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彩铃歌手粥稀稀 被引量:1
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作者 田里 《新西部》 2005年第6期31-33,共3页
新闻背景:“彩铃”是“个性化多彩回铃音业务”的简称。这是中国移动2003年10月推出的“移动梦网”新业务,使用这项业务, 客户可以为呼叫自己移动电话的其他主叫用户设定特殊音效的回铃音。据电信业咨询机构发布的研究报告称,2004年全... 新闻背景:“彩铃”是“个性化多彩回铃音业务”的简称。这是中国移动2003年10月推出的“移动梦网”新业务,使用这项业务, 客户可以为呼叫自己移动电话的其他主叫用户设定特殊音效的回铃音。据电信业咨询机构发布的研究报告称,2004年全国彩铃用户数量已达2200万户,市场规模超过8.6亿元。而这项业务目前正向小灵通、固定电话发展。“彩铃”一经推出,就受到了追求时尚的年轻手机用户青睐, 而在一些热衷于制作彩铃的音乐爱好者中,诞生了中国第一批彩铃歌手。2005年3月,粥稀稀推出了他的首张“彩铃”专辑,被唱片公司以一百万的天价购买,他由此被誉为“彩铃歌手第一人” 展开更多
关键词 “彩铃” 稀稀 音乐工作者 音乐作品 中国
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稀盐酸溶液还原浸出大洋多金属结核的研究 被引量:6
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作者 李先柏 周勤俭 +1 位作者 杨静 姜小平 《矿冶工程》 CAS CSCD 北大核心 1997年第2期50-52,共3页
用亚硫酸铵作还原剂,在常温常压下用稀盐酸溶液浸出大洋多金属结核,探索了结核矿粒度、还原剂亚硫酸铵加入量、HCl浓度、浸出温度、时间及液固比等因素对大洋多金属结核浸出率的影响。当浸出液中HCl为20mol/L、亚硫酸... 用亚硫酸铵作还原剂,在常温常压下用稀盐酸溶液浸出大洋多金属结核,探索了结核矿粒度、还原剂亚硫酸铵加入量、HCl浓度、浸出温度、时间及液固比等因素对大洋多金属结核浸出率的影响。当浸出液中HCl为20mol/L、亚硫酸铵为理论量、10~40℃下浸出30min,有价金属浸出率分别为(%):Cu948,Ni953,Co937,Mn962。 展开更多
关键词 大洋 多金属结核 稀稀盐酸 还原 浸出
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Column leaching process of rare earth and aluminum from weathered crust elution-deposited rare earth ore with ammonium salts 被引量:17
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作者 何正艳 张臻悦 +4 位作者 余军霞 徐志高 徐源来 周芳 池汝安 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第11期3024-3033,共10页
In order to better understand the leaching process of rare earth (RE) and aluminum (Al) from the weathered crust elutiondepositedRE ore, the mass transfer of RE and Al in column leaching was investigated using the... In order to better understand the leaching process of rare earth (RE) and aluminum (Al) from the weathered crust elutiondepositedRE ore, the mass transfer of RE and Al in column leaching was investigated using the chromatographic plate theory. Theresults show that a higher initial ammonium concentration in a certain range can enhance the mass transfer process. pH of leachingagent in the range of 2 to 8 almost has no effect on the mass transfer efficiency of RE, but plays a positive role in the mass transferefficiency of Al under strong acidic condition (pH〈4). There is an optimum flow rate that makes the highest mass transfer efficiency.The optimum leaching condition of RE is the leaching agent pH of 4?8, ammonium concentration of 0.4 mol/L and flow rate of0.5 mL/min. The mass transfer efficiencies of RE and Al both follow the order: (NH4)2SO4〈NH4Cl〈NH4NO3, implying thecomplexing ability of anion. 展开更多
关键词 column leaching process weathered crust elution-deposited rare earth ore rare earth ALUMINUM ammonium salt MASSTRANSFER
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Leaching kinetics of bastnaesite concentrate in HCl solution 被引量:11
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作者 边雪 尹少华 +1 位作者 罗瑶 吴文远 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第10期2306-2310,共5页
The leaching kinetics of bastnaesite concentrate in HCl solution was investigated with respect to the effects of HCl concentration by changing HCl concentration,leaching temperature,liquid to solid ratio,and particle ... The leaching kinetics of bastnaesite concentrate in HCl solution was investigated with respect to the effects of HCl concentration by changing HCl concentration,leaching temperature,liquid to solid ratio,and particle size.A particle size of 25 μm was required to leach 89.6% RE2(CO3)3 and 1.5%REF3 at 90 ℃ for 90 min,when HCl concentration was 6 mol/L and liquid to solid ratio was 15:1.The leaching kinetics of bastnaesite concentrate is represented by shrinking core model with diffusion through a porous product layer.The activation energies for the dissolution reaction of RE2(CO3)3 and REF3 were calculated to be 59.39 kJ/mol and 66.13 kJ/mol respectively. 展开更多
关键词 BASTNAESITE RE2(CO3)3 REF3 leaching kinetics
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Microstructure and properties of WE93 alloy
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作者 何兰强 李永军 +5 位作者 李兴刚 马鸣龙 张奎 王献文 鄢建明 林海涛 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第4期790-794,共5页
