离子刻蚀全息光栅的研究

利用国产的光刻胶和国产离子刻蚀机在蒸镀的铝基衬底上进行刻蚀全息光栅,在国内是一项较新的技术。本文介绍和论述了该试验工作的工艺过程、参数计算和测试方法,得出了试验结果和参数计算值基本吻合的结论,并指出了进一步改善质量的方向。     

Experimental and numerical studies of the O exchange between CO2 and water in the atmosphere-soil invasion flux

The ¹⁸O/¹⁶O ratio of CO₂ is a potentially powerful tracer of carbon dioxide fluxes from the soil to the atmosphere, which is influenced by complex interactions involving both biotic and abiotic soil processes. We use a simplified experimental approach and numerical simulations to examine in isolation the ¹⁸O exchange between CO₂ and soil water associated with the abiotic invasion of atmospheric CO₂ into soil. This allowed us to verify, in particular, whether the ¹⁸O of the retro-diffusion flux of CO₂ from the soil reflects ¹⁸O equilibration with water at the soil surface, or at some depth. Sterile soil samples with known water isotopic composition were placed in a closed box attached to a specially designed flow chamber and the changes in δ¹⁸O of CO₂ between the chamber inlet and outlet, due only to invasion effects, were determined. Numerical simulations constrained by the laboratory gas exchange measurements indicated that between the two commonly used diffusion models [Penman, H.L. (1940). Gas and vapor movements in soil, 1: the diffusion of vapors through porous solids. Int. J. Agric. Sci.30, 437-462; Moldrup, P., Olesen, T., Yamaguchi, T., Schjonning, P., Rolston, D.E. (1999). Modeling diffusion and reaction in soils, IX, the Backingham-Burdine-Campbell equation for gas diffusivity in undisturbed soil. Soil Sci.164, 542-551], only the former provided good agreement with the measurements over a wide range of soil water contents. Based on the model calculations constrained by experimental data, and on comparison of characteristic diffusion/reaction times, we conclude that the depth required for full CO₂-water ¹⁸O equilibration ranges between 2 and 8.5 cm. The depth depends, in order of importance, on (1) soil moisture content; (2) temperature, which dominates the rate of hydration isotopic exchange; (3) CO₂ residence time, which is determined by the time of replacement of the column air above the soil; and (4) soil structure, including porosity, tortuosity and grain size, with the later probably influencing the water surface area exposed to CO₂ exchange. Using field data from a semi-arid forest site in Israel, numerical simulations indicated that the ¹⁸O full equilibrium depth varied at this site between 4 cm (January) and 8 cm (November), being sensitive mostly to temperature and soil water content. Deepening of the equilibration depth as the soil dries should limit the effects of ¹⁸O evaporative enrichment at the surface on the isotopic composition of the soil-atmosphere CO₂ flux.     

泥石流学科的发展和对策

泥石流研究首先要积极投身于国民经济建设主战场,并以泥石流综合防治为契机,促进山区生态经济系统的良性循环,使得根治泥石流灾害与社会、经济、生态环境协调发展。其次,要突破学科的前沿问题——泥石流起动理论和阻力规律。初步提出了实现目标的措施。     

“走出去”的地理学——从人文地理学视角看中非合作研究

中非合作正在成为国际政治和经济舞台上的重要事件。本文选用Endnote和Antconc等信息提取软件对国内外知名文献库中收录的有关中非合作的文章进行了梳理。以“中非合作”作为模糊关键词,对Web of Science、Taylor & Francis、Elsevier和中国知网四大数据库进行搜索,得到相关中外文文献共计623篇。分析发现,中外学者对中非合作议题的关注多集中于政治学和经济学的学科分析框架之下,其他学科视角相对缺乏。从人文地理学视角来看,尽管也有部分经济地理和政治地理学者对该话题进行了探讨,但并未完全脱离政治学和经济学的分析框架,且数量较少、未能体系化。因此,本文从与中非合作最为紧密的政治地理、旅游地理以及社会文化地理等三个方向提出了未来可能成为中非合作研究热点话题的基本研究框架。鉴此,随着国家“一带一路”倡议的逐步实施,期望未来能有更多人文地理学者投入到中非合作研究中,积极发挥中国地理学“走出国门”的大国智力责任和担当,为中非合作研究与实践作出自己的贡献。     

