Subjects: Library Science，Information Science >> Library Science submitted time 2023-07-26 Cooperative journals: 《图书情报工作》
Abstract： [Purpose/significance] By investigating the copyright contracts of library and information science journals, this paper analyzes the existing problems and puts forward suggestions for improvement.[Method/process] It searches the official websites of library and information science journals by search engines, obtains the copyright contracts published by them, and makes statistical analysis of the contract text from the aspects of form, subject, agreement of rights and obligations, authorization time and procedure.[Result/conclusion] The investigation founds some problems existed in the Chinese library and information science journals, such as lack of rigor in the content of copyright contract, and lack of standardization in the procedure of making a contract. Journal publishing units should pay attention to the signing of copyright contracts as an important process. Standardize the signing procedures,improve the contract text and promote open access, so as to ensure the rights and interests of all parties concerned.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2019-08-02 Cooperative journals: 《干旱区地理》
Abstract：全球变暖是当前全球气候变化研究的热点之一，新疆深居亚欧大陆内陆，地形气候复杂，探讨该区域气候变化与海拔的关系对全球气候变化研究具有重要的参考意义。基于1958—2017年新疆41个气象站的月和年平均气候数据，采用一元线性回归、MannKendall（M-K）趋势分析和突变检验等方法分析该地区气候变化的时空分布与海拔的关系。结果表明：1958—2017年新疆年均气温、年均降水量均呈上升趋势，但增加幅度具有时间和空间差异。在时间上，北疆四季平均气温增温幅度均大于南疆（冬季除外），四季降水量增幅北疆大于南疆（夏季除外）；在空间上，北疆气温和降水的增幅均大于南疆。研究区各个站点气温呈现出南部高而北部低的空间格局，年均降水量北部多，南部低。各个站点气温倾向率总体随海拔增加而减少，年均降水量变化率随海拔升高而增加，在不同海拔带内部存在差异。综上所述，受全球气候变暖的影响，近60 a来新疆年均气温和年均降水量均呈上升趋势，尤其是北疆对全球气候变暖的响应较为敏感。
Subjects: Geosciences >> Hydrology submitted time 2023-03-14 Cooperative journals: 《干旱区地理》
Abstract： In arid areas，snowmelt is the main source of water resource formation. Therefore, the formation, transformation and utilization of snow resources are important research topics on the development and utilization of water resources in Xinjiang, China. Further, hydrological model is a key to determine the formation and transformation of water resources. This study uses the field experimental area of Tianshan Snow Station, Chinese Academy of Sciences, as the experimental area. The meteorological data and snowmelt amount were adopted as the independent and dependent variables. A snowmelt model based on temperature change is studied, and a singlefactor simple model is calibrated and validated. Simultaneously, the variation law of snowmelt in the experimental area for many years and the response process of snowmelt to temperature are analyzed. The results indicate that snowmelt still occurs in winter in certain low- temperature ranges. In the study area of Tianshan Mountains, the critical value of daily average temperature of snowmelt is approximately -7 ℃. When the temperature is lower than -7 ℃, snowmelt is basically suspended, reflecting the characteristics of snowmelt in arid areas. In terms of the model, a single factor simple snowmelt model based on temperature exhibits good performance in simulating snowmelt in mountainous areas. During the calibration period (2016—2020), the correlation parameters of Bias, MAE, RMSE, NSE and R2 between the observed and simulated snowmelt values were -0.037, 0.367, 0.482, 0.870, and 0.876 respectively. The values of validation period were -0.210, 0.292, 0.577, 0.845, and 0.811, respectively. The simulation results and correlation coefficients during the validation period indicate that the simulated value of the model has good consistency with the measured value. The advantage is that the amount of snowmelt in the basin can be estimated through the available meteorological data. The results provide a relatively simple algorithm for snowmelt calculation in arid areas and a simple and effective snowmelt submodule for a hydrological model. This study has an important reference value for understanding the change law of snowmelt and the simulation and prediction of snowmelt runoff in subsequent studies
Subjects: Geosciences >> Hydrology submitted time 2018-10-23 Cooperative journals: 《干旱区地理》
Abstract： 塔里木河下游生态系统作为典型的干旱区生态系统，对水分具有较强的依赖性。为了解塔里木河下游间歇性生态输水对地下水埋深变化、植被生长的关系，得出地下水埋深、植被生长变化及间歇性生态输水过程之间的相互影响机理，本研究以塔里木河下游英苏断面为研究区，基于达西定律、植物根系吸水速率计算方法，以及2009—2015年生态输水-地下水位变化-NDVI变化相互耦合关系，对三者之间相互影响过程及影响机理进行定性与定量分析。研究结果表明：（1）输水效益的显现是一个漫长的过程，地下水的响应和下游植被的生态响应均在一个大的空间和时间尺度上将逐步显现，另外由于植物生长具有季节性，当年地下水埋深值在一定程度上可影响次年植物生长。（2）多年研究表明，当地下水埋深低于7 m时，满足乔、灌木植物生长需求；低于6 m时，满足草本植物生长需求。（3）在年总输水量为固定情况下，一年两次是利于河岸植被恢复的最适宜输水次数。由于生态输水-地下水位变化-NDVI变化存在一定的滞后期，建议每年春季4~5月份和夏季7~8月份作为输水期。
Hits
Hits
Downloads
Comment