基于BP神经网络的杭州湾北岸水下地形遥感反演研究

基于BP神经网络模型,利用同一时期的遥感影像和实测杭州湾北岸海图资料,构建了影像灰度值和水深值之间的单隐层BP神经网络模型,用以反演杭州湾北岸水下地形。结果表明,与传统的统计模型比较,所建神经网络模型反演地形的精度达84％。由此可见,基于影像灰度值和水深值建立的BP神经网络模型在反演海岸水下地形方面具有较强的应用价值。     

Using ~(137)Cs tracing technique to estimate wind erosion rates in the typical steppe region, northern Mongolian Plateau

Wind erosion is one of the major factors of land degradation in the typical steppe region, northern Mongolian Plateau. Using 137Cs tracing technique, we estimated the wind erosion rates of different pastures and abandoned farmland at Bayannur and Karakorum in Mongolia. The pastures and cutting grassland at Bayannur were slightly eroded by wind, with the rates of 64.58-169.07 t·km?2·a?1. The abandoned farmland in Karakorum, however, was strongly eroded by wind, with annual surface soil loss of 4.05 mm·a?1, and wind erosion rates up to 6723.06 t·km?2·a?1. The total loss of surface soil due to wind erosion has been 17.4 cm since the cultivation of the steppe land in the 1960s. The wind ero- sion rate at the abandoned farmland was much higher than that at the typical steppe sites, showing that the cultivation led to serious wind erosion in the typical steppe region, northern Mongolian Plateau. By contrast, traditional livestock grazing resulted in less disturbance to the surface soil, and did not in- duce to devastating wind erosion, which plays an important role in maintaining the stability of the steppe ecosystem in the northern Mongolian Plateau.     

一寺而兼两祖庭——论湖北当阳玉泉寺在中国佛教史上的地位和影响

被誉为“荆州丛林之冠”的湖北当阳玉泉寺在中国佛教史上有着极为重要的地位和影响.它既是中国第一个佛教宗派天台宗的祖庭之一,又是禅宗北宗的祖庭.此外玉泉寺还与其它佛教宗派如律宗、净土宗、禅宗南宗等也有着极为密切的关系.隋唐之时,玉泉寺高僧辈出,国师云集;诸宗竞秀,蔚为大观,是当时全国的佛教中心之一.     

王重阳与全真北宗的思想略论

以王重阳的思想为主,对道教全真道北宗的思想,从"识心见性"的心性论、先性后命的修道论、真功真行合一的功夫论三个方面探讨,比较北宗与南宗思想的异同以及北宗在思想史上的地位。     

程师孟诗考

程师孟,诗效白居易而尤简直,与之唱和往来的诗人不下百人.有诗集二十卷,惜已佚,故后世诗名不显.新编《全宋诗》从方志等辑其诗40首,用力甚勤,但《全宋诗》中的程师孟诗存在着疏失,需要对其加以考订、补苴,对其佚诗亦需加以考实.     

Zircon SIMS ages and chemical compositions from Northern Dabie Terrain: Its implication for pyroxenite genesis

We present the results of a detailed micro-scale investigation of zircons from pyroxenites, Daoshicong Northern Dabie using a combination of SIMS and ICPMS. The SIMS measurements gave ages of 134—159 Ma. Its average of (144.5± 6.2) Ma is interpreted as the best estimate of the pyroxenite intrusion. The crystallization of zircons continued for quite a long time and underwent slow cooling. The pyroxenites are products of post-collision magmatism. The REE pattern is HREE-enriched, and its HREE concentrations fall between the magmatic and metamorphic range of gneissic zircons from the Dabie area, which indicate the involvement of crust material in its mantle source.     

北魏政府的廉政爱民措施

从颁布诏令,制造舆论;巡行州郡,察举不法;校阅财产,颁禄酬廉;定期考核,擢廉黜贪等四个方面,对北魏王朝的廉政爱民措施进行论述,旨在说明,北魏王朝在统一和统治中国北方的一百多年间,不光在政治、经济、文化等方面进行了一系列的改革,取得了一定的成就.在加强官员队伍的廉政爱民建设方面也作了积极的尝试,收到了良好的效果,值得我们今天关注和借鉴.     

松辽盆地北部上白垩统嫩江组二 、三段物源分析

通过岩芯观察描述以及分析化验资料的综合分析, 从岩石矿物成分、砂体平面展布、重矿物组合以及锆石-电气石-金红石指数(ZTR 指数) 、泥岩颜色区域分布等方面对物源方向进行了判断。综合分析表明: 松辽盆地北部嫩江组二、三段沉积时期物源随时间变化有所变化, 但变化不大。嫩江组二段沉积时期物源主要来自东方; 嫩江组三段沉积时期物源除东部来的物源外, 东北部物源对盆地北部物源体系也参与贡献, 物源的变化可能是由于嫩二段晚期盆地北部地层隆起。松辽盆地北部在嫩江组二、三段时期主要存在着 3 个方向的物源: 东北、东部以及西部物源。嫩江组二、三段沉积时期, 东部物源为主要物源, 在嫩江组三段沉积的中后期, 东北向物源出现并与东部物源共同起主导作用。西部物源在嫩江组三段沉积的中晚期出现, 影响范围小。     

试论北宋东京城的扩展

北宋东京城一直处在不断的扩展之中,主要表现是城外出现了繁荣的草市,城垣不再是城区的外界。这打破了“筑城以卫君,造郭以守民”的传统模式,在中国城市发展史上翻开了新的一页。东京城扩展的过程伴随着城市生长点（带）的产生与位移。     

塔北与巴楚下丘里塔格群白云岩储层特征对比

针对塔北和巴楚地区下丘里塔格群白云岩储层特征的差异问题,通过岩芯描述、薄片鉴定、阴极发光、扫描电镜、物性分析以及压汞等资料从岩石学、储集空间、物性及孔隙结构几个方面进行研究。结果表明：塔北地区主要为晶粒白云岩和颗粒白云岩;储集空间以晶间孔、晶间溶孔、溶蚀孔洞和裂缝为主,储集空间类型组合多样;喉道主要为粗-细喉型,分选好,孔喉分布均匀,连通性较好,物性较好;此外该区构造破裂作用和岩溶作用发育,也改善了储层物性。巴楚地区以晶粒白云岩和泥微晶白云岩为主;溶蚀孔洞、裂缝的发育程度和规模不如塔北地区,储集空间类型组合较单一;喉道多为细-微喉型,分选差,孔喉分布极不均匀,连通性差,物性较差。塔北地区白云岩储层物性好于巴楚地区,造成该差异的原因主要是受到了沉积作用和成岩作用的共同影响。