Separating contributions from natural and anthropogenic sources in atmospheric methane from the Black Sea region,Romania

The Danube Delta-Black Sea region of Romania is an important wetland, and this preliminary study evaluates the significance of this region as a source of atmospheric CH₄. Measurements of the mixing ratio and δ¹³C in CH₄ are reported from air and water samples collected at eight sites in the Danube Delta. High mixing ratios of CH₄ were found in air (2500–14,000 ppb) and dissolved in water samples (∼1–10 μmol L⁻¹), demonstrating that the Danube Delta is an important natural source of CH₄. The intercepts on Keeling plots of about −62‰ show that the main source of CH₄ in this region is microbial, probably resulting primarily from acetate fermentation. Atmospheric CH₄ and CO data from the NOAA/ESRL (National Oceanic and Atmospheric Administration/Earth System Research Laboratory) were used to make a preliminary estimate of biogenic CH₄ at the Black Sea sampling site at Constanta (BSC). These data were used to calculate ratios of CH₄/CO in air samples, and using an assumed CH₄/CO anthropogenic emissions ratio of 0.6, fossil fuel emissions at BSC were estimated. Biogenic CH₄ emissions were then estimated by a simple mass balance approach. Keeling plots of well-mixed air from the BSC site suggested a stronger wetland source in summer and a stronger fossil fuel source in winter.     

中国政治地理学研究进展——基于国家科学基金资助的分析

国家科学基金(国家自然科学基金和国家社会科学基金的统称)研究立项课题旨在探究重大现实问题以及学科前沿发展,在很大程度上反映了相关学科研究的进展和整体水平。通过分析近20年来中国国家自然科学基金和社会科学基金对政治地理相关议题的资助,以及受资助人在该时期对相关议题的科研情况,得出以下结论：①2011年以来,国内政治地理学逐渐被认可和关注,并呈现出以北京、广州、昆明和上海研究机构为辐射中心的地理特征;②国内政治地理研究重点为边境与边界、环境政治、领土(主权和安全)、行政区划和管治、尺度和空间、社会和文化政治等六大议题;③国内政治地理研究日渐与国际接轨,但行政区划和管治等是独特的研究。整体而言,随着国家科学基金对政治地理研究支持力度的加大,期望能瞄准国际研究前沿和国内需求,建构符合中国国情的政治地理学学科体系。     

山地自然灾害（以泥石流为主）及其防治

我国是一个山地自然灾害严重的国家,尤其是泥石流、滑坡灾害。八十年代以来山地自然灾害频繁,泥石流、滑坡所造成经济损失超过30亿元。本文分析了灾害成因、分布特征以及山地自然灾害的预报和防治。     

Mountain disaster formation in northwest Sichuan

This paper discusses the causes of debris flow, landslide, collapse, water and soil erosion and other mountain disasters in the high mountain-plateau transitional region in northwest Sichuan. Through analysis of geological structure, lithology, earthquakes, landforms, hydrologic regime, meteorological conditions and man-made factors, the authors conclude that the natural conditions of this region favor the formation of debris flow, landslides and other mountain disasters. Moreover, the irrational economic activities of humans such as destroying forest ecosystems stimulate the occurrence of mountain disasters.     

多指标实验设计FUZZY综合评判

对于多因子多指标的正交实验设计,本文提出了实现观测值模糊化的变换方法,并用模糊综合评判获取最优生产方案。较之传统的方法,模糊综合评判更具有科学性和先进性。     

提高叠加地震波分辨率的一种反演方法

子波提取是采用优化快速模拟退火法进行反演，提高叠加地震波分辨率的关键。本文应用最小平方法计算在合成地震记录与井旁地震记录差平方条件下的地震子波，制作合成地震记录，并进行反演以达到提高信噪比的目的。这是一种通过钻井资料来去噪、提高地震分辨率的方法，该方法原理简单、使用方便、效果较理想，有推广的意义。