Artificial intelligence-motivated in-situ imaging for visualization investigation of submicron particles deposition in electric-flow coupled fields

This study delves into the intricate deposition dynamics of submicron particles within electric-flow coupled fields,underscoring the unique challenges posed by their minuscule size,aggregation tendencies,and biological reactivity.Employing an operando investigation system that synergizes microfluidic technology with advanced micro-visualization techniques within a lab-on-a-chip framework enables a meticulous examination of the dynamic deposition phenomena.The incorporation of object detection and deep learning methodologies in image processing streamlines the automatic identification and swift extraction of crucial data,effectively tackling the complexities associated with capturing and mitigating these hazardous particles.Combined with the analysis of the growth behavior of particle chain under different applied voltages,it established that a linear relationship exists between the applied voltage and θ.And there is a negative correlation between the average particle chain length and electric field strength at the collection electrode surface(4.2×10^(5)to 1.6×10^(6)V·m^(-1)).The morphology of the deposited particle agglomerate at different electric field strengths is proposed:dendritic agglomerate,long chain agglomerate,and short chain agglomerate.

A Study on the Geological-Geochemical Dynamicsof Hydrothermal Ore Deposition as Exemplified by the Muping-Rushan Gold Deposit Belt,Eastern Shandong, China

This paper presents a method of establishing a hydrothermal ore-forming reaction system. On the basis of the study of four typical hydrothermal deposits, the folowing conclusions concerning geochemical dynamic controlling during hydrothermal mineralization have been drawn: (1 ) The regional tectonic activities control the concentration and dispersion of elements in the ore-forming process in terms of their effects on the thermodynamic nature and conditions of the ore-forming reaction system. (2) During hydrothermal mineralization the activities of ore-bearing faults can be divided into two stages: the brittle splitting stage and the brirtle-tough tensing stage, which would create characteristically different geodynamic conditions for the geochemical thermodynamic ore-forming system. (3) The hydrothermal ore-forming reaction system is an open dynamic system. At the brittle splitting stage the system was so strongly supersaturated and unequilibrated as to speed up and enhance the crystallization and differentiation of ore-forming fluids. And at the brittle-tough tensing stage, the ore-forming system was in a weak supersaturated state; with decreasing temperature and pressure the crystallization of oreforming material would slow down, and it can be regarded as an equilibrated state. (4) In the later stages of hydrothermal evolution, gold would be concentrated in the residual ore-forming solution. The pulsating fracture activity in this stage led to the crush of pyrite ore and it was then filled with gold-enriched solution, forming high-grade "fissure" gold ore. This ore-forming process could be called the coupling mechanism of ore formation.

In situ Hydrothermal Oxidation of Ternary FeCoNi Alloy Electrode for Overall Water Splitting

Exploring noble metal-free catalyst materials for high efficient electrochemical water splitting to produce hydrogen is strongly desired for renewable energy development.In this article,a novel bifunctional catalytic electrode of insitu-grown type for alkaline water splitting based on FeCoNi alloy substrate has been successfully prepared via a facile one-step hydrothermal oxidation route in an alkaline hydrogen peroxide medium.It shows that the matrix alloy with the atom ratio 4∶3∶3 of Fe∶Co∶Ni can obtain the best catalytic performance when hydrothermally treated at 180℃for 18 h in the solution containing 1.8 M hydrogen peroxide and 3.6 M sodium hydroxide.The as-prepared Fe_(0.4)Co_(0.3)Ni_(0.3)-1.8 electrode exhibits small overpotentials of only 184 and 175 mV at electrolysis current density of 10 mA cm^(-2)for alkaline OER and HER processes,respectively.The overall water splitting at electrolysis current density of 10 mA cm^(-2)can be stably delivered at a low cell voltage of 1.62 V.These characteristics including the large specific surface area,the high surface nickel content,the abundant catalyst species,the balanced distribution between bivalent and trivalent metal ions,and the strong binding of in-situ naturally growed catalytic layer to matrix are responsible for the prominent catalytic performance of the Fe_(0.4)Co_(0.3)Ni_(0.3)-1.8 electrode,which can act as a possible replacement for expensive noble metal-based materials.