The microstructure of WE93 alloy in different states and the mechanical properties at room temperature were investigated, and the creep behavior of the extruded and aged alloy at 200 ℃and at stress of 100, 125 and 15... The microstructure of WE93 alloy in different states and the mechanical properties at room temperature were investigated, and the creep behavior of the extruded and aged alloy at 200 ℃and at stress of 100, 125 and 150 MPa was also discussed. The result shows that the microstructure of as-cast WE93 alloy consists of α-Mg, Mg 12 (MM) and Mg 24 Y 5 with an average grain size of 45 μm. After being homogenized at 535 ℃for 18 h, the Mg 24 Y 5 phase is dissolved completely and there is only Mg 12 (MM) phase left around the grain boundaries. The grains do not grow up as prolonging the homogenization time. The extruded alloy has better mechanical properties than the as-cast alloy, especially the elongation increases to 12.5%. The extruded and aged alloy exhibits the highest yield strength and ultimate tensile strength of 315 and 385 MPa, respectively, however, the elongation decreases to 6.5%. The extruded and aged alloy exhibits good creep resistance at 200 ℃and at stress of 100 150 MPa. The creep stress exponent n is 2.97, suggesting that grain boundary sliding plays a dominant role at the corresponding temperature and applied stresses. 展开更多
关键词 rare-earth magnesium alloy mish-metal microstructure temperature STRESS CREEP
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Competition-density effect in plant populations 被引量:2
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作者 薛立 《Journal of Forestry Research》 SCIE CAS CSCD 2002年第1期48-50,83,共3页
The competition-density effect of plant populations is of significance in theory and practice of forest management and has been studied for long time. The differences between the two reciprocal equations of the compet... The competition-density effect of plant populations is of significance in theory and practice of forest management and has been studied for long time. The differences between the two reciprocal equations of the competition-density effect in nonself-thinning populations and self-thinning populations were analyzed theoretically. This supplies a theoretical basis for analyzing the dynamics of forest populations and evaluating the effect of forest management. 展开更多
关键词 Competition-density effect Self-thinning population Nonself-thinning population
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An improved sparsity estimation variable step-size matching pursuit algorithm 被引量:4
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作者 张若愚 赵洪林 《Journal of Southeast University(English Edition)》 EI CAS 2016年第2期164-169,共6页
To improve the reconstruction performance of the greedy algorithm for sparse signals, an improved greedy algorithm, called sparsity estimation variable step-size matching pursuit, is proposed. Compared with state-of-t... To improve the reconstruction performance of the greedy algorithm for sparse signals, an improved greedy algorithm, called sparsity estimation variable step-size matching pursuit, is proposed. Compared with state-of-the-art greedy algorithms, the proposed algorithm incorporates the restricted isometry property and variable step-size, which is utilized for sparsity estimation and reduces the reconstruction time, respectively. Based on the sparsity estimation, the initial value including sparsity level and support set is computed at the beginning of the reconstruction, which provides preliminary sparsity information for signal reconstruction. Then, the residual and correlation are calculated according to the initial value and the support set is refined at the next iteration associated with variable step-size and backtracking. Finally, the correct support set is obtained when the halting condition is reached and the original signal is reconstructed accurately. The simulation results demonstrate that the proposed algorithm improves the recovery performance and considerably outperforms the existing algorithm in terms of the running time in sparse signal reconstruction. 展开更多
