人为可靠度评估与访谈技巧

人为可靠度分析在核能电厂安全度评估中扮演极为重要的角色,但由于种种限制,其在量化人为误失概率的准确性上经常受到质疑．本文叙述台湾多年执行人为可靠度分析之经验,并特别强调如何强化准备工作与访谈技巧以有效提升分析的一致性与客观性．     

The relationships among plant cover, density, seed rain, and dispersal of Bromus tectorum in high-elevation populations

Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} The invasive species Bromus tectorum L. is recognized as one of the most ecologically and economically devastating weeds in the western United States. Although B. tectorum has been studied extensively, few studies have examined its dispersal and spread. We collected data from sites with B. tectorum in and around Rocky Mountain National Park to quantify the relationships between plant cover/density and seed rain and dispersal distance. Results suggest that there is a positive relationship between density within a patch and local seed rain and that B. tectorum exhibits relatively limited short-distance dispersal (where seeds fell in close proximity to plants and no seeds were found to have dispersed more than 0.1 m from the edge of a patch). These data can inform modelers and managers who are attempting to better understand population dynamics and options for controlling this species. La especie invasora Bromus tectorum L. se considera una de las hierbas más devastadoras ecológica y económicamente del oeste de Estados Unidos. Aunque se ha estudiado extensamente, se han hecho pocos estudios sobre su dispersión y distribución. Colectamos datos de sitios donde crecía B. tectorum en Rocky Mountain National Park y sus alrededores para cuantificar la relación entre la cobertura y la densidad de plantas, la lluvia de semillas y la distancia de dispersión. Los resultados sugieren que hay una relación positiva entre la densidad dentro de una parcela y la lluvia local de semillas, y que B. tectorum exhibe una distancia de dispersión relativamente corta (las semillas caen cerca de las plantas y no encontramos ninguna semilla que se hubiera dispersado a más de 0.1 m del borde de la parcela). Estos datos pueden informar a los modeladores y administradores en su esfuerzo por comprender la dinámica poblacional y las opciones de control para esta especie.     

基于优化地理模拟的长沙市城镇开发边界划定

城镇开发边界划定方法的合理性、科学性研究对未来国家国土空间优化发展具有重要意义。然而目前国内城镇开发边界划定方法的研究缺乏对建设用地驱动因子的模拟和探讨。通过1990—2018年四期土地利用数据,利用土地利用转移矩阵、地理探测器,深入探讨长沙市建设用地变化的成因,并从建设用地驱动机制视角下优化混合元胞自动机模型(mixed-cell cellular automata, MCCA),预测多情景下的长沙市2030年的土地利用结构变化,最终结合城镇用地适宜性评价划定多情景下的城镇开发边界。结果表明:(1)优化后的地理模拟比未优化的模拟结果相比,Kappa系数提高了1.44%,总体精度提高了3.00%,相对熵降低了1.11%;(2)长沙市刚性城镇开发边界面积为7 028.20 km~2,占全域土地总量的59.31%,主要分布在长沙市中心城区;(3)常规情景和一体化情景下长沙市2030年弹性城镇开发边界面积分别为1 021.23 km~2和1 158.60 km~2,且其边界差异主要分布在长沙县。基于建设用地驱动机制优化后的模拟将有助于真实的预测未来土地利用变化,为城镇开发边界的科学划定与土地决策提供技术支撑。     

Inhibition of Rho-associated kinase relieves C5a-induced proteinuria in murine nephrotic syndrome

Childhood nephrotic syndrome is mainly caused by minimal change disease which is named because only subtle ultrastructural alteration could be observed at electron microscopic level in the pathological kidney. Glomerular podocytes are presumed to be the target cells whose protein sieving capability is compromised by a yet unidentified permeability perturbing factor. In a cohort of children with non-hereditary idiopathic nephrotic syndrome, we found the complement fragment C5a was elevated in their sera during active disease. Administration of recombinant C5a induced profound proteinuria and minimal change nephrotic syndrome in mice. Purified glomerular endothelial cells, instead of podocytes, were demonstrated to be responsible for the proteinuric effect elicited by C5a. Further studies depicted a signaling pathway involving Rho/Rho-associated kinase/myosin activation leading to endothelial cell contraction and cell adhesion complex breakdown. Significantly, application of Rho-associated kinase inhibitor, Y27632, prevented the protein leaking effects observed in both C5a-treated purified endothelial cells and mice. Taken together, our study identifies a previously unknown mechanism underlying nephrotic syndrome and provides a new insight toward identifying Rho-associated kinase inhibition as an alternative therapeutic option for nephrotic syndrome.     

服务承载网中基于最大流的服务器放置

针对在服务承载网中,传统的服务器放置方法会出现随着服务器个数的增加降低网络整体性能的问题,提出基于最大流效应的服务器放置算法。该算法不仅考虑到了流量因素,还将带宽、延迟、丢包率等网络节点性能因素简化为"距离因子"进行了考虑,解决了传统服务器放置引起的全局低效和网络拥堵问题,保证最大限度地满足用户的流量请求。经过实验验证,基于最大流效应的服务器放置算法相对于传统的服务器放置算法,在平均情况下,平均相应时间减低10%到25%,传输开销降低25%到50%,显著提高了网络性能。     

RFC分解炉的性能研究

分析了RFC分解炉内的气固流动、阻力特性以及炉内物料停留时间分布等,研究表明炉内大部分区域气体流动表现出明显的旋流流动特点,炉内湍流强度分布比较均匀,并沿轴向流动方向逐步增强。RFC分解炉的料气停留时间比值约为3.7,如果考虑炉出口与C5进口之间的垂直连接管道,则物料依次通过分解炉系统的平均停留总时间约为13.3s。RFC分解炉的3次风旋流流动的阻力系数为74,窑气喷腾流动的阻力系数为13。研究结果与工厂实际生产情况完全符合,为改进分解炉的设计和优化工厂的操作提供参考。