生态地理学概念界定及其经典案例分析

对生态地理学的概念进行了详细讨论和辨析,并将它与相近学科如生物地理学、生态地理区划、宏生态学等进行了比较分析,界定了生态地理学的概念。研究认为：生态地理学是生态学和地理学的交叉学科,是研究生态系统各组分关系和生态过程的地理空间分布格局或/和时间演变规律及其与地理环境耦合机制的学科。生态地理学的目的是揭示不同环境梯度下或不同时间尺度上生态系统各组分关系和生态过程的普适性规律及其成因。同时,结合国内外野外实验平台介绍,在全球变化等研究领域列举了经典案例进行分析：① 全球不同气候带森林凋落物分解和碳汇功能的研究;② 中国不同陆地生态系统碳通量和碳汇功能研究;③ 中国东北样带和南北样带陆地生态系统的脆弱性与适应性研究;④ 中国北方草地样带尺度的生态系统生态学研究。主要目的是在辨析生态地理学概念的基础上指出未来发展方向,推动生态地理学的发展。     

毛乌素沙区1961-2016年降水特征

基于毛乌素沙区10个气象站1961-2016年观测资料，应用Mann-Kendall方法和t检验法对各气象站年降水量进行了突变检验，借助小波分析讨论了各气象站年降水量的周期特征，根据降水量等值线划分结果对整个研究区分区分析了年、季、月和日尺度上的降水变化特征，并在两个时段上分析了季节性降水的差异。结果表明：毛乌素沙区年降水量空间特征差异明显，东部亚区呈上升趋势，中西部亚区呈下降趋势，但变化趋势不显著且无突变发生；降水年内分配不均，干湿季分明，降水集中在5-9月，夏秋季降水占全年降水比重大，季、月和日尺度降水量存在梯度递减变化；年降水量的年际变化过程存在多重时间尺度的自相似结构；近26年的冬春季降水增加显著，但降水波动幅度小于前30年。     

Photosynthetic response of <Emphasis Type="Italic">Scirpus validus</Emphasis> and <Emphasis Type="Italic">Typha orientalis</Emphasis> to elevated temperatures in Dianchi Lake,Southwestern China

Understanding the effects of simulated warming on photosynthetic performance of aquatic plants may provide strong supports for predicting future dynamics of wetland ecosystems in the context of climate change. The plateau wetlands located in Yunnan province are highly sensitive to climate warming due to their high altitude and cold temperature. Here, we conducted a temperaturecontrolled experiment using two temperature manipulations (ambient temperature as the control and 2°C higher than ambient temperature as the warmed treatment) to determine the photosynthetic characteristics of two lakeside dominant species (Scirpus validus Vahl and Typha orientalis C. Presl.) in Dianchi Lake. Net photosynthetic rate (P_n), stomatal conductance (G_s), intercellular CO₂ concentration (C_i), and transpiration rate of S. validus that grew under warmed treatment were all significantly higher than those under the control. G_s and C_i of T. orientalis showed similar patterns as S. validus did. For the response curves of P_n to photosynthetic active radiation (Pn-PAR) and intercellular CO₂ concentration (P_n-C_i), S. validus had higher P_n values under elevated temperatures than the control, while P_n-PAR and P_n-C_i curves of T. orientalis did not separate clearly under two temperature scenarios. Both S. validus and T. orientalis had higher maximum net photosynthetic rate, light saturation point, dark respiration rate, the maximum rate of RuBP carboxylation (V_cmax), maximum electron transport rate driving RuBP regeneration (J_max), the ratio of V_cmax to J_max, triosephosphate utilization, and 1, 5-bishosphate carboxylase ribulose content under warmed treatment than those under the control. This study provides a preliminary step for predicting the future primary production and vegetation dynamics of plateau wetlands in Yunnan province.     

