carbonate

摘要： Carbonate-modified metal-support interfaces allow Ru/MnCO_(3) catalyst to exhibit over 99% selectivity,great specific activity and long-term anti-CO poisoning stability in atmospheric CO_(2) methanation.As a contrast,Ru/MnO catalyst with metal-oxide interfaces prefers reverse water-gas shift rather than methanation route,along with a remarkably lower activity and a less than 15% CH_(4) selectivity.The carbonatemodified interfaces are found to stabilize the Ru species and activate CO_(2) and H_(2) molecules.Ru-CO^(4) species are identified as the reaction intermediates steadily formed from CO_(2) dissociation,which show moderate adsorption strength and high reactivity in further hydrogenation to CH_(4),Furthermore,carbonates of Ru/MnCO_(3) are found to be consumed by hydrogenation to form CH_(4) and replenished by exchange with CO_(2),which are in a dynamic equilibrium during the reaction.Modification with surface carbonates is proved as an efficient strategy to endow metal-support interfaces of Ru-based catalysts with unique catalytic functions for selective CO_(2) hydrogenation.

摘要： Carbonate was added to the silicate system electrolyte to improve the corrosion resistance of the plasma electrolytic oxidation coating on Mg-9Li-3Al(wt%,LA93)alloy.The influences of carbonate on the morphology,structure,and phase composition of the coating were investigated by scanning electron microscopy,energy dispersive spectrometry,X-ray diffraction,and X-ray photoelectron spectroscopy.The corrosion resistance of the coating was evaluated by electrochemical experiment,hydrogen evolution,and immersion test.The results showed that the addition of carbonate resulted in a denser coating with increased hardness,and the corrosion-resistant Li_(2)CO_(3) phase was formed.Electrochemical experiments showed that compared with the coating without carbonate,the corrosion potential of the carbonate coating positively shifted(24 mV),and the corrosion current density was reduced by approximately an order of magnitude.The coating with carbonate addition possessed a high corrosion resistance and long-term protection capability.

摘要： Precipitation was carried out to obtain manganese carbonate by adding a precipitating agent, sodium carbonate (NaCO3). This was followed by calcination of the manganese carbonate (MnCO3) to obtain manganese dioxide (MnO2). For precipitation tests, a pH ranging from 8 to 10, a time of one to two hours, and a temperature of 25°C and 50°C are the parameters that are considered. The calcination of MnCO3 is carried out under the following conditions: time (1, 2, 3, and 4 hours) and temperature (370°C, 420°C, and 470°C). It should be noted that the temperature range selected for the calcination tests is based on thermodynamic data obtained using the HSC CHEMISTRY software. The results obtained show an effective recovery of manganese at 25°C, in one hour, with a pH of 8.5 with a precipitation yield and manganese content in the precipitate around 98.43% and 24.21%, respectively. During calcination tests, results show an increase in mass loss, for a constant calcination time, as temperature increases. On the other hand, increasing the calcination time at a given temperature causes an increase in mass loss. However, a significant decrease in mass loss is noted at 3 hours of calcination. The highest mass loss is obtained at a temperature of 470°C after 4 hours of calcination.

