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Enhanced Natural Convection for Accelerating Melting of Phase Change Material in Cellular Structure through Inserting Fin

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Journal of Thermal Science 2024年第2期33卷 548-563页

作者： KONG Dekui ZHANG Yongcun LIU shutian State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian116024China

The design of thermal conductivity enhancers(TCE) is quite critical to overcoming the disadvantage of the poor thermal conductivity of phase change materials(PCM).The main contribution of this study is firstly to discuss how to actively enhance natural convection of the melted PCM in cellular structure by the fin formed in the structure under the condition of the same metal mass,apart from simultaneously improving heat conduction,which can boost the heat transfer ***,a tailored hybrid fin-lattice structure(HFS) as TCE is designed and fabricated by additive manufacturing(AM).A two-equation numerical method is applied to study the heat transfer of the PCM,and its feasibility is validated with the experimental *** numerical results indicate that enhanced natural convection and improved heat conduction can be obtained simultaneously when a well-designed fin is embedded into a lattice *** enhanced natural convection results in the improved melting rate and the decreased wall temperature;e.g.,the complete melting time and the wall temperature are reduced by 11.6% and 19.7%,respectively,because of the fin for metal ***,the parameters of HFS including the porosity,pore density,and fin dimension have a great impact on the heat *** enhancement effect of the fin for HFS on the melting rate of the PCM increases as the thermal conductivity of the base material *** example,when the fin is introduced into the lattice structure,the complete melting time is reduced by 2..1% for metal *** summary,this study enables us to obtain a good understanding of the mechanism of the heat transfer and provides necessary experimental data for the structural design of HFS fabricated by AM.

关键词： natural convection heat transfer enhancement phase change material additive manufacturing hybrid fin-lattice structure

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Topology Optimization Method for Microscale Structures Described with Integral Nonlocal Theory

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Acta Mechanica Solida Sinica 2024年第1期37卷 63-71页

作者： Jiayu Li Quhao Li shutian Liu State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China

The integration of additive manufacturing and topology optimization makes it possible to fabricate complex configurations,especially for microscale structures,which can guarantee the realization of high-performance structural ***,topology results often contain microstructures(several multicellular scales)similar to the characteristic length of local macrostructures,leading to errors in structural performance analysis based on classical ***,it is necessary to consider the size effect in topology *** this paper,we establish a novel topology optimization model utilizing the integral nonlocal theory to account for the size *** approach consists of an integral constitutive model that incorporates a kernel function,enabling the description of stress at a specific point in relation to strain in a distant *** optimization structures based on nonlocal theory are presented for some benchmark examples,and the results are compared with those based on classical medium *** material layout exhibits significant differences between the two approaches,highlighting the necessity of topology optimization based on nonlocal theory and the effectiveness of the proposed method.

关键词： Topology optimization Microstructures Integral nonlocal theory Size effect

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Non-alcoholic fatty liver degree and long-term risk of incident inflammatory bowel disease: A large-scale prospective cohort study

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中华医学杂志(英文版) 2024年第14期137卷 1705-1714页

作者： Zhang Qian Liu Si Wu Jing Zhu Shengtao Wu Yongdong Wu Shanshan Zhang shutian Department of Gastroenterology Beijing Friendship Hospital Capital Medical University National Clinical Research Center for Digestive Disease Beijing Digestive Disease Center Beijing Key Laboratory for Precancerous Lesion of Digestive Disease Beijing China

