Microscopic analysis of saturated soft clay in Pearl River Delta

A series of researches were carried out for the soil samples in the Pearl River Delta under the action of consolidation loads,such as the quantitative analyses of the pore scale,shape and size distributions of micro-structure units,with an environmental scanning electron microscope (ESEM),a mercury intrusion analyzer and a mineral diffractometer. The experimental results show that the consolidation pressures remarkably change the pore sizes and distribution characteristics of the silt,thus changing its compressibility and permeability. This can be proved by the fact that,in the earlier stage with a consolidation pressure of p<200 kPa,the pore sizes are greater and the compressibility and permeability coefficients are larger. However,they rapidly decrease with the increase in consolidation pressure. And in the later stage with a consolidation pressure of p>200 kPa,the pore sizes are smaller and the compressibility and permeability coefficients are less. Therefore,the empirical formulas of compression coefficient and permeability coefficient vs consolidation load and average pore diameter are deduced.

Comment on in vivo corneal confocal microscopic analysis in patients with keratoconus

Dear Editor,The article by Bitirgen et al;published in the journal presents an interesting analysis of keratoconus patients and controls by in vivo corneal confocal microscopy.However,addressing the following observations regarding the study design used by the authors may help add another dimension to the discussion.The age range of the patient group has been stated as 18-41y and for controls as 18-37y.Although the mean age is similar

Significance and Microscopic Analysis of Deformation in the Cultural Remains of Western Zhou Dynasty-Late Spring and Autumn Period at Daijiayuan Ruins in Huoshan,Anhui Province,China

During an excavation survey to the Daijiayuan vestige of the Western Zhou Dynasty-Late Spring and Autumn Period at Huoshan in Western Anhui,a ground crack related to tectonic movement and filled with silty fine sand was found. This phenomenon was initially confirmed to be due to seismic liquefaction. Many microscopic seismic relics,such as load structure,flow structure,cutoff plane and flotation of organic matter were found in the directional microscopic analysis of deformation. These discoveries and cognitions prove that there were two earthquake events taking place in the Western Zhou Dynasty-Late Spring and Autumn Period in this area. Above-mentioned works enrich and develop the research methods to identify prehistoric earthquake event in eastern China area to a certain extent.

Effect Analysis on the Soaking Technics of Corn Wet Milling in the Laboratory

[Objective] The research aimed to find the optimal condition of corn starch production in the laboratory and analyze the soaking effect.[Method] The orthogonal test was used to determine the suitable technological condition.By the light microscope and the scanning electron microscope,the soaking effect was analyzed.[Result] The suitable soaking condition was：soaking time 48 h,soaking temperature 55 ℃ and SO2 concentration 0.2%.The microscopic analysis result was that the protein matrix was sufficiently decomposed in the suitable soaking condition.The soaking effect had the positive correlation with the decomposed degree of protein matrix.[Conclusion] The research provided the basis for the soaking technics research of corn starch in the laboratory.

Quantitative XRD Analysis of Cement Clinker by the Multiphase Rietveld Method

Quantitative phase analysis of Portland cement clinker samples was performed using an adaptation of the Rietveld method.The Rietveld quantitative analysis program,originally in Fortran 77 code,was significantly modified in visual basic code with windows 9X graph user interface,which is free from the constraint of direct utilizable memory 640 k,and can be conveniently operated under the windows environment.The Rietveld quantitative method provides numerous advantages over conventional XRD quantitative method,especially in the intensity anomalies and superposition problems.Examples of its use are given with the results from other methods.It is concluded that,at present,the Rietveld method is the most suitable one for quantitative phase analysis of Portland cement clinker.

