Regulation effect of the grille spacing of a funnel-type grating water–sediment separation structure on the debris flow performance

The size of pores or the grille spacing of water–sediment separation structures directly affects their regulation effect on the debris flow performance.A suitable pore size or grille spacing can effectively improve the water–sediment separation ability of the structure.The new funnel-type grating water–sediment separation structure(FGWSS)combines vertical and horizontal structures and provides a satisfactory water–sediment separation effect.However,the regulation effect of the grille spacing of the structure on the debris flow performance has not been studied.The regulation effect of the structure grille spacing on the debris flow performance is studied through a flume test,and the optimal structure grille spacing is obtained.An empirical equation of the relationship between the relative grille spacing of the structure and the sediment separation rate is established.Finally,the influence of the water–sediment separation structure on the regulation effect of debris flows is examined from two aspects:external factors(properties of debris flows)and internal factors(structural factors).The experimental results show that the gradation characteristics of solid particles in debris flows constitute a key factor affecting the regulation effect of the structure on the debris flow performance.The optimum grille spacing of the FGWSS matches the particle size corresponding to the material distribution curves d85~d90 of the debris flow.The total separation rate of debris flow particles is related to the grille spacing of the structure and the content of coarse and fine particles in the debris flow.

Optimizing extractants selection for efficient separation of phenols and nitrogen-containing heteroaromatics using hydrogen bond interaction strategies

Focusing on the use of imidazolium ionic liquids and quaternary ammonium salts-based deep eutectic solvents for the separation of phenols and nitrogen-containing heteroaromatics,the role of heteroaromatics as specific sites for hydrogen bond-based separation has been investigated.These environmentally friendly solvents are known for their ability to form hydrogen bonds with heteroatoms,a key aspect in separation processes.We quantified the hydrogen bond interaction energy to reach the threshold energy for efficient O-and N-heteroaromatics separation.This article provides an in-depth study of the structural nuances of different hydrogen bonding sites and their affinity properties while conducting a comparative evaluation of the separation efficiency of ionic liquids and deep eutectic solvents from a thermodynamic perspective.Results showed that phenols with dual hydrogen bonding recognition sites were easier to separate than nitrogen-containing heteroaromatics.Imidazolium ionic liquids were more suitable for the extraction of nonbasic nitrogen-containing heteroaromatics,and quaternary ammonium salts-based deep eutectic solvents are more effective for phenols and basic nitrogen-containing heteroaromatics,which was confirmed by Fourier transform infrared spectroscopy and empirical tests.Therefore,this study provides a theoretical basis for the strategy design and selection of extractants for the efficient separation of O-and N-containing aromatic compounds.

Dependence of lithium metal battery performances on inherent separator porous structure regulation

Boosting of rechargeable lithium metal batteries(LMBs) holds challenges because of lithium dendrites germination and high-reactive surface feature.Separators may experience structure-determined chemical deterioration and worsen Li plating-stripping behaviors when smoothly shifting from lithium-ion batteries(LIBs) to LMBs.This study precisely regulations the crystal structure of β-polypropylene and separator porous construction to investigate the intrinsic porous structure and mechanical properties determined electrochemical performances and cycling durability of LMBs.Crystal structure characterizations,porous structure analyses,and electrochemical cycling tests uncover appropriate annealing thermal stimulation concentrates β-lamellae thickness and enhances lamellae thermal stability by rearranging molecular chain in inferior β-lamellae,maximally homogenizing biaxial tensile deformation and resultant porous constructions.These even pores with high connectivity lower ion migration barriers,alleviate heterogeneous Li^(+) flux dispersion,stabilize reversible Li plating-stripping behaviors,and hinder coursing and branching of Li dendrites,endowing steady cell cycling durability,especially at higher currents due to the highlighted uncontrollable cumulation of dead Li,which offers new insights for the current pursuit of high-power density battery and fast charging technology.The suggested separator structure-chemical nature functions in ensuring cyclic cell stability and builds reliable relationships between separator structure design and practical LMBs applications.