Background: Non-alcoholic fatty liver disease (NAFLD) and inflammatory bowel disease (IBD) have shown similar worsening epidemic patterns globally and shared various overlapping pathophysiological mechanisms. However, evidence on the relationship between NAFLD and IBD risk is lacking. We aimed to investigate the associations between long-term risk of incident IBD and NAFLD in a large prospective ***: Participants from the United Kingdom Biobank cohort (https://***/) who were free of IBD and alcoholic liver disease at baseline were enrolled. Baseline non-alcoholic fatty liver degree was measured by the well-established fatty liver index (FLI). The outcomes of interest included incident IBD, ulcerative colitis (UC), and Crohn’s disease (CD). Multivariable Cox proportional hazard regression was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).Results: Among 418,72. participants (mean FLI: 48.11 ± 30.11), 160,807 (38.40%) participants were diagnosed as NAFLD at baseline. During a median of 12.4 years’ follow-up, 2.46 incident IBD cases (1545 UC, 653 CD, and 148 IBD-unclassified) were identified. Due to limited events, those IBD-unclassified were combined in UC or CD when examining the associated risk of UC or CD, separately. Compared with the lowest quartile of FLI, the highest quartile showed a separately 36.00%, 2..00%, and 58.00% higher risk of incident IBD (HRQ4vs. Q1 =1.36, 95% CI: 1.19-1.55,Ptrend 2., 95% CI: 1.07-1.46,Ptrend=0.047), and CD (HRQ4vs. Q1 =1.58, 95% CI: 1.2.-1.97,Ptrend 2.) and CD (HR =1.36, 95% CI: 1.17-1.58).Conclusions: Higher degree of non-alcoholic fatty liver is associated with increased risk of incident IBD. Interventions aimed at improving NAFLD may be a potential targeted strategy for the detection and treatm

关键词： Non-alcoholic fatty liver disease Inflammatory bowel disease Ulcerative colitis Crohn’s disease Cohort study

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基于因果正则化极限学习机的风电功率短期预测方法

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电力系统保护与控制 2024年第11期52卷 127-136页

作者：杨茂张书天王勃现代电力系统仿真控制与绿色电能新技术教育部重点实验室(东北电力大学) 吉林吉林132012 新能源与储能运行控制国家重点实验室(中国电力科学研究院有限公司) 北京100192

随着风电并网比例的逐年提高,电力系统对风电功率预测的准确性和稳定性提出了更高要求。对于同一风电场而言,为了避免不同特征选择方法所选择的风电场特征子集不同,从因果关系的角度出发,提出了一种基于因果正则化极限学习机(causal reg... 详细信息

随着风电并网比例的逐年提高,电力系统对风电功率预测的准确性和稳定性提出了更高要求。对于同一风电场而言,为了避免不同特征选择方法所选择的风电场特征子集不同,从因果关系的角度出发,提出了一种基于因果正则化极限学习机(causal regularized extreme learning machine, CRELM)的风电功率短期预测方法。首先将极限学习机(extreme learning machine, ELM)建模为结构因果模型(structural causal model, SCM),在此基础上计算隐藏层神经元与输出层神经元之间的平均因果效应向量。然后将该平均因果效应向量与输出层权重相结合构成因果正则化项,在最小化训练误差的同时最大化网络的因果关系,以进一步提升模型的预测准确性和预测稳定性。最后,以国内蒙西某风电场数据为例,与采用特征选择或不采用特征选择的预测模型相对比,验证了所提方法的有效性和适用性。

关键词：特征选择因果正则化结构因果模型平均因果效应向量极限学习机

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知识经济时代的价值创造:企业科技关联会创造超额回报吗?

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中国软科学 2024年第1期 47-58页

作者：张少华梁舒恬广州大学经济与统计学院广东广州510006 广东培正学院数字经济研究所广东广州510830

在知识经济时代,企业科技关联会创造超额回报吗?研究揭示中国资本市场是否存在科技动量效应以及该效应的来源。研究发现:中国资本市场存在显著的科技动量效应。投资科技关联因子构建的多空投资策略可以带来1.06%~1.68%的月度超额回报。... 详细信息

在知识经济时代,企业科技关联会创造超额回报吗?研究揭示中国资本市场是否存在科技动量效应以及该效应的来源。研究发现:中国资本市场存在显著的科技动量效应。投资科技关联因子构建的多空投资策略可以带来1.06%~1.68%的月度超额回报。此超额回报不是风险补偿的结果,而是由于投资者有限注意力造成的错误定价,并且这种错误定价需要1~3个月才可以得到纠正。研究结果对于理解企业研发收益、企业技术溢出、投资组合构建以及中国资本市场有效性等有着重要的参考价值。

关键词：科技关联因子市场异象投资组合分析法 Fama-MacBeth回归分析

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Modifiable risk factors for esophageal cancer in endoscopic screening population:A modeling study

