Experimental study of the effects of a multistage pore-throat structure on the seepage characteristics of sandstones in the Beibuwan Basin:Insights into the flooding mode

To investigate the relationship between grain sizes, seepage capacity, and oil-displacement efficiency in the Liushagang Formation of the Beibuwan Basin, this study identifies the multistage pore-throat structure as a crucial factor through a comparison of oil displacement in microscopic pore-throat experiments. The two-phase flow evaluation method based on the Li-Horne model is utilized to effectively characterize and quantify the seepage characteristics of different reservoirs, closely relating them to the distribution of microscopic pores and throats. It is observed that conglomerate sandstones at different stages exhibit significant heterogeneity and noticeable differences in seepage capacity, highlighting the crucial role played by certain large pore throats in determining seepage capacity and oil displacement efficiency. Furthermore, it was found that the displacement effects of conglomeratic sandstones with strong heterogeneity were inferior to those of conventional homogeneous sandstone, as evidenced by multiple displacement experiments conducted on core samples with varying granularities and flooding systems. Subsequently, core-based experiments on associated gas flooding after water flooding were conducted to address the challenge of achieving satisfactory results in a single displacement mode for reservoirs with significant heterogeneity. The results indicate that the oil recovery rates for associated gas flooding after water flooding increased by 7.3%-16.4% compared with water flooding alone at a gas-oil ratio of approximately 7000 m^(3)/m^(3). Therefore, considering the advantages of gas flooding in terms of seepage capacity, oil exchange ratio, and the potential for two-phase production, gas flooding is recommended as an energy supplement mode for homogeneous reservoirs in the presence of sufficient gas source and appropriate tectonic angle. On the other hand, associated gas flooding after water flooding is suggested to achieve a more favorable development effect compared to a single mode of energy supplementation for strongly heterogeneous sandstone reservoirs.

Bio-soft matter derived from traditional Chinese medicine:Characterizations of hierarchical structure,assembly mechanism,and beyond

Structural and functional explorations on bio-soft matter such as micelles,vesicles,nanoparticles,aggregates or polymers derived from traditional Chinese medicine(TCM)has emerged as a new topic in the field of TCM.The discovery of such cross-scaled bio-soft matter may provide a unique perspective for unraveling the new effective material basis of TCM as well as developing innovative medicine and biomaterials.Despite the rapid rise of TCM-derived bio-soft matter,their hierarchical structure and assembly mechanism must be unambiguously probed for a further in-depth understanding of their pharmacological activity.In this review,the current emerged TCM-derived bio-soft matter assembled from either small molecules or macromolecules is introduced,and particularly the unambiguous elucidation of their hierarchical structure and assembly mechanism with combined electron microscopic and spectroscopic techniques is depicted.The pros and cons of each technique are also discussed.The future challenges and perspective of TCM-derived bio-soft matter are outlined,particularly the requirement for their precise in situ structural determination is highlighted.

Structural characterization and anti-inflammatory activities of novel polysaccharides obtained from Pleurotus eryngii

Natural polysaccharides named PEP-0.1-1,PEP-0-1 and PEP-0-2 from edible mushroom species Pleurotus eryngii were obtained in the present study.Results showed that molecular weights of these polysaccharides were 3235,2041 and 23933 Da,respectively.Further,structural characterization revealed that PEP-0.1-1 had a→4-α-D-Glcp-1→backbone and contained→4)-α-D-Glcp and→4)-β-D-Glcp reducing end groups.PEP-0-1 backbone contained→4-α-D-Glcp-1→and→6-α-3-O-Me-D-Galp-1→,and the side chains containedα-D-Glcp,β-D-Manp-1→andα-D-Glcp-3→.However,PEP-0-2 backbone consisted of→4-α-DGlcp-1→and→6-α-3-O-Me-D-Galp-(1→6)-α-D-Galp-1→while the side chains containedα-D-Glcp andβ-D-Manp-1→.Biological activity analysis was then carried out and found that all these polysaccharides could significantly suppress the relative mRNA expression of toll-like receptor 4,nitric oxide(NO),tumor necrosis factor-α,interleukin(IL)-1βand IL-6 in lipopolysaccharide(LPS)-induced inflammation of RAW264.7 cells,as well as the over secretion of the above cell cytokines.Moreover,Western blotting analysis revealed that all these purified fractions displayed significant inhibition effects on the expression of c-Jun N-terminal kinases protein induced by LPS in mitogen activated protein kinase pathway,along with the relieving on the inhibition effect of LPS on IκB-αprotein expression.In summary,the information generated by the present study could provide a theoretical basis for the exploration of novel healthy food materials from edible mushroom with antiinflammation activities.

