentration and failure zones. The presented results in this article suggest that failure at the rock surface may be managed in a favorable manner by fabricating open flaws on the rock surface. The insights gained from this research can be helpful in managing failure at the boundaries of rock structures.

关键词: surface flaw     heterogeneity     circular hole     numerical modeling     relative displacement    

A multiscale material model for heterogeneous liquid droplets in solid soft composites

《结构与土木工程前沿(英文)》 2021年 第15卷 第5期   页码 1292-1299 doi: 10.1007/s11709-021-0771-3

摘要: Liquid droplets in solid soft composites have been attracting increasing attention in biological applications. In contrary with conventional composites, which are made of solid elastic inclusions, available material models for composites including liquid droplets are for highly idealized configurations and do not include all material real parameters. They are also all deterministic and do not address the uncertainties arising from droplet radius, volume fraction, dispersion and agglomeration. This research revisits the available models for liquid droplets in solid soft composites and presents a multiscale computational material model to determine their elastic moduli, considering nearly all relevant uncertainties and heterogeneities at different length scales. The effects of surface tension at droplets interface, their volume fraction, size, size polydispersity and agglomeration on elastic modulus, are considered. Different micromechanical material models are incorporated into the presented computational framework. The results clearly indicate both softening and stiffening effects of liquid droplets and show that the model can precisely predict the effective properties of liquid droplets in solid soft composites.

关键词: liquid in solid     soft composite     computational modeling     multiscale model     heterogeneity    

Heterogeneous influence of individuals’ behavior on mask efficacy in gathering environments

《工程管理前沿(英文)》   页码 550-562 doi: 10.1007/s42524-022-0193-5

摘要: Wearing masks is an easy way to operate and popular measure for preventing epidemics. Although masks can slow down the spread of viruses, their efficacy in gathering environments involving heterogeneous person-to-person contacts remains unknown. Therefore, we aim to investigate the epidemic prevention effect of masks in different real-life gathering environments. This study uses four real interpersonal contact datasets to construct four empirical networks to represent four gathering environments. The transmission of COVID-19 is simulated using the Monte Carlo simulation method. The heterogeneity of individuals can cause mask efficacy in a specific gathering environment to be different from the baseline efficacy in general society. Furthermore, the heterogeneity of gathering environments causes the epidemic prevention effect of masks to differ. Wearing masks can greatly reduce the probability of clustered epidemics and the infection scale in primary schools, high schools, and hospitals. However, the use of masks alone in primary schools and hospitals cannot control outbreaks. In high schools with social distancing between classes and in workplaces where the interpersonal contact is relatively sparse, masks can meet the need for prevention. Given the heterogeneity of individual behavior, if individuals who are more active in terms of interpersonal contact are prioritized for mask-wearing, the epidemic prevention effect of masks can be improved. Finally, asymptomatic infection has varying effects on the prevention effect of masks in different environments. The effect can be weakened or eliminated by increasing the usage rate of masks in high schools and workplaces. However, the effect on primary schools and hospitals cannot be weakened. This study contributes to the accurate evaluation of mask efficacy in various gathering environments to provide scientific guidance for epidemic prevention.

关键词: COVID-19     masks     behavioral heterogeneity     asymptomatic infection    

Mesoscopic properties of dense granular materials: An overview

Qicheng SUN, Feng JIN, Guohua ZHANG

《结构与土木工程前沿(英文)》 2013年 第7卷 第1期   页码 1-12 doi: 10.1007/s11709-013-0184-z

摘要: A granular material is a conglomeration of discrete solid particles. It is intrinsically athermal because its dynamics always occur far from equilibrium. In highly excited gaseous states, it can safely be assumed that only binary interactions occur and a number of kinetic theories have been successfully applied. However, for granular flows and solid-like states, the theory is still poorly understood because of the internally correlated structures, such as particle clusters and force networks. The current theory is that the mesoscale characteristics define the key differences between granular materials and homogeneous solid materials. Widespread interest in granular materials has arisen among physicists, and significant progress has been made, especially in understanding the jamming phase diagram and the characteristics of the jammed phase. In this paper, the underlying physics of the mesoscale structure is discussed in detail. A multiscale framework is then proposed for dense granular materials.

关键词: granular matter     macroscopic structure     jamming phase transition    

Factors affecting the distribution of microplastics in soils of China

《环境科学与工程前沿(英文)》 2023年 第17卷 第9期 doi: 10.1007/s11783-023-1710-4

摘要:

● Microplastic (MP) abundance in soil of China was highly heterogeneous.