FORMATION AND MICROSTRUCTURE OF POLYETHYLENE MICROPOROUS MEMBRANES THROUGH THERMALLY INDUCED PHASE SEPARATION

Microporous membranes of low-high density polyethylene and their blends were prepared bythermally-induced phase separation of polymer/long-aliphatic chain alcohol (diluent) mixtures.The microstructures of this particular membrane, which depends on the diluent properties,polymer concentration and cooling rate, were observed by scanning electron microscopy.'Beehive-type,'leafy-like, and lacy porous structure morphologies can be formed,depending onthe blend composition and phase separation conditions, which were discussed by the polymer anddiluent crystallization processes.

Determination of optimal grid opening width for herringbone water-sediment separation structures based on sediment separation efficiency

The herringbone water-sediment separation structure(HWSSS) was developed to prevent debris flows. This paper mainly focuses on evaluating the sediment separation efficiency of HWSSS in debris flow prevention and determining the grid opening width D, a crucial structure parameter for HWSSS design. Theoretical analysis on the total sediment separation rate Pt reveals that the efficiency of sediment separation is much related with sediment grain size distribution(GSD) and grid opening width. The lower limit of Pt is deduced from the perspective of safety consideration by transforming debris flow into sediment-laden flow. Hydraulic model tests were carried out. Based on the regression analysis of the experimental data, the quantitative relationships between Pt and D and GSD characteristic values were finally established. A procedure for determining optimal grid opening width is proposed based on these analyses. These results are of significance in evaluating sediment separation effect by HWSSS in debris flow prevention and contribute to a more explicit methodology for design of HWSSS.

Support surface pore structures matter: Effects of support surface pore structures on the TFC gas separation membrane performance over a wide pressure range

In this work, the effects of support surface pore structures(including surface pore size, surface pore density and surface porosity) on the performance of thin film composite(TFC) gas separation membrane over a wide pressure range(from 0.3 to 2.0 MPa) were studied. To fulfill it, the polysulfone(PSf) supports with different surface pore structures were prepared. Two kinds of wide-accepted polymeric membrane materials, i.e., polyvinylamine(PVAm) and Pebax 1657 copolymer, were used as skin layer materials. We pointed out for the first time that the support surface average pore size and pore density could affect the chain mobility of polymer of skin layer at the support surface pore entrance, then, can affect the TFC membrane performance. Besides, we also discussed the effects of support on the TFC membrane performance when the feed pressure changes for the first time. This work can provide guidance for choosing a suitable support for TFC gas separation membrane.

Microstructure evolution and liquid phase separation in Ta-O hypermonotectic melts during laser-cladding

A three-layer Ta_2O_5-containing coating was successfully fabricated by laser cladding on a pure Ta substrate. The maximum thickness of such a coating is about 1.6 mm. The microstructure, phase constitution and elemental distribution in the coating were investigated. Results show that the coating has been metallurgically bonded to the Ta substrate and the microstructure exhibits a graded change along the deposition direction from Ta substrate to the top of coating. In the layers I and II of the graded coating, the microstructure evolution can be confi rmed as a result of hypomonotectic reaction, but in the layer Ⅲ it was formed by hypermonotectic reaction. At the top of coating, the microstructure was still homogeneous although liquid phase separation had occurred, which can be attributed to the fact that the O-rich droplets do not have enough time to fl oat at high cooling rate. The theoretical calculation results show that during laser cladding, the solidifi cation time of the melt pool was less than 0.1 s, which fi ts well with the results from the experiment.

Experimental study on large wood filtration performance by herringbone water-sediment separation structure

A herringbone water-sediment separation structure(hereinafter referred to as "herringbone structure") has been shown to be effective in separating coarse inorganic debris; however, less is known regarding the large wood(LW) filtration effect in this structure. This paper presents preliminary research on the wood filtration effect of the herringbone structure based on physical model tests.The results show that the herringbone structure exhibited effective performance in large wood size segregation, with a 100% component filtration rate for LW that diameter(D) larger than ribbed beam opening width(a). The total filtration rate also exceeded 80% when the Fraud number(Fr) is larger than 2.64 and increased with the increase of Fr. After exceeding Frmax, total filtration rate would be decreased due to overflow. Beside flow condition,structure parameters influence significantly on LW filtration rate. We attempt to explain the filtration process via particle contact trajectory and particle movement trajectory. The inclined angle of ribbed beam(γ) contributed the most variation to the filtration rate via influencing the coincidence with particle contact trajectory and particle movement trajectory. The high sensitivity coefficient of ribbed beam(θ) under relatively low Fr conditions implies remarkable influences on LW filtration effects by causing clogging problem. The ribbed beam opening width(a) together with LW diameter(D) influenced the size segregation performance.