Structural characterization of three acidic polysaccharides from Opuntia dillenii Haw.fruits and their protective effect against hydrogen peroxide-induced oxidative stress in Huh-7 cells

Three novel acidic polysaccharide fractions(OFPP-1,OFPP-2,OFPP-3)with different m olecular weights(803.7,555.1 and 414.5 k Da)were isolated from the peeled Opuntia dillenii Haw.fruits by alkali-extraction,graded alcohol precipitation and column chromatography.Structural analysis indicated that OFPPs were pectic polysaccharides consisting of rhamnose,arabinose and galactose residues.The backbone of OFPP-1 consisted of a repeating unit→6-α-D-Galp A-(1→2)-α-L-Rhap-(1→with T-α-D-Galp A-(1→6)-α-D-Galp A-(1→4)-α-D-Glcp-(1→,T-β-D-Xylp-(1→6)-α-D-Galp A-(1→4)-α-D-Glcp-(1→or T-α-D-Galp A-(1→3)-α-L-Araf-(1→as the side chains.The backbone of OFPP-2 consisted of a disaccharide repeating unit→2)-α-L-Rhap-(1→4)-β-D-Galp A-(1→with T-β-L-Araf-(1→as the branches substituted at the O-4 position of→2,4)-α-LRhap-(1→.Whereas the backbone of OFPP-3 was→2,4)-α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-β-L-Araf-(1→or→2,4)-α-L-Rhap-(1→2)-α-L-Rhap-(1→4)-β-D-Galp A-(1→,which was branched at the O-4 position of→2,4)-α-L-Rhap-(1→.Moreover,these three polysaccharide fractions could protect Huh-7 cells against H2O2-induced oxidative stress to different extents by decreasing the MDA content and increasing the SOD,CAT,GSH-Px activities and the GSH level in the Huh-7 cells.These results suggest that OFPPs have the potential to be used as natural antioxidants.

Characterization of physicochemical and immunogenic properties of allergenic proteins altered by food processing:a review

Food allergens are mainly naturally-occurring proteins with immunoglobulin E(IgE)-binding epitopes.Understanding the structural and immunogenic characteristics of allergenic proteins is essential in assessing whether and how food processing techniques reduce allergenicity.We here discuss the impacts of food processing technologies on the modification of physicochemical,structural,and immunogenic properties of allergenic proteins.Detection techniques for characterizing changes in these properties of food allergens are summarized.Food processing helps to reduce allergenicity by aggregating or denaturing proteins,which masks,modifies,or destroys antigenic epitopes,whereas,it cannot eliminate allergenicity completely,and sometimes even improves allergenicity by exposing new epitopes.Moreover,most food processing techniques have been tested on purified food allergens rather than food products due to potential interference of other food components.We provide guidance for further development of processing operations that can decrease the allergenicity of allergenic food proteins without negatively impacting the nutritional profile.

Fine quantitative characterization of high-H2S gas reservoirs under the influence of liquid sulfur deposition and adsorption

