Effect of Crystalline Structure of Wood on Liquefaction

By means of X ray and gas chromatography analysis, the crystalline structure of untreated wood , alkali treated wood and benzylated wood and their liquefaction in toluene and tetrahydrofufan with HCl as a catalyst were studied .The upper solution of benzylated wood was also studied by GC MS analysis. It proved that the introduction of bulky benzyl group in wood significantly changed the crystalline structure of wood ,enlarging the free volume which facilitated the penetration of solvent into the matrix of treated wood, thus tremendously enhancing thesolubility in solvent,compared to untreated wood and alkali treated wood. The percentage of residue decreased and the combined solvent increased with the increase of weight gain revealed that the liquefaction process became easy. Furthermore, the factors that influenced the liquefaction of benzylated wood were investigated. It showed that the liquefaction performance was improved with the increase of liquefaction time and the amount of catalyst when toluene was used as a solvent, especially in the presence of THF as solvent, there existed the optimum liquefaction time and the amount of catalyst .

Point Defect Phenomena of Crystalline Structure in Some Common Structural Materials

The existence and its movement rule of crystalline structure defect are closely related to the diffusion, solid phase reaction, sintering, phase transformation as well as the physical and chemical properties of materials. Point defect theory has been widely applied in material mineralization research, unfavorable transformation controlling, material modification, the research and development of new materials and so on. Point defect theory is one of the important theories for new material research and development. Herein we mainly discuss the application of point defect theory in some structural material researches.

Studies on the Influence of Sintering Temperature on Crystalline Structures of Mg-Al Spinel Synthesized by Waste Aluminum Slag

Mg-Al spinel is synthesized by using industrial waste-residue and basic magnesium carbonate in the aluminum factory as the main raw materials. The influence of sintering temperature on crystalline structure and microstructure of Mg-Al spinel has been mainly discussed. The crystalline structure of sample is characterized by using XRD, SEM and relevant analytical software. The experimental results show that compared to the conventional synthetic method, the application of waste aluminum slag as the raw material can greatly decrease the synthetic tem-perature. The content of Mg-Al spinel first increases and then decreases with the rise of sintering temperature, and its purity can reach as high as 96wt% at 1550 ℃, which is therefore determined to be the optimum synthetic temperature. SEM observations demonstrate that as the rise of sintering temperature, the grain of Mg-Al spinel grows up obviously with typical octahedral characteristic appearance.

Influence of TiO_2 Mineralizer on the Crystalline Structure of Cordierite Synthesized from Aluminum Slag

By adding small amount of TiO2, aluminum slag could be used to synthesize cor- dierite. α-Al2O3, TiO2 and dehydrated talc could generate solid solution to accelerate the solid-state reaction to form cordierite. The experimental results show that the content of cordierite increases with the increase of TiO2 added. 3.0% of TiO2 is determined to be the best amount, because all crystalline substances are converted into cordierite at this content. Philips X’pert plus software analysis shows that when the content of TiO2 is from 0 to 1.0%, cordierite has the same hexagonal structure as the single crystal and the lattice parameters change slightly; when the content of TiO2 is from 1.0 to 2.0%, the cordierite still keeps hexagonal structure but the lattice parameters change greatly; when the content of TiO2 is from 2.0 to 3.5%, the cordierite is converted from hexagonal into rhombic and the lattice parameters change accordingly.

Influence of Fe_2O_3 Impurity on the Crystalline Structure of Cordierite Synthesized from Waste Aluminum Slag

The influence of Fe2O3 impurity on the crystalline structure of cordierite synthesized from waste aluminum slag is discussed. XRD and SEM techniques were employed to characterize the crystalline structure and microstructure of each specimen. Philips X’pert plus software was used to determine the lattice parameters of each specimen. The results show that the Fe2O3 content of 0.8～1.6wt% is beneficial to the formation of cordierite, with the cordierite amount reaching 90wt%. So 0.8～1.6wt% is considered as the allowable Fe2O3 content in the specimens and 0.8wt% is determined to be the best after overall analysis. Plus software analysis shows that the cordierite in each specimen has the same symmetrical hexagonal structure as the single crystal, and the lattice parameters as well as the lattice dimensions change slightly.

