期刊文献+
共找到36,919篇文章
< 1 2 250 >
每页显示 20 50 100
The US Rare Earth Industry 预览
1
《中国稀土信息:英文版》 2019年第4期F0001-F0001,2-4共2页
Source:USGS[Data in metric tons of rare-earth oxide (REO) equivalent content unless otherwise noted]Domestic Production and Use:Rare earths were mined domestically in 2018. Bastnaesite (or bastnasite), a rare earth fl... Source:USGS[Data in metric tons of rare-earth oxide (REO) equivalent content unless otherwise noted]Domestic Production and Use:Rare earths were mined domestically in 2018. Bastnaesite (or bastnasite), a rare earth fluorocarbonate mineral, was mined as a primary product at a mine in Mountain Pass, CA, which was restarted in the first quarter of 2018 after being put on care-and-maintenance status in the fourth quarter of 2015.Monazite,a phosphate minercl,also may have been prcduced as a separcted concentrcte or in eluded as an accessoc minercl in heavy-mi neral concen trctes.The estimated value of rare-each compo unds and metals imported by the Un ited States in 2018 was$160 million,an in crease frem$137 millicn in 2017.The estimated distriCuticn of rare earths by end use was as follews:catalysta,60%;ceramics and gless,15%;metallurgical applicahcns and alloys,10%;polishing,10%;and other,5%. 展开更多
关键词 US Rare EARTH Industry rcrc-earth oxide(REO)
在线阅读 下载PDF
自然资源一级分类 预览 被引量:1
2
作者 张文驹 《中国国土资源经济》 2019年第1期4-14,共11页
自然资源在人类发展前进的历史中有着重要地位。在自然资源认识和利用上的重大突破,多次起到了划时代的作用。为在新时代里能更好地有所作为,需要认真地总结继承国内外的经验教训,建立起对自然资源认识和利用的科学知识体系。为此,需要... 自然资源在人类发展前进的历史中有着重要地位。在自然资源认识和利用上的重大突破,多次起到了划时代的作用。为在新时代里能更好地有所作为,需要认真地总结继承国内外的经验教训,建立起对自然资源认识和利用的科学知识体系。为此,需要先建立自然资源的科学分类。文章采取二维标准(来源和功能)建立自然资源的一级分类。在来源方面,以马克思《资本论》第一卷德文版原著中的名言"地球是财富之母"为指导,将当代人类能够开发利用的自然资源,分别划入地球外部的四层空间-自下而上为岩石圈、水圈、大气圈、近地太空。这一划分,有利于深入研究自然资源的不同来源,阐明其各自形成与分布的规律,有助于在体制改革中完善"体"的一面。在功能方面,运用系统论的方法,将开发利用的资源品种归并为四组-自然空间本身、自然物质、自然能、自然信息。这一划分,有利于深入研究自然资源的不同存在状态,正确判断其在开发利用中的技术、经济与法理关系,有助于在体制改革中完善"制"的一面。本分类中使用的专业名词,在尊重我国约定俗成的语言习惯基础上,也考虑到全球在人与自然关系方面研究及实践的进展,力求体现科学准确的概念内涵与外延。 展开更多
关键词 地球 地月系统 太阳系 银河星系 自然空间 自然物质 自然能 自然信息 无机资源 生物资源
在线阅读 下载PDF
Xiamen Tungsten’s Half-year Net Profit Reduces By Nearly 80% And Rare Earth Profit Increases By 240.54%
3
《中国有色金属月刊:英文版》 2019年第8期5-6,共2页
On July 15,2019,Xiamen Tungsten Co.,Ltd.(stock code:600549,hereinafter'Xiamen Tungsten'),the largest tungsten producer in China,published its business results report of H1 2018.Based on the report,in H12018,th... On July 15,2019,Xiamen Tungsten Co.,Ltd.(stock code:600549,hereinafter'Xiamen Tungsten'),the largest tungsten producer in China,published its business results report of H1 2018.Based on the report,in H12018,the operating:income was RMB 8.384billion,down by 3.23%YoY,and the net profit attributed to listed shareholders was RMB 77.4066 million,significantly down by 76.83%YoY.These are only the preliminary accounting results,which are not audited by the accounting firm. 展开更多
关键词 EARTH Rare EARTH PROFIT XIAMEN Tungsten’s Half-year Net PROFIT Reduces
Surface energy budget diagnosis reveals possible mechanism for the different warming rate among Earth’s three poles in recent decades
4
作者 Kailun Gao Anmin Duan +1 位作者 Deliang Chen Guoxiong Wu 《科学通报:英文版》 SCIE EI CSCD 2019年第16期1140-1143,共4页
With the introduction of the‘‘Third Pole'[1],the Arctic,Antarctic,and Tibetan Plateau(TP)can be collectively referred to as the‘‘three poles of the Earth'.The cryosphere is an important component of the cl... With the introduction of the‘‘Third Pole'[1],the Arctic,Antarctic,and Tibetan Plateau(TP)can be collectively referred to as the‘‘three poles of the Earth'.The cryosphere is an important component of the climate system because of its effect on Earth’s surface albedo and its role in reducing the amount of heat exchanged between the atmosphere and ocean or land(2)As the dominant parts of the cryosphere,the Arctic,Antarctic,and TP are pivotal and sensitive areas of global climate change.Global warming will weaken the inherent stability of the cryosphere,such as its ice shelves,glaciers and permafrost[3,4]. 展开更多