“地理素养与测绘技能”双驱动的GIS专业大学生创新能力培养模式的探索

在信息技术快速发展和万众创新、大众创业的时代背景下，创新与创新人才已成为国家发展的重要推动力，创新教育和创新人才培养成为高校的重要任务。本文以武汉大学地理信息科学（GIS）专业为例，结合专业特点和优势，探索了"地理素养、测绘技能"驱动下的GIS专业大学生创新能力的培养模式和"厚基础、重知识、强技能"的贯通式培养途径。围绕创新人才培养和成长的内在因素和外部条件，从人才培养方案与课程体系、创新型教师团队与新型教学方法、教学科研创新平台与创新条件、创新人才发展评价与激励机制等4个方面开展了创新型发展探索。结合实践表明，本模式取得了显著的创新成果，产生了良好的示范辐射作用。     

Microwave Type III Burst Group in the 1993 October 2 Flare

Microwave Type III bursts with positive frequency drifting rate were found by Stahli and Benz (1987) for first time. Type III events are especially interesting because they are well-known to be signatures of electron beams in coronal plasma, and they are effective means for diagnosting of source plasma. A microwave burst consisting of some microwave type III burst groups was registered at Beijing Astronomical Observatory with the 2545–2645–2840 MHz synchronous observing system. The distributions of frequency drifting rate, half power duration, and intensity for each impulse in the groups have been statistically analysed. From this analysis, some important parameters for the dynamic process in the flare are deduced and discussed.     

A New Solar Radio Spectrometer at 1.10-2.06 GHz and First Observational Results

An improved Solar Radio Spectrometer working at 1.10-2.06 GHz with much improved spectral and temporal resolution, has been accomplished by the National Astronomical Observatories and Hebei Semiconductor Research Institute, based on an old spectrometer at 1-2 GHz. The new spectrometer has a spectral resolution of 4 MHz and a temporal resolution of 5ms, with an instantaneous detectable range from 0.02 to 10 times of the quiet Sun flux. It can measure both left and right circular polarization with an accuracy of 10% in degree of polarization. Some results of preliminary observations that could not be recorded by the old spectrometer at 1-2 GHz are presented.     

Generalized strain probing of constitutive models

Advanced material constitutive models are used to describe complex soil behaviour. These models are often used in the solution of boundary value problems under general loading conditions. Users and developers of constitutive models need to methodically investigate the represented soil response under a wide range of loading conditions. This paper presents a systematic procedure for probing constitutive models. A general incremental strain probe, 6D hyperspherical strain probe (HSP), is introduced to examine rate‐independent model response under all possible strain loading conditions. Two special cases of HSP, the true triaxial strain probe (TTSP) and the plane‐strain strain probe (PSSP), are used to generate 3‐D objects that represent model stress response to probing. The TTSP, PSSP and general HSP procedures are demonstrated using elasto‐plastic models. The objects resulting from the probing procedure readily highlight important model characteristics including anisotropy, yielding, hardening, softening and failure. The PSSP procedure is applied to a Neural Network (NN) based constitutive model. It shows that this probing is especially useful in understanding NN constitutive models, which do not contain explicit functions for yield surface, hardening, or anisotropy. Copyright © 2004 John Wiley & Sons, Ltd.     

On the microwave millisecond spike emission and its associated phenomena during the impulsive phase of large solar flare

We propose a model of two acceleration regions, which can explain, on the basis of microwave maser caused by a “hollow-beam” distribution of electrons, the presence of millisecond spikes in the event of 1981 May 16 and their absence in the event of 1981 October 12, and the enhanced continuous emission in the latter. We have also uncovered relations among the features, e.g. the Type III_G, Type IV_DCIM and hard x-ray bursts, that accompany the microwave millisecond spikes during the impulsive phase of a large flare.     

试论质量体系有效性的保持

提出了保持质量体系有效运行的前提和基础 ,关键和保证措施 ,并指出了组织企业保持质量体系持续有效的方法和途径。     

Infrared Study of T Tauri Stars Based on IRAS and 2MASS Observations

The IRAS and 2MASS associations for 193 T Tauri stars are identified in this paper. From the color–color diagrams and spectral index, it is found that the IR excesses for most samples are due to thermal emission from the circumstellar material, as suggested previously. It is also found that the IR excesses at IRAS region for few T Tauri stars and the near-IR excesses for some T Tauri stars are likely attributed to free-free emission or free-bound emission from the circumstellar ionized gas. Moreover, It is found in deredened J–H versus H–K color–color diagram that there is a slight separation in different spectral groups. The T Tauri stars locus equation in J–H versus H–K color–color diagram for our sample is also presented.