Influence of Impurity Na_2O on Crystalline Structure of Cordierite Synthesized from Aluminum Sludge

By adding small amount of TiO2, aluminum slag could be used to synthesize cor- dierite. α-Al2O3, TiO2 and dehydrated talc could generate solid solution to accelerate the solid-state reaction to form cordierite. The experimental results show that the content of cordierite increases with the increase of TiO2 added. 3.0% of TiO2 is determined to be the best amount, because all crystalline substances are converted into cordierite at this content. Philips X’pert plus software analysis shows that when the content of TiO2 is from 0 to 1.0%, cordierite has the same hexagonal structure as the single crystal and the lattice parameters change slightly; when the content of TiO2 is from 1.0 to 2.0%, the cordierite still keeps hexagonal structure but the lattice parameters change greatly; when the content of TiO2 is from 2.0 to 3.5%, the cordierite is converted from hexagonal into rhombic and the lattice parameters change accordingly.

Crystal Structures and Physicochemical Properties of Solvated Estradiol

Polymorph screening is currently one of the most important tasks for innovators and for generic companies from both pharmaceutical and intellectual property rights aspects. The hemihydrate form（Form Ⅰ） and formamide solvate（Form Ⅱ） of estradiol are isolated and prepared via systemic crystallization screening in this paper, and the formamide solvate form is reported for the first time. Both polymorphic forms were characterized by single-crystal X-ray structure analysis（SXRD）, powder X-ray diffraction（PXRD）, and thermal analysis（TGA and DSC）. The PXRD experiments indicate that the samples in this study are the pure polymorphic forms via comparing the patterns with the simulated ones. The stability and equilibrium solubility data of the solid-state phase were also examined in order to check the impact of the differences observed in their crystalline structures. It has been found that Forms I and II are of conformational polymorph and Form II is the more thermodynamically stable solid form, while Form I possesses higher solubility, indicating its possibility as an alternate solid form for its further solid formulation development if necessary.

Alkali Metal-incorporated Mesoporous Smectites:Crystallinity and Textural Properties

A series of mesoporous smectite like materials incorporated with alkali metals such as Li, Na, K and Cs has been synthesized with the hydrothermal method. The crystalline and the pore structures of the materials synthesized significantly change with the introduction of alkali metals. The addition of Li gives highly ordered layer phases, while the incorporation of Cs yields much less crystalline structures. Although Na or K has little effect on the crystalline structure, they modify the pore structure.

Highly Improved Microstructure and Properties of Poly(p-phenylene terephthalamide) Paper-based Materials via Hot Calendering Process

In this study,the effect of hot calendering process on the microstructure and properties of poly(p-phenylene terephthalamide)(PPTA) paper-based materials was investigated.The microstructures of the fracture surface,crystalline structure,and single fiber strength of the PPTA paperbased materials as well as the different bonding behaviors between the PPTA fibers and PPTA fibrids obtained before and after the hot calendering process were examined.The results indicated that a high linear pressure would result in a limited improvement of the strength owing to the unimproved paper structure.The optimal values of tensile index and dielectric strength of 56.6 N·m/g and 27.6 kV/mm,respectively,could only be achieved with a synergistic effects of hot calendering temperature and linear pressure(240℃ and 110 k N/m,respectively).This result suggested it was possible to achieve a significant reinforcement and improvement in the interfacial bonding of functional PPTA paper-based materials,and avoid the formation of unexpected pleats and cracks in PPTA paper-based materials during the hot calendering process.

Research of High Temperature Crystalline Structure and Property Evolution of Magnesium Aluminate Spinel

Magnesium aluminate spinel （MgAl2O4） with high purity has been prepared by using anodized waste slag from aluminum factory and （MgCO3）4Mg（OH）2.5H2O as the main raw materials to discuss the change laws and characteristics of crystalline structure, microstructures and properties. X-ray diffraction （XRD） and scanning electron microscopy （SEM）, together with relevant analysis software, were used to characterize the crystal phases and microstructures so as to get MgAl2O4. Results show that when increasing the holding time the amount of MgAl2O4 increases fwstly and then keeps stable, but bulk density and bending strength increase firstly and then decrease. The best holding time is determined to be 3 h because at this time the corresponding MgAl2O4 content is up to 93%, bulk density 3.23 g·cm^3, apparent porosity 4.6% and bending strength 122.4 MPa.

