Numerical modeling of fracture propagation of supercritical CO_(2)compound fracturing

The exploitation of shale gas is promising due to depletion of the conventional energy and intensification of the greenhouse effect.In this paper,we proposed a heat-fluid-solid coupling damage model of supercritical CO_(2)(SC-CO_(2))compound fracturing which is expected to be an efficient and environmentally friendly way to develop shale gas.The coupling model is solved by the finite element method,and the results are in good agreement with the analytical solutions and fracturing experiments.Based on this model,the fracture propagation characteristics at the two stages of compound fracturing are studied and the influence of pressurization rate,in situ stress,bedding angle,and other factors are considered.The results show that at the SC-CO_(2)fracturing stage,a lower pressurization rate is conducive to formation of the branches around main fractures,while a higher pressurization rate inhibits formation of the branches around main fractures and promotes formation of the main fractures.Both bedding and in situ stress play a dominant role in the fracture propagation.When the in situ stress ratio(δ_(x)/δ_(y))is 1,the presence of bedding can reduce the initiation pressure and failure pressure.Nevertheless,it will cause the fracture to propagate along the bedding direction,reducing the fracture complexity.In rocks without bedding,hydraulic fracturing has the lengthening and widening effects for SC-CO_(2)induced fracture.In shale,fractures induced at the hydraulic fracturing stage are more likely to be dominated by in situ stresses and have a shorter reorientation radius.Therefore,fracture branches propagating along the maximum principal stress direction may be generated around the main fractures induced by SC-CO_(2)at the hydraulic fracturing stage.When the branches converge with the main fractures,fracture zones are easily formed,and thus the fracture complexity and damage area can be significantly increased.The results are instructive for the design and application of SC-CO_(2)compound fracturing.

Nickel(II)-Catalyzed Reductive Coupling of Xanthate Esters with Sulfur-Containing and Selenium-Containing Compounds:Synthesis of Unsymmetric Sulfides and Selenides

Unsymmetric sulfides and selenides have great applications in the pharmaceutical field.Herein,we describe the reductive coupling reaction of xanthate esters with sulfur-containing and selenium-containing compounds(thio(seleno)sulfonates and disulfides(selenides))under the nickel-catalyzed condition.It provides a mild and effective method for the synthesis of unsymmetric sulfides and selenides which has the advantages of mild reaction conditions,high yields and a wide range of substrates.

Advanced Technologies for Volatile Organic Compound (VOC) Emission Treatment: An Overview

This paper presents a comprehensive overview of various advanced technologies employed in the treatment of volatile organic compounds(VOCs),which are crucial pollutants in industrial emissions.The study explores different methods,including direct combustion,thermal combustion,catalytic combustion,low-temperature plasma purification,photocatalytic purification,membrane separation,and adsorption methods.Each technology is critically analyzed for its operational principles,efficiency,and applicability under different conditions.Special attention is given to adsorption concentration and catalytic combustion parallel method,highlighting its efficiency in treating low-concentration,high-volume VOC emissions.The paper also delves into the advantages and limitations of each method,providing insights into their effectiveness in various industrial scenarios.The study aims to offer a detailed guide for selecting appropriate VOC treatment technologies,contributing to enhanced environmental protection and sustainable industrial practices.

ONE-CELL-STATE METHOD FOR DETERMINATION OF ELECTRONIC STRUCTURE OF INTERMETALLIC COMPOUNDS

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A meshless method for the compound KdV-Burgers equation

The element-free Galerkin （EFG） method for numerically solving the compound Korteweg-de Vries-Burgers （KdVB） equation is discussed in this paper. The Galerkin weak form is used to obtain the discrete equation and the essential boundary conditions are enforced by the penalty method. The effectiveness of the EFG method of solving the compound Korteweg-de Vries-Burgers （KdVB） equation is illustrated by three numerical examples.

Synthesis of Substituted u-Oxo-bis[tetra-phenyl porphyrinatoiron] Compounds from Free Base Porphyrins by a One-pot Method

A novel method for synthesis of substituted u-oxo-bis[tetraphenyl porphyrinatoiron] compotmds （[TRPPFe]20） based on the reaction among free base porphyrins （TRPPH2）, FeSO4·7H2O and H2O in one pot was proposed and investigated. Four kinds of [TRPPFe]2O were synthesized by this novel synthetic method, and their structures were characterized by elemental analysis, infrared spectra and UV-vis spectroscopy. The reaction conditions, including the effect of different iron salts on the formation of [TRPPFe]2O, the reaction time between FeSO4-7H2O and TRPPH2, the molar ratio of FeSO4-7H2O/TRPPH2 as well as the volume ratio of H2O/DMF, were investigated. The [TRPPFe]2O yield of 93% 98% could be obtained under the following optimal conditions： the reaction time of FeSOn-7H2O with TRPPH2 was about 10 h, the molar ratio of FeSOn-7H2O/TRPPH2 about 5 ： 1, and the volume ratio of H2O/DMF exceeded 2 ： 1. Further research indicated that only TRPPFeCI were formed once FeSOn-7H2O was replaced by FeCl2-4H2O, the reason of which might be that halogen ions in iron salts interfered the formation of [TRPPFe]2O, suggesting that halogen ions should be avoided in this novel synthetic method.