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Chinese Medical Journal 2024年第3期137卷 350-352页

作者： Qian Zhang Fan Wang Hao Feng Jie Xing Shengtao Zhu Hao Zhang Yang Li Wenqiang Wei shutian Zhang Department of Gastroenterology Beijing Friendship HospitalCapital Medical UniversityNational Clinical Research Center for Digestive DiseaseBeijing Digestive Disease CenterBeijing Key Laboratory for Precancerous Lesion of Digestive DiseaseBeijing 100050China Center for Applied Statistics and School of Statistics Renmin University of ChinaBeijing 100872China Statistical Consulting Center Renmin University of ChinaBeijing 100872China National Cancer Center National Clinical Research Center for CancerCancer InstituteChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100021China Peking Union Medical College Hospital Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100730China Department of Gastroenterology Jizhong Energy Fengfeng Group HospitalHandanHebei 056000China RSS and China-Re Life Joint Lab on Public Health and Risk Management Renmin University of ChinaBeijing 100872China

To the Editor:Esophageal cancer,one of the most common cancer types in China,with an estimated 346,633 new cases and 32.,600 deaths in 2.2.,is becoming an increasingly serious clinical and public health problem.^([1])The successful promotion of the self-management strategy has indicated that lifestyle modifications can be valuable in the primary prevention of cancer *** a healthy lifestyle has become a novel strategy for primary prevention and risk reduction in high-risk *** epidemiological studies have identified several lifestyle-related risk factors for esophageal cancer,including smoking and diet.^([2.)Each factor can typically explain a modest proportion of cancer ***,when combined,these known risk factors may substantially affect the risk of esophageal ***,some risk factors for esophageal cancer are non-modifiable,including age,low socioeconomic status,and family *** and how these non-modifiable risk factors affect primary cancer prevention by intervening with modifiable risk factors remain unclear.

关键词： esophageal prevention promotion

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Nonlinear interaction of head-on solitary waves in integrable and nonintegrable systems

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Chinese Physics B 2024年第5期33卷 480-487页

作者：张树甜刘世鲲矫滕菲孙敏胡凤兰黄德财 Department of Applied Physics Nanjing University of Science and TechnologyNanjing 210094China

This study numerically investigates the nonlinear interaction of head-on solitary waves in a granular chain(a nonintegrable system)and compares the simulation results with the theoretical results in fluid(an integrable system).Three stages(the pre-in-phase traveling stage,the central-collision stage,and the post-in-phase traveling stage)are identified to describe the nonlinear interaction processes in the granular *** nonlinear scattering effect occurs in the central-collision stage,which decreases the amplitude of the incident solitary *** with the leading-time phase in the incident and separation collision processes,the lagging-time phase in the separation collision process is *** asymmetrical nonlinear collision results in an occurrence of leading phase shifts of time and space in the post-in-phase traveling *** next find that the solitary wave amplitude does not influence the immediate space-phase shift in the granular *** space-phase shift of the post-in-phase traveling stage is only determined by the measurement position rather than the wave *** results are reversed in the *** increase in solitary wave amplitude leads to decreased attachment,detachment,and residence times for granular chains and *** the immediate time-phase shift,leading and lagging phenomena appear in the granular chain and the fluid,*** results offer new knowledge for designing mechanical metamaterials and energy-mitigating systems.

关键词： integrable system nonintegrable system granular chain solitary wave

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基于文献的叶菜类蔬菜施肥现状分析

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中国蔬菜 2024年第7期 6-15页

作者：李书田中国农业科学院农业资源与农业区划研究所北京100081

利用文献资料分析了我国主要叶菜类蔬菜的施肥现状和施肥效应,阐述了叶菜类蔬菜上氮、磷、钾推荐施肥量,施肥效应包括相对产量、增产量、增产率、产量反应和养分的农学效率。影响叶菜类蔬菜产量的限制因子主要是氮,其次为钾,而后为磷。... 详细信息