Influence of Deposition Temperature on the Structure of Si_3N_4 Thin Film Prepared by MWECR-PECVD

The Si_3N_4 thin film is prepared by MWECR-PECVD at different deposition tem-perature and the structure of the Si_3N_4 thin film is investigated. The results indicate that thestructure of the Si_3N_4 thin film prepared at low deposition temperature is in the amorphousphase. However, when the deposition temperature increases to 280℃, the Si_3N_4 thin film changesto crystalline α-Si_3N_4. With a further increase of the deposition temperature, the grain of theSi_3N_4 thin film becomes more fine, uniform and flat. XRD analysis shows that the structure ofthe Si_3N_4 thin film prepared at 280℃ is of a crystalline structure.

A RAMAN-SPECTROSCOPIC STUDY OF PHASE STRUCTURE OF DRAWN POLYETHYLENE

A drawn high density polyethylene（HDPE）has been measured by Raman spectroscopy and differential scanning calorimetry （DSC）. The crystalline structure of drawn HDPE is analysed by the Raman internal modes in terms of mass fractions of the crystalline orthorhombic phase, the liquid- like amorphous phase and the disordered anisotropic phase. The mass fractions depend on draw temperature T;and draw ratio R;. The fraction of disordered anisotropic amorphous phase changes very little with, the T;and increases with increasing R;. Sum of the mass fractions of crystalline orthorhombic phase and the disordered anisotropic phase increases linearly as the same slope as the crystallinity W;determined from DSC measurements with increasing T;or R;and it is higher than the W;for all the samples. The results show that the mass fraction of disordered anisotropic phase is partially devoted by the taut tie molecules （TTM s） in the amorphous state. The dependence of the disordered anisotropic phase on T;and R;supports the mechanism of plastic deformation of fibre structure.

Influence of Impurity Na2O on Crystalline Structure of Cordierite Synthesized from Aluminum Sludge

Waste aluminum sludge, talc powder and clay were used to synthesize cordierite in this research. The impurities, such as Fe2O3, CaO, K2O and Na2O, in the raw materials have some influence on the structures and properties of the materials. In this paper, we mainly discuss the impact of impurity Na2O on the structure of cordierite, based on which the permitted amount of Na2O was determined. The results show that Na2O with the amount less than 0.6% has little influence on the cordierite formation; while when its amount increasing from 0.6% to 0.7%, the content of cordierite decreases from 86% to 84% and the permitted amount for Na2O in the raw materials is less than 6% with the best amount less than 0.3%. X’pert plus software analysis results show the impurity Na2O has no influence on the cordierite space group and only the lattice parameters vary slightly; but it has much influence on the structure of Mg-Al spinel and the lattice parameters are much changed.

CONFORMATION AND CHAIN PACKING STRUCTURES OF POLY (ρ-PHENYLEN BENZOBISTHIAZOLE) BY MOLECULAR SIMULATION

The conformation, the chain packing stabilization and the unit cell modeling of poly(p-phenylene benzobisthiazole) have been investigated by using molecular simulation techniquein the present work. A coupling behaviour of σ-bond rotations at either side of the pheny-lene ring or the heterocyclic ring was found surely to exceed a length of the repeat unit ofthe polymer chain. For a single chain model, the stable torsion angle of the repeat resultedat 14°. In the crystalline cell minimization, the dihedral angle along the polymer chaincould even be stabilized in various values. It therefore indicates that the intermolecularinteraction does play a considerable role for this polymer forming the conformation. Ac-cording to cohesive energies calculated for these unit cell models, the torsion angle in themost stable crystalline cell is 0°. When the chains packing together, there exist so manyenergy stable wells along the chain axis 0.35--0.36nm apart from neighbouring chains.Most of the unit cells have quite closed cohesive energies. These factors thus cause thedifficulty of forming an unique perfect crystalline structure of the polymer. The presentstudy suggested a number of reasonable unit cells, and the most stable crystalline structurefor this polymer that is monoclinic, non-primitive unit cell.

