检索结果-南通市图书馆

rare earths and Magnetic Refrigeration

在线全文

学校读者我要写书评

暂无评论

Journal of rare earths 2006年第6期24卷 641-647页

作者： Karl A Gschneidner Vitalij K Pecharsky Materials and Engineering Physics Program Ames Laboratory and Department of Materials Science and Engineering Iowa State University Ames Iowa USAJr. Materials and Engineering Physics Program Ames Laboratory and Department of Materials Science and Engineering Iowa State University Ames Iowa USA

Magnetic refrigeration is a revolutionary, efficient, environmentally friendly cooling technology, which is on the threshold of commercialization. The magnetic rare earth materials are utilized as the magnetic refrigerants in most cooling devices, and for many cooling application the Nd2Fe14B permanent magnets are employed as the source of the magnetic field. The status of the near room temperature magnetic cooling was reviewed.

关键词： magnetic refrigeration magnetocaloric effect gadolinium Gd5 ( Si1- x Gex ) 4 La ( Fe 13 - x Six ) Hy Nd2 Fe14 B permanent magnets active magnetic regenerator cycle rare earths

rare earths, Trace Element Characteristics of High-Mg Volcanic Rocks of Yixian Formation in Sihetun West Liaoning Province and Its Apocalypse

在线全文

学校读者我要写书评

暂无评论

Journal of rare earths 2005年第4期23卷 502-506页

作者：张宏张旗 Key Laboratory of Continental Dynamics Northwest University Xi'an 710069 China Institute ofGeology and Geophysics Chinese Academy ofSciences Beijing 100029 China

The high-Mg volcanic rocks of the Yixian Formation in the Sihetun area have the obvious characteristics of mantie-derived lava in rare earth, trace element characteristics with high Mg # （62 - 70） and high content of compatible elements. In the meantime, the volcanic rocks also have the obvious characteristics of Crust-source material in rare earth, trace element characteristics with high ∑ REE （ 158.78 × 10^-6 - 359.66 × 10^-6 ）, high （La/Yb） N （ 14.61 - 29.60）, high La/Nb（2.37 - 7.52） and high Ba/Nb （67.58- 205.96）, obvious positive anomaly of Pb and negative anomaly of Nb, Ta in trace element spider-gram. In Sr-Nd-Pb isotope the （^87Sr/^86Sr）i ratio is higher than 0.706 and the εNd（ t ） ratio is from - 3.4 to - 13, both reflect enriched Mantle characteristics. The characteristics above of the volcanic rocks combined with the content of Sr, Ba, Y, Yb and the ratio of Sr/Y show that the volcanic rocks have the property of the Sanukite rocks in Setouchi Japan beside subduction zone, and illuminate that the Sanukite rocks can be formed not only in island-arc near subduction zone but also in intro-plate. The analysis indicates that the high-Mg volcanic rocks in the Sihetun area result from the collective function of mantle-derived lava and crust-source materials. The result illuminates that the West Liaoning region is very special in tectonic geochemical background in Cretaceous in East China, and is an ideal region for us to further study the characteristics of magmatic activity as well as the process of Crust-Mantle interaction in Eastern China.

关键词： Sanukite trace element characteristics high-Mg volcanic rocks Yixian Formation Sihetun rare earths

rare earths of Two Types Granites in Sawuer Region, Xinjiang

在线全文

学校读者我要写书评

暂无评论

Journal of rare earths 2005年第5期23卷 584-587页

作者：袁峰周涛发谭绿贵范裕岳书仓 School of Resources and Environmental Engineering Hefei University of Technology Hefei 230009 China

The geochemical characteristics of rare earth elements of A type and Ⅰ type granites were studied in the Sawuer region, Xinjiang. The characteristics of two types granites are different obviously,because the A type and Ⅰ type granites formed at different stage of the post-collisional period. The Sentasi intrusion and Wokensala intrusion are the Ⅰ type granites formed at the late of post-collisional period, and there is extrusion translating to extension stress. The characteristics of rare earth elements show that the fractional crystallization of the Ⅰ type granites is indistinct, and the sources of the Ⅰ type granites come from the mantle. The Kuoyitasi intrusion and Qiaqihai intrusion are the A type granites formed at the end of post-collisional period, and there is extension stress. The characteristics of rare earth elements show that the fractional crystallization of the A type granites is distinct. The sources of the A type granites come from the mantle but interfused by the crust.