Geochemistry of hydrothermal gold deposits:A review

Mineral assemblages formed during hydrothermal alteration reflect the geochemical composition of ore-forming fluids. Gold is mainly transported in solution as Au-CI and Au-S complexes. The change of physicochemical conditions such as temperature, pressure, oxygen fugacity, and sulfur fugacity are effective mechanisms for gold precipitation. Gold tends to be concentrated in the vapor phase of fluids at high temperatures and pressures. Au-As and Au-Sb associations are common in gold deposit. Native antimony and/or arsenic -- native gold assemblages may precipitate from hydrothermal fluids with low sulfur fugacity. Hydrothermal fluids forming epithermal gold deposits are Au-saturated in most cases, whereas fluids of Carlin-type are Au-undersaturated. Quasi-steady As-bearing pyrite extracts solid solution Au from hydrothermal fluids through absorption. The capability of As-bearing pyrite to absorb An from under-saturated fluid is the key to the formation of large-scale Carlin-type deposits. With increasing new data, studies on the geochemistry of gold deposits can be used to trace the origin of ore-forming fluids, the source of gold, and the transporting form of Au and other ore-forming elements, such as Si, S, F, Cl, As and Ag.

Using trace elements of magnetite to constrain the origin of the Pingchuan hydrothermal low-Ti magnetite deposit in the Panxi area, SW China

The Pingchuan iron deposit, located in the Yanyuan region of Sichuan Province, SW China, has an ore reserve of 40 Mt with ~60 wt% Fe. Its genesis is still poorly understood. The Pingchuan iron deposit has a paragenetic sequence of an early Fe-oxide–Pyrite stage(Ⅰ) and a late Fe-oxide–pyrrhotite stage(Ⅱ). Stage Ⅰ magnetite grains are generally fragmented, euhedral–subhedral, largesized crystals accompanying with slightly postdated pyrite.Stage Ⅱ magnetite grains are mostly unfragmented, anhedral, relatively small-sized grains that co-exist with pyrrhotite. Combined with micro-textural features and previously-obtained geochronological data, we consider that these two stages of iron mineralization in the Pingchuan deposit correspond to the Permian ELIP magmatism and Cenozoic fault activity event. Both the Stage Ⅰ and Ⅱ magnetites are characterized with overall lower contents of trace elements(including Cr, Ti, V, and Ni) than the ELIP magmatic magnetite, which suggests a hydrothermal origin for them. ‘‘Skarn-like'' enrichment in Sn, Mn, and Zn in the Stage Ⅰ magnetite grains indicate significant material contributions from carbonate wall-rocks due to water–rock interaction in ore-forming processes. Stage Ⅱ magnetite grains contain higher Mn concentrations than Stage Ⅰ magnetite grains, which possibly implies more contribution from carbonate rocks. In multiple-element diagrams, the Stage Ⅰ magnetite shows systematic similarities to Kiruna-type magnetite rather than those from other types of deposits. Combined with geological features and previous studies on oxygen isotopes, we conclude that hydrothermal fluids have played a key role in the generation of the Pingchuan low-Ti iron deposit.

Geochemistry of Rare Earth Elements in Hydrothermal Ore Deposit in Heishan Area,Shaanxi Province

The study on rare earth elements in hydrothermal ore deposit in Heishan area indicates that the REE concentration in rock with very weak negative Ce and Eu anomaly is far higher than those in ore. The REE pattern in ore is characterized by very low REE concentration, typical enrichment in LRE and distinctive negative Eu and Ce anomaly. δ Eu and δ Ce values vary from 0 51～0 6 to 0 71～0 77 and 0 84～0 88 to 0 60～0 78, respectively, as shown in samples from Fe Cu ore to Au ore. Different δ Eu and δ Ce values reveal that temperature gradually decreases and oxygen fugacity gradually increases when ore bearing hydrothermal solution evolves from early to late stage. It is likely that REE in solution is mainly transported in the forms of(RE(CO 3) 3F) 4- , (RE(CO 3)F 2) -, (RE(F,Cl) 2) + , (RE(CO 3) 3) 3- and (RE(CO 3) 4) 5- complexes.