Variable separation solutions and new solitary wave structures to the （l＋l）-dimensional Ito system

A variable separation approach is proposed and extended to the （1＋1）-dimensional physics system. The variable separation solution of （1-F1）-dimensional Ito system is obtained. Some special types of solutions such as non-propagating solitary wave solution, propagating solitary wave solution and looped soliton solution are found by selecting the arbitrary function appropriately.

Performance Prediction of Structured Packing Column for Cryogenic Air Separation with Hybrid Model

A detailed investigation of a thermodynamic process in a structured packing distillation column is of great impor- tance in prediction of process efficiency. In order to keep the simplicity of an equilibrium stage model and the accu- racy of a non-equilibrium stage model, a hybrid model is developed to predict the structured packing column in cryogenic air separation. A general solution process for the equilibrium stage model is developed to solve the set of equations of the hybrid model, in which a separation efficiency function is introduced to obtain the resulting tri-diagonal matrix and its solution by the Thomas algorithm. As an example, the algorithm is applied to analyze an upper column of a cryogenic air separation plant with the capacity of 17000 m3·h-1. Rigorous simulations are conducted using Aspen RATEFRAC module to validate the approach. The temperature and composition distributions are in a good agreement with the two methods. The effects of inlet/outlet position and flow rate on the temperature and composition distributions in the column are analyzed. The results demonstrate that the hybrid model and the solution algorithms are effective in analvzin~ the distillation process for a a cryogenic structured packing column.

Optical Separation of Racemic Phenyl-alanine, and Structure of Complex Consisting of R-Phenylalanine and R-Mandelic Acid

The racemic phenylalanine has been separated by (R)-mandelic acid through the formation of diastereomeric molecular complex. The crystal of the title chiral complex (C8H8O3 C9H11NO2, Mr = 317.33) belongs to monoclinic, space group C2 with a = 19.391(3), b = 5.715(4), c = 15.755(3) ? b = 115.23(1), V = 1579(1) 3, Z = 4, Dc = 1.335 g/cm3, F(000) = 672, m = 0.099 mm-1, R = 0.033 and wR = 0.060 for 1278 observed reflections (I > 2s(I)). The complex consists of (R)-mandelic acid and (R)-phenylalanine in 1:1 molar ratio, and the complex molecules form layered crystal structure by self-assembly through intermolecular H-bonding between carboxyl and carboxylate of the neighboring molecules.

Relationship between Pectic Substances and Strand Separation of Cooked Spaghetti Squash--Part 2. Changes in Firmness, Histological Structure and Pectic Substances during Soaking in Pectin Extractants

The flesh of spaghetti squash separates into strands when cooked. The purpose of this paper is to investigate the cause of strand separation （during cooking） by soaking for 24 h at 35 ℃ in solutions with three kinds of pectin extractant. The changes in strand separation, firmness, histological structure and the pectin of flesh during soaking in 0.01 N HCI solution （pH 2.0）, 0.035 M ammonium oxalate solution （pH 4.0） or 2% sodium hexametaphosphate solution （pH 4.0） were investigated. When flesh was soaked in the HCI solution, the separation into strands and removal of calcium and magnesium were greater than that soaked in other pectin extractants. High methoxyl pectin was extracted by soaking in HC1 solution （pH 2.0） due to removal of polyvalent cations. This result shows that high methoxyl pectin glues strands together in the flesh of spaghetti squash. The shape of the cells which constituted strands was round; on the other hand, that of cells surrounded strands was elongated. When cooked in boiling water or soaked at pH 2.0, the shape of the former cells was maintained, but the latter cells, which contributed to adhesion between strands, broke down. Thus, the flesh separated into strands. When flesh was boiled for 15-30 min, pectin degraded and dissolved in the cooking solution; consequently, the flesh separated into strands and also the middle lamella of cell walls of strands separated. However, pectin remaining in strands maintained their crispness.

