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Distribution of phytoplankton community and its influence factors in an urban river network, East China

Ling Sun, Hui Wang, Yuanqing Kan, Shiliang Wang

《环境科学与工程前沿（英文）》 2018年 第12卷 第6期 doi: 10.1007/s11783-018-1062-7

摘要：

Effects of urban river conditions on phytoplankton community were investigated.

Nitrate utilization and hydrodynamic condition affected phytoplankton distribution.

A winter bloom was induced by abundant ammonia, total phosphorus and organic matters.

The diatoms and euglenoids dominated in an urban beheaded river ecosystem.

关键词： Phytoplankton composition     Spatiotemporal distribution     Functional groups     Nitrate nitrogen     Winter bloom    

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Exploring the coupling relationship of industrial agglomeration and low-carbon economy considering spatiotemporal

《工程管理前沿（英文）》 2023年 第10卷 第2期   页码 285-299 doi: 10.1007/s42524-022-0197-1

摘要： Although China’s construction machinery thrives to meet the needs of construction, a number of challenges still remain to be overcome, such as lack of thorough knowledge of regional disparities and several limitations in terms of carbon emissions and economic development. Meanwhile, a low-carbon economy was proposed and implemented in China. This research aims to investigate the differences in industrial agglomeration of construction machineries and further explore the relationship between industrial agglomeration and low-carbon economy. On this basis, spatiotemporal analysis was performed to evaluate the levels of industrial agglomeration in different regions based on the situations of China’s construction machinery industry. Furthermore, this study explored the interaction between industrial agglomeration and low-carbon economy utilizing the coupling coordination analysis method. Results showed that the coupling coordination of the two subsystems was extremely unbalanced in 2006, and it maintained an increasing trend, reaching a relatively high level in 2018. Finally, suggestions, such as establishing a policy guarantee system and implementing variable policies in different regions, were proposed to provide guidelines for the government decision-making and promote the sustainable development of China’s construction machinery industry.

关键词： spatiotemporal differentiation     industrial agglomeration     low-carbon economy     construction machinery industry     empirical study    

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Distinct community assembly processes underlie significant spatiotemporal dynamics of abundant and rare

《环境科学与工程前沿（英文）》 2022年 第16卷 第6期 doi: 10.1007/s11783-021-1513-4

摘要：

• Season and landform influenced spatiotemporal patterns of abundant and rare taxa.

关键词： Rare taxa     Biogeography     Community assembly     Bacterioplankton     The Yangtze River    

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一种基于非线性时空效应的个性化下一个兴趣点推荐方法

孙曦,吕志民

《信息与电子工程前沿（英文）》 2023年 第24卷 第9期   页码 1273-1286 doi: 10.1631/FITEE.2200304

摘要： 下一个兴趣点（POI）推荐是基于位置的社交网络（LBSN）的一项重要任务，其目标是使用历史签到数据在特定情境下为用户推荐下一个兴趣点。现有研究将用户时空信息线性离散化，然后使用基于循环神经网络（RNN）的方法进行建模。但是这些研究忽略了时空信息对用户偏好的非线性影响以及用户轨迹和候选兴趣点之间的时空相关性。为解决这些问题，本文提出一种时空轨迹（STT）模型。该模型使用具有注意力机制的长短期记忆网络（LSTM）作为基本框架，并将时空信息以编码形式引入模型。在编码信息过程中，使用指数型衰减因子刻画用户兴趣随时间和距离的非线性漂移特性。此外，本文在目标召回过程中设计一个时空匹配模块，该模块通过测量用户历史轨迹与候选集之间的相关性来为用户筛选最有可能的下一个兴趣点。本文使用4个真实数据集评估STT模型性能。实验结果表明，本文所提方法的推荐效果比主流的推荐模型有显著提升。

关键词： 兴趣点推荐     时空效应     长短期记忆网络     注意力机制    

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采用嵌入时空距离的混合蚁群算法求解一类受限车辆路径问题 Research Article

