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Frontiers of Environmental Science & Engineering 2017年第6期11卷 89-98页

作者： Yulong Shi jiaxuan yang Jun Ma Congwei Luo State Key Laboratory of Urban Water Resource and Environment School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150090 China

A novel, functionalized bubble surface can be obtained in dissolved air flotation （DAF） by dosing chemicals in the saturator. In this study, different cationic chemicals were used as bubble surface modifiers, and their effects on natural organic matter （NOM） removal from river water were investigated. NOM in the samples was fractionated based on molecular weight and hydrophobicity. The disinfection byproduct formation potentials of each fraction and their removal efficiencies were also evaluated. The results showed that chitosan was the most promising bubble modifier compared with a surfactant and a synthetic polymer. Tiny bubbles in the OAF pump system facilitated the adsorption of chitosan onto microbubble surfaces. The hydrophobic NOM fraction was preferentially removed by chitosan-modified bubbles. Decreasing the recycle water pH from 7.0 to 5.5 improved the removal of hydrophilic NOM with low molecular weight. Likewise, hydrophilic organic compounds gave high dihaloacetic acid yields in raw water. An enhanced reduction of haloacetic acid precursors was obtained with recycle water at pH values of 5.5 and 4.0. The experimental results indicate that NOM fractions may interact with bubbles through different mechanisms. Positive bubble modification provides an alternative approach for OAF to enhance NOM removal.

关键词： Bubble surface modification Chitosan Disinfection by-product Dissolved air flotation Organic fraction

Impact of preozonation on the bioactivity and biodiversity of subsequent biofilters under low temperature conditions-- A pilot study

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Frontiers of Environmental Science & Engineering 2016年第4期10卷 127-136页

作者： jiaxuan yang Jun MA Dan SONG Xuedong ZHAI Xiujuan KONG State Key Laboratory of Urban Water Resource and Environment Harbin Institute of Technology Harbin 150090 China

The combination of preozonation and subsequent biological granular activated carbon （O3/BAC） filtration is well known as a promising method for the removal of many pollutants. Temperature and nutrients are the dominant factors in external conditions to influence the biological communities. To explore the influence of preozonation under low temperature, the factors such as dissolved oxygen （DO）, dissolved organic carbon （DOC） and NH4^＋-N were analyzed from the sampling ports every week; triphenyl tetrazolium ehloride-dehydrogenase activity （TTC-DHA） and the nitrifying activity were detected along the bed height ofbiofilter at four levels （10. 40. 70 and i 10 cm） on the 90th, 110th, and 130th day; ~nicrobial community, based on 16S rRNA gene-denaturing gradient gel electrophoresis （DGGE）, was monitored on the 130th day of the operation. The observed microbial property showed that preozonation had a positive influence on bioactivity, biomass and nitrifying activity. Community analysis showed no significant difference on the biodiversity of nitrifying bacteria between the parallel filters in the inlet end based on the method employed. This result showed that biofilters＇ performance is not correlated well with microbial biodiversity. The elevated functionality in O3/BAC filters can be a result of increased microbial activity, which was promoted by preozonation.

关键词： Preozonation BAC filtration High ammonia level Bacterial activity Microbial community structurePilot scale study

A new statistical model of wave heights based on the concept of wave breaking critical zone

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Acta Oceanologica Sinica 2015年第5期34卷 81-85页

作者： yang jiaxuan LI Xunqiang ZHU Shouxian ZHANG Wenjing WANG Lei Institute of Noise and Vibration Naval University of Engineering Institute of Meteorology and Marine PLA University of Science and Technology National Key Laboratory on Ship Vibration and Noise College of Harbour Coastal and Offshore EngineeringHohai University

When waves propagate from deep water to shallow water, wave heights and steepness increase and then waves roll back and break. This phenomenon is called surf. Currently, the present statistical calculation model of surf was derived mainly from the wave energy conservation equation and the linear wave dispersion relation, but it cannot reflect accurately the process which is a rapid increasing in wave height near the broken point. So, the concept of a surf breaking critical zone is presented. And the nearshore is divided as deep water zone, shallow water zone, surf breaking critical zone and after breaking zone. Besides, the calculation formula for the height of the surf breaking critical zone has founded based on flume experiments, thereby a new statistical calculation model on the surf has been established. Using the new model, the calculation error of wave height maximum is reduced from 17.62% to 6.43%.

