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Numerical study on the effective thermal conductivity and thermal tortuosity of porous media with different morphologies

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Science China(Technological Sciences) 2024年第6期67卷 1685-1694页

作者： DU shen li Dong li Meng-Jie HE ya-ling Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an710049China

Effective thermal conductivity and thermal tortuosity are crucial parameters for evaluating the effectiveness of heat conduction within porous *** direct pore-scale numerical simulation method is applied to investigate the heat conduction processes inside porous structures with different *** thermal conduction performances of idealized porous structures are directly compared with real foams across a wide range of *** foam structures are reconstructed using X-ray computed tomography and image processing techniques,while Kelvin and Weaire-Phelan structures are generated through periodic unit cell *** detailed temperature fields inside the porous structures are determined by solving the heat conduction equation at the pore *** results present that the equivalent thermal conductivity of Kelvin and Weaire-Phelan structures is similar to and greater than that of the real foam structure with the same strut *** thermal tortuosity of real foam structure is relatively larger and the heat conduction path becomes straighter by adopting the anisotropic *** thermal tortuosity of the fluid channels for Kelvin,Weaire-Phelan,and real foam structures is close to *** thermal conductivity of porous structures with heat transfer fluid increases as the thermal conductivity ratio of fluid to solid becomes larger.A small porosity of porous media leads to a larger equivalent thermal conductivity due to the dominant contribution of porous skeleton in the heat conduction *** derived from parallel and series models,as well as the Maxwell-Eucken models,provide decent predictions of effective thermal conductivity,with an average error of less than 8%in the entire range of thermal conductivity ratio.

关键词： volumetric solar receiver porous morphology direct pore-scale simulation equivalent thermal conductivity thermal tortuosity empirical correlation

High-temperature wetting behavior between slag and refractory

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Journal of Iron and Steel Research(International) 2024年第6期31卷 1304-1319页

作者： Yong-xin Wang ya-ge li ya-bo Gao Zhong Huang Hai-jun Zhang The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

Slag corrosion is one of the main factors of the damage of refractory,and its primary manifestations involve the melting of refractory in slag and the slag penetration into refractory,both of which are highly related to the wetting behavior between slag and *** high-temperature wettability could be characterized by parameters including the surface tension,adhesion work,and spreading coefficient of the slag on refractory surface,and it could be suppressed by altering the slag/refractory interface,thus resulting in an improved anti-corrosion *** this,the key knowledges of the slag corrosion,theory of wetting behavior and test of high-temperature contact angle were firstly ***,the major factors influencing the high-temperature slag wetting behavior were discussed based on the aspects of slag composition,refractory composition,and surface ***,the future research direction was proposed in this field.

关键词： High-temperature wetting Refractory Slag corrosion Surface tension

Effects of Potassium-Solubilizing Bacteria on Growth, Antioxidant Activity and Expression of Related Genes in Fritillaria taipaiensis P. Y. li

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Phyton-International Journal of Experimental Botany 2024年第4期93卷 789-806页

作者： Jiaqi Lang Mingyan Ye ya Luo Yueheng Wang Zhifen shi Xiaotian Kong Xuan li Nong Zhou Chongqing Engineering Laboratory of Green Planting and Deep Processing of Famous-Region Drug in the Three Gorges Reservoir Region College of Biology and Food EngineeringChongqing Three Gorges UniversityChongqing404120China College of Modern Chinese Medicine Industry Chengdu University of Traditional Chinese MedicineChengdu611130China College of Pharmacy Dali UniversityDali671000China

This study aimed to examine the effects of inoculating Fritillaria taipaiensis *** leaves with different strains ofpotassium-solubilizing bacteria (KSB), or combinations thereof, focusing on aspects of photosynthesis and physiologicaland biochemical characteristics. At present, some studies have only studied the rhizosphere microbialcommunity characteristics of F. taipaiensis and have not discussed the effects of different microbial species on thegrowth promotion of F. taipaiensis. This paper will start from the perspective of potassium-solubilizing bacteria toconduct an in-depth study. Seed cultivation commenced at the base with three different KSBs in early October2022. The growth of F. taipaiensis leaves was observed after different treatments. Both single-plant and compoundinoculations were executed. A total of eight treatment groups were established, with aseptic fertilizer and sterilizedsoil functioning as the control group. The results reveal that intercellular CO_(2) concentration (Ci), stomatal conductance(Gs), and transpiration rate (Tr) were at their apex in the S7 group. Most treatment groups exhibited anincrease in leaf area, photosynthetic pigment content, soluble sugar, soluble protein, Superoxide Dismutase(SOD), Peroxidase (POD), Catalase (CAT) activities, and proline content. The expression levels of POD, SOD,and CAT genes were evaluated, following inoculation with different KSB. The highest was the S7 group. Theinoculation with various KSB, or combinations thereof, appears to bolster the growth and development of F. *** composite inoculation group S7, comprising Bacillus cereus, Burkholderia cepacia, and Bacillus subtilis,manifested the most favorable impact on the diverse indices of F. taipaiensis, thereby furnishing valuableinsights for the selection of bacterial fertilizer in the artificial cultivation of F. taipaiensis.