Rare earth element geochemistry of hydrothermal deposits from Southwest Indian Ridge

The REE compositions of hydrothermal deposits and basalt samples from the Southwest Indian Ridge （SWIR） were determined with ICP-MS. The results show that there are significant differences between different types of samples although all samples show relative LREE enrichment. The contents of REE in hydrothermal sulfides and alterated rocks samples are lower （from 7.036× 10^-6 to 23.660×10^-6）, while those in the white chimney deposits are relatively higher （ranging from 84.496 × 10^-6 to 103.511 × 10^- 6）. Both of them are lower than basalts. Chondrite-normalized REE distribution patterns show that sulfides and alterated rocks samples are characterized by significant positive Eu anomalies. On the contrary, white chimney deposits have obvious negative Eu anomalies, which may be caused by abundant calcite existing in the white chimney samples. Both the content and distribution pattern of REE in sulfides suggest that REE most possibly is originally derived from hydrothermal fluids, but influenced by the submarine reducing ore-forming environment, seawater convection, mineral compositions as well as the constraint of mineral crystallizations.

Lincang Superlarge Germanium Deposit in Yunnan Province,China: Sedimentation,Diagenesis,Hydrothermal Process and Mineralization

The mineralization is related closely to sedimentation, diagenesis and hydrothermal processes. In this paper, investigations are carried out on coal occurrence, maceral composition, inorganic minerals, trace elements and huminite reflectance. It is concluded that the source of Lincang superlarge deposit is mainly the muscovite granite in the west edge of the basin. During sedimentation, Ge (germanium) was leached out and entered the basin. Ge was adsorbed by lower organism and humic substances in water. Lincang lignite underwent three thermal processes: peatification, early diagenesis and hydrothermal transformation. During peatification, Ge was adsorbed or complexed by humic colloids. During early diagenesis, the Ge associated with humic acids was hard to mobilize or transport. Most of Ge entered the structure of huminite while a small amount of Ge was associated with residual humic acids as complex or humate. During hydrothermal transformation, the heated natural water or deep fluid from basement encountered the coal layer within tectonic weak zone. SO 2- 4 was reduced by coal organic matter. Pyrite and calcite formed. Hydrothermal process did not contribute significantly to mineralization.

Numerical simulation of hydrothermal mineralization associated with simplified chemical reactions in Kaerqueka polymetallic deposit, Qinghai, China

The Kaerqueka polymetallic deposit, Qinghai, China, is one of the typical skarn-type polymetallic ore deposits in the Qimantage metallogenic belt. The dynamic mechanism on the formation of the Kaerqueka polymetallic deposit is always an interesting topic of research. We used the finite difference method to model the mineralizing process of the chalcopyrite in this region with considering the field geological features, mineralogy and geochemistry. In particular, the modern mineralization theory was used to quantitatively estimate the related chemical reactions associated with the chalcopyrite formation in the Kaerqueka polymetallic deposit. The numerical results indicate that the hydrothermal fluid flow is a key controlling factor of mineralization in this area and the temperature gradient is the driving force of pore-fluid flow. The metallogenic temperature of chalcopyrite in the Kaerqueka polymetallic deposit is between 250 and 350 ℃. The corresponding computational results have been verified by the field observations. It has been further demonstrated that the simulation results of coupled models in the field of emerging computational geosciences can enhance our understanding of the ore-forming processes in this area.

DISCOVERY AND THE IMPLICATION OF A HYDROTHERMAL-METASOMATIC SKARN DEPOSIT IN GANGDISE TECTONIC ZONE,TIBET

Hydrothermal activity from a hydrothermal circulatory system is a special geological event, it is of importance to the formation of some massive sulfide deposits (hydrothermal deposits). The Authors think that Jiama polymetallic ore deposit in Gangdise tectonic zone, Tibet is a special skarn deposit i.e. a “hydrothermal\|metasomatic skarn deposit" bound up with benthonic hydrothermal circulatory system. Its important characteristics are as follows: 1 Evolution of the Gangdise island arc in studied area may be divided into three stages Middle Jurassic volcanic arc stage; Middle—Late Jurassic and Early Cretaceous inter arc sedimentary basin stage; and Eogene magmatic arc stage. The deposit is confined to the inter arc sedimentary basin. Existing data indicate that the volcanic arc provided Jiama deposit with abundant ore\|forming material; the inter arc sedimentary basin provided Jiama deposit with absolutely necessary space; the magmatic arc created reconcentration condition for the Jiama deposit.

