To acquire understanding of Ni enrichment from laterite ore,the mineralogy and crystal chemistry of a low grade limonite type nickel laterite ore sample assaying 0.97% Ni from Indonesia were studied using optical micr...To acquire understanding of Ni enrichment from laterite ore,the mineralogy and crystal chemistry of a low grade limonite type nickel laterite ore sample assaying 0.97% Ni from Indonesia were studied using optical microscopy,X-ray diffraction（XRD）,scanning electron microscopy（SEM） and electron probe microanalysis（EPMA）.According to EPMA results,the mineral includes 80% goethite（（Fe,Ni,Al）O（OH）） with 0.87% Ni,15% silicate minerals with lizardite（（Mg,Fe,Ni）3Si2O5（OH）） and olivine（（Mg,Fe,Ni）2SiO4）,and 1.19% Ni,and other minor phases,such as hematite,maghemite,chromite and quartz,and no Ni was detected.The mineralogy of the laterite ore indicates that due to the complicated association of the various phases and the variable distribution of Ni,this refractory laterite ore can not be upgraded by traditional physical beneficiation processes.展开更多
In this work the statistical mechanical equation of state was developed for volumetric properties of crystalline and amorphous polymer blends.The Ihm-Song-Mason equations of state(ISMEOS) based on temperature and dens...In this work the statistical mechanical equation of state was developed for volumetric properties of crystalline and amorphous polymer blends.The Ihm-Song-Mason equations of state(ISMEOS) based on temperature and density at melting point(T_m and ρ_m) as scaling constants were developed for crystalline polymers such as poly(propylene glycol) + poly(ethylene glycol)-200(PPG + PEG-200),poly(ethylene glycol) methyl ether-300(PEGME-350) + PEG-200 and PEGME-350 + PEG-600.Furthermore,for amorphous polymer blends containing poly(2,6-dimethyl-1,4-phenylene oxide)(PPO) + polystyrene(PS) and PS + poly(vinylmethylether)(PVME),the density and surface tension at glass transition(ρ_g and γ_g) were used for estimation of second Virial coefficient.The calculation of second Virial coefficients(B_2),effective van der Waals co-volume(b) and correction factor(α) was required for judgment about applicability of this model.The obtained results by ISMEOS for crystalline and amorphous polymer blends were in good agreement with the experimental data with absolute average deviations of 0.84%and 1.04%,respectively.展开更多
There are potentially huge amounts of water stored in Earth's mantle, and the water solubilities in the silicate minerals range from tens to thousands of part per minion(ppm, part per million). Exploring water in ...There are potentially huge amounts of water stored in Earth's mantle, and the water solubilities in the silicate minerals range from tens to thousands of part per minion(ppm, part per million). Exploring water in the mantle has attracted much attention from the societies of mineralogy and geophysics in recent years. In the subducting slab, serpentine breaks down at high temperature, generating a series of dense hydrous magnesium silicate(DHMS) phases, such as phase A, chondrodite, clinohumite, etc. These phases may serve as carriers of water as hydroxyl into the upper mantle and the mantle transition zone(MTZ). On the other hand, wadsleyite and ringwoodite, polymorphs of olivine, are most the abundant minerals in the MTZ, and able to absorb significant amount of water(up to about 3 wt.% H_2O). Hence, the MTZ becomes a very important layer for water storage in the mantle, and hydration plays important roles in physics and chemistry of the MTZ. In this paper, we will discuss two aspects of hydrous silicate minerals:(1) crystal structures and(2) equations of state(Eo Ss).展开更多
Profit from high current gain features, 4 H-Si C power Darlington transistor has the capacity for handling high current transmission. In this paper, monolithic Darlington transistors were fabricated using a simultaneo...Profit from high current gain features, 4 H-Si C power Darlington transistor has the capacity for handling high current transmission. In this paper, monolithic Darlington transistors were fabricated using a simultaneous formation process for both n-type(emitter) and p-type(base) ohmic contact. The isolated device shows current gain of 1061 and 823 with collector current density(JC) increasing from 200 to 800 A/cm2, exhibiting a slight current gain drop at high JC. By extracting the interface state density(Dit) between Si O2 and p-type 4 H-Si C, it is found that this advantage owes to the improvement of the shallow bulk minority carrier lifetime in base region. Furthermore, ISE-TCAD(technology computer aided design) simulation was carried out to study the relationship between base minority lifetime and the current gain, from which the total base minority lifetime is estimated to be 48 ns. The open base breakdown voltage(BVCEO) is 850 V at a leakage current of 2 μA due to the electric filed crowding at the isolation bottom between drive bipolar junction transistor(BJT) and output BJT. To solve this, non-isolated devices were also fabricated with improved BVCEOof 2370 V, indicating the superior potential of 4 H-Si C monolithic Darlington transistors for high power application, while the current gain is deceased to 420, which needs further improvement.展开更多
基金Project (50974135) supported by the National Natural Science Foundation of China
文摘To acquire understanding of Ni enrichment from laterite ore,the mineralogy and crystal chemistry of a low grade limonite type nickel laterite ore sample assaying 0.97% Ni from Indonesia were studied using optical microscopy,X-ray diffraction（XRD）,scanning electron microscopy（SEM） and electron probe microanalysis（EPMA）.According to EPMA results,the mineral includes 80% goethite（（Fe,Ni,Al）O（OH）） with 0.87% Ni,15% silicate minerals with lizardite（（Mg,Fe,Ni）3Si2O5（OH）） and olivine（（Mg,Fe,Ni）2SiO4）,and 1.19% Ni,and other minor phases,such as hematite,maghemite,chromite and quartz,and no Ni was detected.The mineralogy of the laterite ore indicates that due to the complicated association of the various phases and the variable distribution of Ni,this refractory laterite ore can not be upgraded by traditional physical beneficiation processes.