Differences in Starch Chain Length Distribution and Structure Characteristics of Early-Indica Rice Under Different Temperature Treatments During Grain-Filling

Effects of temperature during grain-filling on chain length distribution and structure characteristics of 4 early-seasonindica rice cultivars were investigated under the environment-controlled conditions. The plants at flowering stage weresubjected to two temperature treatments until maturity (the mean dairy air temperature, 22 and 32C for optimum temperaturetreatment and high temperature treatment, respectively). The result showed that high temperature during grain-fillingsignificantly decreased the long B-chain content and increased the intermediate B-chain content. But the effect of hightemperature on other starch chains appeared to be cultivar-dependant. The crystalline characteristics of rice starch werealso affected by temperature during grain-filling. The intensity at 18 2q of X-ray diffraction pattern of rice samples underhigh temperature was higher than those under optimum temperature, though all rice starches performed A-crystallinetype. Moreover, the intensity at 18 2q was positive correlation with intermediate B-chain content and negative correlationwith long B-chain content.

Conductive Polymer Composites Fabricated by Disposable Face Masks and Multi-Walled Carbon Nanotubes: Crystalline Structure and Enhancement Effect

Influenced by recent COVID-19,wearing face masks to block the spread of the epidemic has become the simplest and most effective way.However,after the people wear masks,thousands of tons of medical waste by used dis-posable masks will be generated every day in the world,causing great pressure on the environment.Herein,con-ductive polymer composites are fabricated by simple melt blending of mask fragments(mask polypropylene,short for mPP)and multi-walled carbon nanotubes(MWNTs).MWNTs were used as modifiers for composites because of their high strength and high conductivity.The crystalline structure,mechanical,electrical and thermal enhancement effect of the composites were investigated.MWNTs with high thermal stability acted the role of promoting the crystallisation of mPP by expediting the crystalline nucleation,leading to the improvement of amount for crystalline nucleus.MWNTs fibers interpenetrate with each other in mPP matrix to form conducting network.With 2.0 wt% MWNTs loading,the tensile strength and electrical conductivity of the composites were increased by 809% and 7 orders of magnitude.MWNTs fibers interpenetrate with each other in mPP matrix to form conducting network.Thus,more conducting paths were constructed to transport carriers.The findings may open a way for high value utilization of the disposable masks.

STRUCTURE OF Al-Mn-Zn-Mg ALLOY POWDER

The structure of Al-Mn-Zn-Mg alloy powder annealed at 800℃ has been studied by transmisston electron microscopy(TEM).An approximant phase(named as C-phase) to the decagonal phase was found and its crystal structure was determined It belongs to c-center orthorhombic lattice with a=2.35 nm,b=3.27 nm and c=1.22 nm.We stillfound a hexagonal phase with a=0.7) nm and c=0.79 nm,(named as phase) in the annealed alloy powder.The annealed alloy powder is composed of the C-phase,the phase,the decagonal phase and Al solid solution.

Study on the Structure and Properties of Cadmium Removal Adsorbent Made by Ultrafine Silica Powder

An efficient and recyclable cadmium removal adsorbent was prepared by molding and sintering of ultrafine silica powder produced from ferroalloy plant as the main raw materials, with the addition of a certain amount of AI（OH）3 and CaO for modification. XRD and SEM were used to characterize the crystal phases and microstructures of the adsorbent. The influences of different pH, initial cadmium concentration and contacting time on the cadmium adsorption capacity were investigated. The results show that the cadmium removal capacity is up to 0.239 mg/g at the initial Cd2＋ concentration of 5 g/L, pH value of 7 and contacting time of 120 rain when the optimum, mass ratio is 70（ultrafine silica powder）：30（Al（OH）3 and CaO mixture）. The corresponding adsorbent has a porous structure with main crystalline phases of CazAI2SiO7 and CaSiO3. Cadmium is adsorbed and removed mainly by physical adsorption, assisted by chemical adsorption.

Synthesis and Structure of 3-Aryl-5-cyano-6-methylthio pyrimidine2,4-diones

The title compounds of 3-aryl-5-cyano-6-methylthiopyrimidine2.4-diones weresynthesized by the reaction of ethy1 2-cyano-3.3'dimethylthioacrylate with arylureas. The compound(Ar＝p-CH_3OC_6H_4) was recrystallized in acetone/petroleum in space group P2_(1/n) with a＝1. 1602 (2).b=1.5921(3), c＝1.3918 (3)um. β=94.38 (3)°for Z=8. R=0.054.The X-ray analysis showedthat there is H-bond interaction among molecules.