摘要： To solve the problem that it is difficult to identify carbonate low resistivity pays(LRPs) by conventional logging methods in the Rub Al Khali Basin, the Middle East, the variation of fluid distribution and rock conductivity during displacement were analyzed by displacement resistivity experiments simulating the process of reservoir formation and production, together with the data from thin sections, mercury injection and nuclear magnetic resonance experiments. In combination with geological understandings, the genetic mechanisms of LRPs were revealed, then the saturation interpretation model was selected, the variation laws and distribution range of the model parameters were defined, and finally an updated comprehensive saturation interpretation technique for the LRPs has been proposed. In the study area, the LRPs have resistivity values of less than 1 Ω·m, similar to or even slightly lower than that of the water layers. Geological research reveals that the LRPs were developed in low-energy depositional environment and their reservoir spaces are controlled by micro-scale pore throats, with an average radius of less than 0.7 μm, so they are typical microporous LRPs. Different from LRPs of sandstone and mudstone, they have less tortuous conductive paths than conventional reservoirs, and thus lower resistivity value under the same saturation. Archie’s formula is applicable to the saturation interpretation of LRPs with a cementation index value of 1.77-1.93 and a saturation index value of 1.82-2.03 that are 0.2-0.4 lower than conventional reservoirs respectively. By using interpretation parameters determined by classification statistics of petrophysical groups(PGs), oil saturations of the LRPs were calculated at bout 30%-50%,15% higher than the results by conventional methods, and basically consistent with the data of Dean Stark, RST, oil testing and production. The 15 wells of oil testing and production proved that the coincidence rate of saturation interpretation is over 90%and the feasibility of this method has been further verified.

摘要： The continental hydrocarbon generation theory has opened a new field of oil and gas development and once solved the oil and gas shortage problem in China.Since then,geological theories of coalbed methane accumulation,foreland basin oil and gas accumulation,carbonate rock oil and gas accumulation,superimposed basin,and deep oil and gas accumulation have contributed to relieving the pressure of oil and gas shortage in China.

摘要： Melt inclusions in kimberlitic minerals and diamonds indicate that chlorides are important constituents of mantle carbonatite melts.Besides,alkaline chlorides are important constituents of saline high-density fluids(HDFs)found in diamonds from kimberlites and placers around the world.Continuous compositional variations suggest that saline and carbonatitic HDFs could be genetically linked.However,the essence of this link remains unclear owing to the lack of data on phase relations in the chloridecarbonate systems under pressure.Here we studied subsolidus and melting phase relations in the system NaCl–CaCO_(3)–MgCO_(3)at 6 GPa and 1000–1600°Cusing a Kawai-type multianvil press.We found that at 1000°C,subsolidus assemblage consists of halite,magnesite,and aragonite.At higher temperatures,the stabilization of dolomite splits the subsolidus area into two partial ternary fields:halite+magnesite+dolomite and halite+dolomite+aragonite.The minimum on the liquidus surface corresponds to the halite-dolomite-aragonite ternary eutectic,situated at 1100°C.The eutectic melt has Ca#89 and contains 30 wt.%Na Cl(26 mol%2NaCl).The system has two ternary peritectics:halite+dolomite=magnesite+liquid located near the ternary eutectic and magnesite+dolomite=Mg-dolomite+liquid situated between 1300 and 1400°C.Although under dry conditions incipient melting yields carbonatedominated melt,the addition of water facilitates the fusion of Na Cl and expands the liquid field to Na Cl-rich compositions with up to 70 wt.%Na Cl.The obtained results favor the idea that hydrous saline melts/fluids(brines)found as inclusions in diamonds could be a lower temperature derivative of mantle carbonatite melts and disagree with the hypothesis on chloride melt generation owing to the chloridecarbonate liquid immiscibility since no such immiscibility was established.We also studied the interaction of the NaCl–CaCO_(3)–MgCO_(3)system with iron metal and found that carbonate reduction produces Cbearing species(Fe~0,Fe-C melt,Fe_(3)C,Fe_(7)C_(3),C~0)and wüstite containing Na2O,CaO,and MgO.Besides,a carbonate chloride compound,Ca2Cl2CO3,was established among the reaction products.The interaction between Na Cl-bearing carbonate melt shifts its composition toward Mg-poor and Na Cl-rich.Given the above,an alternative hypothesis can be proposed,according to which the interaction of alkaline chloride-bearing carbonate melts formed in the subduction zones with the reduced mantle should be accompanied by diamond crystallization and shift the composition of the melt from carbonatitic to alkali-rich saline.