关键词 Surface energy budget DIAGNOSIS REVEALS possible mechanism for the different warming rate AMONG Earth’s THREE POLES in RECENT decades SAF Earth
Numerical solutions of rotational normal modes of a triaxial two-layered anelastic Earth
5
作者 Wenbin Shen Zhuo Yang +1 位作者 Zhiliang Guo Wenying Zhang 《大地测量与地球动力学:英文版》 2019年第2期118-129,共12页
The Earth’s rotational normal modes depend on Earth model used, including the layer structures,principal inertia moments of different layers and the compliances. This study focuses on providing numerical solution of ... The Earth’s rotational normal modes depend on Earth model used, including the layer structures,principal inertia moments of different layers and the compliances. This study focuses on providing numerical solution of the rotational normal modes of a triaxial two-layered anelastic Earth model without external forces but with considering the complex forms of compliances and the electromagnetic coupling between the core and mantle. Based on the present knowledge of the Chandler wobble(CW) and Free Core Nutation(FCN), we provide a set of complete compliances which could be used for reference in further investigations. There are eight rotational normal mode solutions, four of which might exist in nature. However, in reality only two of these four solutions correspond to the present motion status of the prograde CW and the retrograde FCN. On one hand, our numerical calculations show that the periods and quality factors(Qs) of CW and FCN are respectively 434.90 and 429.86 mean solar days(d) and 76.56 and 23988.47 under frequency-dependent assumption, and the triaxiality prolongs CW about 0.01 d and has hardly effect on FCN. On the other hand, we analyze the sensibility of compliances and electromagnetic coupling parameter on the periods and Qs of CW and FCN and find the sensitive parameters with respect to them. 展开更多
关键词 EARTH ROTATION TRIAXIAL two-layered anelastic EARTH model Compliances ROTATIONAL normal MODES Numerical solution
Process optimization of neodymium chloride solutions precipitated by magnesium bicarbonate
6
作者 Yannan Yan Yang Xu +5 位作者 Xiaowei Huang Zongyu Feng Yongke Hou Kai Li Liangshi Wang Yihanna Hu 《中国稀土学报:英文版》 SCIE EI CAS CSCD 2019年第4期437-442,共6页
Rare earths(REs) are of vital importance for the development of new materials and green energy.Magnesium bicarbonate is one of the most recyclable and environmental-friendly precipitant for REs recovery from leaching ... Rare earths(REs) are of vital importance for the development of new materials and green energy.Magnesium bicarbonate is one of the most recyclable and environmental-friendly precipitant for REs recovery from leaching solutions. Nd2(CO3)3 has difficulties in industrial production. So in this study,the precipitation of neodymium from chloride solution by magnesium bicarbonate are investigated. The effects of feeding method, [HCO3-]/[Nd3+] mole ratio, feeding speed and reaction temperature on yield and impurity(magnesia) content are systematically studied. Results show that the impurity(magnesia)content decreases to 0.010 wt% with a yield approaching to 100% obtained under the conditions of[HCO3-]/[Nd3+] = 3.00 by parallel flow addition at 50 ℃. The major impurity(magnesia) in rare earth carbonates mainly presents in the form of physical absorption, which can be easily removed by scrubbing. Therefore, it offers a promising green process that uses magnesium bicarbonate to produce neodymium carbonate due to its cycling of carbon dioxide, magnesium salt and waste water. 展开更多