关键词： wave height statistical model surf breaking critical zone flume experiments

Array Shape Estimation Using Partitioned Eigenstructure Method with Sources in Unknown Localizations

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Sound & Vibration 2018年第4期52卷 2-5页

作者： Changgeng Shuai Shike Zhang jiaxuan yang Sitong Zhou Institute of Noise&vibration Naval University of EngineeringWuhan430033China National Key Laboratory on Ship Vibration&Noise Wuhan430033China

Advanced array processing approaches require accurate knowledge of the location of individual element in a sensor *** array shape estimation methods require the directions of *** this paper,an array shape estimation method based on eigen-decomposition is *** directions of sources do not need to be considered in advance and optimal array shape is generated through a series of *** further improve the accuracy of this algorithm,a partitioned eigenstructure method is *** simulations using non-partitioned and partitioned method are conducted to verify the performance of the proposed technique.

关键词： Array shape estimation eigenstructure method partitioned array.

Review of the detasseling techniques for maize(Zea mays L.)hybrid seed production

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International Journal of Agricultural and Biological Engineering 2024年第3期17卷 1-11页

作者： Ruirui Zhang jiaxuan yang Liping Chen Chenchen Ding Longlong Li Linhuan Zhang National Research Center of Intelligent Equipment for Agriculture Beijing Academy of Agriculture and Forestry SciencesBeijing 100097China National Center of International Research on Agricultural Aerial Application Technology Beijing 100097China Research Center of Intelligent Equipment Beijing Academy of Agriculture and Forestry SciencesBeijing 100097China

Maize(Zea mays L.)is a critical staple crop globally,integral to human consumption,food security,and agricultural product *** quality and purity of maize seeds,essential for hybrid seed production,are contingent upon effective *** study investigates the evolution of detasseling technologies and their application in Chinese maize hybrid seed production,with a comparative analysis against the United States.A comprehensive examination of the development and utilization of detasseling technology in Chinese maize hybrid seed production was undertaken,with a specific focus on key *** from the United States were included for comparative *** analysis encompassed various detasseling methods,including manual,semi-mechanized,and cytoplasmic male sterility,as well as more recent innovations such as detasseling machines,and the emerging field of intelligent detasseling driven by unmanned aerial vehicles(UAVs),computer vision,and mechanical *** detasseling methods were predominantly employed by *** the challenges of inflexible and occasionally overlooked,applying detasseling machines is efficient and *** present,China’s detasseling operations in hybrid maize seed production are mainly carried out by manual work,which is labor-intensive and *** order to address this issue,China is dedicated to developing intelligent detasseling *** study emphasizes the critical role of detasseling in hybrid maize seed *** United States has embraced mechanized *** application and development of manual and mechanized detasseling were applied later than those in the United States,but latest intelligent detasseling technologies first appeared in *** detasseling is expected to be the future direction,ensuring the quality and efficiency of hybrid maize seed production,with implications for global food security.

关键词： detasseling technique detasseling machine UAVs intelligent agriculture maize hybrid seed production

Cobalt single-atom catalyst tailored ceramic membrane for selective removal of emerging organic contaminants

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Environmental Science and Ecotechnology 2024年第5期21卷 219-229页

作者： jiaxuan yang Jing Zhao Hesong Wang Yatao Liu Junwen Ding Tianyi Wang Jinlong Wang Han Zhang Langming Bai Heng Liang State Key Laboratory of Urban Water Resource and Environment School of EnvironmentHarbin Institute of TechnologyHarbin150090PR China Beijing Key Laboratory for Source Control Technology of Water Pollution College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing100083PR China

