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HYDRODYNAMIC FORCEs FOR OVERTOPPING sPILLWAYs

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Journal of Hydrodynamics 1993年第2期5卷 19-29页

作者： Ashok K.Chugh U.s.Department of the interior,Bureau of Reclamation Eugineering and Research,Deuver,Colorado 80225 U.s. Dep of the interior Denver United States

Expressions are derived for calculating hydrodynamic forces from the unit dis- charge,channel slope,and flow and velocity profiles on an overflow spillway.A sample prob- lem is included to illustrate the use of the id... 详细信息

关键词： hydrodynamic forces spillways embankment dam

Quantitative assessment of the complexity of geological structures in terms of seismic propagators

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science China Earth sciences 2010年第1期53卷 54-63页

作者： FU LiYun Key Laboratory of the Earth’s Deep interior,Institute of Geology and Geophysics,Chinese Academy of sciences,Beijing 100029,China Key Laboratory of the Earth’s Deep interior Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China

How a wave interacts with heterogeneous media has been pursued by many *** complexity of subsurface heterogeneities is seismologically a relative concept to wavelengths of seismic waves.A growing perception is that velocity variations,propagation angles,and computational accuracies are closely related at a variety of scales.A tentative strategy to quantitatively evaluate the complexity of subsurface heterogeneous media is presented in this article to see what scales of geological heterogeneities to be captured by *** express complex subsurface structures as the slowness-and angularheterogeneity spectra to quantify velocity contrasts and dipping-angle distributions of complex geological *** the other hand,the scaling characteristics of a propagator are measured through dispersion analysis by its angular spectra plotted against refractive indexes and propagation angles,respectively.A parameter termed as imaging efficiency is introduced by associating the geological heterogeneity spectra with the propagator's angular spectra to understand the coherent interference between the medium's heterogeneity and the propagator's scaling ***,a complexity coefficient can be defined to evaluate geological complexities in terms of *** application of this strategy is demonstrated to the sEG/EAEG salt model.

关键词： geological heterogeneity spectra seismic imaging propagator’s angular spectra imaging efficiency complexity coefficient

Contribution of glial cells to the neuroprotective effects triggered by repetitive magnetic stimulation:a systematic review

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Neural Regeneration Research 2024年第1期19卷 116-123页

作者： susana A.Ferreira Nuno Pinto Inês serrenho Maria Vaz Pato Graça Baltazar Centro de Investigação em Ciências da saúde(CICs-UBI) Universidade da Beira InteriorCovilhãPortugal Faculdade de Ciências da saúde Universidade da Beira InteriorCovilhãPortugal GRUBI-systematic Reviews Group University of Beira InteriorCovilhãPortugal

Repetitive transcranial magnetic stimulation has been increasingly studied in different neurological diseases,and although most studies focus on its effects on neuronal cells,the contribution of nonneuronal cells to the improvement trigge red by repetitive transcranial magnetic stimulation in these diseases has been increasingly *** systematically review the effects of repetitive magnetic stimulation on non-neuronal cells two online *** of science and PubMed were searched fo r the effects of high-frequency-repetitive transcranial magnetic stimulation,low-frequencyrepetitive transcranial magnetic stimulation,intermittent theta-bu rst stimulation,continuous thetaburst stimulation,or repetitive magnetic stimulation on non-neuronal cells in models of disease and in unlesioned animals or cells.A total of 52 studies were *** protocol more frequently used was high-frequency-repetitive magnetic stimulation,and in models of disease,most studies report that high-frequency-repetitive magnetic stimulation led to a decrease in astrocyte and mic roglial reactivity,a decrease in the release of pro-inflammatory cyto kines,and an increase of oligodendrocyte *** trend towards decreased microglial and astrocyte reactivity as well as increased oligodendrocyte proliferation occurred with intermittent theta-burst stimulation and continuous theta-burst *** papers analyzed the low-frequency-repetitive transcranial magnetic stimulation protocol,and the parameters evaluated were restricted to the study of astrocyte reactivity and release of pro-inflammatory cytokines,repo rting the absence of effects on these paramete *** what concerns the use of magnetic stimulation in unlesioned animals or cells,most articles on all four types of stimulation reported a lack of *** is also important to point out that the studies were developed mostly in male rodents,not evaluating possible diffe rential effects of repetitive transcranial magneti

