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ADDITIONAL PRESSURE LOSSES OF SOLID-LIQUID FLOW IN AN OSCILLATING PIPELINE

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Journal of Hydrodynamics 2002年第1期14卷 75-80页

作者： Xia, jian-Xin Huang, jia-zhen Cent. of Environ. Sci. Peking Univ. Beijing 100871 China

Manganese nodules on the ocean bed become attractive mineral resources because of its huge commercial benefits. In the last decades, a set of hydraulic lifting system with pipeline has been developed to mining these particles. It is inevitable that lifting pipe will oscillate due to its operation and the motion properties of the solid in the two-phase flow will be changed because of the oscillating of pipe-line. The pressure gradient along the lifting pipeline was investigated with a series of experiments. At the same time, a new pressure drop prediction method on the basis of Lagrange simulation technique was worked out by use of an axial momentum balance and this method provides a way to predict the pressure loss of solid-liquid mixture. The results show that compared with the fixed pipe transportation, the pressure gradient of the oscillating pipe is greater than that of the fixed pipe because of the collision and unsteady friction between particles and the pipe wall due to the oscillating motion of the pipe. Moreover, it is found that the prediction results are in good agreement with those of the experiments.

关键词： Two phase flow Underwater mineral resources

miRNAs in non-alcoholic fatty liver disease

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Frontiers of Medicine 2016年第4期10卷 389-396页

作者： zhen He Cheng Hu Weiping jia Shanghai Diabetes Institute Shanghai Key Laboratory of Diabetes Mellitus Shanghai Clinical Center for Diabetes Shanghai Jiao Tong University Affiliated Sixth People's Hospital Shanghai 200233 China

Non-alcoholic fatty liver disease （NAFLD） is a major cause of liver cirrhosis and hepatocellular carcinoma and is a considerable threat to public health, miRNAs are important post-transcriptional regulators of gene expression, and the dysregulation of miRNAs is involved in various biological processes in the liver, including lipid homeostasis, inflammation, apoptosis, and cell proliferation. Recently, a number of studies have described the association between miRNAs and NAFLD progression and have shown that circulating miRNAs reflect histological changes in the liver. Therefore, circulating miRNAs have potential use for the evaluation of NAFLD severity. In this review, we discuss the involvement of miRNAs in NAFLD pathogenesis and the key role of miRNAs in the screening, diagnosis, and staging of NAFLD.

关键词： nonalcoholic fatty liver disease nonalcoholic steatohepatitis hepatocellular carcinoma miRNA

Phylogenomic relationships and molecular convergences to subterranean life in rodent family Spalacidae

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Zoological Research 2021年第5期42卷 671-674页

作者： Yuan-Ting Guo jia Zhang Dong-Ming Xu Li-zhou Tang zhen Liu State Key Laboratory of Genetic Resources and Evolution Kunming Institute of ZoologyChinese Academy of SciencesKunmingYunnan 650223China Kunming College of Life Science University of Chinese Academy of SciencesKunmingYunnan 650204China Center for Yunnan Plateau Biological Resources Protection and Utilization College of Biological Resource and Food EngineeringQujing Normal UniversityQujingYunnan 655011China

All extant species in the rodent family Spalacidae are subterranean and have evolved various traits for underground ***,the phylogenomic relationships among its three subfamilies(Myospalacinae,Spalacinae,and Rhizomyinae)and the molecular basis underlying their adaptations to underground life remain poorly ***,we inferred the phylogenomic relationships among these subfamilies based on de novo sequencing the genome of the hoary bamboo rat(Rhizomys pruinosus).Analyses showed that 50%of the identified 11028 one-to-one orthologous protein-coding genes and the concatenated sequences of these orthologous genes strongly supported a sister relationship between Myospalacinae and Rhizomyinae.