冯振辉1,2,肖人彬1,3

《信息与电子工程前沿（英文）》 2023年 第24卷 第7期   页码 1062-1079 doi: 10.1631/FITEE.2200585

摘要： 本文研究了共享出行背景下一类受限车辆路径问题，该问题以用户订单为核心，每个订单具有预约时间限制以及起始点、目的地两个位置点转换，是典型的具有时间、空间双重约束的扩展车辆路径问题。根据该问题特征，我们建立了以运营成本最低和用户体验度最高为目标的路径规划模型。为更精确地求解模型，根据用户的时间和空间属性定义了时空距离表示函数，进而提出一种嵌入时空距离的混合蚁群算法。该算法可分为两个阶段，首先通过时空聚类，以用户之间时空距离为主要衡量指标对用户进行分类，为问题求解提供启发式信息；其次结合劳动分工策略和时空距离函数，提出一种改进蚁群算法进行优化求解，以得到最终调度路线。基于现有数据集和实际城市环境的仿真案例进行数值实验。与其他启发式算法相比，该算法将基准实例中求得的最短路径长度降低2%–14%；与其他现存路径规划算法相比，该算法在测试实例上求得的综合成本更有竞争力。最后，利用两个实际的城市环境仿真案例进一步验证了所提算法的有效性。

关键词： 受限车辆路径问题；时空距离函数；劳动分工策略；蚁群算法    

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Spatiotemporal expression of Ezh2 in the developing mouse cochlear sensory epithelium

null

《医学前沿（英文）》 2016年 第10卷 第3期   页码 330-335 doi: 10.1007/s11684-016-0459-6

摘要：

The enhancer of zeste 2 polycomb repressive complex 2 subunit (Ezh2) is a histone-lysine N-methyltransferase enzyme that participates in DNA methylation. Ezh2 has also been reported to play crucial roles in stem cell proliferation and differentiation. However, the detailed expression profile of Ezh2 during mouse cochlear development has not been investigated. Here, we examined the spatiotemporal expression of Ezh2 in the cochlea during embryonic and postnatal development. Ezh2 expression began to be observed in the whole otocyst nuclei at embryonic day 9.5 (E9.5). At E12.5, Ezh2 was expressed in the nuclei of the cochlear prosensory epithelium. At E13.5 and E15.5, Ezh2 was expressed from the apical to the basal turns in the nuclei of the differentiating cochlear epithelium. At postnatal day (P) 0 and 7, the Ezh2 expression was located in the nuclei of the cochlear epithelium in all three turns and could be clearly seen in outer and inner hair cells, supporting cells, the stria vascularis, and spiral ganglion cells. Ezh2 continued to be expressed in the cochlear epithelium of adult mice. Our results provide the basic Ezh2 expression pattern and might be useful for further investigating the detailed role of Ezh2 during cochlear development.

关键词： polycomb repressive complex     Ezh2     expression     inner ear     cochlea     development    

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Spatiotemporal evolution and driving factors for GHG emissions of aluminum industry in China

《能源前沿（英文）》 2023年 第17卷 第2期   页码 294-305 doi: 10.1007/s11708-022-0819-7

摘要： China’s aluminum (Al) production has released a huge amount of greenhouse gas (GHG) emissions. As one of the biggest country of primary Al production, China must mitigate its overall GHG emission from its Al industry so that the national carbon neutrality target can be achieved. Under such a background, the study described in this paper conducts a dynamic material flow analysis to reveal the spatiotemporal evolution features of Al flows in China from 2000 to 2020. Decomposition analysis is also performed to uncover the driving factors of GHG emission generated from the Al industry. The major findings include the fact that China’s primary Al production center has transferred to the western region; the primary Al smelting and carbon anode consumption are the most carbon-intensive processes in the Al life cycle; the accumulative GHG emission from electricity accounts for 78.14% of the total GHG emission generated from the Al industry; China’s current Al recycling ratio is low although the corresponding GHG emission can be reduced by 93.73% if all the primary Al can be replaced by secondary Al; and the total GHG emission can be reduced by 88.58% if major primary Al manufacturing firms are transferred from Inner Mongolia to Yunnan. Based upon these findings and considering regional disparity, several policy implications are proposed, including promotion of secondary Al production, support of clean electricity penetration, and relocation of the Al industry.