关键词： Fritillaria taipaiensis bacteria antioxidant enzyme genes leaf physiology and biochemistry photosynthetic characteristics

Improving fault localization with pre-training

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Frontiers of Computer Science 2024年第1期18卷 247-249页

作者： Zhuo ZHANG ya li Jianxin XUE Xiaoguang MAO School of Information Technology and Engineering Guangzhou College of CommerceGuangzhou 511363China Ningbo Artificial Intelligence Institute Shanghai Jiao Tong UniversityNingbo 315000China Institute for Artificial Intelligence Shanghai Polytechnic UniversityShanghai 210209China College of Computer National University of Defense TechnologyChangsha 410073China

1 Introduction For developers,fault localization is the most tedious and time-consuming *** order to reduce the burden of developers,researchers have developed various techniques to help reduce the cost of locating faults based on possibility of containing a fault in program statements[1].Among them,coverage-based fault localization is one of the most studied automated fault localization ***-based fault localization methods utilize a type of preliminary information to localize the faults in programs,which is a matrix of statements’coverage *** value of each element is 1 or 0,in which 1 means a statement is executed and 0 denotes a statement is not executed[1].

关键词： fault statement utilize

Fixed-Time Anti-Disturbance Average-Tracking for Multi-Agent Systems Without Velocity Measurements

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Journal of Systems Science & Complexity 2024年第3期37卷 985-1002页

作者： li Yuling liU Chenglin ZHANG ya CHEN yangyang Key Laboratory of Advanced Process Control for light Industry(Ministry of Education) Institute of AutomationJiangnan UniversityWuci 214122China School of Automation Southeast UniversityNanjing 210096China

In this paper,the authors tackle a fixed-time average-tracking problem for multi-agent systems which do not require velocity measurements and are affected by external mismatched and matched *** objective requires the considered agents with second-order dynamics to follow the average value of several time-varying reference signals,each of which is acquired by only one *** of all,the average value is estimated by using a novel distributed average estimator in a fixed ***,an original observer is created to provide estimated values in a fixed time for external mismatched and matched disturbances as well as unmeasured velocities of ***,the authors propose a novel fixed-time anti-disturbance average-tracking protocol with the aid of the observer and a sliding mode *** the end,the feasibility of theoretical analysis is illustrated by some simulation experiments.

关键词： Average-tracking control fixed-time algorithm fixed-time observer mismatched distur-bances multi-agent systems velocity measurements

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Weighted Composition Operators That Preserve Frames On Weighted Hardy Spaces

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1645-1654页

作者： ya li Dong Rui liu Guo Xiang Lu School of Mathematical Sciences and LPMC Nankai UniversityTianjin300071P.R.China School of Statistics and Mathematics Zhongnan University of Economics and LawWuhan430073P.R.China

In this paper, we characterize weighted composition operators that preserve frames on the weighted Hardy spaces in the unit disk. In particular, we obtain the symbol properties of the bounded invertible weighted composition operators. Moreover, we establish the equivalence between bounded invertible operators and frame-preserving operators. Furthermore, we show that weighted composition operator preserves frames if and only if it preserves the Riesz bases property. Additionally,we investigate the weighted composition operators that preserve tight or normalized tight frames on the Dirichlet space.