关键词 compressed sensing sparse signal reconstruction matching pursuit sparsity estimation
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Creep behavior of SnAgCu solders with rare earth Ce doping 被引量:13
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作者 张亮 薛松柏 +4 位作者 皋利利 曾广 陈燕 禹胜林 盛重 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第3期412-417,共6页
Extensive testing was carried out to study the effects of rare earth Ce doping on the properties of SnAgCu solder alloys.The addition of 0.03%(mass fraction) rare earth Ce into SnAgCu solder may improve its mechanical... Extensive testing was carried out to study the effects of rare earth Ce doping on the properties of SnAgCu solder alloys.The addition of 0.03%(mass fraction) rare earth Ce into SnAgCu solder may improve its mechanical properties,but slightly lower its melting temperature.The tensile creep behavior of bulk SnAgCuCe solders was reported and compared with SnAgCu solders.It is found that SnAgCuCe solders show higher creep resistance than SnAgCu alloys.Moreover,Dorn model and Garofalo model are successfully used to describe the creep behavior of SnAgCu and SnAgCuCe alloys.The parameters of the two creep constitutive equations for SnAgCu and SnAgCuCe solders are determined from separated constitutive relations and experimental results.Nonlinear least-squares fitting is selected to determine the model constants.The experimental data of the stress-creep strain rate curves are in good agreement with the theoretical ones. 展开更多
关键词 rare earth Ce SnAgCu solder creep behavior constitutive equations
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“稀”的语法化与“稀X”类形容词的词汇化
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作者 黄璐 《唐山师范学院学报》 2018年第1期45-49,共5页
通过对"稀"语法化的探究,理清了"稀"语法化的线索,经历了形容词——副词的语法路径,试图从中揭示出"稀"的词义、词性变迁和发展的一些特点及规律。探析了"稀X"类形容词的词汇化,并揭示了词汇... 通过对"稀"语法化的探究,理清了"稀"语法化的线索,经历了形容词——副词的语法路径,试图从中揭示出"稀"的词义、词性变迁和发展的一些特点及规律。探析了"稀X"类形容词的词汇化,并揭示了词汇化动因。 展开更多
关键词 语法化 稀X 词汇化 动因
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Bernoulli-based random undersampling schemes for 2D seismic data regularization 被引量:2
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作者 蔡瑞 赵群 +3 位作者 佘德平 杨丽 曹辉 杨勤勇 《Applied Geophysics》 SCIE CSCD 2014年第3期321-330,351,352,共12页
Seismic data regularization is an important preprocessing step in seismic signal processing. Traditional seismic acquisition methods follow the Shannon–Nyquist sampling theorem, whereas compressive sensing(CS) prov... Seismic data regularization is an important preprocessing step in seismic signal processing. Traditional seismic acquisition methods follow the Shannon–Nyquist sampling theorem, whereas compressive sensing(CS) provides a fundamentally new paradigm to overcome limitations in data acquisition. Besides the sparse representation of seismic signal in some transform domain and the 1-norm reconstruction algorithm, the seismic data regularization quality of CS-based techniques strongly depends on random undersampling schemes. For 2D seismic data, discrete uniform-based methods have been investigated, where some seismic traces are randomly sampled with an equal probability. However, in theory and practice, some seismic traces with different probability are required to be sampled for satisfying the assumptions in CS. Therefore, designing new undersampling schemes is imperative. We propose a Bernoulli-based random undersampling scheme and its jittered version to determine the regular traces that are randomly sampled with different probability, while both schemes comply with the Bernoulli process distribution. We performed experiments using the Fourier and curvelet transforms and the spectral projected gradient reconstruction algorithm for 1-norm(SPGL1), and ten different random seeds. According to the signal-to-noise ratio(SNR) between the original and reconstructed seismic data, the detailed experimental results from 2D numerical and physical simulation data show that the proposed novel schemes perform overall better than the discrete uniform schemes. 展开更多
关键词 Seismic data regularization compressive sensing Bernoulli distribution sparse transform UNDERSAMPLING 1-norm reconstruction algorithm.