In order to clarify the influence of liquid sulfur deposition and adsorption to high-H2S gas reservoirs,three types of natural cores with typical carbonate pore structures were selected for high-temperature and high-pressure core displacement experiments.Fine quantitative characterization of the cores in three steady states(original,after sulfur injection,and after gas flooding)was carried out using the nuclear magnetic resonance(NMR)transverse relaxation time spectrum and imaging,X-ray computer tomography(CT)of full-diameter cores,basic physical property testing,and field emission scanning electron microscopy imaging.The loss of pore volume caused by sulfur deposition and adsorption mainly comes from the medium and large pores with sizes bigger than 1000μm.Liquid sulfur has a stronger adsorption and deposition ability in smaller pore spaces,and causes greater damage to reservoirs with poor original pore structures.The pore structure of the three types of carbonate reservoirs shows multiple fractal characteristics.The worse the pore structure,the greater the change of internal pore distribution caused by liquid sulfur deposition and adsorption,and the stronger the heterogeneity.Liquid sulfur deposition and adsorption change the pore size distribution,pore connectivity,and heterogeneity of the rock,which further changes the physical properties of the reservoir.After sulfur injection and gas flooding,the permeability of TypeⅠreservoirs with good physical properties decreased by 16%,and that of TypesⅡandⅢreservoirs with poor physical properties decreased by 90%or more,suggesting an extremely high damage.This indicates that the worse the initial physical properties,the greater the damage of liquid sulfur deposition and adsorption.Liquid sulfur is adsorbed and deposited in different types of pore space in the forms of flocculence,cobweb,or retinitis,causing different changes in the pore structure and physical property of the reservoir.

Physicochemical, structural characterization, and antioxidant activities of chondroitin sulfate from Oreochromis niloticus bones

In this study,chondroitin sulfate was extracted from Oreochromis niloticus bones(OCS)and isolated to three fractions(OCS-1,OCS-2,and OCS-3).The physicochemical properties and structure characterization including monosaccharide,disaccharide compositions,molecular weight(Mw)of OCS were determined by HPAEC,HPLC-SAX,HPGPC,FT-IR spectra,and 1D/2D NMR.Moreover,their thermal properties,crystalline structure,and microstructure were also analyzed.Results showed that their Mw were between 10 kDa and 50 kDa.CS-6 was the predominant disaccharide unit in four OCS,and the CS-4/CS-6 ratios were close to CS from shark cartilage.Besides,the results of antioxidant activity showed that different fractions of OCS had a distinct DPPH radical,hydroxyl radical,and ABTS+radical scavenging activity.OCS-1 has the highest scavenging activities in DPPH and hydroxyl radical compared with other fractions,which showed a higher medicinal value.Those findings may lay some theoretical basis for the potential application development of OCS.

Structural characterizations andα-glucosidase inhibitory activities of four Lepidium meyenii polysaccharides with different molecular weights

Four polysaccharides(MCPa,MCPb,MCPc,MCPd)were obtained from Lepidium meyenii Walp.Their structures were characterized by chemical and instrumental methods including total sugar,uronic acid and protein content determi-nation,UV,IR and NMR spectroscopy,as well as monosaccharide composition determination and methylation analy-ses.Four polysaccharides were a group of glucans with different molecular weights ranging from 3.12 to 14.4 kDa,and shared a similar backbone chain consisting of(1→4)-glucose linkages with branches attached to C-3 and C-6.Furthermore,bioactivity assay showed that MCPs had concentration-dependent inhibitory activity onα-glucosidase.MCPb(Mw=10.1 kDa)and MCPc(Mw=5.62 kDa)with moderate molecular weights exhibited higher inhibitory activ-ity compared with MCPa and MCPd.

Structural characterization and immunostimulatory activity of a water-soluble polysaccharide from abalone(Haliotis discus hannai Ino)muscle

A water-soluble polysaccharide from abalone muscle(AMPP)was isolated.The contents of carbohydrate,protein,uronic acid,and sulfate in AMPP were 83.5%,0.5%,2.7%,and 2.6%,respectively.High-performance liquid chromatography analysis indicated that AMPP was homogeneous and had an average molecular weight of approximately 3.2 kDa.The main monosaccharides of AMPP were glucose(Glc)and mannose with a molar ratio of 99.7:0.3.The structural characteristics of AMPP were elucidated through methylation analysis,Fourier transform infrared spectroscopy,and nuclear magnetic resonance spectroscopy.The linkages of AMPP consisted of terminal,1,4-linked,1,6-linked,and 1,4,6-linked Glcp with a molar ratio of 3.1:7.2:1.0:2.5.In one repeat unit of the proposed AMPP structure,the backbone chain was composed of eight 1→4 glycosidic bonds and one 1→6 glycosidic bond,with three branch chains linked by 1→6 glycosidic bond.In addition,AMPP was found to possess potent immunostimulatory activity via rising phagocytosis of RAW264.7 cells and promoting secretion of TNF-α.