摘要： The Ordovician fracture-vug carbonate reservoirs of Tarim Basin,are featured by developed vugs,caves and fractures.The strong heterogeneity results in huge uncertainty when these reservoirs are quantitatively characterized using merely static seismic data.The effective quantitative characterization of the reservoirs has been an urgent problem to be solved.This study creatively proposes the"second quantitative characterization"technique with the combination of dynamic and static data based on the primary static quantitative characterization and fully considering lots of key influence factors when conducting characterization.In this technique,dynamic analysis methods such as well testing,production rate transient analysis,dynamic reserve evaluation and dynamic connectivity evaluation are used to get understandings on this kind of reservoir.These understandings are used as statistical parameters to constrain the inversion of seismic wave impedance to improve the relationship between wave impedance and porosity and determine the fracture-vug morphology,calculate dynamic reserves,and then a more accurate fracture-vugmodel can be selected and used to calculate the oil-water contact inversely based on the results of"second quantitative characterization".This method can lower the uncertainties in the primary quantitative characterization of fracture-vug reservoirs,enhance the accuracy of characterization results significantly,and has achieved good application results in the fracture-vug carbonate reservoirs of Tarim Basin.

摘要： Sperm fertility and motility requires the presence of a functional flagellum to act as a motor to enable sperms to move in fluids.Cyclic adenosine monophosphate(cAMP),as a regulator of many biological pathways,contributes in mammalian sperms to the production of soluble adenyl cyclase,a process which is regulated through Ca2+and HCO3-dependent mechanisms and triggers widespread physiological alterations essential to sperm viability.The aim of this study was to investigate the effect of sodium hydrogen carbonate(NaHCO3)on human sperm adenylyl cyclase activity.Studies show that flagellum is essential for sperms to keep their motility.Furthermore,multiple cellular and molecular players and pathways(i.e.,capacitance)are critical for normal maturation of sperms in final stages[1].Sperm capacity is an incorrect maturation process observed in the female reproductive system or can be tested in specific environments,the end point of which has been shown to allow the sperm to withstand the acrosome reaction and fertilize the egg.Interactions between membrane components(e.g.,ion channels)and intracellular skeletal proteins are strictly regulated and are important for promoting these signaling pathways.

摘要： Pepsi,a drink for indigestion百事,一种治疗消化不良的饮料Like many other carbonated drinks,Pepsi began to be sold as a remedy for indigestion.Pharmacist Caleb Bradham prepared it in the soda fountain of his pharmacy using a mixture of sugar,caramel,water,lemon oil,kola nuts,and nutmeg.The original name was"Brad’s Drink",which he sold with the slogan:Exhilarating,Invigorating,Aids Digestion.

摘要： Objective The Zhangjiawa iron deposit is the largest-tonnage and representative iron skarn deposit,with proven reserves of 290 Mt at an average of 46%Fe(up to>65%),in the Laiwu district,eastern North China Craton(NCC)(Figs.1 a,b;Duan and Li,2017).Iron mineralization at Zhangjiawa is mainly hosted along a northern contact zone between the Kuangshan dioritic intrusion and Middle Ordovician carbonate rocks that host numerous evaporite intercalations(Figs.1b,c).

摘要： Paper developed fluid sensitive experiments basing on the cores of carbonate reservoir with high content H2S and CO2 gas in Kazakhstan Zhanazhol, middle and northeast parts of Sichuan Basin of China. Results show there is certain level fluids sensitivity in cores, and alkali sensitivity is the most serious. Petrography analysis that dolomite, calcite, microcrystalline quartz, gypsum, illite, CaS, asphalt are common in the study area carbonate reservoir. Alkali working fluids intrude into reservoir, change reservoir original acidic environment. Alkali working fluids consumption of acidic and destruction rock interface, resulting more sensitive mineral exposure and physical and chemical changes occur, which cause more serious formation damage. Alkali fluids intrusive, cause sulfur deposition. Based on such formation damage mechanism, the article says to vigorously develop technology of temporary shielding.