Subjects: Nuclear Science and Technology >> Nuclear Science and Technology submitted time 2024-05-06
Abstract：安全壳作为核电站的最后一道屏障，在极端情况下能够承受事故产生的内部压力，防止放射性物质泄漏。非能动安全壳冷却系统能够将安全壳内部的热量及时导出至外部循环水箱，降低事故发生时安全壳内部的温度和压力，对于保证安全壳的完整性具有重大作用。为有效评估非能动安全壳闭式冷却系统的安全性和可靠性，减少核事故的发生概率，利用数值模拟的方法对 HPR1000 中非能动安全壳闭式冷却系统进行模化分析，并对比已有实验结果进行模型验证。获得了安全壳内换热器管外传热系数、PCS 水箱温度、换热器相对高度等参数对非能动闭式冷却系统性能及启动时流动传热特性的影响规律，并以此来估算安全壳的临界值用以优化非能动安全壳闭式冷却系统，增强安全壳的安全性和可靠性。
Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： To study the important effects of the water-holding capacity of litter in plantation plants in coal minedumps on soil and water conservation and ecosystem restoration in mining areas, litter accumulation amount, thethickness, water-holding rate, water-holding capacity, and water absorption rate of different decomposition stageswere investigated in four typical plantations of the same age (Populus simonii, Ulmus pumila, Pinustabulaeformis, and Robinia pseudoacacia forests) in the Antaibao opencast coal mine reclamation area, throughfield investigation and soaking extraction. The results showed that the litter accumulation amount in the P.simonii forest was higher than that in the R. pseudoacacia and U. pumila forests (P < 0.05). The water-holdingcapacity and litter rate at different decomposition degrees changed logarithmically with immersion time (P <0.01). The order of the water absorption rate of litter was R. pseudoacacia forest > U. pumila forest > P. simoniiforest > P. tabulaeformis forest, and the water absorption rate showed a significant power function withimmersion time (P < 0.01). In conclusion, the litter of the P. simonii forest had the strongest water- holdingcapacity, whereas the R. pseudoacacia forest had the fastest water absorption rate. Therefore, from theperspective of the water conservation capacity of litter, P. simonii forest should be prioritized and mixed with theR. pseudoacacia forest, which is more conducive to water conservation in the reclamation area of opencast coalmines.
Subjects: Library Science，Information Science >> Library Science submitted time 2023-10-08 Cooperative journals: 《知识管理论坛》
Abstract： [Purpose/significance] Collaborative innovation is the strategic choice and fundamental driving force to orderly relieve Beijing’s non-capital functions and promote coordinated development of Jing-Jin-Ji region. [Method/process] According to the strategic needs of collaborative development of JingJin-Ji Region, this paper proposed the design ideas and general framework of collaborative innovation and development map system based on GIS. Then system application was demonstrated from three aspects, i.e. spatial distribution characteristics and stock analysis of innovation resources, the correlation analysis among innovation subjects, and the information integration display of innovation spatial pattern. [Result/conclusion] It can be concluded that the system can effectively process innovation resource space data and attribute data, and vividly show spatial distribution of innovation resources and collaborative development trend in JingJin-Ji region. It is efficient to track and monitor regional development trend of collaborative innovation in time and is helpful to reveal innovation resources spatial distribution characteristics and existing problems, providing data for the collaborative innovation development level and efficiency evaluation in Jing-Jin-Ji region.
Subjects: Biology >> Radiobiology submitted time 2023-08-08
Abstract： Purpose: To investigate the mechanism by which mitochondrial ribosomal protein MRPS28 affects carbon ion irradiation-induced apoptosis in A549 cells.
Methods: siRNA was used to knock down MRPS28 and establish a stable MRPS28-knockdown A549 cell line; Cells were irradiated with carbon ion and X-ray; CCK-8 assay was performed to assess cell proliferation; Clonogenic survival assay measured cell survival rate; Flow cytometry detected apoptosis, reactive oxygen species (ROS), and mitochondrial membrane potential; qRT-PCR examined relevant genes; Western Blot analyzed apoptosis-related proteins.
Results: Exposure of non-small cell lung cancer A549 cells to carbon ion irradiation led to decreased MRPS28 expression; Compared to the control group, MRPS28 knockdown reduced A549 cell proliferation and clonogenic survival, increased ROS levels, decreased mitochondrial membrane potential, and induced apoptosis through the p53-mediated mitochondrial apoptotic pathway; MRPS28 knockdown combined with carbon ion irradiation significantly reduced A549 cell proliferation and survival, promoting apoptosis after irradiation.
Limitation: MRPS28 down-regulation increased the sensitivity of A549 cells to carbon ion irradiation, but the specific mechanism requires further investigation.
Conclusion: This study preliminarily demonstrates that MRPS28 down-regulation is involved in carbon ion irradiation-induced apoptosis in A549 cells and enhances A549 cell sensitivity to carbon ion.
