Research and Application of Log Defect Detection and Visualization System Based on Dry Coupling Ultrasonic Method

In order to optimize the wood internal quality detection and evaluation system and improve the comprehensive utilization rate of wood,this paper invented a set of log internal defect detection and visualization system by using the ultrasonic dry coupling agent method.The detection and visualization analysis of internal log defects were realized through log specimen test.The main conclusions show that the accuracy,reliability and practicability of the system for detecting the internal defects of log specimens have been effectively verified.The system can make the edge of the detected image smooth by interpolation algorithm,and the edge detection algorithm can be used to detect and reflect the location of internal defects of logs accurately.The content mentioned above has good application value for meeting the requirement of increasing demand for wood resources and improving the automation level of wood nondestructive testing instruments.

Simulation of Wetting and Drying Processes in A Depth Integrated Shallow Water Flow Model by Slot Method

A particular porosity method named ＂slot method＂ is implemented in a depth-integrated shallow water flow model （DIVAST） to simulate wetting and drying processes. Discussed is the relationship between the shape factors of the ＂slot＂ and the preset depth used in ＂wetting-drying＂ algorithm. Two typical tests are conducted to examine the performance of the method with the effect of the shape factors of the ＂slot＂ being checked in detail in the first test. Numerical results demonstrate that： 1 ） no additional effort to improve the finite difference scheme is needed to implement ＂slot method＂ in DIVAST, and 2） ＂slot method＂ will simulate wetting and diying processes correctly if the shape factors of the ＂slot＂ being selected properly.

Synthesis of PZT power by wet-dry method and its structure

To prepare PZT powder at lower temperature, lead zirconate titanate (PZT) powder (x(Zr)/x(Ti)=56?44) was prepared by wet-dry method. Glycol was used as the solvent, and zirconium oxychloride was used as zirconium source. The properties and structure of the powder were analyzed by XRD, SEM and Sedimentograph. The effects of sintering parameter such as sintering temperature, keeping time and heating-up velocity on structure of PZT power were investigated. The results show that homogeneous PZT with single-phase perovskite structure can be obtained after sintering at 730 ℃ for 2 h, and the average size of PZT powder is about 113 nm.

Preparation of TiO_2-MoO_3 nano-composite photo-catalyst by supercritical fluid dry method

A series of TiO 2-MoO 3 nano-composite photocatalysts were prepared by supercritical fluid dry method(SCFD) and an impregnation technique with TiCl 4 and (NH 4) 6Mo 7O 24 ·4H 2O as the starting materials. The catalysts were characterized by the means of XRD, TEM and UV-Vis. Methyl orange was used as model compound for the evaluation of their catalytic activities. The results indicated that the photo-catalyst prepared by SCFD had the advantages of small size(12.84 nm), narrow distribution and good dispersivity. The presence of small amount of Mo in composite catalyst gives rise to the red shift of its absorbance wavelength, decrease of its energy gap and increase of the utility of visible light. Furthermore, higher surface acidity of the photo-catalyst was obtained as the result of the addition of MoO 3. Compared with pure TiO 2, the catalytic activity of the TiO 2-MoO 3 nano-composite photo-catalyst was improved significantly. As the doping concentration of the composite catalysts was controlled at 0.6%(molar percentage), 100% degradation of methyl orange was achieved with in 1.2 h irradiation time.

Study on Industrial Application of Hydrogen Sulfide Removal by Wet Oxidation Method with High Gravity Technology

The removal of hydrogen sulfide from gas plays an important role in rational utilization of resources and environ- mental protection. In this paper, the process of hydrogen sulfide removal by wet oxidation method in a rotating packed bed was investigated in a scale for treating 10 000 Nm3/h of gas. On the basis of studying the influence of the species and con- centration of alkali source, the liquid/gas volume ratio, the high gravity factor, and the hydrogen sulfide content in feed gas on the desulfurization effect, the suitable technological conditions were obtained. The hydrogen sulfide removal efficiency could reach 98.0% under these conditions. The results of continuous operation of process facilities showed that the high gravity method has many merits including higher desulfurization rate, good stability in operation, lower liquid/gas volume ratio, greater operation elasticity, and apparent energy saving effects.

