Projection of Extreme Temperatures in Hong Kong in the 21st Century

The possible changes in the frequency of extreme temperature events in Hong Kong in the 21st century were investigated by statistically downscaling 26 sets of the daily global climate model projections (a combination of 11 models and 3 greenhouse gas emission scenarios, namely A2, A1B, and B1) of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. The models’ performance in simulating the past climate during 1971–2000 has also been verified and discussed. The verification revealed that the models in general have an acceptable skill in reproducing past statistics of extreme temperature events. Moreover, the models are more skillful in simulating the past climate of the hot nights and cold days than that of the very hot days. The projection results suggested that, in the 21st century, the frequency of occurrence of extremely high temperature events in Hong Kong would increase significantly while that of the extremely low temperature events is expected to drop significantly. Based on the multi-model scenario ensemble mean, the average annual numbers of very hot days and hot nights in Hong Kong are expected to increase significantly from 9 days and 16 nights in 1980–1999 to 89 days and 137 nights respectively in 2090–2099. On the other hand, the average annual number of cold days will drop from 17 days in 1980–1999 to about 1 day in 2090–2099. About 65 percent of the model-scenario combinations indicate that there will be on average less than one cold day in 2090–2099. While all the model-emission scenarios in general have projected consistent trends in the change of temperature extremes in the 21st century, there is a large divergence in the projections between difierent model/emission scenarios. This reflects that there are still large uncertainties in the model simulation of the future climate of extreme temperature events.     

Hydrogeology,Chemical and Microbial Activity Measurement Through Deep Permafrost

Little is known about hydrogeochemical conditions beneath thick permafrost, particularly in fractured crystalline rock, due to difficulty in accessing this environment. The purpose of this investigation was to develop methods to obtain physical, chemical, and microbial information about the subpermafrost environment from a surface‐drilled borehole. Using a U‐tube, gas and water samples were collected, along with temperature, pressure, and hydraulic conductivity measurements, 420 m below ground surface, within a 535 m long, angled borehole at High Lake, Nunavut, Canada, in an area with 460‐m‐thick permafrost. Piezometric head was well above the base of the permafrost, near land surface. Initial water samples were contaminated with drill fluid, with later samples <40% drill fluid. The salinity of the non‐drill fluid component was <20,000 mg/L, had a Ca/Na ratio above 1, with δ¹⁸O values ～5‰ lower than the local surface water. The fluid isotopic composition was affected by the permafrost‐formation process. Nonbacteriogenic CH₄ was present and the sample location was within methane hydrate stability field. Sampling lines froze before uncontaminated samples from the subpermafrost environment could be obtained, yet the available time to obtain water samples was extended compared to previous studies. Temperature measurements collected from a distributed temperature sensor indicated that this issue can be overcome easily in the future. The lack of methanogenic CH₄ is consistent with the high sulfate concentrations observed in cores. The combined surface‐drilled borehole/U‐tube approach can provide a large amount of physical, chemical, and microbial data from the subpermafrost environment with few, controllable, sources of contamination.     

Industrial relocation of Hong Kong manufacturing firms: towards an expanding industrial space beyond the Pearl river delta

This paper explores the recent industrial relocation of Hong Kong manufacturing firms in the Pearl River Delta. Based on a combination of recent surveys, four in-depth case studies and nearly 20 firm interviews through the end of 2008, the paper argues that in response to a dynamic business environment in the region, some Hong Kong manufacturing firms in the PRD are forced to design new spatial strategies. The paper also identifies the different relocation strategies adopted by Hong Kong manufacturing firms, namely, total relocation, stratified relocation and “pseudo relocation”. The industrial space of Hong Kong manufacturing firms will be expanded beyond the PRD. In addition, the new round of relocation of Hong Kong manufacturers is a response to the initiative ushered in by the provincial and local governments in order to achieve the objectives of industrial upgrading, sustainable environment and regional balanced development.     

阿尔金断裂带中侏罗世走滑活动及其断裂规模的探讨 ——来自软沉积物变形的证据

阿尔金断裂带是青藏高原北部边界,它不仅切割了高原北部的不同构造单元,控制了高原北部的几何学特征及基本的构造格架,而且还是调节青藏高原变形和高原物质向东挤出的重要断裂之一,对它的形成时代、活动历史以及断裂带的生长过程和演化的研究是认识青藏高原形成过程和动力学问题的关键之一.本文以阿尔金断裂带中段肃北县城南部出露的中侏罗纪陆相湖沼地层为研究对象,在野外中侏罗世剖面中,共发现26层软沉积物变形层.软沉积物变形的方式主要是不同类型的砂土液化,包括负载、球-枕状构造、卷曲变形、液化角砾、液化底劈和砂火山构造;软沉积变形大多发生在细砂岩和泥质粉砂岩层中,细砂岩层易液化、变形剧烈;粒度统计显示发生液化的沙粒粒径在0.05～0.5mm之间,主要为0.2～0.3mm,这些砂土液化的软沉积物变形特征与历史地震和模拟实验获取的易液化扰动区间高度一致,因此,中侏罗世地层中发育的软沉积物变形是由于地震震动而形成.根据震级与液化最大震中距的关系,推测发生的最小震级在Ms6～6.5之间,根据软沉积变形的类别与震级之间的关系推断最大可能发生的震级为7.5级.根据软沉积变形层出现的频率和组合关系,我们认为肃北剖面反应的是一个地震幕,发生的地震事件至少在4次以上,表明在中侏罗世(古)阿尔金断裂带发生了强烈的走滑运动,并且至少断裂带已延展到肃北一带,结合索尔库里地区晚三叠纪左旋走滑活动形成的糜棱岩以及玉门地区白垩纪的火山活动和软沉积物变形的事实,指示着阿尔金断裂带至少经历了晚三叠纪、中侏罗纪、晚白垩纪及新近纪的强烈走滑活动,并且其断裂带由索尔库里地区向东西两端逐渐扩展生长,由早期百千米到上千千米、一千多千米至约两千千米长的现今规模.     