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PERFORMANCE OF SIMPLE-ENCODING IRREGULAR LDPC CODES BASED ON SPARSE GENERATOR MATRIX
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作者 唐蕾 仰枫帆 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2006年第3期202-207,共6页
A new method for the construction of the high performance systematic irregular low-density paritycheck (LDPC) codes based on the sparse generator matrix (G-LDPC) is introduced. The code can greatly reduce the enco... A new method for the construction of the high performance systematic irregular low-density paritycheck (LDPC) codes based on the sparse generator matrix (G-LDPC) is introduced. The code can greatly reduce the encoding complexity while maintaining the same decoding complexity as traditional regular LDPC (H-LDPC) codes defined by the sparse parity check matrix. Simulation results show that the performance of the proposed irregular LDPC codes can offer significant gains over traditional LDPC codes in low SNRs with a few decoding iterations over an additive white Gaussian noise (AWGN) channel. 展开更多
关键词 belief propagation iterative decoding algorithm sparse parity-check matrix sparse generator matrix H LDPC codes G-LDPC codes
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Petrogenesis of Early Cretaceous riebeckite granophyres in southern Da Hinggan Mts. 被引量:2
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作者 WANG Jianguo HE Zhonghua +2 位作者 CHAO Lin WU Qing JIN Ling 《Global Geology》 2013年第1期26-34,共9页
This Aliwula area in paper reports lithologic features, K-Ar age and geochemical data of riebeckite granophyres from the southern Da Hinggan Mts., aiming to reveal the petrogenesis of riebeckite granophyres. K- Ar age... This Aliwula area in paper reports lithologic features, K-Ar age and geochemical data of riebeckite granophyres from the southern Da Hinggan Mts., aiming to reveal the petrogenesis of riebeckite granophyres. K- Ar age of riebeckite granophyres is 126± 2 Ma, implying that the riebeckite granophyres formed in the Early Cretaceous. The granophyres are rich in riebeckites and with a lot of melt-fluid inclusion in its quartz pheno- crysts. The granophyres are characterized by extensive enrichment in Si02, FeO, and (Na20 + K20) and de- pletion in MgO and CaO, strong negative Eu anomalies and strong positive Ce anomalies. Additionally, the rie- beckite granophyres not only have high total REE contents and display enrichment of HFSEs (for example Zr, Hf, Nb, Ta), but also are strong in depletion of LILEs ( e. g. Ba, Sr) as well as high Ga/A1 ratios. Primitive mantle-normalized REE pattern significantly displays REE M-W tetrad effect. REEs fractionate evidently and highly enrich in LREE, but are uneven distribution in the rocks. Taken together, we conclude that the riebeck- ite granophyres are similar to typical A-type granite, which could be derived from stretching environments in the Early Cretaceous. The granophyres originated from residual melt which underwent highly differentiation process, and were formed in magmatic-hydrothemal transition stage at last. 展开更多
关键词 PETROGENESIS geochemistry riebeckite granophyres southern Da Hinggan Mrs.