关键词 RARE earth MAGNESIUM BICARBONATE PRECIPITATION process YIELD
基于Google Earth的控制点信息的一体化集成实验与分析 预览
7
作者 张庆余 张涛 王友存 《测绘科学技术》 2019年第1期30-35,共6页
控制点信息及属性信息是各种工程项目设计、实施及验收的基准。为提高控制点信息存储、查询与更新效率,更直观形象反应控制点变化,需对传统纸媒控制点信息保存方式进行电子化管理。本文依托Google Earth全球地理信息系统平台,并通过KML... 控制点信息及属性信息是各种工程项目设计、实施及验收的基准。为提高控制点信息存储、查询与更新效率,更直观形象反应控制点变化,需对传统纸媒控制点信息保存方式进行电子化管理。本文依托Google Earth全球地理信息系统平台,并通过KML语言将经过预处理的实验控制点数据及其各类属性信息进行一体化集成。实验结果表明:基于Google Earth的控制点信息一体化集成对区域性或更大范围控制点建库管理具有一定的参考价值。 展开更多
关键词 GOOGLE EARTH 控制点信息 KML 一体化集成
在线阅读 下载PDF
Recent progress on earth abundant electrocatalysts for hydrogen evolution reaction(HER)in alkaline medium to achieve efficient water splitting-A review 预览
8
作者 Jamesh Mohammed-Ibrahim xiaoming Sun 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第7期111-160,共50页
Developing earth-abundant-electrocatalysts for hydrogen evolution reaction is one of the promising ways to achieve efficient water-splitting for hydrogen production(a clean chemical fuel).This paper reviews the activi... Developing earth-abundant-electrocatalysts for hydrogen evolution reaction is one of the promising ways to achieve efficient water-splitting for hydrogen production(a clean chemical fuel).This paper reviews the activity,stability and durability for hydrogen evolution reaction in alkaline medium of different types of recently reported potential electrocatalysts such as Ni,Co,NiCo,Fe,Cu,W,Mo,Se,Mn.Zn,V,and metal free based earth-abundant-electrocatalysts.Further,this paper reviews the strategies used to achieve the remarkably low overpotential(including r/i0:<35mV),high long term stability(including^:100 h)and high durability(including>5000 cycles)of potential earth-abundant-electrocatalysts for hydrogen evolution reaction in alkaline medium and those are better or well comparable with the state-of-the-art,noble,Pt/C electrocatalyst.Finally,this paper summarizes the efficient strategies such as preparing porous structured materials,preparing nanostructured materials with superaerophobic surface,preparing nanostructured materials,preparing carbon composites/integrating electrocatalysts with carbon,preparing amorphous materials,preparing materials w让h oxygen vacancies/defects,preparing metal chalcogenides,preparing bimetallic/multi-metallic materials,doping metals or heteroatoms,preparing electrocatalysts with core-shell structure,decorating electrocatalysts with amines,preparing homojunction/heterojunction structured materials,preparing hollow structured materials,and preparing boronrich surface to enhance the activity,stability,and durability for HER. 展开更多
关键词 HER ELECTROCATALYST ELECTROCHEMICAL water SPLITTING EARTH abundant ELECTROCATALYST Hydrogen energy
在线阅读 下载PDF
Space Trash Removal 预览
9
作者 Chris Palmer 《工程(英文)》 2019年第4期607-608,共2页
March 2019 saw the culmination of the RemoveDEBRIS satellite mission,which demonstrated a set of technologies that could one day help address the problem of space trash.This burgeoning collection of debris in low Eart... March 2019 saw the culmination of the RemoveDEBRIS satellite mission,which demonstrated a set of technologies that could one day help address the problem of space trash.This burgeoning collection of debris in low Earth orbit is inching toward a crisis that threatens to make the region of space within 2000 km of the Earth’s surface very difficult to use. 展开更多
