林业科技是衢州林业发展的主动力

<正> 衢州是浙江三大林区之一,人口238万,其中农业人口200万人,总面积88.47万公顷,林业用地62万公顷,有林地55.67万公顷,森林覆盖率65.4％。森林蓄积量1242万立方米,经济林10.67万公顷,竹林6万公顷,毛竹10700万株,林业生产在农业经济中占有重要的地位。 1985年衢州恢复地级市建制,辖四县一市一区。针对我市人口密度大,人均林地少,     

基于越南遥感时间序列数据的湄公河三角洲土地利用及河岸变化检测研究

通过采用先进的遥感技术,基于光学和雷达时间序列卫星影像（陆地卫星,SPOT和雷达卫星）,本文对金瓯半岛（位于湄公河三角洲南部）土地覆被变化及湄公河河岸侵蚀情况进行了检测研究。鉴于金瓯半岛典型的土地覆被类型为红树林,通过对1973-2008年红树林遥感影像分析发现,近年来红树林林地面积急剧下降,超过一半的红树林已经转变为虾养殖场。与此同时,检测发现湄公河河岸已经被严重侵蚀,且侵蚀趋势正加速恶化。具体而言,田河和口河的左右两岸被认为是遭受严重侵蚀的热点区域。本文以1966-1968年地形图作为基准线数据,与1989-2009年卫星影像数据进行比照分析,此外采用数字海岸线分析系统（DSAS）模型对未来变化趋势进行了预测。     

形变数字化资料综合评价

以观测条件及观测质量居全国前列的山东泰安台为例．对固体潮形变观测的数字化与模拟资料的一致性、精度等方面进行了对比研究，认为固体潮的数字化与模拟观测资料的形态、观测精度、方差及均值无显著差异。通过对潮汐因子中误差、相位滞后及仪器零漂等参量的计算，对山东、上海及江苏各套形变数字化仪器观测资料的连续性、稳定性及观测质量进行了综合分析。在数字化倾斜仪中，水管倾斜仪的稳定性及精度较高，石英摆存在一定程度的漂移，垂直摆倾斜仪的漂移较大且资料精度较低。伸缩仪也存在精度较低的情况，但数字化资料精度略高于模拟资料；压容及体应变仪资料精度较高，但压容仪漂移较大，仪器稳定性不及体应变仪；体应变仪受气压、水位影响较显著。山东各形变台观测贤料总体质量较好，上海余山、江苏常熟台次之，江苏徐州台较其它台受降雨干扰大、漂移大，资料的稳定性及精度较低，说明台址条件是决定观测质量的重要因素之一。     

Period–colour and amplitude–colour relations in classical Cepheid variables – III. The Large Magellanic Cloud Cepheid models

Period–colour (PC) and amplitude–colour (AC) relations are studied for the Large Magellanic Cloud (LMC) Cepheids under the theoretical framework of the hydrogen ionization front (HIF)–photosphere interaction. LMC models are constructed with pulsation codes that include turbulent convection, and the properties of these models are studied at maximum, mean and minimum light. As with Galactic models, at maximum light the photosphere is located next to the HIF for the LMC models. However, very different behaviour is found at minimum light. The long-period  ( P > 10 d)  LMC models imply that the photosphere is disengaged from the HIF at minimum light, similar to the Galactic models, but there are some indications that the photosphere is located near the HIF for the short-period  ( P < 10 d)  LMC models. We also use the updated LMC data to derive empirical PC and AC relations at these phases. Our numerical models are broadly consistent with our theory and the observed data, though we discuss some caveats in the paper. We apply the idea of the HIF–photosphere interaction to explain recent suggestions that the LMC period–luminosity (PL) and PC relations are non-linear with a break at a period close to 10 d. Our empirical LMC PC and PL relations are also found to be non-linear with the F -test. Our explanation relies on the properties of the Saha ionization equation, the HIF–photosphere interaction and the way this interaction changes with the phase of pulsation and metallicity to produce the observed changes in the LMC PC and PL relations.     

Excitation mechanism ofNi 5199 Å lines in the day Airglow

Production rates of N(² D) metastable atoms in the daytime atmosphere have been calculated for different possible processes, using positive ion composition and reaction rate data, available presently. Emission rates of the 5199 Å doublet of Ni are calculated by separately and jointly considering the deactivation of N(² D) atoms by electrons and molecular oxygen.From a comparison of the computed results with the observational data, an attempt has been made to identify the processes of importance to the production and deactivation of N(² D). For further confirmation of the proposed mechanism the variation of integrated intensity of this radiation with solar activity has been obtained. The calculated values may be compared with intensity data obtained in future at different levels of solar activity.     

Hydrogeologic and hydraulic characterization of aquifer and nonaquifer layers in a lateritic terrain (West Bengal,India)

The hydrogeologic and hydraulic characteristics of a lateritic terrain in West Bengal, India, were investigated. Test drilling was conducted at ten sites and grain-size distribution curves (GSDCs) were prepared for 275 geologic samples. Performance evaluation of eight grain-size-analysis (GSA) methods was carried out to estimate the hydraulic conductivity (K) of subsurface formations. Finally, the GSA results were validated against pumping-test data. The GSDCs indicated that shallow aquifer layers are coarser than the deeper aquifer layers (uniformity coefficient 0.19–11.4). Stratigraphy analysis revealed that both shallow and deep aquifers of varying thickness exist at depths 9–40 and 40–79 m, respectively. The mean K estimates by the GSA methods are 3.62–292.86 m/day for shallow aquifer layers and 0.97–209.93 m/day for the deeper aquifer layers, suggesting significant aquifer heterogeneity. Pumping-test data indicated that the deeper aquifers are leaky confined with transmissivity 122.69–693.79 m²/day, storage coefficient 1.01?×?10^?7–2.13?×?10^?4 and leakance 2.01?×?10^?7–34.56?×?10^?2 day^?1. Although the K values yielded by the GSA methods are generally larger than those obtained from the pumping tests, the Slichter, Harleman and US Bureau Reclamation (USBR) GSA methods yielded reasonable values at most of the sites (1–3 times higher than K estimates by the pumping-test method). In conclusion, more reliable aquifers exist at deeper depths that can be tapped for dependable water supply. GSA methods such as Slichter, Harleman and USBR can be used for the preliminary assessment of K in lateritic terrains in the absence of reliable field methods.     

嘉峪关气氡映震情况讨论及玉门地震前水氡(嘉峪关,酒泉)异常特征

分析了1990年以来在祁连山断裂带上发生的7次地震前,嘉峪关气氡观测点和酒泉水氡的变化情况,发现在1990年10月20日天祝6．2级地震、1992年1月12日嘉峪关5．4级地震、1995年7月22日永登5．8级地震和2002年12月14日玉门5．9级地震前,嘉峪关气氡观测点均记录到短期的破年变异常,而酒泉水氡在玉门地震前为明显的突变型中期异常。     

渤海,黄海及沿岸强震聚类分析

采用聚类分析方法,研究了渤海、黄海及沿岸强震（Ｍ≥６）的空间分布。研究结果划分出了强震活动区及一些离散发生的强震。渤海的强震往往参与河北、山东、辽宁沿岸的强震分期、分区活动,且以强度高为特征;南黄海强震区自成体系,存在多期活动,与沿岸强震关系不大,以频度高为特点;北黄海内呈弱活动区的状态;朝鲜半岛强震独立成区,未向黄海内部延伸。文中给出分区的构造解释,并提出海域强震存在时空差异,在沿岸及海洋的防震