关键词: Microplastic distribution     Microplastic heterogeneity     Effecting factors     Agriculture     Socio-economic factors    

Temporal and spatial stability of the EM/PM molecular subtypes in adult diffuse glioma

《医学前沿(英文)》 2023年 第17卷 第2期   页码 240-262 doi: 10.1007/s11684-022-0936-z

摘要: Detailed characterizations of genomic alterations have not identified subtype-specific vulnerabilities in adult gliomas. Mapping gliomas into developmental programs may uncover new vulnerabilities that are not strictly related to genomic alterations. After identifying conserved gene modules co-expressed with EGFR or PDGFRA (EM or PM), we recently proposed an EM/PM classification scheme for adult gliomas in a histological subtype- and grade-independent manner. By using cohorts of bulk samples, paired primary and recurrent samples, multi-region samples from the same glioma, single-cell RNA-seq samples, and clinical samples, we here demonstrate the temporal and spatial stability of the EM and PM subtypes. The EM and PM subtypes, which progress in a subtype-specific mode, are robustly maintained in paired longitudinal samples. Elevated activities of cell proliferation, genomic instability and microenvironment, rather than subtype switching, mark recurrent gliomas. Within individual gliomas, the EM/PM subtype was preserved across regions and single cells. Malignant cells in the EM and PM gliomas were correlated to neural stem cell and oligodendrocyte progenitor cell compartment, respectively. Thus, while genetic makeup may change during progression and/or within different tumor areas, adult gliomas evolve within a neurodevelopmental framework of the EM and PM molecular subtypes. The dysregulated developmental pathways embedded in these molecular subtypes may contain subtype-specific vulnerabilities.

关键词: glioma progression     molecular classification     EM/PM subtyping     intratumor heterogeneity    

Changes in lncRNAs and related genes in β-thalassemia minor and β-thalassemia major

null

《医学前沿(英文)》 2017年 第11卷 第1期   页码 74-86 doi: 10.1007/s11684-017-0503-1

摘要:

β-thalassemia is caused by β-globin gene mutations. However, heterogeneous phenotypes were found in individuals with same genotype, and still undescribed mechanism underlies such variation. We collected blood samples from 30 β-thalassemia major, 30 β-thalassemia minor patients, and 30 matched normal controls. Human lncRNA Array v2.0 (8 × 60 K, Arraystar) was used to detect changes in long non-coding RNAs (lncRNAs) and mRNAs in three samples each from β-thalassemia major, β-thalassemia minor, and control groups. Compared with normal controls, 1424 and 2045 lncRNAs were up- and downregulated, respectively, in β-thalassemia major patients, whereas 623 and 349 lncRNAs were up- and downregulated, respectively, in β-thalassemia minor patients. Compared with β-thalassemia minor group, 1367 and 2356 lncRNAs were up- and downregulated, respectively, in β-thalassemia major group. We selected five lncRNAs that displayed altered expressions (DQ583499, X-inactive specific transcript (Xist), lincRNA-TPM1, MRFS16P, and lincRNA-RUNX2-2) and confirmed their expression levels in all samples using real-time polymerase chain reaction. Based on coding-non-coding gene co-expression network and gene ontology biological process analyses, several signaling pathways were associated with three common organ systems exhibiting β-thalassemia phenotypes: hematologic, skeletal, and hepatic systems. This study implicates that abnormal expression levels of lncRNAs and mRNA in β-thalassemia cases may be correlated with its various clinical phenotypes.

关键词: β-thalassemia     long non-coding RNA     mRNA     phenotypic heterogeneity     pathway    

标题 作者 时间 类型 操作

Numerical simulation of damage in high arch dam due to earthquake

Hong ZHONG , Gao LIN , Hongjun LI

期刊论文

Heterogeneity of the tumor immune microenvironment and clinical interventions

期刊论文

用于介观模拟电子束选区熔化的数据挖掘技术

钱亚, 闫文韬, 林峰

期刊论文

bottleneck of phosphonic acid anchoring groups aiming toward enhancing the stability and efficiency of mesoscopic

期刊论文

Intratumor heterogeneity, microenvironment, and mechanisms of drug resistance in glioma recurrence and

Zhaoshi Bao, Yongzhi Wang, Qiangwei Wang, Shengyu Fang, Xia Shan, Jiguang Wang, Tao Jiang

期刊论文

Heterogeneity of chronic obstructive pulmonary disease: from phenotype to genotype

null

期刊论文

Effect of catalyst layer mesoscopic pore-morphology on cold start process of PEM fuel cells

Ahmed Mohmed DAFALLA, Fangming JIANG

期刊论文

Computational modeling of fracture in concrete: A review

Luthfi Muhammad Mauludin, Chahmi Oucif

期刊论文

Analysis of stress and failure in rock specimens with closed and open flaws on the surface

期刊论文

A multiscale material model for heterogeneous liquid droplets in solid soft composites

期刊论文

Heterogeneous influence of individuals’ behavior on mask efficacy in gathering environments

期刊论文

Mesoscopic properties of dense granular materials: An overview

Qicheng SUN, Feng JIN, Guohua ZHANG

期刊论文

Factors affecting the distribution of microplastics in soils of China

期刊论文

Temporal and spatial stability of the EM/PM molecular subtypes in adult diffuse glioma

期刊论文

Changes in lncRNAs and related genes in β-thalassemia minor and β-thalassemia major

null

期刊论文