关键词 EARTH DEBRIS ORBIT
在线阅读 免费下载
Tuning up-conversion luminescence in Er3+-doped glass ceramic by phase-shaped femtosecond laser field with optimal feedback control
10
作者 Lian-Zhong Deng Yun-Hua Yao +8 位作者 Li Deng Huai-Yuan Jia Ye Zheng Cheng Xu Jian-Ping Li Tian-Qing Jia Jian-Rong Qiu Zhen-Rong Sun Shi-An Zhang 《物理学前沿:英文版》 SCIE CSCD 2019年第1期123-129,共7页
Tuning the color output of rare-earth ion doped luminescent nanomaterials has important scientific significance for further extending applications in color displays, laser sources, optoelectronic devices, and biolabel... Tuning the color output of rare-earth ion doped luminescent nanomaterials has important scientific significance for further extending applications in color displays, laser sources, optoelectronic devices, and biolabeling. In previous studies, pre-designed phase modulation of the femtosecond laser field has been proven to be effective in tuning the luminescence of doped rare-earth ions. Owing to the complex light–matter interaction in the actual experiment, the dynamic range and optimal efficiency for color tuning cannot be determined with the pre-designed phase modulation. This article shares the development of an adaptive femtosecond pulse shaping method based on a genetic algorithm, and its use to manipulate the green and red luminescence tuning in an Er3+-doped glass ceramic under 800-nm femtosecond laser field excitation for the first time. Experimental results show that the intensity ratio of the green and red UC luminescence of the doped Er3+ ions can be either increased or decreased conveniently by the phase-shaped femtosecond laser field with an optimal feedback control. The physical control mechanisms for the color tuning are also explained in detail. This article demonstrates the potential applications of the adaptive femtosecond pulse shaping technique in controlling the color output of doped rare-earth ions. 展开更多
关键词 nonlinear optics UPCONVERSION LUMINESCENCE rare earth ions LUMINESCENT NANOMATERIALS
Comparison of Seismic Design Codes between China and the United States for Reinforced Soil Retaining Walls 预览
11
作者 XU Peng TIAN Hongcheng +1 位作者 JIANG Guanlu WANG Zhimeng 《中国地震研究:英文版》 CSCD 2019年第1期147-152,共6页
Because of its excellent seismic performance, reinforced soil retaining walls are increasingly used in civil engineering. Although many countries have published corresponding design codes, the differences between them... Because of its excellent seismic performance, reinforced soil retaining walls are increasingly used in civil engineering. Although many countries have published corresponding design codes, the differences between them are still relatively large. Using the FHWA Code and the Code for Seismic Design of Railway Engineering (CSDRE), stability calculations of reinforced soil retaining walls were carried out and the similarities and differences between these two design codes were analyzed. According to the comparative analysis, the following conclusions are drawn: the inertia force, the earth pressure and the tensile force of reinforcements calculated from the CSDRE are less than those from the FHWA Code, and the safety factor calculated from the former is larger. Although the M-O method is recommended to calculate the dynamic earth pressure, the FHWA Code suggests a higher action point as compared to the CSDRE. 展开更多
关键词 SEISMIC performance Reinforced soil retaining WALL INERTIA FORCE Earth pressure TENSILE FORCE
在线阅读 免费下载
科技之害与“诗意地栖居”——论海德格尔“天地人神”对神性的召唤 预览
12
