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Influence of carbon on the giant magnetocaloric effect of LaFe_11.7Si_1.3

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Rare Metals 2006年第5期25卷 556-561页

作者： LI Junqin LIU Fusheng AO Weiqin ZHUANG Yinghong zhou kaiwen Department of Materials Science and Engineering Shenzhen University and Shenzhen Key Laboratory of Special Functional Materials Shenzhen518060 China Key laboratory of Nonferrous Metal Materials and New Processing Technology Ministry of Education Guangxi University Nanning 530004China

The influences of carbon on phase formation, Curie temperature, and magnetic entropy change of the NaZn13-type LaFe11.7Si1.3 were investigated. Seven carbon-containing alloys, LaFe11.7Si1.3Cx with x = 0, 0.03, 0.06, 0.10, 0.20, 0.30, and 0.50, respectively, were prepared for this investigation. Experimental results show that addition of a small amount of carbon in LaFe11.7Sil.3 is favorable for the formation of the NaZn13-type structure of LaFe11.7Si1.3Cx. The lattice constant increases with C addition and x increases in the alloy because of the introduction of C as interstitial atoms. The Curie temperature of LaFe11.7Si1.3Cx increases from 194 K to 225 K as x increases from 0 to 0.5. Large magnetic entropy changes were observed in these carbon-containing alloys LaFe11.7Si1.3Cx because of their first-order structural/magnetic transition. The maximum magnetic entropy change of 27.5 ***^-1K^-1 at 202 K for the 0-1.56 T magnetic field change was observed in the alloy with x = 0.06. The large magnetic-entropy changes corresponding to low magnetic field change, and the low cost of the material of LaFe11..7Si1.3Cx makes it a promising candidate to be used as magnetic refrigerants in the corresponding temperature range.

关键词： LaFe11.7Si1.3 carbon addition magnetocaloric effect

Influence of Sn substitution for Co in RCo_2 (R= Gd,Tb,Dy) alloys on the structure and magnetocaloric effect

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Rare Metals 2007年第2期26卷 97-102页

作者： ZHUANG Yinghong DENG Jianqiu LI Junqin ZHAN Yongzhong ZHU Qiming zhou kaiwen The Key Laboratory of New Processing Technology for Nonferrous Metal and Materials of Chinese Ministry of Education Guangxi University Nanning 530004 China Shenzhen Key Laboratory of Special Functional Materials ＆ Department of Materials Science and Engineering Shenzhen University Shenzhen 518060 China

The phases and the magnetocaloric effect in the alloys R（Co1-xSnx）2 with X = 0, 0.025, 0.050, 0.075, and 0.100 were investigated by X-ray diffraction analysis and magnetization measurement. The substitution of Sn in RCo2 is limited. The cubic MgCu2-type structure for the alloys of RCo2 was confirmed by X-ray powder diffraction and the remaining alloys mainly consisted of the RCo2 phase, along with some RCo3 and R5Sn3 impurity phases. The impurity phases increase with the increase of Sn content. The Tc of the alloys is not very sensitive to the Sn substitution for Dy（Co1-xSnx）2 and Tb（Co1-xSnx）2, whereas in Gd（Co1-xSnx）2, the Curie temperatures significantly increase. The maximum magnetic entropy changes in the alloys Dy（Co1-xSnx）2 （x = 0, 0.025, 0.050, 0.075） are 5.78, 5.43, 3.88, and 2.98 J·kg^-1·K^-1, respectively, and those in the Tb（Co1-xSnx）2 （x = 0, 0.025） are 3.44, and 2.29 J·kg^-1·K^-1 respectively in the applied field change of 0-2.0 T.