Analysis of inclusion and purity in steelmaking process

The paper mainly discussed the inclusions and the purity of molten steel and continuous casting slab in tapping,argon-bubbling,LF refining,VD vacuum degassing and continuous casting tundish processes during the steel making.At the same time,the improvement measures of smelting process were indicated. Si-Al-Ba alloy and Ca-Si deoxidation eventually were adopted in 120 t converter.The amount of the tapping was about 135t.After feeding Al wire and adding premelted slag in furnace,picked up the sample after the bottom argon-bubbling which had been done for over 5 minutes.The lime,fluorite,calcium carbide and Al powders were used to produce white slag in LF.Then the alloy compositions were adjusted. Feeding Ca wire after the treatment,and took out over 5 minutes' soft converting.The VD vacuum degassing should be kept for 15 minutes bellow 1.5 torr.After that,Ca wire could be fed.Finally,casting the slab into the size of 260 mm×2 280 mm. The research showed: (1) In converter procedure,the dephosphorization effect turned out good when the ratio of dephosphorization was 88.2%.The final oxygen and nitrogen contents satisfied the demand,and the effects of the final control and bottom-blowing were good. (2) During the LF refining process,the nitrogen seldom added.It showed the excellent sealing effect and the optimization of techniques on operating which had reached the domestic leading level. (3) After the VD vacuum degassing process,the Si,Mn,P,O,N contents were almost steady.The sulphur content kept decreasing to 0.003%and the[H]content was 1.9 ppm.The effect of the vacuum degassing process was good. (4) The oxygen content was controlled at 11 ppm in the continuous casting process,and the nitrogen content had increased to 53ppm with theΔ[N]28 ppm.Therefore,in order to prevent the molten steel from reoxidization,the protection of the continuous casting should be controlled rigorously. (5) The inclusions that existed before the LF refining process were mostly MnO-Al_2O_3-SiO_3 composite inclusions,while the inclusions were mostly calcium-aluminates inclusions after feeding Ca wires to LF or VD furnace.When the Ca/Al had reached to 0.1,7 Al_2O_3 12CaO were produced.The compositions and the sizes of the inclusions in continuous casting slab had changed obviously after the Ca treatment.The sizes were all within 100μm. (6) In order to prepare for the exploitation of the high-quality clean steel,the best process for feeding Ca wire,in LF or VD,and whether it should take one-step wire-feeding way or two-step way as well as the techniques of feeding Ca wire need to be studied further.The desulphurization in LF refining process didn' t reach balance.The ratio of desulphurization could be improved if extending the LF refining time and improving the kinetic condition.

Analysis of Metallographic Characteristics of Aluminum Alloy for Turbocharged Impellers

In this paper, the composition, two-dimensional and three-dimensional microstructure of heat-resistant wrought aluminum alloy with strong oxidation resistance, heat resistance and easy processing are analyzed by using direct reading spectrometer, metallographic microscope and scanning electron microscope. The main alloy elements of heat-resistant forging aluminum alloy include Cu, Mg, Si, Ni and Fe. The α solid solution of each element in aluminum consists of S phase (Al2CuMg), Mg2Si phase, bright gray Al2CuNi phase and dark brown Al9FeNi phase. The distribution of each phase in the aluminum alloy is determined by the three-dimensional energy spectrum analysis of the microstructure, and the distribution of each phase in the crystal position is analyzed. The mechanism of heat resistance, easy processing type and wear resistance is obtained, which provides the theoretical basis for the development and use of heat-resistant forged aluminum alloy.

The Effect of Graphene Oxide on Mechanical Properties of Cement Mortar

Cement is widely used in engineering applications,but it has both the characteristics of high brittleness and poor bending resistance.In this paper,the effects of different amounts ofgraphene oxide on the flexural strength and compressive strength of cement mortar were studied by doping a certain amount of graphene oxide with cement mortar,and the strengthening mechanism of graphene oxide on cement mortar was obtained through microstructure detection.It is found that graphene oxide has a significant enhancement effect on the macroscopic mechanical properties of cement mortar,and graphene oxide provides nano-nucleation sites and growth templates for cement mortar,accelerates the hydration process,reduces the voids between hydration products,greatly increases the compactness,and improves the macroscopic properties of cement-based materials.

Effects of temperatures and pH values on rheological properties of cemented paste backfill

In this study,different influence mechanisms associated with temperatures and pH values were investigated through cemented paste backfill(CPB)systems.CPB samples were prepared with temperatures ranging from 10 to 50℃ in 10℃ increments and pH values of 3,7,and 13.Then,the CPB mixture were subjected to rheological tests,thermogravimetric analysis(TG),derivative thermogravimetry analysis(DTG),Fourier-transform infrared spectroscopy(FT-IR),and scanning electron microscopy(SEM).Results demonstrated that the temperatures had significant effects on the rheological properties of CPB,whereas the effects of pH values were relatively unapparent.Higher temperatures(over 20℃)were prone to bring higher shear stress,yield stress,and apparent viscosity with the same pH value condition.However,an overly high temperature(50℃)cannot raise the apparent viscosity.Non-neutral conditions,for pH values of 3 and 13,could strengthen the shear stress and apparent viscosity at the same temperature.Two different yield stress curves could be discovered by uprising pH values,which also led to apparent viscosity of two various curves under the same temperatures(under 50℃).Microscopically,rheological properties of CPB were affected by temperatures and pH values which enhanced or reduced the cement hydration procedures,rates,products and space structures.