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Directional migration behavior of cerium during sintering process of mischmetal doped cemented carbide 被引量:4
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作者 张立 陈述 +2 位作者 熊湘君 余贤旺 王元杰 《Journal of Central South University of Technology》 EI 2008年第1期6-10,共5页
Three observation methods were used to investigate the existing form and the behavior of rare earth during the sintering process of high activity mischmetal (RE, with lanthanum and cerium) doped WC-8%Co-0.048%RE(ma... Three observation methods were used to investigate the existing form and the behavior of rare earth during the sintering process of high activity mischmetal (RE, with lanthanum and cerium) doped WC-8%Co-0.048%RE(mass fraction) alloy with low carbon-containing level by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS), considering the fact that the addition amount of rare earth in the alloy is very minute. The directional migration process and mechanism of cerium were discussed. First, the sinter skin (surface) is observed. oxide on the sinter skin, and lanthanum in these cerium observed, and lanthanum containing phase/micro-zone in It is shown that there exists a dispersedly distributed cerium containing enrichment positions is very minute. Secondly, the polished section is the alloy is identified. Finally, based on the fact that the fracture of cemented carbide is resulted from the heterogeneous phase or other defects within the microstructure, the fracture surface is observed and cerium containing phase/micro-zone in the fracture source approximately 260 μm from the surface is identified. These combined observations reveal adequately the fact that lanthanum and cerium get separated and cerium predominantly migrates towards the surface during the sintering process. 展开更多
关键词 cemented carbide rare earth surface segregation directional migration liquid phase sintering
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Chracteristics and formation setting of granodiorite in Zhalute County,Inner Mongolia 被引量:2
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作者 ZHAO Qingying LI Chunfeng +1 位作者 WANG Guoliang LI Xuefei 《Global Geology》 2009年第3期156-159,共4页
Based on field investigation and study of petrology, mineralogy, geochemistry and isotopic geochronology for the granodiorite, the authors discussed the formation setting of the granodiorite. The pluton is calci alkal... Based on field investigation and study of petrology, mineralogy, geochemistry and isotopic geochronology for the granodiorite, the authors discussed the formation setting of the granodiorite. The pluton is calci alkalic and peraluminous granite in which light rare earth elements (LREE) are intensively enriched, heavy rare earth elements are relatively poor, the ratio of LREE to heavy rare earth elements (HREE) is 7.12, and the fractionation of REE is good. The pluton formed in late orogenic setting which is relatively steady. 展开更多
关键词 granodiorite GEOCHEMISTRY formation setting INNER-MONGOLIA Huhehade
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Attenuated adenomatous polyposis of the large bowel: Present and future 被引量:2
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作者 luca roncucci monica pedroni francesco mariani 《World Journal of Gastroenterology》 SCIE CAS 2017年第23期4135-4139,共5页
Attenuated adenomatous polyposis(AAP) is a poorly understood syndrome, that can be defined as the presence of 10-99 synchronous adenomas in the large bowel, and it is considered a phenotypic variant of familial adenom... Attenuated adenomatous polyposis(AAP) is a poorly understood syndrome, that can be defined as the presence of 10-99 synchronous adenomas in the large bowel, and it is considered a phenotypic variant of familial adenomatous polyposis(FAP). This definition has the advantage of simplicity, but it may include sporadic multiple adenomas of the large bowel at an extreme, or FAP cases on the other side. AAP shows a milder phenotype than FAP, with an older age of onset of adenomas and cancer, and less frequent extracolonic manifestations. AAP may be diagnosed as a single case in a family or, less frequently, it may be present in other family members, and it shows distinct pattern of inheritance. In less than 50% of cases, it may be caused by adenomatous polyposis coli(APC) or MUTYH mutations, referred to as APC-associated polyposis, inherited as an autosomal dominant trait, or MUTYH-associated polyposis, which shows an autosomal recessive mechanism of inheritance, respectively. Surveillance should rely on colonoscopy at regular intervals, with removal of adenomas and careful histological examination. When removal of polyps is not possible or advanced lesions are observed, the surgical approach is mandatory, being subtotal colectomy with ileo-rectal anastomosis the treatment of choice. Studies on this syndrome are lacking, and controversies are still present on many issues, thus, other clinical and genetic studies are requested. 展开更多