关键词： magnetic refrigeration materials magnetocaloric effect magnetization rare earth compounds

Nutrient distributions and nitrogen-anomaly(N^(*))in the tropical North Pacific Ocean

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Acta Oceanologica Sinica 2022年第11期41卷 23-33页

作者： Aiqin Han Yu Wang Yunlong Huo Cai Lin kaiwen zhou Fangfang Kuang Hui Lin Third Institute of Oceanography Ministry of Natural ResourcesXiamen 361005China

Based upon cruise observations broadly covering the tropical North Pacific during July-November 2017,together with data obtained from the World Ocean Circulation Experiment Hydrographic Program,this study examined the distribution of dissolved inorganic nitrogen(DIN,nitrate(NO_(3)^(-))+nitrite(NO_(2)^(-))),dissolved inorganic phosphorus(DIP)and related N^(*)(nitrogen-anomaly,N^(*)=N-16P+2.9,where N and P are the concentrations of DIN(>1.0μmol/L)and DIP(>0.1μmol/L)),used as an index of N2fixation,in the upper 1000 m of the water *** concentrations displayed distinct spatial variability in the upper ocean but became relatively constant at a depth of 1000 m:they were high at low latitudes and in the eastern region,with an obvious nutricline at~150 m(DIN,~32.0μmol/L;DIP,~2.4μmol/L)and then generally increased with depth;they decreased markedly(DIN,~1.2μmol/L;DIP,~0.1μmol/L;at~150 m)at high latitudes and in the western region,where a nutricline was not *** N^(*)index showed significant meridional and zonal variation,with the most negative values located at low latitudes and in the eastern region(~10°N,~150°-170°E),while becoming positive towards the northwest(the north of~18°N,~160°E westward).A N^(*)concentration larger than 2.0μmol/L which often used as an indicator of N2fixation,was observed between 155°E and 165°E;N^(*)values were 2.0μmol/L to6.0μmol/L at~15°-28°N,i.e.,much higher than those in the southern sector(0-2.0μmol/L at~5°-10°N).Zonally,N^(*)decreased gradually from west(-2.0μmol/L to 4.0μmol/L,~145°-165°E)to east(-2.0μmol/L to-8.0μmol/L,~155°W)along~10°N,which was consistent with the distribution of Trichodesmium abundance and N2fixation ***,since such region was also supplied with aeolian deposition,high N^(*)was probably not only induced by N2fixation but also influenced by iron and/or nitrogen deposition.

关键词： tropical North Pacific Ocean nutrients nitrogen anomaly nitrogen fixation aeolian deposition

Baseline establishment for metals in the western Clarion-Clipperton Zone

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Acta Oceanologica Sinica 2022年第11期41卷 12-22页

作者： Cai Lin Yang Liu Ronggen Jiang Jinmin Chen Baohong Chen Weili Wang kaiwen zhou Hui Lin Third Institute of Oceanography Ministry of Natural ResourcesXiamen 361005China

Resource exploitation in the Clarion-Clipperton Zone(CCZ)is of major research interest worldwide,but its influence on the environment is poorly understood,especially due to the lack of baseline values for metals in the surrounding *** work aimed to establish the baseline values of 17 metals(Ba,Ca,K,Mg,Mn,Na,Ag,As,B,Cd,Co,Cr,Cu,Hg,Ni,Pb,and Zn)using normalization,the cumulative frequency curve method considering a total of 172 samples taken from 8 multitube cores and 1 box sediment core collected in the western CCZ during the COMRA-45 cruise campaign from August to September *** baseline values of the evaluated metals were as follows:1932 mg/kg for Ba,29512 mg/kg for Ca,18150 mg/kg for K,17120 mg/kg for Mg,6747 mg/kg for Mn,28546 mg/kg for Na,0.571 mg/kg for Ag,5.00 mg/kg for As,94.4 mg/kg for B,0.626 mg/kg for Cd,104 mg/kg for Co,76.1 mg/kg for Cr,370 mg/kg for Cu,0.028 mg/kg for Hg,190 mg/kg for Ni,27.5 mg/kg for Pb and 156 mg/kg for *** findings would fill the baseline value gap in the study area and further improve accuracy of environmental impact assessments on the impact of resource exploitation.