Double Convective Hydrothermal System beneath Massive Sulfide Orebody in Gacun Deposit,Southwestern China

The Gacun Kuroko-type deposit, Southwestern China, is hosted in rhyolitic rocks associated with the underlying mafic rocks occurred in the - 1000 m deep fault - bounded basin within the intra -arc rifting zone which formed on the Triassic Yidun island - arc. Two vertically separated alteration systems are recognized: one is conformable or semiconformable alteration zone developed in - 150 m thick mafic unit 1-1.5 km below the massive sulfide ore body; the other is discordant alteration pipe directly surrounded around stockwork ore within rhyolitic unit. The lower conformable alteration zone extending for several kilometers along strike is characterized by silicification and epidotization which result in the development of quartz vein and quartz-epidote vein systems in mafic lava flows and replacement of primary minerals and groundmass in spilitized mafic volcanics and dikes by quartz, epidote - group minerals and sodic plagioclase. Sulfides often occur in the vein system and altered mafic volcanics. Quartz solubility relation indicates that silicification is a consequence of interaction of Si- saturated fluids with mafic rocks in a higher temperature system (T>340℃), intensifying by intrusion of mafic dike or high-level acidic magma chamber. The alteration pipe of diameter about 2 km shows a similar mineralogical zoning to Kuroko deposits of Japan. The sequence is quartz + hyalophane; sericite + chlorite + quartz and zeolite-like zones from core to margins of the pipe. The chlorite core only occurs in the root part of the alteration pipe and downwards transfers into epidote - chlorite and epidote - quartz vein swarm extending 500 m downwards. The felsic rocks away from the orebody and alteration pipe took place district-scale alteration, which has typical low-temperature mineral association: illite + albite + quartz + calcite. Whole -rock and quartz δ18O values indicate that district - scale alteration is a result of interaction of seawater with rocks at lower temperature (T<200℃)under water-dominated condition. However, the altered rocks from the pipe show remarkably δ18O enrichment, and bulk -rock δ18O values decreased gradually toward stockwork orebody from 15.1‰-l5. 75‰ in zeolite-like zone and 12. 05‰-14. 2‰ in sericite - quartz zone to 11.3 ‰ - 14. 4‰ in quartz - hyalophane zone. The filled temperatures of fluid inclusions in quartz and sphalerite lie in the ranges of 280 -320 ℃ for quartz - hyalophane zone and 250 ℃ to 297 ℃ for sericite-quartz zone. The estimated δ18O values of hydrothermal fluids are 7. 98‰ and3.2‰, respectively, based on quartz δ18O data in the deposit. The lower conformable alteration is considered to be approximately coeval with the alteration pipe, based on the SiO2 concentration in the fluids, which restrict the main fluid - rock reaction zone to be located in mafic horizon by quartz barometer, and metal element flux calculation and sulfide - epidote vein system developed both in alteration systems. High - salinity fluid inclusions in gangue quartz (>8% eq. NaCl) from stockwork ore and in quartz phenocryst (>40% eq. NaCl) in footwall rhyolite strongly suggest the existence of hot-saline brine to react with mafic complex and leach metal components, which probably originates mainly from magmatic fluid derived from high-level acidic magma chamber. The brine layer located in mafic unit possibly heats and drives the overlying single -pass convective seawater reacting with felsic rocks. The 'density window' may be expected to occur on the interface between seawater and brine layer, when the brine becomes to be gravitationally instability by the turbulent entrainment of seawater during magmatic and/or tectonic activities. The sulfide mineralization and alteration pipe is inter preted as an effect of the 'density window' through which the mixed fluids of brine with seawater adiabatically discharges upwards.

