New Sr Isotope Evidence to Support the Material Source of the Mengyejing Potash Deposit in the Simao Basin from Ancient Marine Halite or Residual Sea

Objective The Mengyejing potash deposit in the Simao Basin is the only producing area of solid potash at present in China. There is still controversy about the material source and distribution of the potash in this deposit （Shen Lijian et al., 2017）, which has influenced not only the prospecting direction and efficiency but also the understanding of the control of Tethys tectonic evolution on the formation and distribution of the mineral resources. This work analyzed the Sr isotope geochemical characteristics of evaporites from core samples in the well MZK-3 in order to further clarify the material source and to explore the potash distribution in the Simao Basin.

Carbon dioxide catalytic conversion to nano carbon material on the iron–nickel catalysts using CVD-IP method

The over-consumption of fossil fuels resulted in the large quantity emission of carbon dioxide （CO2）, which was the main reason for the climate change and more extreme weathers. Hence, it is extremely pressing to ex- plore efficient and sustainable approaches for the carbon-neutral pathway of CO2 utilization and recycling. In our recent works with this context, we developed successfully a novel ＂chemical vapor deposition integrated process （CVD-IP）＂ technology to converting robustly CO2 into the value-added solid-form carbon materials, The monometallic FeNi0-Al2O3 （FNi0） and bimetallic FeNix-Al2O3 （FNi2, FNi4, FNi8 and FNi20） samples were synthesized and effective for this new approach. The catalyst labeled FNi8 gave the better performance, exhibited the single pass solid carbon yield of 30%. These results illustrated alternative promising cases for the CO2 capture utilization storage （CCUS）, by means of the CO2 catalytic conversion into the solid-form nano carbon materials.

Ore-Forming Material Sources of the Shizishan Pb-Zn Deposit in Western Hunan Province,China

Objective The Shizishan Pb-Zn deposit is located in the southeastern margin of the Yangtze Block,and its Pb-Zn orebodies are mainly hosted in the Lower Cambrian Qingxudong Formation limestone.Previous researches have investigated the geological characteristics,geochemistry and fluid inclusions of this deposit.

Influence of Tacking Sequence on Residual Stress and Distortion of Single Sided Fillet Submerged Arc Welded Joint

Submerged arc welding （SAW） is advantageous for joining high thickness materials in large structure due to high material deposition rate. The non-uniform heating and cooling generates the thermal stresses and subsequently the residual stresses and distortion. The longitudinal and transverse residual stresses and angular distortion are generally measured in large panel structure of submerged arc welded fillet joints. Hence, the objective of this present work is to quantify the amount of residual stress and distortion in and around the weld joint due to positioning of stiffeners tack. The tacking sequence influences the level of residual stress and proper controlling of tacking sequences is required to minimize the stress. In present study, an elasto-plastic material behavior is considered to develop the thermo mechanical model which predicts the residual stress and angular distortion with varying tacking sequences. The simulated result reveals that the tacking sequence heavily influences the residual stress and deformation pattern of the single sided fillet joint. The finite element based numerical model is calibrated by comparing the experimental data from published literature. Henceforth, the angular distortions are measured from an in-house developed experimental set-up. A fair agreement between the predicted and experimental results indicates the robustness of the developed numerical model. However, the most significant conclusion from present study states that tack weld position should be placed opposite to the fillet weld side to minimize the residual stress.

Effective exposure of nitrogen heteroatoms in 3D porous graphene framework for oxygen reduction reaction and lithium–sulfur batteries