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-11 Cooperative journals: 《干旱区研究》
Abstract：为了探讨近30 a来我国干旱区荒漠植被的净初级生产力 (NPP)及其与水热因子相关性随时间的变化，运用CASA(Carnegie Ames Stanford approach)模型估算我国荒漠植被1982—2015年生长季的NPP，并运用线性回归和GIS空间分析方法分析了NPP的时空变化特征，利用滑动相关系数分析了荒漠植被NPP与水热因子的关系。结果表明：① 单位面积NPP均值为42 g·m-2·a-1，NPP整体水平较低。空间上呈西北部、东部边缘较高，中部、南部和中东部较低的分布特征。② 荒漠植被NPP年均总量为5.783×1013 g·a-1。从荒漠植被NPP的年际变化来看，1982—2015年中国荒漠植被NPP总量以1.64×1012 g·(10a)-1的线性速率（P=0.054）上升，荒漠植被生长状况总体上不断改善，但总量趋势呈现阶段性变化，1982—1993年荒漠植被NPP总量呈极显著增长态势（1.25×1012g·a-1，P0.05）。从空间变化来看，47.65%的荒漠植被NPP呈增加态势，主要分布在阿拉善高原、天山北麓、塔里木盆地西部边缘、柴达木盆地的东南边缘、阿尔金山南麓和昆仑山脉。③ 从荒漠植被NPP与各气候因子之间的相关关系随时间的变化来看，NPP与气温的滑动相关系数随时间的变化保持为负相关，与降水、干燥度的滑动相关系数保持为正相关，与太阳总辐射的滑动相关系数随时间变化并未表现出显著的变化趋势。总体上，荒漠植被与水热因子的相关关系在研究时段均有进一步减弱的态势，即荒漠植被NPP对气候因子的变化愈来愈不敏感。
Subjects: Psychology >> Social Psychology submitted time 2019-01-28
Abstract： Although previous studies have found that a conformity effect exists widely, whether people are affected by groups in the evaluation of creative products, the new products with the basic characteristics of novelty and practicability, remains a question to be studied. Compared to artistic products, such products are closely related to real life, reflecting actual creativity, and they are typical creative products in life. Although such products reveal new perspectives for consumers, they also promote a sense of uncertainty. Research shows that when faced with uncertainty, participants are more likely to follow others. Almost all studies on this subject have involved the evaluation of creativity, yet novelty and practicability are two important aspects of creativity. Researchers have studied the characteristics of creativity or creative products; however, creative products can be divided into innovative products and renovative products according to their originality. Therefore, we plan to compare the conformity effect of the two kinds of creative products in the evaluation of novelty and practicability in this study. An “initial evaluation–conformity induced–delay re-evaluation” paradigm was used in Experiment 1, in which participants were first asked to evaluate the practicability (or novelty) of creative products; then the 200 undergraduates' average rating and the participants' own ratings were revealed. The group rating would be revealed as higher or lower than or similar to the participants' rating. Thirty-minutes later, participants evaluated the task again were entirely unexpected. To further analyze the difference in conformity degree between the two types of creative products, the subjects were required to make a certainty judgment on the novelty and practicality of the product in Experiment 2. Experiment 1 revealed that participants had decreased their practicability (or novelty) ratings when the group rating was lower than their first rating, increased their practicability (or novelty) ratings when the group rating was higher than their first rating, and did not change their ratings significantly when the group rating was comparable to their first rating. In the evaluation of practicability, it was found that the conformity of variation (the second rating–the first rating) of innovative products was significantly higher than that of renovative products. Nevertheless, in the evaluation of novelty, the two types of creative products had the same conformity of variation. Similarly, Experiment 2 found that the uncertainty of the evaluation of the practicability of the innovative product was greater than that of the renovative product. In the evaluation of the novelty of the two kinds of products, the degree of uncertainty was the same. In summary, both the evaluation of novelty and the practicability of creative products had a conformity effect. In the practicality evaluation of innovative products, it was easier for respondents to follow others, which might be caused by the greater uncertainty in the practical evaluation of innovative products than in that of renovative products. Nevertheless, in the absence of knowledge of new things, blindly following the crowd is likely to have unimaginable consequences. For long-term development, we should fully understand that innovative products are practical and decide what to do the next. "
Subjects: Biology >> Ecology submitted time 2018-06-09 Cooperative journals: 《生态学报》
Abstract：基于1982-2015年气象数据，采用线性趋势分析和GIS空间分析方法对我国近34年季节性昼夜增温的时空格局进行分析；并结合GIMMS-NDVI 3g遥感数据和植被区划数据，采用偏相关分析方法探讨不同植被分区植被对季节性不对称性增温的响应。结果表明：（1）近34年来中国昼夜气温普遍存在极为显著的上升趋势；昼夜增温在各季节均表现出不对称特征，且该不对称特征存在明显的季节性差异，春季、夏季、秋冬和冬季白天增温速率分别为夜间增温速率的1.49倍、0.98倍、0.73倍和1.69倍；（2）不同分区植被对季节性昼夜不对称增温的响应各异：相对于夜间增温，白天增温对植被活动影响程度更大，影响区域更为广泛；春季和冬季昼夜增温对植被活动的影响范围更广，且春、秋季昼夜增温对植被NDVI的上升普遍起到促进作用；（3）季节非对称性昼夜增温对不同分区的植被活动有不同的影响，这种影响程度随季节的变化存在明显差异。通过分析中国昼夜增温的季节性变化趋势及其对不同类型植被的影响，有助于加深我们对全球气候变化背景下季节性昼夜不对称增温对中国陆地植被动态影响的认识。
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