Hydrothermal Sedimentary Mineralization of the Super-large Bamianshan Fluorite Deposit in Zhejiang Province, China

The Bamianshan fluorite deposit is a super-large one recently discovered in Zhejiang Province of China. This paper presents an analysis of its geological background, orebody and ore characteristics, petrochemical characteristics of host rocks, rare earth elements （REE） of rocks and ores, fluid inclusions in fluorite and Sm-Nd isotopic features in an effort to study its sedimentary mineralization. The result shows that the super-large Bamianshan fluorite deposit is of hydrothermal sedimentation genesis, deformed by the later hydrothermal fluid. Integrated with host rocks and orebody characteristics, it is inferred that the deposit originates from the Cambrian sedimentary rocks. And the later magmatic activities deformed some orebodies in different degrees, forming steeply dipping vein orebodies in the tectonic belts regionally.

In-situ deposition of apatite layer to protect Mg-based composite fabricated via laser additive manufacturing

Biodegradable magnesium(Mg) and its alloy show huge potential as temporary bone substitute due to the favorable biocompatibility and mechanical compatibility. However, one issue deserves attention is the too fast degradation. In this work, mesoporous bioglass(MBG)with high pore volume(0.59 cc/g) and huge specific surface area(110.78 m^(2)/g) was synthesized using improved sol-gel method, and introduced into Mg-based composite via laser additive manufacturing. Immersion tests showed that the incorporated MBG served as powerful adsorption sites, which promoted the in-situ deposition of apatite by successively adsorbing Ca2+and HPO42-. Such dense apatite film acted as an efficient protection layer and enhanced the corrosion resistance of Mg matrix, which was proved by the electrochemical impedance spectroscopy measurements. Thereby, Mg based composite showed a significantly decreased degradation rate of 0.31 mm/year. Furthermore,MBG also improved the mechanical properties as well as cell behavior. This work highlighted the advantages of MBG in the fabrication of Mg-based implant with enhanced overall performance for orthopedic application.

On Optimal Frequencies of Acoustic in-situ Detector for Seafloor Hydrothermal Vents

The approach to determine working frequencies of acoustic in-situ detector for seafloor hydrothermal fluid is presented. Based on the research of deep-sea noise and the sound generated by mid-ocean ridge black smoker hydrothermal vents, and on the hydrothermal-vent animal hearing ranges, coupled with influences of suspended particles of hydrothermal on acoustic attenuation under different frequencies, the optimal frequency range for detection of acoustical signal near black smokers is determined. The optimal frequencies providing the maximum ratio of receiver signal to background noise are obtained. We have developed a laboratory experimental setup for the optimal frequencies selection. In particular, we evaluated time-of-flight performance with respect to the source signal parameters of center frequency and bandwidth. The experimental results confirm the effectiveness of our approach. Current results indicate that individual transducers operated in the range of 18 - 25 kHz are immune to most interfering sounds and suitable for our system.

Negative Haloes and Geochemical Field Systems of Hydrothermal Deposits

Primary haloes of hydrothermal deposits were previously considered as positive haloes. Although it has been recently suggested that primary haloes incude positive and negative ones, almost all the research work on primary haloes has still focused on positive haloes for various reasons. In order to understand the source of ore substances a number of large hydrothermal deposits related to magmatism including porphyry, skarn and vein type deposits have been studied. It has been found that negative haloes exist on the peripheries of positive haloes of a mineral deposit. On the basis of the study the authors propose the concept of the geochemical field system of ore-forming elements of hydrotherreal deposits, i. e., with the orebody as the centre outwards there occur the mineralized field, positive halo field, depleted field and background field successively.