The Separation of Powers from Functions and the Establishment of a New Structure of Management and Operation of State-owned Assets

The development of the socialist market economy demands the furtherintensification of the reform of the management operating system (MOS)of the state-owned assets, the strengthening of the efficiency in the man-agement of state-owned assets,and the improvement of the operating bene-

Structure identification for compound I separated and purified from taxoids-produced endophytic fungi (Alternaria. alternata var. taxi 1011)

Endophytic fungi are widely found in almost all kinds of plants. Many endophytic fungi can produce some physio-logical active compounds, which are same to or analog to those isolated from their hosts. Producing physiological active com-pounds through microbial fermentation can give a new way to resolve resource limitation and to find out alternative source. Through the methods of organic solvent extraction, thin layer chromatography (TLC) and column chromatography, compound I was isolated, purified from the liquid fermentation metabolites of the taxoids-produced endophytic fungi (Alternaria. alternata var. taxi 1011 Y. Xiang et LU An-guo) that was screened from the bark of Taxus. cuspidata Sieb.et Zucc.. Compound I was identified as one kind of taxoids type III, based on the analyzing results by using the methods of ultraviolet spectroscopy (UV), infrared spectroscopy (IR), mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR). This study provides a com-pleted method for separation and purification of the endophytic fungi as well as structure identification of its fermentation me-tabolite

Asphaltenes: Separations, structural analysis and applications

Asphaltenes, complex aromatic compounds from various carbonaceous sources, could be obtained by solvent dissolution, filtration and adsorption. It was difficult to clarify the molecular structures and chemical properties of asphaltene due to its structural similarity, composition complexity and source dependences. Many techniques, like Mass spectrometry, Chromatography, Nuclear magnetic resonance spectroscopy, Infrared spectroscopy, Roman spectroscopy, Fluorescence spectroscopy, X-ray diffraction analysis and Small-angle scattering techniques and so on, have revealed some valuable descriptions of asphaltenes chemical compositions and fundamental structures. Moreover, advanced Mass spectrometry,Atomic force microscopy and Scanning tunneling microscopy could provide more clear and essential molecular compounds and structures in asphaltenes. In addition, several asphaltenes models have succeeded to illustrate aggregation properties asphaltene. In this work, the progress on asphaltene separation, characterization and application was summarized, and the similarities and differences between coal-derived asphaltenes and petroleum asphaltenes were compared. Furthermore, the reactivity of asphaltenes has been discussed in the aspect of hydroprocessing, pyrolysis and gasification. Asphaltene was excellent carbon precursor for functional carbon material due to its high aromaticity and carbon yield;several porous carbon nanosheets from asphaltenes that would be prospective electrode materials after being graphitized were shown. Pitch-based carbon fiber derived from coal-derived asphaltenes displayed a tensile strength of 1.0 GPa and elastic modulus of 350 MPa, respectively. These powerful advances will provide asphaltenes promising developments.

Separate Analysis of Remote Sensing Information of Structures of Different Geological Periods and Quantitative Study of Corresponding Tectonic Stress Fields

The structural feature shown on a remote sensing image is a synthetic result ofcombination of the deformations produced during the entire geological history of an area.Therefore, the respective tectonic stress field of each of the different stages in the complexdeformation of an area can be reconstructed in three steps: (1) geological structures formed atdifferent times are distinguished in remote sensing image interpretation; (2) structuraldeformation fields at different stages are determined by analyzing relationships betweenmicrostructures (joints and fractures) and the related structures (folds and faults); and (3)tectonic stress fields at different stages are respectively recovered through a study of the featuresof structural deformation fields in different periods. Circular structures and related circlular and radial joints are correlated in space to con-cealed structural rises. The authors propose a new method for establishing a natural model ofthe concealed structural rises and calculating the tectonic stress field by using quantitative dataof the remote sensing information of circular structures and related linear structures.