Characterization and ultraviolet-visible shielding property of samarium-cerium compounds containing Sm_(2)O_(2)S prepared by co-precipitation method

Since ultraviolet(UV)light,as well as blue light,which is part of visible light,is harmful to skin,samarium-cerium compounds containing Sm_(2)O_(2)S were synthesized by co-precipitation method.This kind of compounds blocks not only UV light,but also blue light.The minimum values of average transmittance(360-450 nm)and band gap of samarium-cerium compounds were 8.90%and 2.76 eV,respectively,which were less than 13.96%and 3.01 eV of CeO_(2).Elemental analysis(EA),X-ray diffraction(XRD),Fourier transformation infrared(FTIR),and Raman spectra determined that the samples contained Ce_(4)O_(7),Sm_(2)O_(2)S,Sm_(2)O_(3),and Sm_(2)O_(2)SO_(4).The microstructure of samples was analyzed by scanning and transmission electron microscopies(SEM and TEM).X-ray photoelectron spectrum(XPS)showed that cerium had Ce^(3+)and Ce^(4+) valence states,and oxygen was divided into lattice oxygen and oxygen vacancy,which was the direct cause of the decrease of average transmittance and band gap.

Mobile Equilibrium Method for Determining Composition and Stability Constant of Coordination Compounds of the Form M_mR_n

A new method is proposed for determining the composition and stability constant of coordination compounds of the form M m R n ; it can be used to differentiate mono and poly nuclear coordination compounds. The equation derived is lg( A i/(A max - A i) m)=n lg c′ R+lg( m·β(c M/A max ) ( m -1) ). The method is based on Bent French limited logarithm method. The demonstration of the proposed method has yielded correct results for Sc 3+ chlorophosphonazo Ⅲ system and Fe 3+ Chromazurol S system.

Validation for Microbial Limit Test Method of Compound Yu E Nose Drops

[Objectives] This study was conducted to establish a method for microbial limit test of Compound Yu E Nose Drops.[Methods] According to the Chinese Pharmacopoei (General Rules in the fourth part of the 2015 edition),the microbial limit test method for Compound Yu E Nose Drops was verified.[Results] Compound Yu E Nose Drops has a strong inhibitory effect on Staphylococcus aureus and Bacillus subtilis,and the inhibitory activity was significantly eliminated after increasing the diluent (1∶ 20).The recoveries were all in the range of 0.5-2.0 when the total quantities of aerobic microbes were determined by the dilution method (1∶ 20).When the total quantities of mould and yeast were determined by the conventional method,the recoveries were both in the range of 0.5-2.0.When examining control bacteria,Escherichia coli,S.aureus and Pseudomonas aeruginosa can all be detected in the test groups by the test liquid dilution method.[Conclusions] For Compound Yu E Nose Drops,the total quantities of aerobic microbe can be counted by the dilution method;the quantities of mould and yeast can be examined by the conventional plate method;and the conventional method can be used for control microbe examination.

Discussion on the Quality Evaluation Method of Traditional Chinese Medicine Compound Preparations

As an important representative of the modernization of the Chinese medicine industry,traditional Chinese medicine(TCM)compound preparations are an indispensable part of the development of TCM.The complex ingredients and unclear action mechanism of TCM compound preparations restrict the development of TCM.In line with this problem,the modern TCM research has made extensive remarkable achievements.From the single indicator in the past to multiple indicator,the research on the combination of TCM fingerprints and pharmacodynamics also has made great progress.The introduction of quality evaluation methods such as the"quantitative analysis of multi-components by a single marker","dose-effect"indicator,"Bioactive Equivalent Combinatorial Components"(BECCs)and TCM quality markers have brought new ideas for quality control of TCM compound preparations.