作者 黄健 《成都理工大学学报:社会科学版》 2019年第5期54-60,共7页
海德格尔“诗意地栖居”的美学思想以对神性的探索为凝聚点,其存在论所蕴含的神性是此在的“人”生存的法则依据。但是,现代科学和技术对神性的驱逐,以及人对自身定位的模糊和对神性的遗忘,合力使神性隐而不彰。因此,他欲重构“天地人... 海德格尔“诗意地栖居”的美学思想以对神性的探索为凝聚点,其存在论所蕴含的神性是此在的“人”生存的法则依据。但是,现代科学和技术对神性的驱逐,以及人对自身定位的模糊和对神性的遗忘,合力使神性隐而不彰。因此,他欲重构“天地人神”四方一体世界体系,以其所蕴生的“命运”神性,召唤一种更高意义上衡量“人与他者”关系的神性尺度。“诗意地栖居”便是他解救“人”的危难处境所寻求的道路,这样的道路是通过艺术(本质是诗歌)来聆听命运的神性之声而实现的。但海德格尔思想中的乌托邦色彩与宗教神秘性合力造成的局限性,使他只是给出了一个预言性、模糊性的命运神性召唤。 展开更多
关键词 海德格尔 天地人神 神性 存在 艺术
在线阅读 下载PDF
Bioleaching of trace elements and rare earth elements from coal fly ash 预览
13
作者 Stephen Park Yanna Liang 《国际煤炭科学技术学报:英文版》 2019年第1期74-83,共10页
Coal fly ash originated from coal combustion has high concentrations of metals. If suitable leaching techniques are identified, then coal fly ash could serve as a useful source of valuable minerals including rare eart... Coal fly ash originated from coal combustion has high concentrations of metals. If suitable leaching techniques are identified, then coal fly ash could serve as a useful source of valuable minerals including rare earth elements (REEs). In this study, three microbial strains, Candida bombicola, Phanerochaete chrysosporium and Cryptococcus curvatus were tested on their performance of leaching trace elements and REEs from fly ash. Through comparing mineral loss and leaching efficiencies resulting from indirect leaching or use of the culture supernatant, C. bombicola was identified to be the best leading to the highest mineral loss and extracting efficiencies of trace elements and REEs among the three strains. The highest mineral loss observed from using the supernatant of this yeast strain was 59.7%. Among all trace elements, As and Mo had the highest leaching efficiency of 80.9% and 79.5%. respectively. The same leaching test led to 67.7% of Yb and 64.6% of Er dissolved from the ash. This study, thus, demonstrated that bioleaching is feasible for leaching metals out of fly ash. The C. bombicola strain deserves further investigation due to its robust actions on metal leaching. 展开更多
关键词 CRYPTOCOCCUS curvatus CANDIDA bombicola PHANEROCHAETE CHRYSOSPORIUM - Coal fly ash BIOLEACHING Rare earth elements Trace metals
在线阅读 下载PDF
植根大地的诗意——赏王继红心斋系列剪纸 预览
14
作者 李志红 《淄博师专论丛》 2019年第2期77-80,共4页
剪纸,是最靠近大地、最接近人类生命本真的最接地气的艺术。继红剪纸,就是用这样的一种艺术形式,表达了她对大自然、生命、人情、期冀的诗意理解。欣赏继红“心斋系列剪纸”的七幅作品,我们不仅收获了温暖、感动和美好,也找到了寻求人... 剪纸,是最靠近大地、最接近人类生命本真的最接地气的艺术。继红剪纸,就是用这样的一种艺术形式,表达了她对大自然、生命、人情、期冀的诗意理解。欣赏继红“心斋系列剪纸”的七幅作品,我们不仅收获了温暖、感动和美好,也找到了寻求人生诗意的路径。 展开更多
关键词 大地 生命 诗意 剪纸
在线阅读 免费下载
Facile Synthesis of Functional Poly(ε-caprolactone) via Janus Polymerization
15
作者 Huan Qiu Zhe-Ning Yang Jun Ling 《高分子科学:英文版》 SCIE CAS CSCD 2019年第9期858-865,共8页
Functionalized aliphatic polyesters attract increasing attentions as biocompatible and biodegradable polymers with broad applications in biological science. In this contribution, we propose a facile and controllable s... Functionalized aliphatic polyesters attract increasing attentions as biocompatible and biodegradable polymers with broad applications in biological science. In this contribution, we propose a facile and controllable synthetic technique for functional poly(ε-caprolactone)(PCL) via Janus polymerization, which comprises cationic ring-opening copolymerization (ROP) of ε-caprolactone (CL) with 3,3-bis(chloromethyl)oxacyclobutane (CO) and (coordinated) anionic ROP of CL at a single propagating chain by rare earth metal triflates (RE(OTf)3)and propylene oxide, thus generating block copolymers in one step. The compositions of the copolymers of poly(CLb-(CL-r-CO)) can be modulated by various RE(OTf)3. Scandium triflate catalyzes Janus