湖北九宫山甜槠群落结构与优势种的空间分布格局研究

通过对湖北九宫山国家级自然保护区甜槠群落建立的1ha固定森林样地进行植物群落调查,分析了样地内木本植物物种组成、区系成分、种群径级结构和空间分布格局,结果表明:(1)样地内木本植物(DBH≥1 cm)共有132种,隶属于42科78属,其中,杜鹃花科、壳斗科、樟科、蔷薇科、冬青科等是优势科,短柄袍、鹿角杜鹃、青冈、长叶石栎、甜槠等是优势种.(2)样地内植物科、属的分布类型均以泛热带分布类型为主,分别为30.95％和20.51％.(3)样地内所有木本植物个体的径级结构均呈倒"J"型,幼龄个体数量大,森林群落更新状况良好.(4)样地内木本植物个体的空间分布格局以聚集分布为主,部分优势物种在小尺度上呈聚集分布,而在较大尺度上则为随机分布.     

Effects of climate variables on the transmission of COVID-19: a systematic review of 62 ecological studies

Environmental Science and Pollution Research - The new severe acute respiratory syndrome coronavirus 2 was initially discovered at the end of 2019 in Wuhan City in China and has caused one of the...     

Protective effects of dietary betaine on intestinal barrier function and cecal microbial community in indigenous broiler chickens exposed to high temperature environment

Environmental Science and Pollution Research - High temperature environment causes reduction in productivity in broilers by disrupting the intestinal barrier function. This study aimed to...     

Improved product selectivity of electrochemical reduction of carbon dioxide by tuning local carbon dioxide concentration with multiphysics models

Environmental Chemistry Letters - Electrochemical reduction of carbon dioxide (CO2) is promising to alleviate carbon emissions and produce fuels and materials in a circular way, yet effective...     

创新价值链视角下企业创新效率差异及影响因素分析——基于江苏省国家高新区企业的验证

中国经济新常态背景下,高新区企业创新增效提质是增强高新区创新能力的内生动力.从创新价值链视角出发,将企业创新过程分为技术开发阶段和经济转化阶段,运用两阶段DEA模型分别对2016年江苏省12个国家高新区、11个技术领域以及各高新区内不同技术类型企业的整体和分阶段创新效率进行测度,并构建Tobit回归模型探究每个阶段企业创新效率的影响因素.研究表明:(1)江苏省国家高新区整体创新效率有较大提升空间,其中技术开发效率表现优于经济转化效率.(2)高创新效率的技术领域集中在电子与信息、新材料等,生物医药、环境保护和光机电一体化等技术领域整体创新效率处于较低水平.(3)以各阶段创新效率均值为分界,划分创新资源利用的四种模式,大部分高新区企业处于高开发-低转化和低开发-高转化型模式,存在技术创新与经济转化联系不够紧密的现象.(4)资本投入水平、劳动力的“质”和“量”、政府支持力度对企业创新效率的影响存在明显的阶段差异性.最后,根据研究结果,从强化知识交流网络、集聚多元化人才、调整资源投入产出评估方式及采取扬优补短式效率提升路径四个方面给出提升高新区企业创新效率的政策建议.     

Enhanced arsenate removal from aqueous solution by Mn-doped MgAl-layered double hydroxides

Environmental Science and Pollution Research - In this study, Mn-doped MgAl-layered double hydroxides (LDHs) were successfully synthesized for efficient removal arsenate from aqueous solution. The...     

A new prediction method of industrial atmospheric pollutant emission intensity based on pollutant emission standard quantification

● Established a quantification method of pollutant emission standard. ● Predicted the SO₂ emission intensity of single coking enterprises in China. ● Evaluated the influence of pollutant discharge standard on prediction accuracy. ● Analyzed the SO₂ emissions of Chinese provincial and municipal coking enterprises. Industrial emissions are the main source of atmospheric pollutants in China. Accurate and reasonable prediction of the emission of atmospheric pollutants from single enterprise can determine the exact source of atmospheric pollutants and control atmospheric pollution precisely. Based on China’s coking enterprises in 2020, we proposed a quantitative method for pollutant emission standards and introduced the quantification results of pollutant emission standards (QRPES) into the construction of support vector regression (SVR) and random forest regression (RFR) prediction methods for SO₂ emission of coking enterprises in China. The results show that, affected by the types of coke ovens and regions, China’s current coking enterprises have implemented a total of 21 emission standards, with marked differences. After adding QRPES, it was found that the root mean squared error (RMSE) of SVR and RFR decreased from 0.055 kt/a and 0.059 kt/a to 0.045 kt/a and 0.039 kt/a, and theR² increased from 0.890 and 0.881 to 0.926 and 0.945, respectively. This shows that the QRPES can greatly improve the prediction accuracy, and the SO₂ emissions of each enterprise are highly correlated with the strictness of standards. The predicted result shows that 45% of SO₂ emissions from Chinese coking enterprises are concentrated in Shanxi, Shaanxi and Hebei provinces in central China. The method created in this paper fills in the blank of forecasting method of air pollutant emission intensity of single enterprise and is of great help to the accurate control of air pollutants.     

长江三角洲城市群工业用水效率评价及时空差异研究

在水资源约束趋紧的背景下，选取长江三角洲城市群中26个城市2005~2014年的面板数据，运用SBM模型对工业用水效率进行测算，并基于可分解的泰尔指数分析长江三角洲城市群内部工业用水效率的空间差异。结果显示：（1）长江三角洲城市群工业用水效率水平整体偏低，在不考虑与考虑非期望产出的情况下，工业用水效率10a平均值分别为 0.591 8.和 0.519 7;（2）工业用水效率的地区内部差异是造成总差异的主要部分，并且有随时间递增的趋势，其中安徽省对于地区内部差异的贡献率最大，其次为浙江省，江苏省贡献率最低;（3）江苏省各城市工业用水效率虽然差异不大但整体水平较低，而上海市工业用水效率较高并处于稳步上升状态。因此，缩小地区内部差异是实现长江三角洲城市群工业用水效率整体上升的重要途径。     

WRF模式参数化方案对江西山地风电场的风模拟研究

在WRF模式中选取不同的陆面过程、边界层以及近地面层参数化方案，设计了6种不同的参数化方案组合，模拟江西省某高山风电场测风塔2016年1月和2017年1月逐时风速、风向，并与同期实测数据进行比较，选出MRF边界层参数、WSM3微物理过程参数和Noah陆面过程参数作为最优参数化组合方案。对最优参数化组合方案的模拟结果进行整一年的逐时模拟效果检验，结果表明：最优参数化组合方案对全年风速模拟效果较好，模拟结果风速日变化趋势及风速段（0~24时）分布与实测基本一致，模拟的风速峰值及概率偏大，主要是由于模式的精度不足以准确描述山地风场复杂下垫面造成的。模式最优参数化方案对风向模拟与实测主导风向分布一致且风向频率相似     

Evaluation of ecotourism development in rural regions of China

The current status of ecotourism in rural China was analyzed in this paper.Empirical surveys covering the whole country indicate that ecotourism in rural China has attracted a large number of tourists who,however,didn’t generate revenues that can match the number.Although the environmental quality of those rural ecotourism destinations is high with little negative impacts,several problems have already appeared,suggesting a need to monitor those areas.The current practice of interpretation in most rural ecotourism destinations did not provide environmental education opportunities to the tourists.And local communities need more effective ways to decide on the prospects of local ecotourism development by themselves.Finally,a few recommendations for improving the sustainability of ecotourism destinations were provided.