关键词： astrocyte glia high-frequency repetitive magnetic stimulation inflammation low-frequency repetitive magnetic stimulation microglia neurologic disorders oligodendrocyte repetitive magnetic stimulation theta-burst stimulation

Geochemistry of Trace Elements during Ore-Forming Processes in Yinshan Deposit

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Journal of Earth science 2001年第3期 38-45页

作者： Ling QicongLaboratory for study the Earth's interior and Geofluids, Institute of Geochemistry, Chinese Academy of sciences, Guiyang 550002 Faculty of Earth sciences, China University of Geosciences, Wuhan 430074Liu CongqiangInstitute of Geochemistry, Chi

Detailed studies on trace elements in ores, wallrocks of intrusion and orebodies in Yinshan deposit show that ΣREE increased in all samples except in those close to the intrusion and orebodies. Altered wallrocks with lower w(LREE)/w(HREE) ratios were depleted in Eu, as compared with their fresh counterparts. The calculation results suggest that less than 31 % of the increment of REE might have been caused by mass transfer and that the remaining percentage might have been responsible for the addition of REE into the rock from hydrothermal fluid that caused rock alteration. The acting hydrothermal fluid was characterized by low w(LREE)/w(HREE) ratio with a strong positive anomaly. The reductive state of the hydrothermal fluid resulted in the loss of Eu by reducing Eu3+ into more mobile Eu2+. In other trace elements, Hf, Th, U, V, Cr, Co, Nb, Mo, Ta, Zr and Rb show immobility, Y, sc and sr were carried off while Cu, Pb, Zn, Ag, sn and Ba were introduced into altered wallrocks by hydrothermal fluid during hydrothermal alteration.

关键词： geochemistry of trace elements hydrothermal alteration metamorphic phyllite of shuangqiaoshan Group Yinshan deposit.

Experimental studies on silicate structures of basaltic glasses quenched at 1 650℃ and 1—3.5 GPa

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Chinese science Bulletin 1999年第5期44卷 461-466页

作者： ZHUWeiguo, XIEHongsen, XU Jian, HOUWei, ZHANG Yueming, QUO Jie and XU Zhuming Earth ’s interior Material Laboratory, Institute of Geochemistry, Chinese Academy of sciences, Guiyang 550002, China Institute of Earth science, Academia sinica , Taibei, Taiwan, China Earth’s interior Material Laboratory Institute of Geochemistry Chinese Academy of Sciences Guiyang China Institute of Earth science Academia Snica Taibei Taiwan China

A series of melting experiments was carried out at 1 650℃ and 1.00-3.00 GPa using alkaline basalt as starting material. The compositions of quenched basaltic glasses in the products were detected by electron micro probe. Their CIPW norms were calculated and their refractive indices were determined by the oil-infused method. The Raman spectrum of the quenched basaltic glasses indicates that their main structural species are monomer [siO4]4-, chain [si2O6]4- and sheet [si2O5]2- . The relationship at the same temperature between the proportions of integrated areas of structural species, and compositions and pressures was discussed.

关键词： quenched basaltic glass structure of melt Raman spectrum.

study on the Electrical Conductivity of 0.025 mol NaCl solution at 0.25-3.75 GPa and 20-370℃

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Acta Geologica sinica(English Edition) 1997年第3期71卷 273-281页

作者： Zheng Haifei Xie Hongsen Xu Yousheng song Maoshuang Guo Jie and Zhang Yueming Earth’s interior Material Laboratory,Institute of Geochemistry,Chinese Academy of sciences,Guiyang,Guizhou