polymerization to yield the copolymers containing the highest CO contents among all the RE(OTf)3 catalysts used with complete conversion of CL. The chlorine in CO repeating units is ready to be transferred into azide group which affords the modification sites to react with 9-ethynyl-9-fluorenol and mPEG-alkyne, respectively, via copper(I)-catalyzed azide-alkyne cycloaddition reaction with quantitative conversions of azides, as confirmed by FTIR analyses. According to NMR and SEC analyses, copolymers (PCC-g-PEG) bearing a homo-PCL block and a PEG-grafted block of poly(CO-co-CL) demonstrate well-defined chemical structures. The investigations on thermal properties reveal the strong phase separation between PCL and PEG blocks. The amphiphilic PCC-g-PEG is able to sei住assemble into micelles in aqueous solution while cylindrical and lamellar morphologies are observed in bulk. We provide an efficient protocol to synthesize functional PCL combining onestep Janus polymerization and precise post-polymerization click reaction. 展开更多
关键词 JANUS POLYMERIZATION FUNCTIONAL poly(ε-caprolactone) Poly(3 3-bis(chloromethyl)oxacyclobutane) RING-OPENING POLYMERIZATION Rare earth metal CATALYSTS
Contribution of Mountain River Materials to the Continental Shelf off Southeastern Hainan Island Since the Mid-Holocene 预览
16
作者 TIAN Xu JIANG Zuzhou +8 位作者 GAO Wei LIU Zhaoqing LIU Xiling FAN Ying QIN Shengjie JING Chunlei XU Yue LIU Baohua XU Fangjian 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第5期1123-1129,共7页
The concentrations of rare earth elements(REEs)in the bulk sediment of Core X2,which was collected from southeastern Hainan Island,were analyzed to investigate the relative contributions of various provenance regions ... The concentrations of rare earth elements(REEs)in the bulk sediment of Core X2,which was collected from southeastern Hainan Island,were analyzed to investigate the relative contributions of various provenance regions since mid-Holocene.The results show that sediments in Core X2 were primarily derived from Hainan Island with lesser amounts from Taiwan and limited input from the Pearl River.Based on the application of quantitative inversion to model the REE data,the average contributions of river materials from southeastern Hainan Island and southwestern Taiwan to the study area were 68%and 32%,respectively.Furthermore,starting at 4.0 kyr BP,the transport of fluvial sediments from Taiwan to the study region increased due to enhanced hydrodynamics in South China Sea(SCS).These results indicate that the contributions of mountain river materials from Hainan Island and Taiwan to the continental shelf of northern SCS are non-negligible.Furthermore,these results demonstrate that mountain rivers can play an important role in the material cycle of continental margins and may feature a greater impact than large river systems in specific continental shelf areas. 展开更多
关键词 CONTINENTAL SHELF South China Sea MID-HOLOCENE rare earth elements PROVENANCE
在线阅读 下载PDF
Mechanism of Janus Polymerization: A DFT Study
17
作者 Tian-Wen Bai Xu-Feng Ni +1 位作者 Jun Ling Zhi-Quan Shen 《高分子科学:英文版》 SCIE CAS CSCD 2019年第10期990-994,I0004,共6页