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.

Pore Structure and Permeability Characterization of Highrank Coal Reservoirs: A Case of the Bide-Santang Basin, Western Guizhou, South China

The methods of nuclear magnetic resonance(NMR)spectroscopy,mercury injection porosimetry(MIP),and gas-water relative permeability(GWRP)were used to reveal the pore structure and permeability characteristics of high-rank coal reservoirs in the Bide-Santang basin,western Guizhou,South China,to provide guidance for coalbed methane(CBM)exploration and exploitation and obtain direct insights for the development of CBM wells.The results indicate that the coal reservoirs in the study area are characterized by well-developed adsorption pores and poorly developed seepage pores.The bimodal NMR transverse relaxation time(T2)spectra and the mutation in the fractal characteristic of the MIP pore volume indicate poor connectivity between the adsorption pores and the seepage pores.As a result,the effective porosity is relatively low,with an average of 1.70%.The irreducible water saturation of the coal reservoir is relatively high,with an average of 66%,leading to a low gas relative permeability under irreducible water saturation.This is the main reason for the low recovery of high-rank CBM reservoirs,and effective enhanced CBM recovery technology urgently is needed.As a nondestructive and less time-consuming technique,the NMR is a promising method to quantitatively characterize the pores and fractures of coals.

Synthesis,Crystal Structure and Characterization of a New Coordination Polymer from the Self-assembly of CoCl_2 Salt and Flexible Ligand 1,3-Bis(4-pyridyl)propane

A new 1D coordination polymer [Co（bpp）3Cl2（H2O）2]n 1 （bpp = 1,3-bis（4-pyridyl）-propane） was synthesized and characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system,space group Ibca with a = 16.569（9）,b = 17.240（10）,c = 27.087（16） ,V = 7738（8） 3,Z = 8,Dc = 1.306 g/cm3,Mr = 760.65,λ（MoKa） = 0.71073 ,μ = 0.623 mm1,F（000） = 3192,the final R = 0.0678 and wR = 0.2011. The Co（II） atom is coordinated in a slightly distorted octahedral CoN4Cl2 geometry by two Cl atoms in the axial positions,four N atoms from the two bridging bpp ligands and two pendant bpp ligands. The CoN4Cl2 octahedra are connected by the bridging bpp ligands to form a 1D neutral coordination polymer chain. The chains are linked by face-to-face π-π interactions between adjacent pendant bpp ligands to give rise to a 3D supramolecular architecture. The photoluminescent investigation indicates that the emission of 1 is attributed to ligand-centered emission. The variable-temperature magnetic susceptibility measurement shows weak antiferromagnetic behavior in the coπmplex.

Optimization of Synthesis of Spherical Lignosulphonate Resin and Its Structure Characterization

Calcium lignosulphonate was used to synthesize a spherical lignosulphonate resin in a cheap and non-toxic disperse medium by reversed phase suspension polymerization. The process conditions were optimized by orthogonal experiments. Under .the optxmal conditxons （T=95 ℃, CHCl= 3 mol·L^-1, mHCHO： mCLS=7%, WCLS=50%）, globulation took about 20 min and the product was featured with excellent spherical shape, narrow particle size range, 61.20% of water retention capacity, 0.83 mmol·ml^- 1 of total volume exchange capacity and 3.46 mmol·g^- 1 of total exchange capacity. The results of Scanning Electron Micrograph and Scanning Probe Micrograph indicate that spherical lignosulphonate resin has a rugged surface with porous microstructure in the gel skeleton. The average pore size of dry samples was determined to be 10.46 nm. by the BET method.