Experimental Investigation of Dust Deposit within Ceramic Filter Medium during Filtration-Cleaning Cycles

The penetration and deposit of particles within the medium is thought to be one reason that the residual pressure drop of the rigid ceramic filter increase with cycle number.In this study,the change in the microstructure of a single layer ceramic filter candle during filtration-cleaning cycle was observed by scanning electron microscope(SEM) and the resistance property of the filter was monitored accordingly.The experimental results show that there exists a serious dust deposit within the filter medium,especially at the surface region.This should be responsible for the decrease of the filter permeability.The deposit law of dust in the filter medium during filtration-cleaning cycle was then studied by measuring the deposit depth,the deposit amount,the particles distribution within the medium,the size distribution of deposited particles,and so on.Particles migration and fine particles penetration were found to be the main reasons,for which dust deposit within the filter medium became aggravated with cycle number.Based on a differential form of Ergun equation,an expression for the pressure drop of a used ceramic filter was developed with a good agreement with experimental results.Then,the effect of dust deposit on the residual pressure drop was studied at the different face velocities and dust sizes.It was found that face velocity and dust size significantly influence dust deposit within filter medium,and then the operation performance of the filter.

Adsorbability of Mycobacterium phlei on hematite surface

The adsorption of microorganisms on the mineral surface is the base of microorganisms that are considered as mineral processing reagents. The principles of the use of a highly hydrophobic and negatively charged bacterium, Mycobacterium phlei, as a flocculating-flotating agent for finely divided hematite were investigated. The flocculating-floating recovery is strongly dependent on the pH and the dosage of the bacterium. Generally the pH should be controlled over the range of 5.5-7, and the dosage should be controlled about 16 mg/L. The infrared spectrometry analysis indicates that the six functional groups of M. phlei, substituted aromatic compound groups, -（CH2） n-groups, -CH2（-CH3） groups, carbonyl groups, aromatic hydrocarbon groups, and carboxyl groups, are on the hematite surface, among which the first five ones contribute physical adsorption and only the carboxyl groups provide chemisorption. Microscopic analysis reveals that the dimensions and tight aggregation degree of the flocs of hematite particles formed by M. phlei are also impacted by the pH and the content of M. phlei in flotation.

Microstructure and Strain Fatigue Dislocation Structure of 7075-RRA Aluminum Alloy

The microstructure and the strain fatigue dislocation substructure of 7075-RRA (Retrogression and Reaging) aluminum alloy have been studied by using transmission electron microscopy. From these, a competitive mechanism of cyclic microscopic softening/hardening is put forward to explain the relation between macroscopic cyclic stability behavior and microscopic substructure.

Dyeability of Polylactide Fabric with Hydrophobic Anthraquinone Dyes

The dyeability of polylactide fabric has been investigated with the substituted aminoanthraquinone hydophobic dyes. Their application to the polylactide fabric led to good exhaustion values and good wash fastness between 4 and 3. MIcroscopic assessment ot cross-sections ot the dyed polylactlde fibres confirmed that these dyes could penetrate into the fibres. The nature of the substituted amino groups showed little influence on the wash fastness, but clearly influenced.the exhauslion and light fastness.

A Mesoscopic Self-assembled Ring of a Femtomole Fluorescein Sessile Droplet on Glass Slide Support

Since the solvent evaporation of a droplet on a hydrophobically pretreated glass slide, femtomole amount of fluorescent materials is carried by the evaporation and results in outward capillary flow to the perimeter of the droplet spot where the solute deposits, and forms a fluorescent ring like deposit (RLD) with submicrometer-scale structures.