利用文献资料分析了我国主要叶菜类蔬菜的施肥现状和施肥效应,阐述了叶菜类蔬菜上氮、磷、钾推荐施肥量,施肥效应包括相对产量、增产量、增产率、产量反应和养分的农学效率。影响叶菜类蔬菜产量的限制因子主要是氮,其次为钾,而后为磷。叶菜类蔬菜推荐施肥比农民习惯施肥减少氮、磷肥用量,适当增加钾肥用量,但却增加了产量。因此,在叶菜类蔬菜上合适的推荐施肥方法是实现节肥增效的有效途径。

关键词：叶菜类蔬菜施肥现状施肥效应

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基于Cov-AHP与云模型的装配式建筑施工安全风险评价研究

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西安理工大学学报 2024年第03期40卷 429-437页

作者：李树天马斌王聪西安理工大学土木建筑工程学院商洛学院城乡规划与建筑工程学院

为提升装配式建筑施工安全风险识别与管控能力，本研究基于“4M1E”施工管理理论，通过差异度排比法从5个方面筛选2.个典型影响因素，构建了装配式建筑施工安全风险评价指标体系，建立了基于Cov-AHP与云模型的风险评价模型，并以西安市... 详细信息

为提升装配式建筑施工安全风险识别与管控能力，本研究基于“4M1E”施工管理理论，通过差异度排比法从5个方面筛选2.个典型影响因素，构建了装配式建筑施工安全风险评价指标体系，建立了基于Cov-AHP与云模型的风险评价模型，并以西安市某装配式建筑为例开展实证研究。结果表明，施工环境和参建人员对装配式建筑施工安全的影响最大，施工材料次之，组织管理和施工方法相对较小，评价结果与装配式建筑施工现状相吻合，进一步论证了该模型的适用性与科学性。研究结果为装配式建筑施工安全风险识别与管控提供了新思路，同时也为同类项目的风险评估提供了经验与借鉴。

关键词：装配式建筑施工管理风险评价 Cov-AHP 协方差矩阵云模型

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Haplotype-resolved T2. genome assemblies and pangenome graph of pear reveal diverse patterns of allele-specific expression and the genomic basis of fruit quality traits

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Plant Communications 2024年第10期5卷 100-120页

作者： Qionghou Li Xin Qiao Lanqing Li Chao Gu Hao Yin Kaijie Qi Zhihua Xie Sheng Yang Qifeng Zhao Zewen Wang Yuhang Yang Jiahui Pan Hongxiang Li Jie Wang Chao Wang Loren H.Rieseberg Shaoling Zhang shutian Tao National Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization Sanya Institute of Nanjing Agricultural UniversityCollege of HorticultureNanjing Agricultural UniversityNanjingJiangsu 210095China Pomology Institute Shanxi Agricultural UniversityTaiguShanxi 030801China Department of Botany and Biodiversity Research Centre University of British ColumbiaVancouverBCCanada

Hybrid crops often exhibit increased yield and greater resilience,yet the genomic mechanism(s)underlying hybrid vigor or heterosis remain unclear,hindering our ability to predict the expression of phenotypic traits in hybrid ***,we generated haplotype-resolved T2. genome assemblies of two pear hybrid varieties,‘Yuluxiang’(YLX)and‘Hongxiangsu’(HXS),which share the same maternal parent but differ in their paternal *** then used these assemblies to explore the genome-scale landscape of allele-specific expression(ASE)and create a pangenome graph for *** was observed for close to 6000 genes in both hybrid cultivars.A subset of ASE genes related to aspects of fruit quality such as sugars,organic acids,and cuticular wax were identified,suggesting their important contributions to ***,Ma1,a gene regulating fruit acidity,is absent in the paternal haplotypes of HXS and YLX.A pangenome graph was built based on our assemblies and seven published pear *** data for 139 cultivated pear genotypes(including 97 genotypes sequenced here)were subsequently aligned to the pangenome graph,revealing numerous structural variant hotspots and selective sweeps during pear diversifica*** predicted,the Ma1 allele was found to be absent in varieties with low organic acid content,and this association was functionally validated by Ma1 overexpression in pear fruit and ***,these results reveal the contributions of ASE to fruit-quality heterosis and provide a robust pangenome reference for high-resolution allele discovery and association mapping.

关键词： pear haplotype-resolved assembly allele-specific expression fruit quality traits pangenome graph

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