关键词： aluminum     material flow analysis     GHG (greenhouse gas) emissions     LMDI (logarithmic mean divisa index)    

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Spatiotemporal variation in water footprint of grain production in China

Pute WU,Yubao WANG,Xining ZHAO,Shikun SUN,Jiming JIN

《农业科学与工程前沿（英文）》 2015年 第2卷 第2期   页码 186-193 doi: 10.15302/J-FASE-2015060

摘要： Water shortage has become a significant constraint to grain production in China. A more holistic approach is needed to understand the links between grain production and water consumption. Water footprint provides a framework to assess water utilization in agriculture production. This paper analyzes the spatiotemporal variation in water footprint of grain production (WFGP) in China from 1951 to 2010. The results show that, jointly motivated by the improvement of agricultural production and water use efficiency, WFGP in all areas showed a decreasing trend. National average WFGP has decreased from 3.38 to 1.31 m ·kg . Due to regional differences in agricultural production and water use efficiency, spatial distribution of WFGP varies significantly and its pattern has changed through time. Moreover, WFGP may show significant differences within areas of similar climatic conditions and agricultural practices, indicating that there is a strong need to improve the management of water use technology. Statistical analysis revealed that regional differences in grain yield are the main cause for variations in spatiotemporal WFGP. However, the scope for further increases in grain yield is limited, and thus, the future goal of reducing WFGP is to decrease the water use per unit area.

关键词： water footprint     grain production     grain secu- rity     water scarcity     water-saving    

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SPATIOTEMPORAL VARIATION OF WATER QUALITY AND ALGAL BIOMASS IN ERHAI LAKE AND ITS ENVIRONMENTAL MANAGEMENT

《农业科学与工程前沿（英文）》 2023年 第10卷 第4期   页码 566-578 doi: 10.15302/J-FASE-2023520

摘要：

Elucidating the spatiotemporal pattern of water quality and algal biomass is crucial for accurately tracing pollution sources and reducing the risk of algal blooms in lake systems. This study analyzed the spatiotemporal variability of water quality and algal biomass in Erhai Lake from 1994 to 2021 using water quality index (WQI), Mann-Kendall test and Sen’s slope combined methods. The potential causes of water quality deterioration and algal biomass dynamics were also elucidated. The results showed that the historical changes in the water environment of Erhai Lake mainly had three stages: satisfactory (1994‒2001), deteriorating (2002‒2010) and improving (2011‒2021). The changes in water quality and algal biomass were primarily affected by total nitrogen, total phosphorus and chemical oxygen demand in different stages. The water environment of Erhai Lake is currently improving significantly, starting in the southern area that is furthest from the sources of agricultural pollution, especially in summer and autumn. This is attributed to the implementation of control measures resulting in lower pollutant loads at particular times and places. Therefore, it is necessary to continue to promote standardized livestock farming, to strengthen rural wastewater collection and to investigate measures such as the interruption of the endogenous cycle.

关键词： Erhai Lake     control measures     water environment     water quality index (WQI)    

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Copper and zinc interaction on water clearance and tissue metal distribution in the freshwater mussel

Tianxiang XIA, Xuehua LIU

《环境科学与工程前沿（英文）》 2011年 第5卷 第2期   页码 236-242 doi: 10.1007/s11783-010-0218-8

摘要： Copper and zinc interaction on clearance from water and distribution in different tissues was investigated for the freshwater mussel, , under laboratory conditions. Clearance rate of Cu or Zn from water was highly dependent on exposure concentration. Interaction effect was most evident at 300 μg·L Cu exposure and depressed the Zn clearance rate significantly ( <0.05). However, the presence of 100 μg·L and 300 μg·L Zn hardly affected the Cu clearance rate. The 300 μg·L Cu presence enhanced Cu accumulation in each tissue most significantly ( <0.01), but caused Zn content to decrease in the gills by 62% ( <0.05), viscera by 49% ( <0.05) and foot by 31% ( <0.05), and increase in the mantle by 97% ( <0.05) and the muscles by 243% ( <0.05) for different Zn exposure treatments. The response of metal accumulation in various tissues of the test mussels indicated that Zn transferred from the gills, viscera and foot to the mantle and muscles might be one of the important characteristics of the Zn regulatory mechanism by leading to a narrow range of Zn concentration in the different tissues.