文摘In this work the statistical mechanical equation of state was developed for volumetric properties of crystalline and amorphous polymer blends.The Ihm-Song-Mason equations of state(ISMEOS) based on temperature and density at melting point(T_m and ρ_m) as scaling constants were developed for crystalline polymers such as poly(propylene glycol) + poly(ethylene glycol)-200(PPG + PEG-200),poly(ethylene glycol) methyl ether-300(PEGME-350) + PEG-200 and PEGME-350 + PEG-600.Furthermore,for amorphous polymer blends containing poly(2,6-dimethyl-1,4-phenylene oxide)(PPO) + polystyrene(PS) and PS + poly(vinylmethylether)(PVME),the density and surface tension at glass transition(ρ_g and γ_g) were used for estimation of second Virial coefficient.The calculation of second Virial coefficients(B_2),effective van der Waals co-volume(b) and correction factor(α) was required for judgment about applicability of this model.The obtained results by ISMEOS for crystalline and amorphous polymer blends were in good agreement with the experimental data with absolute average deviations of 0.84%and 1.04%,respectively.
基金supported by the National Natural Science Foundation of China(Grant Nos.41590621&41473058)the Fundamental Research Funds for the Central University(Grant No.G1323531512)MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources(Grant No.MSFGPMR07),China University of Geosciences at Wuhan
文摘There are potentially huge amounts of water stored in Earth's mantle, and the water solubilities in the silicate minerals range from tens to thousands of part per minion(ppm, part per million). Exploring water in the mantle has attracted much attention from the societies of mineralogy and geophysics in recent years. In the subducting slab, serpentine breaks down at high temperature, generating a series of dense hydrous magnesium silicate(DHMS) phases, such as phase A, chondrodite, clinohumite, etc. These phases may serve as carriers of water as hydroxyl into the upper mantle and the mantle transition zone(MTZ). On the other hand, wadsleyite and ringwoodite, polymorphs of olivine, are most the abundant minerals in the MTZ, and able to absorb significant amount of water(up to about 3 wt.% H_2O). Hence, the MTZ becomes a very important layer for water storage in the mantle, and hydration plays important roles in physics and chemistry of the MTZ. In this paper, we will discuss two aspects of hydrous silicate minerals:(1) crystal structures and(2) equations of state(Eo Ss).
基金supported by the National Key Research and Development Program(Grant No.2016YFB0400500)the National Grid Science&Technology Project(Grant No.5455DW150006)+2 种基金the Natural Science Basic Research Plan in Shaanxi Province of China(Grant No.2017JM6003)the Industrial Research Project of Science and Technology Department of Shaanxi Province(Grant No.2016GY-076)the 111 Project(Grant No.B12026)
文摘Profit from high current gain features, 4 H-Si C power Darlington transistor has the capacity for handling high current transmission. In this paper, monolithic Darlington transistors were fabricated using a simultaneous formation process for both n-type(emitter) and p-type(base) ohmic contact. The isolated device shows current gain of 1061 and 823 with collector current density(JC) increasing from 200 to 800 A/cm2, exhibiting a slight current gain drop at high JC. By extracting the interface state density(Dit) between Si O2 and p-type 4 H-Si C, it is found that this advantage owes to the improvement of the shallow bulk minority carrier lifetime in base region. Furthermore, ISE-TCAD(technology computer aided design) simulation was carried out to study the relationship between base minority lifetime and the current gain, from which the total base minority lifetime is estimated to be 48 ns. The open base breakdown voltage(BVCEO) is 850 V at a leakage current of 2 μA due to the electric filed crowding at the isolation bottom between drive bipolar junction transistor(BJT) and output BJT. To solve this, non-isolated devices were also fabricated with improved BVCEOof 2370 V, indicating the superior potential of 4 H-Si C monolithic Darlington transistors for high power application, while the current gain is deceased to 420, which needs further improvement.