The electrical conductance of 0.025 mol NaCl solution was measured at0.25-3.75 GPa and 20-370℃. As shown by the results, the conductance increases with temper-ature, and there is a liner relation between the reciprocal of temperature and the logarithm ofthe conductance but their slopes are different at different pressures. The relations between theconductance and pressure is rather complex and there are some discontinuities: in the range of2.25-3.75 GPa, the conductance increases with the pressure; in the range of 1.25-2.0 GPa, theconductance is not related to the pressure; and at a pressure of 0.75 GPa, the conductance ishigher than that at the pressures nearby. This reflects that the NaCl solution has rather differentproperties of electronic chemistry at various pressures, and probably is an important cause forthe existence of the layers with high electrical conductance and low velocity in the Earth's crustand mantle.

关键词： high T/ P NaCl solution electrical conductivity low-velocity and high-conductance layer

Experimental measurement of the electrical conductivity of single crystal olivine at high temperature and high pressure under different oxygen fugacities

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Progress in Natural science:Materials International 2006年第4期16卷 387-393页

作者： DAI Lidong, LI Heping, LIU Congqiang, CUI Tongdi, sHAN shuangming, YANG Changjun, LIU Qingyou and DENG Heming Laboratory of the Earth’s interior Materials and Fluid Geochemistry, Institute of Geochemistry, Chinese Academy of sciences, Guiyang 550002, China Graduate school of the Chinese Academy of sciences, Beijing 100039, China Institute of Geochemistry, Chinese Academy of sciences, Guiyang 550002, China Guizhou University, Guiyang 550004, China Laboratory of the Earth'' s interior Materials and Fluid Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China Graduate school of the Chinese Academy of sciences Beijing 100039 China Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China Guizhou University Guiyang 550004 China)

At 1.0-4.0 GPa and 1123-1473 K and under oxygen fugacity-controlled conditions (Ni + NiO, Fe + Fe3O4, Fe + FeO and Mo+ M0O2 buffers), a YJ-3000t Model six-anvil solid high-pressure apparatus and a sarltron-1260 Impedance/Gain-Phase analyzer were employed to conduct an in situ measurement of the electrical conductivity of single crystal olivine. Experimental results showed that: (1) within the range of experimentally selected frequencies (103-106 Hz), the electrical conductivity of the sample is of great dependence on the frequency; (2) with the rise of temperature ( T), the electrical conductivity (σ) will increase, and the Arrenhius linear relationship is established between lgσ and 1/T; (3) under the control of oxygen buffer Fe+ Fe3O4, with the rise of pressure, the electrical conductivity tends to decrease whereas the activation enthalpy and independent-of-temperature preexponential factor tend to increase, with the activation energy and activation volume of the sample estimated at (1. 25 ± 0.08) eV and (0.105 ±0.025) cm3/mol, respectively; (4) under given pressure and temperature conditions, the electrical conductivity tends to increase whereas the activation energy tends to decrease with increasing oxygen fugacity; and ( 5) the mechanism of electrical conduction of small polarons can provide insight into the behavior of electrical conduction of olivine under high pressure and high temperature.

关键词： olivine high temperature and high pressure electrical conductivity oxygen fugacity small polaron.

Grain Boundary Conductivities of Peridotite at High Temperature and High Pressure

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地学前缘 2009年第S1期16卷 218-219页

作者： Lidong Dai~1,Heping Li~1,Haiying Hu~(1,2),shuangming shan~1 1.Laboratory for study of the Earth’s interior and Geofluids,Institute of Geochemistry,Chinese Academy of sciences,Guiyang 550002,China. 2.Graduate school of the Chinese Academy of sciences,Beijing 100080,China

The grain boundary conductivities of dry synthetic peridotite are conducted by virtue of YJ-3000t multi-anvil press and solartron-1260 Impedance /Gain-phase Analyzer at conditions of 4.0 GPa, 1373 K and frequency rang... 详细信息

关键词： peridotite electrical conductivity oxygen fugacity

Quantitative assessment of the complexity of geological structures in terms of seismic propagators

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Quantitative assessment of the complexity of geological stru...