Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： In recent years, the general model is one of the most important development trends of artificial intelligence. With the rapidly increasing research and deployment of general models, the social and ethical effects of general models have received extensive attention. Grounded in the characteristics of general models, this article analyzes the potential ethical challenges of the models at three levels: algorithm, data, and computing power. The detailed challenges include uncertainty, truthfulness, reliability, bias, toxicity, fairness, privacy, and environmental issues. Also, through the lens of philosophy of technology, it elaborates the important reasons for the ethical challenges: the “mirroring” effect and transparency problem caused by the data-driven general models’ mediation between human and the world. This relation can be depicted as “human-model (data)-world”. Finally, from the perspectives of governance tools and governance mechanisms, this article reviews the current countermeasures and reflects on their limitations. It is recommended to establish an open, full-process, value-embedded ethical restraint mechanism to ensure that the general model develops in accordance with legal and ethical requirements.
Subjects: Biology >> Ecology submitted time 2017-11-29 Cooperative journals: 《中国生态农业学报》
Abstract： The characteristics of soil respiration in cropland slopes are different from those in cropland plains. In order to accurately evaluate greenhouse gases emission in Northeast China farmland, it was necessary to study the patterns and factors influencing soil respiration in different cropland slopes. The study was conducted on a typical cropland slope in a mollisol region in Northeast China. An entire cropland slope was divided into four slope positions based on change in gradient ― summit, shoulder-slope, back-slope and toe-slope. The LI-8100 probe was used to monitor soil respiration throughout the maize growing period. Water content and temperature of the surface soil (0-20 cm soil layer) were respectively measured using soil moisture meter and thermometer. The relationship between soil carbon dioxide (CO2) flux and the impact of temperature, soil moisture content were then analyzed for different slop positions (summit, shoulder-slope, back-slope and toe-slope). The study laid the basis for scientific evaluation of soil respiration and carbon balance in mollisol in cropland slopes. The results showed that CO2 flux in summer was higher than in spring and autumn. Peak soil respiration occurred during the period from maize silking to tasseling, which was from July 3 to August 23 in the study area. During this period, the cumulative respiration was 58.7%–59.9% of total soil respiration for the whole growing period of maize across the four slope positions, indication it was the main period of soil respiration in mollisol regions in Northeast China. The peak rate of soil respiration was significantly different in each slope position (P < 0.05). It was significantly higher in the toe-slope position [7.56 μmol(CO2)∙m-2∙s-1] than at the summit [5.60 μmol(CO2)∙m-2∙s-1], shoulder-slope [6.08 μmol(CO2)∙m-2∙s-1] and back-slope [6.47 μmol(CO2)∙m-2∙s-1]. The results showed that soil respiration rates among different slope positions in typical mollisol regions were significantly different, especially in summer. CO2 flux had a positive, linear correlation with soil temperature for all the slope positions (P < 0.05). The exponential equation best expressed the relationship between soil temperature and soil respiration rate. Then temperature sensitivity (Q10) was the strongest for the back-slope position, compared with the others. There was an insignificant correlation between soil respiration and soil volumetric water content. These results indicated that change in soil temperature significantly influenced soil respiration rate. The cumulative emission of CO2 in toe-slope [523.97 g(CO2-C)∙m-2] was 18.5%, 22.8% and 34.9% higher than in back-slope [443.13 g(CO2-C)∙m-2], shoulder-slope [426.81 g(CO2-C)∙m-2] and summit [388.50 g(CO2-C)∙m-2], respectively. This was caused by the migration and redistribution of organic carbon, the change in soil bulk density, and the related effect on soil under the different environmental factors. The results of the study suggested that it was necessary to consider the respiration characteristics of different slope positions in order to limit any deviations in the monitoring results in cropland plains in the scientific evaluation of soil respiration on cropland slopes.
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-11-23 Cooperative journals: 《工程热物理学报》
Abstract：本文对变质量流率蒸汽浸没射流压力振荡特性开展了实验研究，发现蒸汽质量流率随时间延长呈指数规律下降。蒸汽射流凝结经历了稳定凝结、振荡凝结、过渡和喘振四个阶段，射流初始水温越高，各个凝结区域转换点对应的蒸汽质量流率越高。在不同的凝结区域，蒸汽质量流率和过冷水温度对振荡特性的影响程度不同。相同蒸汽质量流率时，初始水温越高振荡频率越小。振荡强度均方根值和峰值均在凝结振荡区达到最大，且初始水温越高，最大值对应的蒸汽质量流率越高，振荡强度峰值最高可达70 kPa。
Subjects: Dynamic and Electric Engineering >> Engineering Thermophysics submitted time 2017-10-31 Cooperative journals: 《工程热物理学报》
Abstract：本文对变质量流率蒸汽浸没射流压力振荡特性开展了实验研究，发现蒸汽质量流率随时间延长呈指数规律下降。蒸汽射流凝结经历了稳定凝结、振荡凝结、过渡和喘振四个阶段，射流初始水温越高，各个凝结区域转换点对应的蒸汽质量流率越高。在不同的凝结区域，蒸汽质量流率和过冷水温度对振荡特性的影响程度不同。相同蒸汽质量流率时，初始水温越高振荡频率越小。振荡强度均方根值和峰值均在凝结振荡区达到最大，且初始水温越高，最大值对应的蒸汽质量流率越高，振荡强度峰值最高可达70 kPa。
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