关键词： baseline metals normalization cumulative frequency curve

Magnetocaloric effect of (Gd_(1-x)Nd_x)Co_2 alloys in low magnetic field

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Rare Metals 2008年第4期27卷 350-353页

作者： CHEN Xiang ZHUANG Yinghong YAN Jialin zhou kaiwen LI Kefeng Key laboratory of the Ministry of Education of China for Nonferrous Metal Materials and New Processing Technology Guangxi University Nanning 530004 China Department of Physics and Electronic Informational Engineering Neijiang Teachers College Neijiang 641002 China

The phases and magnetocaloric effect in the alloys （Gd1-xNdx）Co2 with x = 0, 0.1, 0.2, 0.3, and 0.4 were investigated by X-ray diffraction analysis and magnetization measurement. The samples are single phase with a cubic MgCu2-type structure. The To decreases obviously with increasing Nd content from 404 K of the alloy with x = 0 to 272 K of the alloy with x = 0.4; forx = 0.3, the To is 296 K, which is near room temperature. In the samples （Gd1-xNdx）Co2 with x = 0.0, 0.1, 0.2, 0.3, and 0.4, the maximum magnetic entropy change is 1.471, 1.228, 1.280, 1.381 and 1.610 J·kg^-1·K^-1, respectively, in the applied field range of 0-2.0 T. The results of Arrott plots confirmed that the transition type were second order magnetic transition forx = 0, 0.3, and 0.4.

关键词： magnetic refrigeration materials magnetocaloric effect magnetic entropy change phase transition

Temporal and spatial distribution characteristics of nutrients in Clarion-Clipperton Fracture Zone in the Pacific in 2017

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Acta Oceanologica Sinica 2022年第1期41卷 1-10页

作者： Baohong Chen kaiwen zhou Kang Wang Jigang Wang Sumin Wang Xiuwu Sun Jinmin Chen Cai Lin Hui Lin Third Institute of Oceanography Ministry of Natural ResourceXiamen 361005China Institute for Advanced Ocean Study Ocean University of ChinaQingdao 266003China

This research investigated eight stations in Clarion-Clipperton Fracture Zone(CCFZ)in the eastern tropical Pacific in 2017 to study the spatial distribution characteristics of nutrients and chlorophyll a(Chi a)concentration,and compared nutrient concentrations and molar ratios with those of other investigations 20 years ago in the same *** study found that dissolved inorganic nutrient(N,P and Si)concentrations were lowest in the upper layer,and increased from surface to some depths,then they decreased a little to the bottom.N was the limited nutrient factor for the growth of phytoplankton *** nutrient concentrations and molar ratios have no obvious changes in 2017 comparing those in 1998-2003,supplemented from the equatorial Pacific,nutrient concentrations in the study area were higher than those in seamounts in the North Pacific and Station ***,this study used Generalized Additive Models(GAMs)to infer the underlying bottom-up factors controlling phytoplankton abundance(Chi a concentration),showing that depth,salinity and PO^-P concentration were major factors controlling the growth of phytoplankton ***,this study can provide basic data and theoretical support for the development of polymetallic nodule area and its long-term impact assessment on the environment.

关键词： nutrients Chla GAMs CCFZ Pacific

The particle fluxes in sediment traps from Niulang Guyot area in the Northwest Pacific Ocean

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Acta Oceanologica Sinica 2022年第11期41卷 34-44页

作者： Xiuwu Sun Jinmin Chen Baohong Chen Cai Lin Yang Liu Jiang Huang Zhong Pan kaiwen zhou Qing He Fangfang Kuang Hui Lin Laboratory of Marine Ecological and Environment Early Warning and Monitoring Third Institute of OceanographyMinistryof Natural ResourcesXiamen 361005China Ocean Dynamics Laboratory Third Institute of OceanographyMinistry of Natural ResourcesXiamen 361005China