关键词： interaction     mussel     copper     zinc     clearance     distribution    

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Nitrogen distribution in the products from the hydrothermal liquefaction of sp. and sp.

《化学科学与工程前沿（英文）》 2022年 第16卷 第6期   页码 985-995 doi: 10.1007/s11705-021-2126-y

摘要： The high contents of nitrogen-containing organic compounds in biocrude obtained from hydrothermal liquefaction of microalgae are one of the most concerned issues on the applications and environment. In the project, Chlorella sp. and Spirulina sp. were selected as raw materials to investigate the influence of different reaction conditions (i.e., reaction temperature, residence time, solid loading rate) on the distribution of nitrogen in the oil phase and aqueous phase. Three main forms of nitrogen-containing organic compounds including nitrogen-heterocyclic compounds, amide, and amine were detected in biocrudes. The contents of nitrogen-heterocyclic compounds decreased with temperature while amide kept increasing. The effect of residence time on the components of nitrogen-containing organic compounds was similar with that of temperature. However, the influence of solid loading rate was insignificant. Moreover, it was also found that the differences of amino acids in the protein components in the two microalgae might affect the nitrogen distribution in products. For example, nitrogen in basic amino acids of Spirulina sp. preferred to go into the aqueous phase comparing with the nitrogen in neutral amino acids of Chlorella sp. In summary, a brief reaction map was proposed to describe the nitrogen pathway during microalgae hydrothermal liquefaction.

关键词： microalgae     hydrothermal liquefaction     biocrude     nitrogen distribution    

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Thermodynamic models and energy distribution of single-phase heated surface in a boiler under unsteady

Xiyan GUO, Yongping YANG

《能源前沿（英文）》 2011年 第5卷 第1期   页码 69-74 doi: 10.1007/s11708-010-0117-7

摘要： A coal-fired power unit frequently operates under unsteady conditions; thus, in order to acquire scientific energy analysis of the unit, thermodynamic analysis of a single-phase heated surface in a boiler under such conditions requires investigation. Processes are analyzed, and distributions of energy and exergy are qualitatively revealed. Models for energy analysis, entropy analysis, and exergy analysis of control volumes and irreversible heat transfer processes are established. Taking the low-temperature superheater of a 610 t/h-boiler as an example, the distribution of energy, entropy production, and exergy is depicted quantitatively, and the results are analyzed.

关键词： thermodynamic model     energy distribution     boiler     unsteady conditions    

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Estimation of distribution algorithm enhanced particle swarm optimization for water distribution network

Xuewei QI,Ke LI,Walter D. POTTER

《环境科学与工程前沿（英文）》 2016年 第10卷 第2期   页码 341-351 doi: 10.1007/s11783-015-0776-z

摘要： The optimization of a water distribution network (WDN) is a highly nonlinear, multi-modal, and constrained combinatorial problem. Particle swarm optimization (PSO) has been shown to be a fast converging algorithm for WDN optimization. An improved estimation of distribution algorithm (EDA) using historic best positions to construct a sample space is hybridized with PSO both in sequential and in parallel to improve population diversity control and avoid premature convergence. Two water distribution network benchmark examples from the literature are adopted to evaluate the performance of the proposed hybrid algorithms. The experimental results indicate that the proposed algorithms achieved the literature record minimum (6.081 M$) for the small size Hanoi network. For the large size Balerma network, the parallel hybrid achieved a slightly lower minimum (1.921M?) than the current literature reported best minimum (1.923M?). The average number of evaluations needed to achieve the minimum is one order smaller than most existing algorithms. With a fixed, small number of evaluations, the sequential hybrid outperforms the parallel hybrid showing its capability for fast convergence. The fitness and diversity of the populations were tracked for the proposed algorithms. The track record suggests that constructing an EDA sample space with historic best positions can improve diversity control significantly. Parallel hybridization also helps to improve diversity control yet its effect is relatively less significant.