关键词： Weighted composition operators Weighted Hardy spaces frames invertible

Height and body mass index trajectories from 1975 to 2015 and prevalence of stunting,underweight and obesity in 2016 among children in Chinese cities:findings from five rounds of a national survey

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World Journal of Pediatrics 2024年第4期20卷 404-412页

作者： Xin‑Nan Zong Hui li ya‑Qin Zhang Department of Growth and Development Capital Institute of PediatricsBeijing 100020China

Background A more comprehensive assessment of growth and nutrition in children is required in China due to rapid socioeconomic *** aimed to investigate height and body mass index(BMI)trajectories from 1975 to 2015 and the prevalence of stunting and obesity in 2016 among children in Chinese *** A total of 904,263 children from birth to 6.9 years were collected from a series of nationally representative surveys in *** and BMI trajectories and prevalence of stunting,underweight,overweight and obesity were *** The average height level of Chinese urban children under 7 years presented a positive secular trend from 1975 to 2015;however,a slowing tendency occurred in 2005‒*** apparent increase was observed at the 5th,50th and 95th percentiles of BMI in urban children aged 3 years and older,with a more prominent increase at the 95th *** total prevalence of stunting and underweight under 7 years was 1.4%and 2.0%,*** total prevalence of overweight and obesity under 7 years was 12.6%and 4.3%,respectively,with 12.7%and 4.9%for boys,12.6%and 3.6%for girls,12.1%and 4.0%in urban areas and 13.1%and 4.5%in suburban rural *** The average height level of Chinese urban children has reached World Health Organization child growth standards since 2005 and presented a slowing tendency in secular trend in 2005‒*** attention and efforts and public health interventions should be urgently made to combat overweight and obesity among preschool children.

关键词： Body mass index Children Height Obesity Stunting

Distribution assessment of soil erosion with revised RUSLE model in Tianshan Mountains

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Journal of Mountain Science 2024年第3期21卷 850-866页

作者： WEI wenyu liU ya ZHANG lixia li Lanhai State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China Reaserch Center of Educational in Xinjiang Xinjiang Normal UniversityUrumqi 830017China

aSoil degradation caused by soil erosion is one of the world's most critical environmental *** erosion in the Tianshan Mountains has caused various environmental problems in the surrounding *** study used remote sensing data to analyze the distribution of the factors influencing soil erosion,and the revised universal soil loss equation(RUSLE)to calculate the total amount and distribution characteristics of soil erosion in the Tianshan Mountains in *** to the large error of RUSLE in soil erosion estimation in mountainous areas,this study modified RUSLE equation based on the characteristics of snow cover in the Tianshan *** results show that the average soil erosion was 1690.3 t/(km^(2)·year),of which insignificant erosion,slight erosion and moderate erosion accounted for 42,8%,22.4%and 9.9%,*** erosion and above accounted for 13.3%.The accuracy of the soil erosion modulus calculated by the RUSLE was only 61.9%,with an average error of 1631.9 t/(km^(2)·year).The average error of the double-coefficient correction method was 1259.1 t/(km^(2)·year),and the average error of the modified formula method was reduced by 40.3%compared with the RUSLE,reaching 973.7 t/(km^(2)·year),and its accuracy reached 76.2%.Very severe erosion and catastrophic erosion are distributed on mountain ridges with higher elevation and on the northern area with higher *** cover has a certain inhibitory effect on soil erosion,and snow cover in alpine mountains is a factor that cannot be ignored in soil erosion research.

关键词： RUSLE Snow cover Erosion categories High-elevation area

Effects of surface energy and substrate on modulus determination of biological films by conical indentation

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Science China(Technological Sciences) 2024年第6期67卷 1757-1764页

作者： DING Yue li Cheng-ya NIU XinRui WANG Gang-Feng Department of Engineering Mechanics SVLXi’an Jiaotong UniversityXi’an710049China Department of Mechanical Engineering City University of Hong KongHong Kong SAR999077China

Micro-/nano-indentation has become prevalent in evaluating the mechanical characteristics of biological samples,such as cells and ***,the existing contact models describing conical indentation ignore the joint effects of surface energy and substrate,and consequently cannot accurately extract the Young's modulus of biological samples deposited on *** finite element methods,we examine the conical indentation of biological films on substrates while taking surface energy into *** on the dimensional analysis,the explicit relationship between load and indentation depth is achieved for films with their moduli varying from 0.001 to 100 times that of the *** the classical Sneddon's model was employed to analyze the load-depth data,the measured modulus could reach 18 times the real modulus for films on harder substrates,but only 4%of the real modulus for films on softer ***,in micro-/nano-indentations,neglecting the contribution of surface energy would result in an overestimation of the Young's modulus of films depending on the contact *** analytical expression provided here can be utilized to precisely deduce the mechanical characteristics of biological films deposited on substrate from the load and indentation depth data of a conical indentation.

关键词： biological film surface effect substrate effect indentation