关键词 Attenuated adenomatous polyposis Genetic testing SURVEILLANCE Attenuated familial adenomatous polyposis Adenomatous polyposis coli MUTYH
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Numerical simulation and optimization of red mud separation thickener with self-dilute feed 被引量:4
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作者 周天 李茂 +1 位作者 周谦 周孑民 《Journal of Central South University》 SCIE EI CAS 2014年第1期344-350,共7页
In order to acquire the flow pattern and investigate the settling behavior of the red mud in the separation thickener,computational fluid dynamics(CFD),custom subroutines and agglomerates settling theory were employed... In order to acquire the flow pattern and investigate the settling behavior of the red mud in the separation thickener,computational fluid dynamics(CFD),custom subroutines and agglomerates settling theory were employed to simulate the three-dimensional flow field in an industrial scale thickener with the introduction of a self-dilute feed system.The simulation results show good agreement with the measurement onsite and the flow patterns of the thickener are presented and discussed on both velocity and concentration field.Optimization experiments on feed well and self-dilute system were also carried out,and indicate that the optimal thickener system can dilute the solid concentration in feed well from 110 g/L to 86 g/L which would help the agglomerates' formation and improve the red mud settling speed.Furthermore,the additional power of recirculation pump can be saved and flocculants dosage was reduced from 105g/t to 85g/t in the operation. 展开更多
关键词 separation thickener self-dilute feed system numerical simulation optimization experiments computational fluiddynamics
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Minimal Sufficiency in Rare Populations
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作者 Mohammad Moradi Jennifer A. Brown Miriam Hodge 《Journal of Mathematics and System Science》 2012年第5期281-285,共5页
It is well understood that for conventional survey designs the set of unordered distinct units in a sample is a minimally sufficient statistic. This means that for inferential statistic of the sample, the value of the... It is well understood that for conventional survey designs the set of unordered distinct units in a sample is a minimally sufficient statistic. This means that for inferential statistic of the sample, the value of the sampled units rather than the sample design is important. Sampling rare populations presents distinct challenges. Examples of rare populations are in biology with rare and endangered animals where there are only a few remaining individuals, or in social science, with the low incidence of people from an unusually high (or low) income group. Sampling rare populations tends to result in the case that many of the sample units do not contain information on the characteristic of interest (e.g., the rare animal, or people from the unusual income group). For finite rare populations the set of unordered distinct rare-units in a sample is a minimally sufficient statistic. In an example case study of a rare buttercup, the properties of the minimal sufficient estimator are explored. We compare the efficiency of the estimator for the population total based on the minimally sufficient statistic, with the standard estimator for a range of sample sizes. The variance of the minimally sufficient estimator was always smaller than the variance of the sufficient estimator. For rare populations where non-rare units can be distinguished from rare units because they have the same fixed value, the minimal sufficient statistic is the rare units, if any, in the sample. 展开更多
关键词 Rare population finite population SUFFICIENCY minimal sufficiency.