In-situ hydrothermal synthesized γ-Al_2O_3/O-g-C_3N_4 heterojunctions with enhanced visible-light photocatalytic activity in water splitting for hydrogen

In this work, γ-Al2O3and hydrogen peroxide treated g-C3N4(O-g-C3N4) were combined through a novel in-situ hydrothermal method to form heterojunction structured photocatalysts. These photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy and photoluminescence spectroscopy (PL). FT-IR results indicate that oxygen functional groups can be grafted on the surface of O-g-C3N4by hydrogen peroxide treatment. The visible light photocatalytic hydrogen evolution rate was investigated in 10 vol% TEOA aqueous solution. The optimal Al2O3mass content is set to be 20 wt% and the corresponding hydrogen evolution rate is 1288 µmol/h/g which is approximately 6, 3 folds that of pristine g-C3N4and O-g-C3N4respectively and 1.6 folds that of mechanical mixed composite with the same Al2O3mass content. The photocurrent density–time curves were carried out under visible light illumination for four on–off cycles. The electrochemical impedance spectroscopy (EIS) measurements verified the enhanced separation efficiency of electron–hole pairs. This work raised a new method to form the heterojunction structured photocatalysts and achieved a remarkable improvement of the photocatalytic activity in water splitting for hydrogen under visible light irradiation. © 2016

Metallogenic Regularity of Hydrothermal Uranium Deposits in the Migmatite of the Kangdian Axis

1 Introduction The Kangdian axis is an important polymetallic metallogenic belt in Southwest China,and it is also an area with a lot of hydrothermal uranium mineralization(Wang Hongjun,et al.,2009.The basic

Magmatic Hydrothermal Origin of the Wenyu Copper Polymetallic Deposit, Southern Lancangjiang Zone, SW China

The Wenyu copper polymetallic deposit, with proven reserves of about 0.23 Mt Cu, 394 t Ag and 0.04 Mt Pb, is located in the central part of the Lancangjiang volcanic rock belt （Fig. l a）, which is one of the most potential copper polymetallic exploration areas in SW China.

Hydrothermal alteration processes in the giant Dahutang tungsten deposit, South China: Implications from litho-geochemistry and mass balance calculation

The giant Dahutang tungsten(W)deposit has a total reserve of more than 1.31 Mt WO3.Veinlet-disseminated scheelite and vein type wolframite mineralization are developed in this deposit,which are related to Late Mesozoic biotite granite.Four major types of alterations,which include albitization,potassic-alteration,and greisenization,and overprinted silicification developed in contact zone.The mass balance calculate of the four alteration types were used to further understanding of the mineralization process.The fresh porphyritic biotite granite has high Nb,Ta,and W,but low Ca and Sr while the Jiuling granodiorite has high Ca and Sr,but low Nb,Ta,and W concentrations.The altered porphyritic biotite granite indicated that the Nb,Ta,and W were leached out from the fresh porphyritic biotite granite,especially by sodic alteration.The low Ca and Sr contents of the altered Neoproterozoic Jiuling granodiorite indicate that Ca and Sr had been leached out from the fresh granodiorite by the fluid from Mesozoic porphyritic biotite granites.The metal W of the Dahutang deposit was mainly derived from the fluid exsolution from the melt and alteration of W-bearing granites.This study of alteration presents a new hydrothermal circulation model to understand tungsten mineralization in the Dahutang deposit.

In-situ wafer bowing measurements of GaN grown on Si(111) substrate by reflectivity mapping in metal organic chemical vapor deposition system

In this work, the wafer bowing during growth can be in-situ measured by a reflectivity mapping method in the 3×2 Thomas Swan close coupled showerhead metal organic chemical vapor deposition（MOCVD） system. The reflectivity mapping method is usually used to measure the film thickness and growth rate. The wafer bowing caused by stresses（tensile and compressive） during the epitaxial growth leads to a temperature variation at different positions on the wafer, and the lower growth temperature leads to a faster growth rate and vice versa. Therefore, the wafer bowing can be measured by analyzing the discrepancy of growth rates at different positions on the wafer. Furthermore, the wafer bowings were confirmed by the ex-situ wafer bowing measurement. High-resistivity and low-resistivity Si substrates were used for epitaxial growth. In comparison with low-resistivity Si substrate, Ga N grown on high-resistivity substrate shows a larger wafer bowing caused by the highly compressive stress introduced by compositionally graded Al Ga N buffer layer. This transition of wafer bowing can be clearly in-situ measured by using the reflectivity mapping method.