Extension of high-order harmonics and generation of an isolated attosecond pulse in the chirped laser field

This paper theoretically investigates the high-order harmonic generation cutoff extension using intense few-cycle linearly chirped laser pulses. It shows that the cutoff of the harmonic can be extended remarkably by optimising the chirping parameters. The time-frequency characteristics of high-order harmonics with different chirping parameters are analysed by means of wavelet transform of the dipole acceleration. It also gives out the classical three-step model pictures of electron. By superposing a properly selected range of the harmonic spectrum, it obtains an isolated 65as pulse.     

A strip adjustment procedure to mitigate the impact of inaccurate mounting parameters in parallel lidar strips

Lidar (laser scanning) technology has been proven as a prominent technique for the acquisition of high-density and accurate topographic information. Because of systematic errors in the lidar measurements (drifts in the position and orientation information and biases in the mirror angles and ranges) and/or in the parameters relating the system components (mounting parameters), adjacent lidar strips may exhibit discrepancies. Although position and orientation drifts can have a more significant impact, these errors and their impact do not come as a surprise if the quality of the GPS/INS integration process is carefully examined. Therefore, the mounting errors are singled out in this work. The ideal solution for improving the compatibility of neighbouring strips in the presence of errors in the mounting parameters is the implementation of a rigorous calibration procedure. However, such a calibration requires the original observations, which may not be usually available. In this paper, a strip adjustment procedure to improve the compatibility between parallel lidar strips with moderate flight dynamics (for example, acquired by a fixed-wing aircraft) over an area with moderately varying elevation is proposed. The proposed method is similar to the photogrammetric block adjustment of independent models. Instead of point features, planar patches and linear features, which are represented by sets of non-conjugate points, are used for the strip adjustment. The feasibility and the performance of the proposed procedure together with its impact on subsequent activities are illustrated using experimental results from real data.     

Authigenic iron oxide formation in the estuarine mixing zone of the Yangtze River

Estuaries are elementary geochemical fronts where river water and seawater mix. Within this mixing zone, iron and other non-conservative elements can undergo complex reactions to form new solid phases. In order to understand authigenic iron oxide formation in the Yangtze River Estuary, two onsite water-mixing sets of experiments were conducted, one by mixing variable amounts of unfiltered Yangtze River water with filtered East China Sea water of different salinity (set 1), the other by mixing variable amounts of filtered Yangtze River water with filtered East China Sea water of different salinity (set 2). In set 2, the minerals newly formed in the course of mixing were investigated by means of a scanning electron microscope fitted with an energy-dispersive X-ray analytical system. It was found that ferrihydrite and lepidocrocite were formed in these mixing experiments, coexisting in nearly equal amounts. These iron oxides appear as aggregated particles with a large grain-size range of several microns to more than 100 μm. The electrolytic properties of seawater played an important role in the formation of these authigenic iron oxides. Kaolinite and organic aggregates were also found in the experimentally mixed pre-filtered waters. Amounts of newly formed suspended matter (set 2) were one to three orders of magnitude lower than those of total suspended matter (TSM) (set 1). This implies that newly formed minerals represent only a very small proportion of TSM in the estuarine mixing zone of the Yangtze River.     

塔中1井储层段岩石学特征及成岩作用

本文对塔中１井储层段进行了岩芯、薄片、阴极发光等观察和分析，划分出了角砾白云岩、残余颗粒白云岩和晶粒白云岩３种岩石类型，识别出了白云石化、硅化、方解石化、重晶石化、萤石化、黄铁矿化、自生粘土矿物化以及溶解、压溶等成岩作用类型；归纳出塔中１井储层段经历了３个成岩阶段、４种成岩环境的改造和叠加，并在物性测定的基础上给出３个岩性段的储集条件．     

Interactions of aquaculture and waste disposal in the coastal zone

Throughout the world, the coastal zones of many countries are used increasingly for aquaculture in addition to other activities such as waste disposal. These activities can cause environmental problems and health problems where they overlap. The interaction between aquaculture and waste disposal, and their relationship with eutrophication are the subjects of this paper. Sewage discharge without adequate dispersion can lead to nutrient elevation and hence eutrophication which has clearly negative effects on aquaculture with the potential for toxic blooms. Blooms may be either toxic or anoxia-causing through the decay process or simply clog the gills of filter-feeding animals in some cases. With the development of aquaculture, especially intensive aquaculture, many environmental problems appeared, and have resulted in eutrophication in some areas. Eutrophication may destroy the health of whole ecosystem which is important for sustainable aquaculture. Sewage discharge may also cause serious public health problems. Filter-feeding shellfish growing in sewage-polluted waters accumulate micro-organims, including human pathogenic bacteria and viruses, and heavy metal ion, presenting a significant health risk. Some farmed animals may also accumulate heavy metals from sewage. Bivalves growing in areas affected by toxic algae blooms may accumulate toxins (such as PSP, DSP) which can be harmful to human beings.     