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Facile and Efficient Method for the Adsorption and Separation of Lanthanum Rare Earth Metal Oxide Using Iron(Ⅱ) Sulfide Nanoparticles Coated on Magnetite
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作者 Siyamak Bagheriyan 《Journal of Chemistry and Chemical Engineering》 2011年第9期824-827,共4页
A novel iron sulphide adsorbent using magnetite embedded with nanosized Fe3O4 was prepared and applied to separation lanthanum (Ⅲ) from aqueous solution. This adsorbent combines the advantages of magnetic nanoparti... A novel iron sulphide adsorbent using magnetite embedded with nanosized Fe3O4 was prepared and applied to separation lanthanum (Ⅲ) from aqueous solution. This adsorbent combines the advantages of magnetic nanoparticle with magnetic separability and high affinity toward rare earth metals, which provides distinctive merits including easy preparation, high adsorption capacity, easy isolation from sample solutions by the application of an external magnetic field. The adsorption behaviors of lanthanum (Ⅲ) from an aqueous medium, using iron sulphide magnetite nanoparticles were studied using equilibrium batch and column flow techniques. The effect ofpH, contents of loaded iron sulphide nanoparticles, ionic strength, adsorbent dose, contact time, and temperature on adsorption capacity of the magnetic beads was investigated. All of the results suggested that the FeS/Fe3O4 Nanoparticles could be excellent adsorbents for La(Ⅲ) contaminated water treatment. 展开更多
关键词 nano magnetite Lanthanum ion Adsorption.
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Behavior of rare earth elements in granitic profiles, eastern Tibetan Plateau, China 被引量:2
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作者 Lifeng Cui Zhiqi Zhao +4 位作者 Congqiang Liu Sheng Xu Taoze Liu Chenglong Tu Hu Ding 《Acta Geochimica》 EI CAS CSCD 2017年第3期552-555,共4页
Rare earth elements(REEs) can record geologic and geochemical processes. We studied two granitic regolith profiles from different climatic zones in eastern Tibetan Plateau and found that(1)∑ RREEs ranged from119.65 t... Rare earth elements(REEs) can record geologic and geochemical processes. We studied two granitic regolith profiles from different climatic zones in eastern Tibetan Plateau and found that(1)∑ RREEs ranged from119.65 to 275.33 mg/kg in profile ND and5.11–474.55 mg/kg in profile GTC, with average values of205.79 and 161 mg/kg, respectively. ∑RREEs was higher in accumulation horizon and semi-regolith;(2) Influenced by climate, the fractionation of light and heavy REEs(LREEs and HREEs) varied during weathering. The ratio of LREEs/HREEs in pedosphere was higher than semi-regolith in tropical profile;(3) A negative Eu anomaly in both profiles was the result of bedrock weathering. A positive Ce anomaly was observed in all layers of profile ND, and only in the upper 100 cm of profile GTC. This indicates that redox conditions along the regolith profile varied considerably with climate.(4) Normalized by chondrite,LREEs accumulated much more than HREEs; REE distribution curves were right-leaning with a V-type Eu anomaly in both profiles. 展开更多
关键词 Chemical weathering Eu anomaly Critical zone Soil weathering
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Characterization of terbium-doped nano-hydroxyapatite and surface modification
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作者 赵颜忠 杨敏 +2 位作者 张海斌 朱军 周科朝 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第7期1548-1555,共8页
The control synthesis of nanoparticles was the implementation process of material ideal design. Nano-hydroxyapatite(HAP) was prepared by a hydrothermal method with calcium nitrate and diammonium hydrogen phosphate as ... The control synthesis of nanoparticles was the implementation process of material ideal design. Nano-hydroxyapatite(HAP) was prepared by a hydrothermal method with calcium nitrate and diammonium hydrogen phosphate as raw material, to study its characteristics for morphology modification by arginine-functionalization and doping with rare earth such as Tb^(3+). The crystallization, grain size and dispersibility of the sample HAP were analyzed and discussed. The results show that the surface Zeta potential of arginine-functionalized HAP is changed, and the growth rate of HAP is inhibited to a certain extent during the synthesis. The structure of HAP/Arg is not affected during the synthesis by a small amount of rare earth ions doped such as Tb^(3+), and has a single phase of HAP with good dispersibility. The synthesized HAP is also of nano-sized level. Nano-hydroxyapatite argininefunctionalized and doped with rare earth such as Tb^(3+), is suitable for the application of gene delivery as a gene carrier. 展开更多
关键词 hydroxyapatite hydrothermal nanometer sized arginine doping adding nitrate powders adsorbed
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