The flux of settling particles in the ocean has been widely explored since 1980s due to its important role in biogenic elements cycling,especially in the transport of particulate organic carbon(POC)in the deep ***,research in the seamount area of the oligotrophic subtropical Northwest Pacific Ocean is *** this work,two sediment traps were deployed at the foot and another two at the hillside of Niulang Guyot from August2017 to July *** magnitude and composition of particle fluxes were *** main factors influencing the spatial variations of the fluxes were *** results indicated a low particulate flux from Niulang Guyot area in the Northwest Pacific Ocean,reflecting low primary productivity of the oligotrophic *** total mass flux(TMF)decreased from 2.57 g/(m^(2)·a)to 0.56 g/(m^(2)·a)with increasing depth from 600 m to 4850 m.A clear seasonal pattern of TMF was observed,with higher flux in summer than that in *** peak flux of 26.52 mg/(m^(2)·d)occurred in August at 600 m,while the lowest value of 0.07 mg/(m^(2)·d)was shown in February at 4850 *** settling particles at the deep layers had similar biochemical composition,with calcium carbonate(CaCO_(3))accounting for up to 90%,followed by organic matter and opal,characteristics of Carbonate *** POC flux decreased more rapidly in the twilight layer because of faster decomposition,remineralization,and higher temperature.A small fraction of POC was transported into the deep ocean by biological *** fluxes were mainly controlled by the calcareous ballasts besides the primary productivity of the surface *** advection may be another important factor affecting the flux in the seamount *** combination of settled matters rich in foraminiferal tests with topography and currents may be the reason for regulating the local abundance of benthos on *** results will fill in the knowledge gap of sedimentation flux,improve the understanding of ecosyste

关键词： sediment trap flux seamount POC Northwest Pacific Ocean

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瞬变电磁法在矿井水文地质探测中的应用研究

山西冶金 2022年第3期45卷 278-279页

作者：周凯文晋能控股煤业集团云岗矿地质测量部山西大同037017

为有效避免矿井发生水文地质灾害,能够更好地探测采煤作业面含水体情况,采用瞬变电磁法对矿井巷道掘进工作面进行超前探测,并将该探测技术应用在矿井裂隙水、老空区积水、不充水陷落柱以及充水陷落柱等水文地质中。

关键词：瞬变电磁法矿井裂隙水老空区积水充水陷落柱

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基于卡尔曼滤波的翼型表面压力实时重构方法

空气动力学学报 2023年第4期41卷 64-72,I0002页

作者：刘余丹周楷文刘应征温新上海交通大学机械与动力工程学院上海200240 空气动力学国家重点实验室绵阳621000

为实现基于稀疏数据的翼型表面压力实时重构,提出了一种基于压缩感知与卡尔曼滤波器的数据融合方法,该方法主要包括线下建立数据库和线上实时感知两部分。首先,在线下通过粒子图像测速技术、压敏漆、计算流体力学等方法对翼型表面压力... 详细信息

为实现基于稀疏数据的翼型表面压力实时重构,提出了一种基于压缩感知与卡尔曼滤波器的数据融合方法,该方法主要包括线下建立数据库和线上实时感知两部分。首先,在线下通过粒子图像测速技术、压敏漆、计算流体力学等方法对翼型表面压力进行全场采样,并采用本征正交分解对所测得的全场压力数据进行降维,建立含有主导相干流动结构的模态数据库以及各模态时间系数之间的状态转换关系。其次,在线上基于压缩感知,利用离散压力传感器所测量数据与压力场主导模态,通过求解L1范数下的最优化问题,对各主导模态的时间系数进行初步求解。最后,将线下所得各模态时间系数之间的状态转换关系放入卡尔曼滤波器,作为其系统模型进行预测;将线上所求得各模态时间系数放入卡尔曼滤波器,作为其观测值进行校正。以CFD模拟翼型压力作为验证数据,对该方法的性能进行评估,结果显示:该方法与仅采用压缩感知进行重构对比,升力重构误差从18.15%减小至6.39%。

关键词：流场重构数据融合压缩感知卡尔曼滤波器动态模态分解