Syntheses, Structures and Characterization of Two New Pb^II Polymers Built on a Kinked Flexible Thiodiacetic Acid Ligand

Two new PbII metal-organic coordination polymers,namely,[Pb（tda）]n（1） and [Pb（tda）（phen）]n（2）（H2 tda = thiodiglycolic acid,phen = 1,10-phenanthroline）,were synthesized under hydrothermal conditions and characterized by elemental analysis,IR,UV spectra,TG technique and X-ray crystallography.Complex 1 crystallizes in the orthorhombic system,space group Iba2 with a = 9.0417（14）,b = 19.360（4）,c = 7.5741（12）,C4H4O4PbS,Mr = 355.32,V = 1325.8（4）3,Dc = 3.560 g·cm-3,F（000） = 1264,μ（MoKa） = 25.711 mm-1,S = 1.086 and Z = 8.The final refinement gave R = 0.0387 and wR = 0.0986 for 3077 observed reflections with I 2σ（I）.Complex 1 is a 2D infinite grid-like（4,4） topological structure constructed by PbII atoms and tda anions,in which tda ligands exhibit bis（syn,syn-bridging bidentate,chelating-bridging tetradentate） mode.Complex 2 crystallizes in the triclinic system,space group P1 with a = 8.3570（17）,b = 8.7591（18）,c = 10.895（2）,α = 76.00（3）,β = 80.50（3）,γ = 77.61（3）°,C16H12N O4PbS,Mr = 535.53,V = 750.4（3）3,Dc = 2.370 g·cm-3,F（000） = 504,μ（MoKa） = 11.405 mm-1,S = 1.018 and Z = 2.The final refinement gave R = 0.0332 and wR = 0.0629 for 3360 observed reflections with I 2σ（I）.Complex 2 is a 1D chain structure,in which phen ligands are attached on both sides of the 1D chain and tda ligand exhibits a bis（syn,syn-bridging bidentate,chelating tridentate） mode.Finally,complex 2 is extended into a 2D supramolecular structure by strong π···π stacking interactions.

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.

Solvothermal Synthesis and Characterization of [TM(1,2-dap)3]HgSb2Se5(TM = Co,Fe)with a Chain Structure

One organic-decorated quanternaery [TM（1,2-dap）3]Hg Sb2Se5（1,2-dap = 1,2-dianinopropane, TM = Co（1）, Fe（2）） compound has been solvothermally synthesized. The compounds crystallize in triclinic space group P 1, with a = 11.248（6）, b = 11.542（7）, c = 12.180（12） A, V =1268.7（16） A^3, Z = 2, F（000） = 1010 for 1 and a = 11.311（5）, b = 11.558（5）, c = 12.180（9） A, V =1276.5（12） A^3, Z = 2, F（000） = 1008 for 2. The crystal structure consists of one-dimensional anionics chains composed of Hg Se4 tetrahedra and SbSe3 trigonal pyramids sharing corners and[TM（dap）3]^2＋ cations. The [HgSb2Se＋5^2-]∞ anionic chains run along the [001] direction, and are surrounded by the [TM（dap）3]^2＋ cations. Meanwhile, 8-ring [Hg2Sb2Se4] and 6-ring [HgSb2Se2] are alternately found. The compounds were structurally characterized by elemental analysis,thermogravimetric analysis, infrared spectroscopy and UV-Vis diffuse reflectance spectroscopy.

A facile method for fabrication of nano-structured Ni-Al_2O_3 graded coatings: Structural characterization

Powder charges of micron-size Ni and Al2O3were utilized to deposit nano-structured Ni-Al2O3composite coatings on analuminum plate fixed at the top end of a milling vial using a planetary ball mill.Composite coatings were fabricated using powdermixtures with a wide range of Ni/Al2O3mass ratio varying from1:1to plain Ni.XRD,SEM and TEM techniques were employed tostudy the structural characteristics of the coatings.It was found that the composition of the starting mixture strongly affects the Al2O3content and the microstructure of the final coating.Mixtures containing higher contents of Al2O3yield higher volume fractions of theAl2O3particles in the coating.Though Ni-Al2O3composite coatings with about50%of Al2O3particles were successfully deposited,well-compacted and free of cracks and/or voids coatings included less than20%(volume fraction)of Al2O3particles which weredeposited from powder mixtures with Ni/Al2O3mass ratios of4:1or higher.Moreover,mechanical and metallurgical bondings arethe main mechanisms of the adhesion of the coating to the Al substrate.Finally,functionally graded composite coatings withnoticeable compaction and integrity were produced by deposition of two separate layers under identical coating conditions.