关键词： underground life rodent

Synthesis of ultralong Si_3N_4 nanowires by a simple thermal evaporation method

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Rare Metals 2013年第2期32卷 186-190页

作者： Wen-Qi Wang Xiao-Ping Zou Nan-jia zhou Guang Zhu Gui-Ying Wang zhen-Sheng Peng Anhui Key Laboratory of Spintronics and Nano-materials (Cultivating Base) Suzhou University Research Center for Sensor Technology Beijing Key Laboratory for SensorBeijing Information Science and Technology University Department of Materials Science and Engineering Northwestern University Structure Research Laboratory University of Science and Technology of China

Largescale vaporsolid synthesis of ultralong silicon nitride （Si3N4） nanowires was achieved by using simple thermal evaporation of mixture powders of active carbon and monoxide silicon. The products were charac terized by Xray diffraction, scanning electron microscopy, energydispersive Xray spectroscopy, and transmission electron microscopy. The results suggest that the silicon nitride nanowires have a smooth surface, with lengths of up to several hundreds of microns and diameters of 100300 nm. A detailed study of both the chemical and structural composition was performed. Such ultralong sil icon nitride nanowires demonstrate potential applications as materials for constructing nanoscale devices and as reinforcement in advanced composites.

关键词： Si3N4 nanowires Ultralong Thermal evaporation

Clause-level Relationship-aware Math Word Problems Solver

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Machine Intelligence Research 2022年第5期19卷 425-438页

作者： Chang-Yang Wu Xin Lin zhen-Ya Huang Yu Yin jia-Yu Liu Qi Liu Gang zhou Anhui Province Key Laboratory of Big Data Analysis and Application School of Data ScienceUniversity of Science and Technology of ChinaHefei 230026China Institute of Artificial Intelligence Hefei Comprehensive National Science CenterHefei 230088China Laboratory of Mathematical Engineering and Advanced Computing Information Engineering UniversityZhengzhou 450001China

Automatically solving math word problems,which involves comprehension,cognition,and reasoning,is a crucial issue in artificial intelligence *** math word problem solvers mainly work on word-level relationship extraction and the generation of expression solutions while lacking consideration of the clause-level *** this end,inspired by the theory of two levels of process in comprehension,we propose a novel clause-level relationship-aware math solver(CLRSolver)to mimic the process of human comprehension from lower level to higher ***,in the lower-level processes,we split problems into clauses according to their natural division and learn their *** the higher-level processes,following human′s multi-view understanding of clause-level relationships,we first apply a CNN-based module to learn the dependency relationships between clauses from word relevance in a local ***,we propose two novel relationship-aware mechanisms to learn dependency relationships from the clause semantics in a global ***,we enhance the representation of clauses based on the learned clause-level dependency *** expression generation,we develop a tree-based decoder to generate the mathematical *** conduct extensive experiments on two datasets,where the results demonstrate the superiority of our framework.

关键词： Artificial intelligence(AI) artificial neural network(ANN) computational mathematics machine intelligence machine learning

Spatial patterns of leaf nitrogen and phosphorus stoichiometry across southeast to central Tibet

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Journal of Mountain Science 2022年第9期19卷 2651-2663页

作者： WANG Wei ZHAO jia-min XING zhen College of Resources and Environmental Sciences Tibet Agriculture&Animal Husbandry UniversityNyingchi 860000China Research institute of Tibet Plateau Ecology Tibet Agriculture&Animal Husbandry UniversityNyingchi 860000China

Leaf N and P stoichiometry in terrestrial ecosystems has been widely investigated in recent years owing to the importance of these elements in improving the predicted vegetation responses to global *** vertical distribution of leaf N and P stoichiometry has attracted increasing attention because of the dramatic changes in environmental factors at regional ***,the characteristics of leaf N and P stoichiometry in the southeast Qinghai–Tibet plateau(SET)are not clear,although this area is sensitive to global ***,we analyzed the leaf N and P concentrations in dominant plant species on natural altitudinal gradients on the Duoxiongla(DXL),Sejila(SJL),Mila(ML),and Gangbala(GBL)mountains across the SET all the way to central *** results showed that the leaf N concentrations were comparable among the regions,whereas the leaf P concentrations dramatically decreased from SET to central Tibet(CT).The leaf N concentrations were 23.6,21.3,20.8,and 22.4 g kg^(-1),and the leaf P concentrations were 2.40,2.49,1.94,and 1.59 g kg^(-1) on the SJL,DXL,ML and GBL mountains,*** leaf N/P ratios on the DXL,SJL,ML,and GBL mountains were 8.81,10.3,11.2,and 14.2,*** the increasing trend of the leaf N/P ratio from southeast Qinghai–Tibet plateau to central Tibet,N limitation might widely exist in well vegetated ecosystems in the Qinghai–Tibet plateau.