The introduction of nitrogen heteroatoms into carbon materials is a facile and efficient strategy to regulate their reactivities and facilitate their potential applications in energy conversion and storage. However,most of nitrogen heteroatoms are doped into the bulk phase of carbon without site selectivity, which significantly reduces the contacts of feedstocks with the active dopants in a conductive scaffold. Herein we proposed the chemical vapor deposition of a nitrogen-doped graphene skin on the 3D porous graphene framework and donated the carbon/carbon composite as surface N-doped grapheme（SNG）. In contrast with routine N-doped graphene framework（NGF） with bulk distribution of N heteroatoms, the SNG renders a high surface N content of 1.81 at%, enhanced electrical conductivity of 31 S cm^（-1）, a large surface area of 1531 m^2 g^（-1）, a low defect density with a low I_D/I_G ratio of 1.55 calculated from Raman spectrum, and a high oxidation peak of 532.7 ℃ in oxygen atmosphere. The selective distribution of N heteroatoms on the surface of SNG affords the effective exposure of active sites at the interfaces of the electrode/electrolyte, so that more N heteroatoms are able to contact with oxygen feedstocks in oxygen reduction reaction or serve as polysulfide anchoring sites to retard the shuttle of polysulfides in a lithium–sulfur battery. This work opens a fresh viewpoint on the manipulation of active site distribution in a conductive scaffolds for multi-electron redox reaction based energy conversion and storage.

Optical properties of titanium oxide films obtained by cathodic arc plasma deposition

Structural and optical properties of nanometric titanium oxide（TixOy） films obtained by cathodic arc plasma deposition were investigated. Phase analysis by x-ray diffraction and Fouriertransform infrared spectroscopy showed the presence of anatase, rutile, Ti_2O_3, Ti_4O_7 and amorphous phases. Scanning electron microscopy images showed well-developed surface morphology with nano-patterns. Spectroscopic ellipsometry revealed film thicknesses of 53 and50 nm, variable refractive indices dependent on the light wavelength and close to zero extinction coefficients for wavelengths higher than 500 nm. On the basis of ultraviolet–visible spectroscopy data and using the Tauc equation, band gap values for direct and indirect electron transitions were determined.

The genetic relationship between Habo alkaline intrusion and its surrounding deposits, Yunnan Province, China: geological and S–Pb isotopic evidences

The Habo alkaline intrusion, which is located in the south of the Sanjiang area, Yunnan Province, China, is a typical Cenozoic alkaline intrusion. There are a series of small to medium-sized Au and Pb-（Zn） deposits around this intrusion. Those deposits are spatially associated with the Habo alkaline intrusion. （1） The δ^34S values of sulfides from Au deposits range from -1.91‰ to 2.69 ‰, which are similar to those of Pb-（Zn） deposits （-3.82 ‰ to -0.05 ‰） and both indicate a much greater contribution from magma. （2） The Habo alkaline intrusion has relatively homogeneous Pb isotopic compositions with ^206pb/^204pb ranging from 18.608 to 18.761, ^207pb/^204pb from 15.572 to 15.722 and ^20spb/^204pb from 38.599 to 39.110. These Pb isotope ratios are similar to those of Au deposits, whose ^206pb/^204pb range from 18.564 to 18.734, ^20Tpb/^20apb from 15.582 to 15.738 and ^208pb/^204pb from 38.592 to 39.319. Pb ratios in both the intrusion and Au deposits suggest that Pb mainly derived from the depth, probably represents a mixture of mantle and crust. Pb-（Zn） deposits, however, show a decentralized trait, and most of them are similar to that of the alkaline intrusion with ^206pb/^204pb ranging from 18.523 to 18.648, ^207pb/^204pb from 15.599 to 15.802, and ^20spb/^204pb from 38.659 to 39.206. （3） In the plumbotectonic diagram ^20Tpb/^204pb versus ^206pb/^204pb, almost all of Au and Pb-（Zn） deposits have the same projection area with the Habo alkaline intrusion, which indicates that those deposits almost share the same source with the alkaline intrusion. （4） Isotopic age of the Habo alkaline intrusion is 36-33 Ma, which is similar to that of Beiya, whose ore- related alkaline porphyries age is 38-31 Ma and molybdenite Re-Os age is 36.9 Ma. Therefore, along with S-Pb isotope traits, we suggest that the Habo Au and Pb-（Zn） deposits should be typically Ailaoshan-Red RiverCenozoicalkaline-related deposits and ore-forming ages of these deposits should be later than that of the Habo alkaline intrusion.