Numerical Simulation of Aerodynamic Interaction Effects in Coaxial Compound Helicopters

The so-called coaxial compound helicopter features two rigid coaxial rotors,and possesses high-speed capabilities.Nevertheless,the small separation of the coaxial rotors causes severe aerodynamic interactions,which require careful analysis.In the present work,the aerodynamic interaction between the various helicopter components is investigated by means of a numerical method considering both hover and forward flight conditions.While a sliding mesh method is used to deal with the rotating coaxial rotors,the Reynolds-Averaged Navier-Stokes(RANS)equations are solved for the flow field.The Caradonna&Tung(CT)rotor and Harrington-2 coaxial rotor are considered to validate the numerical method.The results show that the aerodynamic interaction of the two rigid coaxial rotors significantly influences hover’s induced velocity and pressure distribution.In addition,the average thrust of an isolated coaxial rotor is smaller than that of the corresponding isolated single rotor.Compared with the isolated coaxial rotor,the existence of the fuselage results in an increment in the thrust of the rotors.Furthermore,these interactions between the components of the considered coaxial compound helicopter decay with an increase in the advance ratio.

A Mapping Method of Using the Compound Use Cases to Generate User Interface

To support the requirement analysis of the user interfaces and the auto generation of the final user interfaces, we should improve the traditional modeling method which centered on the system and the implementation, and turn to use the modeling method which centered on the usage and the user. The compound use cases describe the system function from the user point of view. Based on the compound use cases, we can generate the final user interfaces.

Effect of Different Drying Methods on the Volatile Compounds Jinmudan Oolong Tea

Jinmudan,a new tea variety from Fujian Province has an excellent quality with a unique aroma like magnolia frogrance.To monitor the changes in the tea volatile compounds during the Jinmudan Oolong tea manufacturing(drying) process,the volatiles of tea samples were extracted and analyzed.Characteristic volatile compounds in Jinmudan Oolong tea were nerolidol,α-farnesene,linolenic acid,palmitic acid,indole,phenylacetaldehyde,cisjasmone,β-phenylethanol,etc.The content of nerolidol was the highest in four tested samples.The composition of the volatile compounds in microwave drying sample was simple,but its concentration was high,in which the main volatile compounds were alcohols and esters.The processing with combination of traditional drying craft and modern aroma-improvement technique could obviously improve the tea aroma,especially in level of epoxy linalool and jasmine lactone.

DETERMINATION OF STABILITY CONSTANTS OF THE COORDINATION COMPOUNDS OF Au(Ⅲ)-2-MERCAPTOPYRIDINE-1-OXIDE AND METHYL DERIVATIVES——METHOD OF DUAL-WAVELENGTH CORRESPONDING SOLUTIONS

In this paper,we report the deductive formula used for the method of dual-wavelength corresponding solutions under condition of having ligand interference and the stability constants of three new coordination compounds [AuL_2]^+determined with this method.The stability of the three compounds,the necessity of controlling pH in experimental systems and the advantage of this method are discussed in detail.

A NEW METHOD FOR SYNTHESIS OF O-ISOPROPYL SUBSTITUTED AROMATIC COMPOUNDS

Heteroatom-directed aromatic lithiation reactions used for the regiospecific synthesis of o-isopropyl substituted phenolic and benzyl alcoholic compounds are described.

Study on extracting alumina from fly ash by compound additive activation method

According to the chemical and mineral composition characteristics of the fly ash,alumina can be extracted from fly ash through the calcining method by using sodium carbonate and calcium carbonate additives.The effects on leaching rate of alumina have been investigated. The results showed that the fly ash can be activated effectively and the leaching rate of alumina can be improved to more than 92% through this method. The best process parameters were the ratio of raw materials,i. e. the material weight ratio of fly ash,calcium carbonate and sodium carbonate was 1. 0∶1. 2∶0. 9. The activating temperature was 850℃-900℃,activating time was 3 h. This process has a potential application prospect and improves the value of comprehensive utilization of fly ash.

Validation of Microbial Limit Test Methods of Compound Gangbangui Capsule

[Objectives] This study was conducted to establish a method for microbial limit test of Compound Gangbangui Capsule. [Methods] According to the Chinese Pharmacopoei 2015 edition of the four general rules,the microbiological limits of non-sterile products were verified. [Results]Compound Gangbangui Capsule has a strong inhibitory effect on S. aureus,and the antimicrobial activity was significantly eliminated after increasing the diluent（ 1∶ 20）; and the recoveries were in the range of 0. 5-2. 0 when the total quantities of aerobic microbes were determined by dilution method（ 1∶ 20）. When the total quantities of mould and yeast were determined by conventional method（ 1∶ 20）,the recoveries were from 0. 5 to 2. 0,and Escherichia coli can be detected in experimental groups by the test solution dilution method. [Conclusions]With the plate method,the total quantities of aerobic bacteria and the quantities of mould and yeast were examined by increasing diluent and conventional method,respectively,and control bacteria,E. coli was examined by conventional method. This method has been proved effective for microbial limit test of Compound Gangbangui Capsule,and can effectively control the quality of the preparation. The method is accurate and reliable.