Water reuse is an effective way to solve the issues of current wastewater increments and water resource ***,a promising method for water reuse,has the characteristics of low energy consumption,easy operation,and high adaptability to coupling with other water treatment ***,emerging organic contaminants(EOCs)in municipal wastewater cannot be effectively intercepted by ultrafiltration,which poses significant challenges to the effluent quality and sustainability of ultrafiltration ***,we develop a cobalt single-atom catalyst-tailored ceramic membrane(Co1-NCNT-CM)in conjunction with an activated peroxymonosulfate(PMS)system,achieving excellent EOCs degradation and anti-fouling *** interfacial reaction mechanism effectively mitigates membrane fouling through a repulsive interaction with natural organic *** generation of singlet oxygen at the Co-N3-C active sites through a catalytic pathway(PMS/PMS*/OH*/O*/OO*/1 O_(2))exhibits selective oxidation of phenols and sulfonamides,achieving>90%removal *** findings elucidate a multi-layered functional architecture within the Co1-NCNT-CM/PMS system,responsible for its superior performance in organic decontamination and membrane maintenance during secondary effluent *** highlights the power of integrating Co1-NCNT-CM/PMS systems in advanced wastewater treatment frameworks,specifically for targeted EOCs removal,heralding a new direction for sustainable water management.

关键词： Single-atom catalytic ceramic membrane Peroxymonosulfate activation Selective oxidation Interfacial response Multi-layer functional zones

基于模态展开法的水下航行器辐射噪声远场预测方法研究

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振动与冲击 2019年第24期38卷 197-202,242页

作者：周思同帅长庚杨家轩海军工程大学振动噪声研究所武汉430033 船舶振动噪声重点实验室武汉430033 中国人民解放军92337部队辽宁大连116023 海军潜艇学院山东青岛266199

为了通过圆柱体表面离散声压或振速数据,实现对有限长圆柱壳体的辐射声场预测,提出“基于模态展开法的声场预测”算法。该算法将介质中有限长圆体的径向振动用轴向及周向模态表示,并建立各阶模态与全息面之间的传递函数矩阵,通过匹配全... 详细信息

为了通过圆柱体表面离散声压或振速数据,实现对有限长圆柱壳体的辐射声场预测,提出“基于模态展开法的声场预测”算法。该算法将介质中有限长圆体的径向振动用轴向及周向模态表示,并建立各阶模态与全息面之间的传递函数矩阵,通过匹配全息面声压或振速来确定各阶模态系数;在此基础上,少量远场声压数据进行最小二乘意义下的参数匹配,获取最优的轴向及周向模态阶数,最终实现辐射声场的预测;通过点声源、圆柱体模型及船舶模型的数值仿真及消声室试验,验证了该方法的准确性和有效性。仿真及实验结果表明:与圆柱统计最优近场声全息方法相比,所提出的方法在全息孔径以外不会出现周期性虚像,适用于有限长圆柱体的辐射声场预测。

关键词：声学信号处理统计最优近场声全息模态展开法声场预测

Meeting 24-h Movement Guidelines is Related to Better Academic Achievement:Findings from the YRBS 2019 Cycle

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International Journal of Mental Health Promotion 2022年第1期24卷 13-24页

作者： Shaoying Liu Qian Yu Md Mahbub Hossain Scott Doig Ran Bao Yaping Zhao Jin Yan Xun Luo jiaxuan yang Arthur F.Kramer Liye Zou College of Sports Science Haikou University of EconomicsHaikouChina College of Sports Science Jishou UniversityJishouChina Exercise Psychophysiology Laboratory Institute of KEEP Collaborative InnovationSchool of PsychologyShenzhen UniversityShenzhenChina Department of Health Promotion and Community Health Sciences School of Public HealthTexas A&M UniversityCollege StationUSA College of Education and Health Professions Limestone UniversitySouth CarolinaUSA School of Physical Education and Sport Training Shanghai University of SportShanghaiChina The Library of Shandong University of Sport ShandongChina Priority Research Centre in Physical Activity and Nutrition School of EducationUniversity of NewcastleCallaghanAustralia Beckman Institute University of IllinoisUrbanaIllinoisUSA Canter for Cognitive&Brain Health Northeastern UniversityBostonUSA