Study on the Pyrolytic Carbon Generated by the Electric Heating CVD Method

A new method of fabricating C/C composite materials, namely electric heating CVD method, was used, which electrified the carbon fiber directly by using the conductivity of itself. Acetylene was used as the carbon source with nitrogen as dilution gas, and the pyrolytic carbon started to deposit on the carbon fiber surface when the deposition temperature was reached. The morphology of pyrolytic carbon was characterized by SEM, and the surface properties of carbon fibers before and after CVD were characterized by Raman spectroscopy. The experimental results show that the electric heating method is a novel method to fabricate C/C composite materials, which can form a dense C/C composite material in a short time. The order degree and the average crystallite size of the carbon fiber surface were decreased after the experiment.

Structure and Properties of Nanostructured Vacuum-Deposited Foils of Invar Fe–(35–38 wt%)Ni Alloys

The process of electron beam vacuum deposition of the Fe-（35-38 wt%）Ni alloys at substrate temperatures Ts from 300 to700 ℃ were used to produce vacuum-deposited foils with the FCC structure, differing by the size of characteristic microstructural elements （grains and subgrains）. It was shown that refinement of foil microstructural elements to nanoscale is accompanied by their microhardness increase up to 4-5 GPa. The change of the thermal expansion coefficient （TEC） of the nanostructured （NS） foil of the Fe-35.1Ni alloy within the temperature range from -50 to 150 ℃ has some deviation from that observed for cast Invar alloy of the same composition. It has been found that the main factors affecting the peculiarities of thermal expansion of the NS foil can be related to the presence of small fraction of BCC- phase in them, high level of crystalline lattice microstrains and inhomogeneous magnetic order in FCC- phase. It was shown that as a result of additional thermal treatment of NS foils their invar properties become similar to that observed for cast Invar alloy but mechanical properties remain on the same level.

Electrophoretic deposition and an investigation of co-dopants effect on luminescence property of Mg2SiO4:Eu3+phosphors

Forsterite particles doped with europium ions（Eu^（3＋）） were synthesized via a solution combustion method. The effect of co-dopants on photoluminescence intensity was described. Different percentages of calcium（Ca^（2＋））, zinc（Zn^（2＋））, barium（Ba^（2＋）） and strontium（Sr^（2＋）） were added to the Mg2SiO4：Eu^（3＋）host.The synthesized sample was characterized by X-ray diffraction, transmission electron microscopy,scanning electron microscopy, spectrofluorometer and the FTIR spectroscopy. X-ray diffraction（XRD）results revealed that dominant phase was forsterite in all samples. Additionally, a negligible amount of periclase phase was recognized in the samples. The average size of the synthesized particles was less than 200 nm. The presence of co-dopant led to an enhancement in the photoluminescent property of the synthesized samples. The maximum increase in photoluminescence intensity was obtained by Ba^（2＋）ions as a co-dopant. Condensed films of photoluminescence particles were produced by utilizing electrophoresis technique to deposit particles. The results showed that polyvinyl pyrrolidone was the best surface modifier to raise the mass deposition of the samples on the substrate.

Scalable gas-phase processes to create nanostructured particles

The properties of nanoparticles are often different from those of larger grains of the same solid material because of their very large specific surface area. This enables many novel applications, but properties such as agglomeration can also hinder their potential use. By creating nanostructured particles one can take optimum benefit from the desired properties while minimizing the adverse effects. We aim at developing high-precision routes for scalable production of nanostructured particles. Two gas-phase synthesis routes are explored. The first one - covering nanoparticles with a continuous layer - is carried out using atomic layer deposition in a fluidized bed. Through fluidization, the full surface area of the nanoparticles becomes available. With this process, particles can be coated with an ultra-thin film of constant and well-tunable thickness. For the second route - attaching nanoparticles to larger particles - a novel approach using electrostatic forces is demonstrated. The micron-sized particles are charged with one polarity using tribocharging. Using electrospraying, a spray of charged nanoparticles with opposite polarity is generated. Their charge prevents agglomeration, while it enhances efficient deposition at the surface of the host particle. While the proposed processes offer good potential for scale-up, further work is needed to realize large-scale processes.