Janus polymerization is featured as a combination of cationic and anionic growing ends in one living polymer chain. In the copolymerization of THF and CL catalyzed by lutetium triflates and initiated by propylene oxid... Janus polymerization is featured as a combination of cationic and anionic growing ends in one living polymer chain. In the copolymerization of THF and CL catalyzed by lutetium triflates and initiated by propylene oxide, three stages are identified by kinetic study including(1) fast cationic polymerization with slow anionic one,(2) fast anionic polymerization with dormant cationic one, and(3)reactivation of cationic polymerization with coupling of anionic and cationic chain ends. In this work, density functional theory(DFT)calculation is employed to investigate the reaction details of ionic polymerization and dormancy. A “tripedal crow” configuration is proposed to illustrate the unique high-coordinated ligand exchange configuration in anionic polymerization in different stages. The trigger of dormancy is determined as chain structures rather than concentration of triflate anion according to both calculation and experimental results. 展开更多
关键词 Rare earth metal catalysts Ring-opening polymerization Ionic polymerization Reaction mechanism Quantum chemicalcomputation
Google Earth在矿山地形地貌调查中探讨 预览
18
作者 范国锋 《能源技术与管理》 2019年第4期25-26,119,共3页
简要阐述了矿山地形地貌调查存在的问题及原因,介绍了Google Earth具有强大影像资源,提出了基于西安80系下坐标与WGS-84系下坐标转换思路与方法。通过在泰山隆安煤业的应用,证明该方法减轻了测量人员调查工作量,为矿井提供了直观的地形... 简要阐述了矿山地形地貌调查存在的问题及原因,介绍了Google Earth具有强大影像资源,提出了基于西安80系下坐标与WGS-84系下坐标转换思路与方法。通过在泰山隆安煤业的应用,证明该方法减轻了测量人员调查工作量,为矿井提供了直观的地形地貌信息。 展开更多
关键词 Google Earth 坐标转换 地形地貌调查
在线阅读 下载PDF
Analysis of Chinese rare earth market during the first half of 2019 预览
19
《中国稀土信息:英文版》 2019年第9期1-4,共4页
1.Rare earth market With the approaching of the Spring Festival,the supply and demand of rare earth was stable with a slight decline and the prices were hovering at the bottom in January 2019.On January 9,China Northe... 1.Rare earth market With the approaching of the Spring Festival,the supply and demand of rare earth was stable with a slight decline and the prices were hovering at the bottom in January 2019.On January 9,China Northern Rare Earths reduced the listing prices. 展开更多
关键词 ANALYSIS CHINESE RARE earth MARKET 2019
在线阅读 下载PDF
An alkaline fusion mechanism for aluminate rare earth phosphor: cation-oxoanion synergies theory
20
作者 Yi-Fan Liu Shen-Gen Zhang +1 位作者 Bo Liu Han-Lin Shen 《稀有金属:英文版》 SCIE EI CAS CSCD 2019年第4期299-305,共7页
Waste aluminate rare earth phosphor is an important rare earth elements (REEs) secondary resource, which mainly consists of BaMgAl1()O|7:Eu2+(BAM) and CeMgAl11O19:Tb^3+(CMAT). Alkaline fusion process is widely used to... Waste aluminate rare earth phosphor is an important rare earth elements (REEs) secondary resource, which mainly consists of BaMgAl1()O|7:Eu2+(BAM) and CeMgAl11O19:Tb^3+(CMAT). Alkaline fusion process is widely used to recycle REEs from aluminate phosphor, but the related theory remains imperfect. In this paper, a series of alkaline fusion experiments of CMAT were performed to describe the phase change law of CMAT reactions. Based on comprehensive analysis, cation-oxoanion synergies theory (COST) was proposed to explain the aluminate phosphor structure damage. On the mirror plane of aluminate phosphor crystal structure, alkali metal cations (Na^+,K^+) would substitute rare earth ions, while free oxoanion (OH^-, CO3^2-, O2^2-) can combine with rare earth ions. These two ionic forces ensure that rare earth ions can be substituted by cations. Then, the structure is decomposed. Morphological analysis shows that observable expression of COST can be described by shrinking core model after simplification. Reaction rate constant calculated indicates that the reaction degree is nanometers per second. COST provides a more complete mechanism, and it can help improve rare earth recycling technology furtherly. 展开更多
关键词 ALUMINATE PHOSPHOR ALKALINE fusion RARE earth Mechanism
上一页 1 2 250 下一页 到第
使用帮助 返回顶部 意见反馈