Research on the intermediate phase of 40CrMnSiB steel shell under different heat treatments

In this study, 40 Cr Mn Si B steel cylindrical shells were tempered at 350, 500 and 600 ℃ to study the effect of tempering temperature on the dynamic process of expansion and fracture of the metal shell. A midexplosion recovery experiment for the metal cylinder under internal explosive loading was designed, and the wreckage of the casings at the intermediate phase was obtained. The effects of different tempering temperatures on the macroscopic and microscopic fracture characteristics of 40 Cr Mn Si B steel were studied. The influence of tempering temperatures on the fracture characteristic parameters of the recovered wreckage were measured and analyzed, including the circumferential divide size, the thickness and the number of the circumferential divisions. The results show that as the tempering temperature was increased from 350 to 600 ℃, at first, the degree of fragmentation and the fracture characteristic parameters of the recovered wreckage changed significantly and then became essentially consistent. Scanning electron microscopy analysis revealed flow-like structure characteristics caused by adiabatic shear on different fracture surfaces. At the detonation initiation end of the casing, fracturing was formed by tearing along the crack, which existed a distance from the initiation end and propagated along the axis direction. In contrast, the fracturing near the middle position consists of a plurality of radial shear fracture units. The amount of alloy carbide that was precipitated during the tempering process increased continuously with tempering temperature, leading to an increasing number of spherical carbide particles scattered around the fracture surface.

Thermal Insulation and Strength of Autoclaved Light Concrete

The primary objective of this study was to develop an autoclaved light concrete （ALC） material with ultra-thermal insulation property and to investigate the relationship between its physical characteristics and mechanical properties. Through tests of dry bulk density and compressive strength, relationship of physical characteristics and mechanical properties of samples were studied, resulting in a material with ultra-thermal insulation property. Scanning electron microscope （SEM） and energy-dispersive X-ray spectroscopy （EDX） were applied to analyze the micro-morphology and elemental composition of samples. To identify the product phases, X-ray diffraction （XRD） was engaged. The test results showed that compressive strength and thermal coefficient were reduced with the increasing of aluminum powder within the mixtures. As a result the optimal thermal coefficient and compressive strength of samples were improved to 0.061 W/（m·k） and 1.2 MPa, respectively. SEM, EDX and XRD analyses showed that calcium silicate hydrate and tobermorite crystal were main resultant phases.

Nano-silver induced ceramic coloring via control of glaze interface and phase separation

As a kind of rare materials,nano-silver has broad application prospects in the fields of catalysis,medical treatment,new energy and so on.However,there are few reports on the systematic research of nano-silver in ceramic glazes.In this work,different color ceramic glazes were produced by tuning the nano-silver content and optimizing the firing process.The crystalline phase composition,micro-morphology and elemental distribution of fired glazes were analyzed and discussed in depth.The elemental composition and distribution of the samples were studied.The surface of the glazes with varying Ag contents fired under the reducing atmosphere exhibited blue-white.And the blue color is attributable to Rayleigh scattering that may arise because the phase-separation structures existed in glazes.Interestingly,the color of the ceramic glazes with varying Ag contents changed to golden-yellow when the ceramic glazes were fired under the air atmosphere.Golden-yellow color of the samples fired under the air atmosphere is mainly attributable to the silver nanoparticles,though Ag^(+) may be existed in the glazes.

Origin of natural sulphur-bearing immiscible inclusions and H_(2)S in oolite gas reservoir, Eastern Sichuan

Based on results of microscopic observation and laser Raman analysis about fluid in-clusions,multiple special forms of immiscible inclusions that contain sulphur,liquid hydrocarbon,bi-tumen,etc.were discovered in samples collected from the H_(2)S gas reservoir-containing carbonates in the Lower Triassic Feixianguan Formation in the Jinzhu-Luojia area,Kai County,Sichuan Province.Based on the lithology and burial history of the strata involved as well as measurement results of homogenization temperature of fluid inclusions,bitumen reflectivity,etc.,it is concluded that the H_(2)S in the gas reservoir resulted from the thermal reaction between hydrocarbons in reservoir and CaSO_(4)in the gypsum-bearing dolostone section at the high temperature(140℃―170℃)oil-cracked gas for-mation stage in Late Cretaceous.Thereafter,research on a great number of immiscible inclusions in the reservoir reveals that elemental sulphur resulted from oxidation of part of the earlier-formed H_(2)S and further reaction between sulphates,hydrocarbons and H_(2)S in geological fluids in H_(2)S-bearing gas reservoir at a temperature of 86℃―89℃and a pressure of 340×10^(5)Pa and during the regional uplift stage as characterized by temperature decrease and pressure decrease in Tertiary.Meanwhile,gyp-sum,anhydrite and calcite formed at this stage would trap particles like elemental sulphur and result in a variety of special forms of immiscible inclusions,and these inclusions would contain information concerning the complexity of the fluids in the reservoir and the origin of H_(2)S and natural sulphur in the gas reservoir.