关键词： granite post-collisional Sawuer region Xinjiang rare earths

Comparison of rare earths doping(neodymium and samarium) on structural and magnetic properties of Ni-Zn-Bi nanoferrites

在线全文

学校读者我要写书评

暂无评论

Journal of rare earths 2024年第3期42卷 534-542,I0004页

作者： Shilpa Taneja Preeti Thakur Dinesh Kumar Yassine Slimani Atul Thakur NanoLatticeX Amity University HaryanaGururam122413HaryanaIndia Nanotechnology Wing Innovative Science Research SocietyShimla177002India Centre for Nanotechnology Amity University HaryanaGururam122413HaryanaIndia Department of Biophysics Institute for Research and Medical Consultations(IRMC)Imam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam31441Saudi Arabia School of Electronics and Information Engineering Nanjing University of Information Science&TechnologyNanjing210044China

Excellent magnetic properties in ferrites are required for high-frequency applications and for wastewater treatment. Thus, the present study shows the comparison of magnetic and structural properties of Nd and Sm substituted Ni-Zn-Bi ferrites with the series Ni_(0.5)Zn_(0.5)Bi_(0.04)Nd_(x)Fe_(1.96-x)O_4(with step size 0.002)and Ni_(0.5)Zn_(0.5)Bi_(0.04)Sm_(x)Fe_(1.96-x)O_4(with step size 0.02) prepared using citrate precursor method. The impact of the substitution of rare earth ions(Nd and Sm) on magnetic properties of the synthesized samples is observed using a vibrating sample magnetometer(VSM). The saturation magnetization values enhance considerably from 52 to 58 emu/g for Nd^(3+)ions and 39 to 57 emu/g for Sm^(3+) ions, thus, making these materials magnetically hard. Further, the higher value of coercivity is also observed ranging from133 to 167 Oe for Nd^(3+)ions and 81 to 155 Oe for Sm^(3+) ions. The shape of hysteresis loops indicates a super paramagnetic and ferromagnetic behavior in the obtained samples. The squareness ratio value is<0.5, suggesting the uniaxial anisotropy of particles and hence, these ferrites are suitable for microwaveabsorbing and in permanent magnetic materials. The X-ray diffraction(XRD) pattern shows the formation of pure cubic crystallites, where, lattice parameters range from 0.840 to 0.839 nm and from 0.838to 0.839 nm for Nd^(3+)and Sm^(3+) ions substitution, respectively. The crystallite size ranges between 28.63to 29.89 nm and 18.33 to 26.23 nm, for substitution of Nd^(3+)and Sm^(3+) ions, respectively. Field emission scanning electron microscopy(FESEM) shows the formation of homogeneous grains, whereas, energy dispersive spectrometer(EDS) counts describe the purity of the samples. The Sm concentration x = 0.10has the maximum surface area with value of 42.6 m^(2)/g which proves to be having good data storage application due to high surface area. The zero-field cooled(ZFC) and field cooled(FC) data show that Nddoped Ni-Zn-Bi nano

关键词： Citrate precursor X-ray diffraction Vibrating sample magnetometer Coercivity Field emission scanning electron microscopy rare earths

Effects of 4f Electron Characteristics and Alternation Valence of rare earths on Photosynthesis: Regulating Distribution of Energy and Activities of Spinach Chloroplast

在线全文

学校读者我要写书评

暂无评论

Journal of rare earths 2007年第4期25卷 495-501页

作者：刘晓晴苏明玉刘超张易司文会洪法水 College of Life Sciences Suzhou University Suzhou Polytechnical Institute of Agriculture

Chloroplasts were isolated from spinach treated with taCl3, CeCl3, and NdCl3. Because of owning 4f electron characteristics and alternation valence, Ce treatment presented the highest enhancement in light absorption, energy transfer from LHC Ⅱ to PS Ⅱ, excitation energy distribution from PS Ⅰ to PS Ⅱ, and fluorescence quantum yield around 680 nm. Compared with Ce treatment, Nd treatment resulted in relatively lower enhancement in these physiological indices, as Nd did not have alternation valence. La treatment presented the lowest enhancement, as La did not have either 4f electron or alternation valence. The increase in activities of whole chain electron transport, PS ⅡDCPIP photoreduction, and oxygen evolution of chloroplasts was of the following order： Ce〉Nd 〉La〉 control. However, the photoreduction activities of spinach PS I almost did not change with La, Ce, or Nd treatments. The results suggested that 4f electron characteristics and alternation valence of rare earths had a close relationship with photosynthesis improvement.

关键词： 4f electron characteristic and alternation valence spinach chloroplast energy transfer and distribution photochemical activity rare earths

Progress in the extraction and separation of rare earths and related metals with novel extractants: A review

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2018年第9期61卷 1319-1328页

作者： KUANG ShengTing LIAO WuPing State Key Laboratory of rare Earth Resource Utilization ERC for the Separation and Purification of REs and Thorium Changchun Institute of Applied Chemistry Chinese Academy of Sciences School of Applied Chemistry and Engineering University of Science and Technology of China

rare earths(REs) play a key role in high-tech fields and the associated thorium is a vital element for nuclear energy. However, to be used in high-tech industry or nuclear energy, these elements must first be recovered from the deposits and purified. As solvent extraction is the main technology for the recovery and purification of the metals, the review mainly presents our recent works on the extraction and separation of tetravalent cerium cation by neutral α-aminophosphonates, the individual rare earth separation by α-aminophosphonic acids, and the continuous preparation of high-purity thorium. The extraction and separation of some other metals are also discussed.

