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一种由铣刀刃形求螺旋槽形状方法的探讨

根据无瞬心包络原理,用向量法推导一种由已知铣刀刃形求螺旋槽形状的简便计算公式和方法.     

The unification of RBLs with XBLs

Many astronomers have discussed the property of BL Lacertae objects, including the variation of spectrum, the correlation of multi-wave bands and the property of polarization, which could give good information for studying intrinsic correlation of components and position of BL Lacertae objects. In the paper, we investigated the properties of RBLs and XBLs and RBLs/XBLs (these objects can also be found by radio survey as by X-ray survey). Firstly, we collected the light curve of 28 BL Lacertae objects, and gained their short timescales by Structure Function (SF). Secondly, we analyzed the distribution of the short timescales of some BL Lacertae objects, including 28 objects’ timescales calculated by SF, as well as the distribution of the redshift and the black hole mass and the flux densities of the multi-wavebands (radio, near-infrared, optical and Gamma-ray). Based on statistical analysis, the result of the paper support the unification model of RBLs and XBLs.     

新疆和田河流域柽柳沙堆的生物地貌发育过程

Tamarix nabkha is one of the most widespread nabkhas,distributing in the arid region of China.Based on the observations outdoors and the simulation experiments in laboratories,analysis in this paper refers to the biological geomorphologic features and growth process of Tamarix nabkhas in the middle and lower reaches of the Hotan River,Xin- jiang.And the results indicate that the ecological type of Tamarix in the study area is a kind of Tugaic soil habitat based on the deep soil of the Populus Diversifolia f...     

彗星等离子体某些特征的讨论

本文讨论了彗星中尘埃粒子的充电机制 ,带电特性和平衡电势的变化规律 ,分析了彗星尘埃的破碎特性和临界半径 ,得出了很有意义的结果     

南极MIL 090070月球陨石的岩石矿物学特征

MIL 090070陨石是2009年美国南极陨石搜寻项目(ANSMET)在南极横断山脉米勒山区(Miller Range)发现的一块月球陨石,属于斜长岩质月表角砾岩。它具有典型的碎屑结构,主要由岩屑、晶屑、玻屑和细粒基质组成。岩屑以复合斜长岩质岩屑和斜长岩岩屑为主,其次为辉长岩质斜长岩岩屑、辉长岩岩屑、辉长苏长岩岩屑、辉长岩质橄长岩岩屑和橄榄辉长岩岩屑等。晶屑有普通辉石、易变辉石、斜长石、尖晶石、石英和钛铁矿等矿物。玻屑主要为斜长石质的玻屑,呈细长或弯曲条状,多具裂纹。MIL 090070陨石的矿物组成主要为斜长石（86 vol%,An92—99）、橄榄石（6 vol%,Fo53—89）、辉石（7 vol%,En25—83Fs7—43Wo2—45）,以及少量的尖晶石、钛铁矿和石英等;其中,辉石有单斜辉石和斜方辉石二种。MIL 090070陨石中橄榄石和辉石的Fe-Mn值分布明显不同于地球、火星、金星和小行星的样品,基本落在月球岩石范围。MIL 090070陨石在多期次冲击和胶结作用下,岩屑的矿物成分和粒度不断变化,岩屑类型更多样,更复杂。基于MIL 090070陨石的岩石矿物学特征、碎屑类型及结构的特征等研究,可以进一步丰富我们对月球物质的形成及月岩—月壤演化过程的认识。     

Analog simulation of urban construction land supply and demand in Chang-Zhu-Tan Urban Agglomeration based on land intensive use

Journal of Geographical Sciences - Urban land intensive use is an important indicator in harmonizing the relationship between land supply and demand. The system dynamics (SD) can be used to...     

南极半岛周边海域表层沉积物粒度分布特征及其环境指示意义

基于南极半岛周边海域表层沉积物调查以及收集的资料,并通过分析表层沉积物粒度数据研究沉积物类型和分布特征,探讨沉积物的变化规律。南极半岛周边海域的沉积物类型比较丰富,主要分为四大类:砾质、砂质、粉砂质以及泥质沉积物;根据不同的水深和地貌单元可分为陆架(或岛架)碎屑沉积物、陆坡(或岛坡)沉积物和深海沉积物。研究区沉积物属于冰海沉积物,并可划分为残副冰碛物和混合副冰碛物。沉积物的搬运介质以冰川、冰筏为主,海流对沉积物的影响较为明显,沉积物类型随地形变化而呈有规律的分布。     

Early middle Holocene climate oscillations recorded in the Beihuqiao Core,Yuhang, Zhejiang Province,China

A long-standing controversy exists concerning the spatial and temporal characteristics of Holocene climate change in China. Zhejiang is located in the southeast of China, where the East Asian monsoon dominates the climate and a Neolithic culture flourished. In recent years, geographers have debated the climatic conditions existing at the time of the Neolithic cultures. This study reconstructed the sedimentary environment between 11.30 and 4.17 cal ka BP based on a multi-proxy analysis of a 14.3 meter sediment core, drilled in Beihuqiao, Zhejiang Province, China. The results show: (1) The climate was getting warm between 11.50 and 8.77 cal ka BP. Grain size became finer from the bottom to the top layer, accompanied by an increase in the chemical index of alteration (CIA), Mg/Sr ratio, the percentage of clay, pollen concentrations, and a decrease in SiO₂/Al₂O₃ ratio, and the value of bases–alumina (ba), as well as other trace elements. (2) Between 8.77 and 7.99 cal ka BP, the sediment is composed of gray-yellow and gray silt. The percentage of CaO and the ratio of CaO + Na₂O + K₂O to Al₂O₃ is much higher. The pollen concentration sharply decreases. The climate was cold and dry in the early stages of this period, but became relatively warmer and wetter in the later stages. (3) The Holocene Climatic Optimum occurred at 7.99–5.68 cal ka BP. Higher contents of clay, total Fe₂O₃, Al₂O₃, CIA, the chemical proxy of alteration, pollen concentration, evergreen pollens, and high values of Mg/Sr are observed at this stage, coinciding with a lower SiO₂/Al₂O₃ value, (CaO + Na₂O + K₂O)/Al₂O₃ ratio, and an obvious reduction in silt/clay, and SiO₂ and CaO concentrations. (4) During the period 5.68–4.17 cal ka BP, the temperature in the study area declined in a stepwise fashion. The grain size became finer, and the Mg/Sr ratio decreased gradually.     

欧亚黄土沉积环境对比研究

本文对采自中国、法国、比利时等国43块黄土样品进行实验室处理后,分析对比了它们在碳酸盐含量、粒度组成、重矿物组成及粘土矿物成分方面的共同特性及差异性。结果表明,中国黄土碳酸盐含量稳定,西欧不同类型的黄土碳酸盐含量差别很大。在粒度组成上,欧亚黄土并没有本质的差别,但西欧不同层位的黄土粒度组成呈有规律变化。对西欧重矿物的分析可以追溯黄土的物质来源,粘土矿物含量在欧亚不同黄土中也有差别。比较结果说明,欧洲的黄土堆积受第四纪冰期、间冰期的气候波动影响较大,中国黄土在堆积期间始终处在干旱、半干旱的气候条件下。