莒县农村居民点整理潜力研究

1农村居民点用地存在的问题1.1平房户型多且分散建筑容积率低莒县农村居民点户型中平房比重高达98.6%,二层楼房占1.1%,三层及以上户型仅占0.3%,建筑容积率低,单层平房占到98.6%,分布分散,有10个乡镇的农村居民点密度低于日照市平均水平。农村居民点用地“平面扩张有余,立体利用     

Determination of Early Paleozoic metamorphic event in the Longshan Complex and its geological implicationSCIEI北大核心CSCD

长期以来,陇山杂岩的归属问题一直存在争议。本文对出露于秦岭-祁连山结合部位的陇山杂岩中石榴黑云斜长片麻岩和石榴斜长角闪岩进行了详细的岩石学、P-T温压计算、独居石和榍石U-Pb年代学研究。通过详细的岩相学观察,石榴黑云斜长片麻岩的变质峰期矿物组合为石榴子石+黑云母+斜长石+石英;石榴斜长角闪岩中则识别出了以石榴子石+单斜辉石+角闪石+斜长石+石英为峰期的变质矿物组合。通过传统温压计计算,石榴黑云斜长片麻岩(样品21LS40)和石榴斜长角闪岩样品(样品21LS42-1)的峰期变质P-T条件分别为700℃、0.72GPa和710℃、0.74GPa。激光剥蚀电感耦合等离子体质谱(LA-ICP-MS) U-Pb数据表明,石榴黑云斜长片麻岩中独居石的206Pb/238U的加权平均年龄为407~435Ma。石榴斜长角闪岩中榍石的下交点年龄分别为410±7Ma、409±5Ma和426±10Ma,榍石中Zr含量温度计的计算结果分别为750℃、751℃和748℃(假定压力为0.7GPa)。本文从变质作用的角度出发,将陇山杂岩与秦岭杂岩进行温压条件和变质时代对比研究,认为陇山杂岩与东秦岭杂岩高压-超高压岩石的最后一期退变质作用和西秦岭天水地区的秦岭杂岩麻粒岩相变质作用类似,可能为北秦岭造山带的西延。     

Deformation Movement of Hugely-Thick Conglomerate Stratum in Longwall Top Coal Caving

Geotechnical and Geological Engineering - In the process of longwall top coal caving, the deformation and movement of the overlying hugely-thick conglomerate stratum (HTCS) directly affects the...     

西沙石岛生物礁的矿物组成及其环境指示意义

通过对西科1井岩心碳酸盐岩样品进行矿物组成分析, 来研究礁体的发育过程和古海洋环境的变化.初步研究结果表明: 西科1井岩心碳酸盐岩的矿物由低镁方解石、高镁方解石、文石和白云石组成.矿物组成特征表明, 井深35.4 m处为一重要的地层界面或环境变化界面.在岩心(井深0~748 m)中共识别出5个白云岩层, 其中上新统莺歌海组一层(井深: 289.3~312.3 m, 厚约23 m), 上中新统黄流组三层(分别位于井深: 373.3~412.7 m, 厚约39.4 m; 424.7~450.6 m, 厚约26.1 m; 469.70~564.96 m, 厚约95.2 m), 中中新统梅山组一层(井深: 615.20~636.96 m, 厚约21.7 m).各层的白云岩化程度不尽相同, 5层白云岩中白云石矿物含量的最大值在79.3%~100%之间.生物礁的发育主要受控于古海洋环境的变化, 与古气候变化有关的海平面升降间接地控制了岛礁碳酸盐岩的白云岩化作用.石岛西科1井中的5层白云岩应该是在较长时间稳定环境条件下发育而成, 主要应该是蒸发泻湖渗透回流作用下早期形成的方解石类碳酸岩白云岩化的结果, 但并不排除混合水白云岩化作用的可能性.      

加拿大纽芬兰省稀有稀土矿化特征与勘查进展

纽芬兰省稀有稀土成矿地质条件优越,矿化主要与侵入的过碱性长英质岩及其喷出岩有关,矿化围岩为中元古代火成岩系,矿床成因类型为岩浆型和热液交代型,且以前者为主,典型矿床为世界级大型原生Strange Lake(Nd-Y-Zr-REE)矿床。目前,地球化学方法是区内寻找稀有稀土矿床最有效的勘探工具,拉布拉多主要勘查区为Letitia Lake、Red Wine Mountains、Flowers River和Strange Lake,纽芬兰岛主要勘查区为Fortune Bay、Clode Sound、Trinity Bay和Lost Pond。