关键词： rare earths extraction separation extractants thorium

Degradation of Extraction from Seaweed and Its Complex with rare earths for Organophosphorous Pesticides

在线全文

学校读者我要写书评

暂无评论

Journal of rare earths 2007年第1期25卷 93-99页

作者：汪东风孙继鹏杜德红孙丽平陈振德薛长湖 College of Food Science and Engineering Ocean University of ChinaQingdao 266003 China Qingdao Academy of Agricultural Science Qingdao 266100 China

On the basis of several experiments carried out in China, it was proved that both seaweed liquid fertilizer and rare earth （RE） could promote the growth of crops and increase their yield. The effects of extraction from seaweed and its complex with RE on the degradation of organophosphorous pesticides and the yield of vegetables were investigated. The resuits showed that the extract and its complex with RE could degrade organophosphorous pesticides in neutral solvent. The residues of the pesticides treated by the extract decreased by 96.88 %, 52.30%, 49.52%, and 22.88 %, respectively, for chlorpyrifos, dichlorvos, omethoate, and dimethoate, and those by the complex decreased by 95.99%, 54.23%, 48.79%, and 25.66%, respectively, when compared with the control. The residues of chlorpyrifos and dimethoate in spinach sprayed with the complex were decreased by 90.64% and 76.56%, respectively, compared with those in spinach from control plots when the interval between spraying and sampling was 8 d. The fresh weight of brassica chinensis and cabbage increased by 28.62% and 18.72%, and their dry weight increased by 44.49% and 14.74%, respectively, compared with those of the controls. The chlorpyrifos and dimethoate residues in brasscia chinese were decreased by 36.36% and 50.00%, respectively, and their rate of decrease in cabbage was 40.00% and 75.00%, respectively, on 5th day after spraying with the complex, when compared with those in the vegetable from control. These results suggest that this complex can increase the agricultural productivity and reduce the use of pesticide residues in the production of vegetables.

关键词： seaweed extraction organophosphorous pesticides degradation rare earths

Distribution and Behaviour of rare earths in Laser Coating

在线全文

学校读者我要写书评

暂无评论

Journal of rare earths 1998年第3期16卷 19-24页

作者：沈以赴陈继志冯钟潮梁勇 Department of Materials Sciences and Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

The behaviour of RE added into steel surface by laser rapid solidification processing(LRSP) and their effects on surface properties were studied. Experimental results show that RE can be added into steel surface layer by LRSP of RE containing coating. The RE in the steel surface can react with oxygen and sulphur, then be dissolved in the grains or grain boundaries, and form intermetallic compounds RE 2Fe 17 . The addition of RE by LRSP has very strong effects on the properties of steel surface.

关键词： rare earths Laser treatment Surface coating

Effect of rare earths on Plant under Supplementary Ultraviolet-B Radiation: Ⅰ Effect of Cerium on Growth and Photosynthesis in Rape Seedlings Exposed to Supplementary Ultraviolet-B Radiation

在线全文

学校读者我要写书评

暂无评论

Journal of rare earths 2005年第5期23卷 569-575页

作者：梁婵娟黄晓华周青 Key Laboratory of Industrial Biotechnology Ministry of Education Southern Yangtze University Wuxi 214036 China College of Chemistry and Environmental Science Nanjing Normal University Nanjing 210097 China

Effect of cerium （Ce^3＋） on growth and photosynthesis in rape seedlings exposed to two levels of ultraviolet-B radiation （UV-B, 280 - 320 nm） was studied with hydroponics under laboratory conditions. The growth of rape seedlings exposed to two levels of UV-B irradiation （0.15 and 0.35 W· m^-2/T2） was both heavily restrained. The aboveground growth indices including stem （plant） height, leaf number, leaf area, leaf fresh/dry weight and stem fresh/dry weight were obviously decreased by 13.2% - 44.1% （T1） and 21 .4% - 49.3% （T2）. Compared to CK, and except active absorption area of roots, the belowground indices main root length, root volume and fresh/dry weight by 14.1% -35.6% （T1） and 20.3% - 42.6% （T2）, respectively. For Ce ＋ UV-B treatments, the aboveground and belowground growth indices were decreased by 4.1% - 23.6%, 5.2% -23.3% （Ce＋T1） and 10.8% -28.4%, 7.0% -27.8% （Ce ＋T2）, lower than those of UV-B treatments mentioned above. These results show that Ce has protective effect on plant against injury of UV-B radiation. Furthermore, the protective effect of Ce on seedlings exposed to T1 level of UV-B radiation is superior to T2 level. Chlorophyll content, net photosynthesis rate, transpiration rate, stomatal conductance and water use efficiency in UV-B treatments decrease dramatically, whereas intercellular CO2 concentration increases. Although these indices in Ce ＋ UV-B treatments decrease compared with those of CK, the decrease in Ce ＋ UV-B treatments are lower than those in UV-B treatment. This phenomenon indicates that the ecophysiological protective effect of Ce is based on improving photosynthesis in plants. The dynamic curves of photosynthesis indices show that the course of light-repair is shortened and the injury to rape seedlings by UV-B radiation stress is alleviated by Ce.

关键词： Cerium ultraviolet-B radiation rape seedlings photosynthesis rare earths