关键词： particle swarm optimization (PSO)     diversity control     estimation of distribution algorithm (EDA)     water distribution network (WDN)     premature convergence     hybrid strategy    

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Hazard and vulnerability evaluation of water distribution system in cases of contamination intrusion

Kunlun XIN, Tao TAO, Yong WANG, Suiqing LIU

《环境科学与工程前沿（英文）》 2012年 第6卷 第6期   页码 839-848 doi: 10.1007/s11783-012-0409-8

摘要： In this paper, it proposed an index system for hazard and vulnerability evaluations of water distribution networks, based on the simulation of contamination events caused by pollutant injections at different junctions. It attempted to answer the following two questions in the case of contamination events: 1) Which are the most hazardous junctions? 2) Which are the most vulnerable junctions? With EPANET toolkit, it simulated the propagation of the contaminant, and calculated the peak concentration of the contaminant and mass delivered at different nodes. According to types of consumers, different weights were assigned to the consumer nodes for assessing the influence of the contaminant on the consumers. Using the method proposed herein, both the hazard index and vulnerability index were calculated for each node in the pipe network. The presented method was therefore applied to the water network of the city of Zhenjiang, which contains two water plants, two booster pump stations with storage tanks. In conclusion, the response time, the relationships between the peak concentration of contaminant and the total absorption are the most important factors in hazard and vulnerability evaluation of the water distribution network.

关键词： water distribution network     hazard     vulnerability     contaminant accident    

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Calculation method of load distribution on pipe threaded connections under tension load

Shoujun CHEN, Lianxin GAO, Qi AN

《机械工程前沿（英文）》 2011年 第6卷 第2期   页码 241-248 doi: 10.1007/s11465-011-0219-x

摘要：

This paper presents a new calculation method that can calculate the load distribution on pipe threaded connections under tension load. On the basis of elastic mechanics, the new method was developed by analyzing each thread tooth, and a new deformation and covariant equation by making a mechanics analysis on each thread tooth was obtained. Compared with the traditional method proposed by the previous references, the new deformation and covariant equation could be used to describe the relation between the previous and the next thread tooth. By applying the new method on the sample of P-110S pipe threaded connection, the obtained results show that the load on thread tooth mainly concentrates on the four or five threads engaged and the middle teeth were not utilized well to bear the loads. The model offers a new way to calculate the loads carried on the thread teeth under tension load.

关键词： load distribution     calculation method     pipe threaded connections     tension load    

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标题 作者 时间 类型 操作

Distribution of phytoplankton community and its influence factors in an urban river network, East China

Ling Sun, Hui Wang, Yuanqing Kan, Shiliang Wang

期刊论文

Exploring the coupling relationship of industrial agglomeration and low-carbon economy considering spatiotemporal

期刊论文

Distinct community assembly processes underlie significant spatiotemporal dynamics of abundant and rare

期刊论文

一种基于非线性时空效应的个性化下一个兴趣点推荐方法

孙曦,吕志民

期刊论文

采用嵌入时空距离的混合蚁群算法求解一类受限车辆路径问题

冯振辉1,2,肖人彬1,3

期刊论文

Spatiotemporal expression of Ezh2 in the developing mouse cochlear sensory epithelium

null

期刊论文

Spatiotemporal evolution and driving factors for GHG emissions of aluminum industry in China

期刊论文

Spatiotemporal variation in water footprint of grain production in China

Pute WU,Yubao WANG,Xining ZHAO,Shikun SUN,Jiming JIN

期刊论文

SPATIOTEMPORAL VARIATION OF WATER QUALITY AND ALGAL BIOMASS IN ERHAI LAKE AND ITS ENVIRONMENTAL MANAGEMENT

期刊论文

Copper and zinc interaction on water clearance and tissue metal distribution in the freshwater mussel

Tianxiang XIA, Xuehua LIU

期刊论文

Nitrogen distribution in the products from the hydrothermal liquefaction of sp. and sp.

期刊论文

Thermodynamic models and energy distribution of single-phase heated surface in a boiler under unsteady

Xiyan GUO, Yongping YANG

期刊论文

Estimation of distribution algorithm enhanced particle swarm optimization for water distribution network

Xuewei QI,Ke LI,Walter D. POTTER

期刊论文

Hazard and vulnerability evaluation of water distribution system in cases of contamination intrusion

Kunlun XIN, Tao TAO, Yong WANG, Suiqing LIU

期刊论文

Calculation method of load distribution on pipe threaded connections under tension load

Shoujun CHEN, Lianxin GAO, Qi AN

期刊论文