MICROPHASE SEPARATED STRUCTURES AND PROPERTIES OF PDMS-MDIPEG COPOLYMER SURFACE

A series of poly(dimethylsiloxane)(PDMS)-4,4′-diphenylmethanediisocyanate(MDI)-poly(ethylene glycol)(PEG) multiblock copolymers were synthesized by employing two-step growth polymerization and investigated by AFM,XPS. contact angle system,protein adsorption and platelets adhesion measurements,respectively.It was found that as the molecular weight of PDMS increased,the surface of copolymers had increasing phase separation,while the increase in the molecular weight of PEG decreased the phase separation extents of the copolymer surface.XPS and contact angle measurements showed that the greater the phase separation extent was,the lower both the surface enrichment of PDMS and the surface free energy of the copolymer film were.The protein adsorption experiments indicated that the best phase separation did not exhibit the best biocompatibility.

SYNTHESIS AND CHARACTERIZATION OF AMPHIPHILIC GRAFT COPOLYMER CONTAINING MICROPHASE SEPARATED AND LONG POLY(ETHYLENE OXIDE) SIDE CHAIN STRUCTURES

Acryloyl terminated Poly (ethyleneoxide)macromonomers (PEO-A) with different PEO chain lengths have been prepared by deactivation of PEO alkoxide with acryloyl chloride. A new kind of amphiphilic polystyrene-g-poly (ethylene oxide)graft copolymer containing both microphase separated and PEO side chain structures has been synthesized from radical copolymerization of PEO-A macromonomer with styrene. After careful purification by a newly-developed method called 'selective dissolution', the well-defined structure of the purified copolymers was confirmed by IR, ~1H-NMR and GPC. Various experimental parameters controlling the copolymerization were studied in detail. The results indicated that the feed ratio of styrene to macromonomer(S/M) was the most important determining factor for the composition of the copolymers. A detailed 'comb- model' was proposed to describe the molecular structure of the graft copolymers. Finally, this amphiphilic graft copolymers may readily form microphase separated structures as clearly indicated by transmission electron microscopy.

Balanced Polysulfide Containment and Lithium Ion Transport in Lithium-Sulfur Batteries via Nitrogen-doped Carbon Hollow Multi-shelled Structures on Modified Separators

Representing the next-generation technology in lithium-ion batteries,lithium-sulfur(Li-S)batteries offer increased specific energy without relying on scarce metals like nickel and cobalt,but suffer from a low practical specific energy due to poor conductivity and a short lifespan due to the shuttle effect of polysulfides.Balancing the confinement of polysulfides and the transport of lithium ions requires highly elaborate modifiers for separators.Hollow multi-shelled structures(HoMSs)show promise as hierarchical mesostructures for separators,offering multiple shell layers and internal cavities that effectively inhibit polysulfide shuttle.Thoughtful design of these structures is crucial to address these challenges effectively.In this study,nitrogen-doped carbon HoMS(NC HoMS)was created using polymer templates through a precisely controlled polymerization process.Batteries featuring NC HoMS-modified separators exhibit improved capacity and cycling stability in comparison to those utilizing commercial separators.Especially,triple-shelled NC HoMS strikes a balance in polysulfide containment and lithium ion transport.Featuring a sulfur loading of 6.34 mg/cm^(2),the Li-S battery can consistently complete 100 charge-discharge cycles,starting with a discharge capacity of 966.4 mA·h/g with a 75.8%capacity retention rate.NC HoMS holds potential as the separator modifier in addressing the polysulfide shuttle problem and facilitating the Li-ion transportation for advanced Li-S batteries.

Chemical composition and structure characterization of distillation residues of middle-temperature coal tar

The distillation residues of middle-temperature coal tar(DRMCT) were separated into saturate, aromatic, resin and asphaltene fractions by using the combination of solvent extraction and column chromatography separation.The isolated four fractions have been further characterized through the combination of elemental analysis,Fourier transform infrared(FTIR) spectra, proton nuclear magnetic resonance spectrum(~1H NMR) and molecular weight analysis. The analysis results confirm the view that the saturate fraction from DRMCT was mainly composed of long-chain alkanes and almost all of the heteroatoms(S, N and O) were existed in aromatic structures.The asphaltene fraction had the highest molecular weight, the most amount of heteroatom(especially oxygen)and was the most condensed with shortest alkyl side chains among all the fractions. In addition, for the heavier components, the resin and asphaltene fractions from DRMCT contained lower ratio of H/C, lower molecular weight and higher aromaticity degree when compared with crude oils.