Radioactive removal by adsorption on Yesan clay and zeolite

The adsorption of Cs, Sr, Ni, and Co radioactive substitutes onto Yesan clay and zeolite was studied through batch and column tests using Cs, Sr, Ni, and Co as substitutes for radioactive isotopes. Adsorption values of 0.189–1.865 μg/g onto Yesan clay and 0.595–9.055 μg/g onto zeolite were observed, with the radioactive substitutes being almost 100 % adsorbed from the onset of column testing. Adsorption was achieved through ionic bonding. These materials demonstrated suitability for use as backfill or foundation materials for nuclear power plants, radioactive waste disposal facilities, and other radioactive facilities.     

Sterile neutrinos as dark matter in clusters and galaxies

The recent analysis of MiniBooNE experiment suggests that a better fit of the data arises if there are 2 types of sterile neutrinos. If the sterile neutrinos were produced during the early epoch of the Big Bang, they would be slightly degenerate. I show that the existence of 2 types slightly degenerate sterile neutrinos can fully explain the dark matter problem, the cusp problem, the hot gas density profile in clusters and the rotation curves of galaxies.     

Mesozoic age of the uril formation of the Amur Group, Lesser Khingan terrane of the Central Asian foldbelt: Results of U-Pb and Lu-Hf isotopic studies of detrital zircons

U-Pb (LA-ICPMS) geochronological studies established the minimum age of detrital zircons from metasedimentary rocks of the Uril Formation of the Amur Group of ～240 Ma, which approximately corresponds to the lower age boundary of formation of their protoliths. The upper boundary of accumulation of sedimentary rocks of this formation is governed by the age of superimposed structural-metamorphic transformations (220–210 Ma). It follows that the age of protoliths of metasedimentary rocks of the Uril Formation is Triassic in contrast to the previously suggested Early Precambrian age. At the same time, previous estimations of the Nd model age of metasedimentary rocks of the Tulovchikha Formation of the Amur Group and intruding gabbroic rocks are 1.7 and 0.5 Ga, respectively. In other words, the age of this formation is 1.7–0.5 Ga. All of this indicates a combination of sedimentary and volcanic rocks of different ages in the section of the Amur Group. Judging from the Lu-Hf isotopic-geochemical studies of zircons, the major sources of protoliths for metasedimentary rocks of the Uril Formation are Neoproterozoic igneous rocks and also Early and Late Paleozoic and Early Mesozoic igneous rocks, the formation of which was related to the reworking of the Neo- and Mesoproterozoic continental crust.     

Impacts of landscape fragmentation on simulated precipitation fields in the Amazonian sub-basin of Ji-Paraná using the Eta model

Numerical studies on impacts of landscape fragmentation due to land use and land cover change (LUCC) on precipitation fields over the Ji-Paraná basin in the Amazon region are carried out using atmospheric Eta model. Experiments consider historical data about LUCC over the basin from 1978 to 2000 and compare simulations under LUCC conditions with simulations under pristine conditions. In agreement with previous observational studies, model results do not show statistically significant impacts on precipitation in the region. Results indicate that variability in precipitation in this region is mainly controlled by large-scale atmospheric characteristics and soil moisture conditions. However, some limitations are identified in the model simulations, mainly associated to the diurnal cycle of precipitation.     

深基坑双层土体空间效应分析

随着城市的不断发展,基坑开始由传统的二维模式向三维空间转变。该文借助于坑壁土体的三维破坏模式,推导出双层土体的破坏模型,在此模型基础上基于土体塑性上限理论及极限平衡分析理论,提出了考虑空间效应的土压力计算公式以及相应的空间效应影响系数。该计算公式可用于基坑土钉墙、护坡桩、地下连续墙等支护系统的设计。     

Dynamical evolution of an unstable gravastar with zero mass

Using the conventional gravastar model, that is, an object constituted by two components where one of them is a massive infinitely thin shell and the other one is a de Sitter interior spacetime, we physically interpret a solution characterized by a zero Schwarzschild mass. No stable gravastar is formed and it collapses without forming an event horizon, originating what we call a massive non-gravitational object. The most surprise here is that the collapse occurs with an exterior de Sitter vacuum spacetime. This creates an object which does not interact gravitationally with an outside test particle and it may evolve to a point-like topological defect.