Long-term research has been done on the unstable behaviors and electron emission from microprotrusions, but the whole reason is still not clear. It is difficult to study instabilities experimentally since vacuum break...Long-term research has been done on the unstable behaviors and electron emission from microprotrusions, but the whole reason is still not clear. It is difficult to study instabilities experimentally since vacuum breakdown can happen. In this model, we show the factors that lead to thermal instability during field emission. After the Nottingham flux inversion, we see a considerable rise in temperature above a threshold electric field, followed by a thermal runaway. Cathode spots experience unexpected thermal defects and breakdowns, which is a phenomenon known as the Nottingham Inversion Instability. Although the idea of micro protrusions is frequently used in modeling studies, this study concentrates on the thermal effects during field emission from a planar cathode without taking the existence of such protrusions into account. The study reveals how Nottingham’s heating effect changes from heating to cooling. In our study, we have investigated the interaction between Nottingham, Joule heating, and effective work function. The results also imply that faster reaching critical temperature is associated with larger maximum beta values. These discoveries have significance for the design and improvement of high-voltage systems and help to understand vacuum breakdown. The possibility of cathode spot ignition and subsequent vacuum breakdown is predicted by our model, which would make it possible to create a self-consistent model for that.展开更多
Nutrient enrichment has been identified as the major cause of University of Nottingham Malaysia Campus (UNMC) Lake’s water quality degradation. This study critically examines the nature, source and delivery of nutrie...Nutrient enrichment has been identified as the major cause of University of Nottingham Malaysia Campus (UNMC) Lake’s water quality degradation. This study critically examines the nature, source and delivery of nutrients into the lake and observes that uncontrolled anthropogenic activities along the catchment area are the major sources. The chemical analyses of the water samples drawn from different sampling points were carried out in the laboratory and the total phosphorus readings were in the range of 20 to 55.7 μg/L with the inflow 1 recording the highest level. The chlorophyll a concentrations in the lake water were between 39 to 65 μg/L which exceeded Malaysian water quality standard. However, the silicate and nitrate levels were found to be in lower concentrations. Dissolved oxygen and pH readings obtained through in situ measurements in the lake water showed that there was oxygen depletion in the water during the night while it increased during the day, also the lake was acidic in the night and became alkaline in the day. All the findings were integrated to draw realistic restoration goals for the lake.展开更多
组织学分级系统（ Histological classification system ，HCS）是判断和预测乳腺癌生物学行为的重要分级系统之一，本文结合国际相关文献，综述该系统的研究进展和发展方向。文献检索回顾HCS的起源及发展历程，详述Nottingham分级系统...组织学分级系统（ Histological classification system ，HCS）是判断和预测乳腺癌生物学行为的重要分级系统之一，本文结合国际相关文献，综述该系统的研究进展和发展方向。文献检索回顾HCS的起源及发展历程，详述Nottingham分级系统内容，分析该系统的不足，介绍新型分级系统。乳腺癌HCS发展已有百年历史，当前应用最广的Nottingham分级系统，是以癌细胞形态学为基础的系统，其存在纳入指标单一、评估变异大和评估效率低等缺点。国际上最新开发了“核＋增殖”分级系统、计算机辅助分级系统和综合预测模型等多种分级系统。乳腺癌HCS的未来发展方向将是运用高通量分析方法，在癌细胞和肿瘤微环境基础上，分析与预后密切相关的分子信息，预测患者预后和指导个体化治疗。展开更多
文摘Long-term research has been done on the unstable behaviors and electron emission from microprotrusions, but the whole reason is still not clear. It is difficult to study instabilities experimentally since vacuum breakdown can happen. In this model, we show the factors that lead to thermal instability during field emission. After the Nottingham flux inversion, we see a considerable rise in temperature above a threshold electric field, followed by a thermal runaway. Cathode spots experience unexpected thermal defects and breakdowns, which is a phenomenon known as the Nottingham Inversion Instability. Although the idea of micro protrusions is frequently used in modeling studies, this study concentrates on the thermal effects during field emission from a planar cathode without taking the existence of such protrusions into account. The study reveals how Nottingham’s heating effect changes from heating to cooling. In our study, we have investigated the interaction between Nottingham, Joule heating, and effective work function. The results also imply that faster reaching critical temperature is associated with larger maximum beta values. These discoveries have significance for the design and improvement of high-voltage systems and help to understand vacuum breakdown. The possibility of cathode spot ignition and subsequent vacuum breakdown is predicted by our model, which would make it possible to create a self-consistent model for that.
文摘Nutrient enrichment has been identified as the major cause of University of Nottingham Malaysia Campus (UNMC) Lake’s water quality degradation. This study critically examines the nature, source and delivery of nutrients into the lake and observes that uncontrolled anthropogenic activities along the catchment area are the major sources. The chemical analyses of the water samples drawn from different sampling points were carried out in the laboratory and the total phosphorus readings were in the range of 20 to 55.7 μg/L with the inflow 1 recording the highest level. The chlorophyll a concentrations in the lake water were between 39 to 65 μg/L which exceeded Malaysian water quality standard. However, the silicate and nitrate levels were found to be in lower concentrations. Dissolved oxygen and pH readings obtained through in situ measurements in the lake water showed that there was oxygen depletion in the water during the night while it increased during the day, also the lake was acidic in the night and became alkaline in the day. All the findings were integrated to draw realistic restoration goals for the lake.
文摘组织学分级系统（ Histological classification system ，HCS）是判断和预测乳腺癌生物学行为的重要分级系统之一，本文结合国际相关文献，综述该系统的研究进展和发展方向。文献检索回顾HCS的起源及发展历程，详述Nottingham分级系统内容，分析该系统的不足，介绍新型分级系统。乳腺癌HCS发展已有百年历史，当前应用最广的Nottingham分级系统，是以癌细胞形态学为基础的系统，其存在纳入指标单一、评估变异大和评估效率低等缺点。国际上最新开发了“核＋增殖”分级系统、计算机辅助分级系统和综合预测模型等多种分级系统。乳腺癌HCS的未来发展方向将是运用高通量分析方法，在癌细胞和肿瘤微环境基础上，分析与预后密切相关的分子信息，预测患者预后和指导个体化治疗。