关键词： Leaf N and P concentration Southeast Tibet Stoichiometry Spatial variations

Research on the steam–gas pressurizer model with Relap5 code

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Nuclear Science and Techniques 2017年第5期28卷 1-8页

作者： Xi-zhen Ma Hai-Jun jia Yang Liu Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Tsinghua University Beijing 100084 China

Steam–gas pressurizers are self-pressurizing, and since steam and noncondensable gas are used to sustain their pressure, they experience very complicated thermal–hydraulic phenomena owing to the presence of the latter. A steam–gas pressurizer model was developed using Relap5 code to investigate such a pressurizer's thermal–hydraulic *** important thermal–hydraulic processes occurring in the pressurizer model include bulk flashing, rainout, wall condensation with noncondensable gas, and interfacial heat and mass transfer. The pressurizer model was verified using results from insurge experiments performed at the Massachusetts Institute of Technology. It was found that noncondensable gas was one of the important factors governing the pressure response, and the accuracy of the developed model would change with different mass fractions and types of noncondensable gas.

关键词： Relap5 code Noncondensable gas Heat and mass transfer Steam–gas pressurizer Condensation

An efficient formulation based on the Lagrangian method for contact–impact analysis of flexible multi-body system

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Acta Mechanica Sinica 2016年第2期32卷 326-334页

作者： Peng Chen Jin-Yang Liu jia-zhen Hong Department of Engineering Mechanics School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiaotong University

In this paper,an efficien formulation based on the Lagrangian method is presented to investigate the contact–impact problems of f exible multi-body ***,the penalty method and the Hertz contact law are the most commonly used methods in engineering ***,these methods are highly dependent on various non-physical parameters,which have great effects on the simulation ***,a tremendous number of degrees of freedom in the contact–impact problems will influenc thenumericalefficien *** of these two problems,a formulation combining the component mode synthesis method and the Lagrangian method is presented to investigate the contact–impact problems in fl xible multi-body system ***,the finit element meshing laws of the contact bodies will be studied preliminarily.A numerical example with experimental verificatio will certify the reliability of the presented formulationincontact–***,aseries of numerical investigations explain how great the influenc of the finit element meshing has on the simulation *** the limitations of the element size in different regions are summarized to satisfy both the accuracy and efficien y.

关键词： Multi-body dynamics Contact–impact analysis Lagrangian method Component mode synthesis

Factors influencing water quality indices in a typical urban river originated with reclaimed water

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Frontiers of Environmental Science & Engineering 2017年第4期11卷 73-82页

作者： jiao Zhang zhen Wei Haifeng jia Xia Huang State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China

The water quality in a typical urban river segment originated with reclaimed water in Beijing was monitored for two years to investigate the evolution of water quality along the rivcr, and statistical analysis was applied to determine factors influencing water quality of such river recharged by reclaimed water. It was found that no significant change in pollutant concentrations （including COD, NH4＋-N, TN and TP） was observed during this time, and their average values were close to those of the original reclaimed water. However, turbidity and algal contents fluctuated temporally in the direction of river flow. Statistical analysis showed that turbidity was strongly positively correlated with algal contents for flow rate 〈 0.1 m.s-1. whereas it was strongly positively correlated with both algalcontents and TOC for flow rate 〉 0. 1m. s-1. It was observed that diatom was the absolute predominant phyla with Melosira as the major species. In terms of algal bloom control, the specific growth rate of algae was strongly correlated to temperature, and was influenced by flow rate as well. Compared with two other rivers originated with reclaimed water and one originated with natural water, the Shannon Wiener index in the objective river was the lowest, with values between 0.7 and 1.6, indicating a high risk for algal bloom. Statistics showed that Shannon Wiener index was strongly negatively correlated to nutrient salts and cations.

关键词： Reclaimed water Urban river Turbidity Algae Flow rate