This research is designed to investigate the relationship between the 24-h movement guidelines(24-HMG)and self-reported academic achievement(AA)using nationally representative data derived from the 2019 *** Youth Risk Behaviour Survey.A multiple-stage cluster sampling procedure has been adopted to ensure a representative sample(N=9127 adolescents;mean age=15.7 years old;male%=49.8%).Logistic regression has been adopted to obtain the odds ratio(OR)regarding the associations between adherence to 24-HMG and AA while controlling for ethnicity,body mass index,sex and *** prevalence of meeting the 24-h movement guidelines in isolation and combination varied greatly(physical activity=23.3%,screen time=32.5%,sleep=22.3%,and 24-HMG=2.8%),while the percentage of highest-class AA was 42.5%.Compared with the situation when none of 24-HMG is met,the achievement of any of the combined guidelines(except for meeting the physical activity guidelines)was significantly associated with higher odds of achieving first-class *** the sleep guideline had 1.42 times increased likelihood to achieve highest-class AA as compared with not meeting the sleep *** screen time guidelines and physical activity guidelines,respectively,were 1.32 and 1.13 times more likely to report first-class AA;but meeting the guidelines of physical activity was not significantly related to *** the 24-HMG had the highest odds of achieving first-class AA(OR=2.01,95%CI:1.47-2.73).In both sexes,adolescents who met 24-HMG self-reported better AA(boys OR=2.05,95%CI:1.34-3.15;girls OR=2.26,95%CI:1.36-3.76).Significant relationships were observed in adolescents from 9-10th grade,but not higher *** research findings suggest that optimal movement behaviours can be seen as an important element to better academic achievement among *** studies can adopt our discoveries to promote adolescents’academic achievement through implementing optimal 24-h movement behaviour

关键词： Sedentary behaviour physical activity sleep academic performance high school students U.S.

回应性倡导:政策倡导中社会组织有效行动的解释框架——基于T市与S市的双案例研究

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公共行政评论 2019年第2期12卷 123-142,M0006,M0007页

作者：杨佳譞孙涛南开大学周恩来政府管理学院

论文旨在探讨政策倡导过程中社会组织有效行动的关键因素。论文引入"模糊-冲突"模型解释社会组织行动与政府行为转变的关系,通过T市与S市的两个社会组织实现政策倡导的案例比较,发现政府所处的政策情境与社会组织政策倡导之间的关联。... 详细信息

论文旨在探讨政策倡导过程中社会组织有效行动的关键因素。论文引入"模糊-冲突"模型解释社会组织行动与政府行为转变的关系,通过T市与S市的两个社会组织实现政策倡导的案例比较,发现政府所处的政策情境与社会组织政策倡导之间的关联。社会组织回应政府的政策要求并给出清晰的行动方案,促使政府所处的政策情境转向,进而借助政府执行政策的力量完成政策倡导。在此过程中政府可以得到专业与清晰的政策方案,利于自身政策的实施,而社会组织则可以借助政府权威的力量,克服倡导过程中的阻碍。论文从政策过程的角度给出社会组织实现政策倡导的解释,提供了对政策倡导与政社关系的新认识。

关键词：政策倡导社会组织模糊-冲突模型政府-社会关系

基于DBTCAN算法的船舶轨迹聚类与航路识别

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上海海事大学学报 2022年第3期43卷 7-12页

作者：杨家轩刘元大连海事大学航海学院辽宁大连116026 大连海事大学辽宁省航海安全保障重点实验室辽宁大连116026

为解决船舶轨迹聚类算法效率不高,检测精度低,丢失轨迹局部特征等问题,将具有噪声的基于密度的空间聚类(density-based spatial clustering of applications with noise,DBSCAN)算法由传统的点聚类推广为线聚类,提出一种可以直接对完整... 详细信息

为解决船舶轨迹聚类算法效率不高,检测精度低,丢失轨迹局部特征等问题,将具有噪声的基于密度的空间聚类(density-based spatial clustering of applications with noise,DBSCAN)算法由传统的点聚类推广为线聚类,提出一种可以直接对完整船舶轨迹进行聚类的具有噪声的基于密度的轨迹聚类(density-based trajectory clustering of applications with noise,DBTCAN)算法。该算法采用Hausdorff距离作为船舶轨迹之间的相似度度量,可以对不同长度的船舶轨迹进行聚类。针对DBTCAN算法需要人工确定输入参数的问题,提出一种参数自适应确定方法。选取渤海海域的船舶自动识别系统(automatic identification system,AIS)数据进行实验,结果表明,该算法能够在大量复杂的船舶轨迹中找到相似的轨迹并对其进行聚类,聚类结果与实际交通流情况一致。本文的研究成果可以为相关部门进行航线规划和海上交通监管提供依据。

关键词：船舶轨迹聚类具有噪声的基于密度的轨迹聚类(DBTCAN) Hausdorff距离自适应参数航路识别