Pore-throat structure characteristics and its impact on the porosity and permeability relationship of Carboniferous carbonate reservoirs in eastern edge of Pre-Caspian Basin

Carboniferous carbonate reservoirs at the eastern edge of the Pre-Caspian Basin have undergone complex sedimentation,diagenesis and tectonism processes,and developed various reservoir space types of pores,cavities and fractures with complicated combination patterns which create intricate pore-throats structure.The complex pore-throat structure leads to the complex porosity-permeability relationship,bringing great challenges for classification and evaluation of reservoirs and efficient development.Based on the comprehensive analysis on cores,thin sections,SEM,mercury intrusion,routine core analysis and various tests,this paper systematically investigated the features and main controlling factors of pore-throats structure and its impact on the porosity-permeability relationship of the four reservoir types which were pore-cavity-fracture,pore-cavity,pore-fracture and pore,and three progresses are made.(1)A set of classification and descriptive approach for pore-throat structure of Carboniferous carbonate reservoirs applied to the eastern edge of the Pre-Caspian Basin was established.Four types of pore-throat structures were developed which were wide multimodal mode,wide bimodal mode,centralized unimodal mode and asymmetry bimodal mode,respectively.The discriminant index of pore-throat structure was proposed,realizing the quantitative characterization of pore-throat structure types.(2)The microscopic heterogeneity of pore reservoir was the strongest and four types of pore-throat structures were all developed.The pore-fracture and pore-cavity-fracture reservoirs took the second place,and the microscopic heterogeneity of pore-cavity reservoir was the weakest.It was revealed that the main controlling factor of pore-throat structure was the combination patterns of reservoir space types formed by sedimentation,diagenesis and tectonism.(3)It was revealed that the development of various pore-throat structure types was the important factor affecting poroperm relationship of reservoirs.The calculation accuracy of permeability of reservoirs can be improved remarkably by subdividing the pore-throat structure types.This study deepens the understanding of pore-throat structure of complicated carbonate reservoirs,and is conducive to classification and evaluation,establishment of precise porosity-permeability relationship and highly efficient development of carbonate reservoirs.

Characterization of Interface State Density of Ni/p-GaN Structures by Capacitance/Conductance-Voltage-Frequency Measurements

For the frequency range of I kHz-lOMHz, the interface state density of Ni contacts on p-GaN is studied using capacitance-voltage （C-V） and conductance-frequency-voltage （G-f-V） measurements at room temperature. To obtain the real capacitance and interface state density of the Ni/p-GaN structures, the effects of the series resistance （Rs） on high-frequency （SMHz） capacitance values measured at a reverse and a forward bias are investigated. The mean interface state densities obtained from the CHF-CLF capacitance and the conductance method are 2 ×1012 e V-1 cm-2 and 0.94 × 1012 eV-1 cm-2, respectively. Furthermore, the interface state density derived from the conductance method is higher than that reported from the Ni/n-GaN in the literature, which is ascribed to a poor crystal quality and to a large defect density of the Mg-doped p-GaN.

Fabrication and structure characterization of ITO transparent conducting film by sol-gel technique

Using In(NO3)3·5H2O and acetylacetone as raw materials and anhydrous SnCl4 as dopant, the transparent conducting indium tin oxide(ITO) films were prepared by sol-gel and dip-coating technique. The phase transformation, structure properties and physical properties (sheet resistance and transmittance) of the films were investigated by DTA-TG, XRD, SEM, four-probe method and UV-Vis spectrometry. The results indicate that it is feasible to fabricate ITO films on the quartz substrates by sol-gel technique, and the ITO films are formed by accumulating of particles with the size of several decades of nanometers. The prepared ITO film has cubic bixbyite structure, and (111) is its preferred plane. After five-times dip-coating, the ITO film has a thickness less than 150 nm, a sheet resistance of 110Ω/□, a resistivity of 1.65×10-3 Ω·cm and a transparency of 90%.