Evaluation of umami taste components of mushroom (Suillus granulatus) of different grades prepared by different drying methods

Suillus granulatus is a valuable wild edible mushroom with a strong umami taste.Different grades of S.granulatus were dried by different methods,including natural air drying(ND),hot air drying(HAD),vacuum drying(VD),and freeze drying(FD).Results showed that VD samples of all grades had the highest equivalent umami concentration(EUC)value(P<0.05).The second grade of ND samples showed the highest EUC value(P<0.05).The first grade of HAD samples showed the highest EUC value(P<0.05).The third grade of FD samples showed the highest EUC value(P<0.05).The third grade of VD samples had a higher EUC value than the other grades of samples dried by VD.Electronic tongue results indicated no significant differences between samples of all grades dried by all methods.Thus,umami taste components are affected by drying method and grade.VD is an appropriate drying method for all sample grades.ND,HAD,and FD are suitable for second-,first-,and third-grade samples,respectively.

Preparation of calcium stannate by modified wet chemical method

A modified wet chemical route for low-temperature synthesis of the calcium stannate CaSnO3, a potentialmaterial for dielectric applications is reported. Firstly, a precursor CaSn(OH)6 was prepared using tin tetrachloride,calcium chloride and sodium hydroxide at room temperature. Then the precursor was annealed at relatively low tem-perature of 600 ℃ to obtain CaSnO3. The phase identification, thermal behavior and surface morphology of the sam-ples were characterized by element analysis, X-ray diffraction (XRD), thermo-gravimetric (TG) analysis and deriva-tive thermo-gravimetric (DTG) analysis, Fourier transform infrared spectroscopy (FTIR) and scanning electron mi-croscopy (SEM) in detail. The results show that CaSnO3 obtained by this method possesses a cubic perovskitestructure with average grain size of 5 μm.

Effects of Different Drying Methods on the Functional and Structural Properties of Dietary Fiber from Peanut Shell

[Objectives] This study was conducted to investigate the drying methods,functional and structure properties of dietary fiber( DF) from peanut shells.[Methods]Peanut shells were used as a raw material to prepare peanut shell dietary fiber( DF) by hot air drying( HA) and vacuum freeze drying( VF),respectively,and their functional and structural characteristics were compared in detail. [Results]The solubility,water holding capacity,oil holding capacity and swelling capacity of HA-DF and VF-DF were 2. 15 %,7. 63 g/g,7. 73 g/g,10. 35 ml/g and 3. 85 %,14. 98 g/g,15. 25 g/g,15. 85 ml/g,respectively. The total phenol contents were 2. 623 and 5. 173 mg GAE/g,respectively. The IC(50) values of ·OH,O2^-· and DPPH free radicals were 4. 16 and 4. 09 mg/ml,7. 90 and 3. 32 mg/ml,and 3. 19 and 3. 09 mg/ml,respectively. The molecular weight of VF-DF was smaller,and it had narrow molecular weight distribution and denser particles. Electron microscopy showed that VF-DF had a porous network like honeycomb and swelled structure. [Conclusions]This study can provide a theoretical basis for the functional modification and comprehensive utilization of peanut shell dietary fiber.

Effect of drying methods on the discoloration of three major domestic softwood species in Korea

Japanese pine, Korean pine and larch are three major softwood species in Korea. Their colors are relatively light, thus easily discolored due to drying and UV irradiation. In this study, they were dried with five different drying methods, steam treated and exposed to weathering. Their colors were measured using a spectrophotometer and comparisons made both among species and drying methods. For Japanese and Korean pines, high temperature dried and steam-dried specimens showed distinct color differences compared with the controls. Steam treatment discolored the dried specimens of Japanese and Korean pines but did not discolor those of larch. After weathering for 144 days the specimens of Japanese pine showed slight color differences among drying methods.

Preparation and Characterization of Porous Spherical LiFePO_4/C by Spray Drying and Carbothermal Method

The porous spherical LiFePO4/C powders were prepared by spray drying and carbothermal method （SDCTM）. Cheaper trivalent iron ion was used as the precursor. The pure olivine phase can be prepared with the spray drying and subsequent heat-treatment. The average particle size is around 10μm, and the value of porosity is 63.04%. The results indicate that the initial discharge capacity decreases with increasing charge/ discharge rate and reduces from 138.8 mAh · g^-1 at C/20 rate to 98.3 mAh ·g^-1 at 2C rate, while the polarization between the charge and discharge plateaux is enlarged from 53 mv to 347 mv. However, the average discharge efficiency is up to 99.5% at 2C rate compared to 80.6% at C/20 rate from the second cycle.

Effects of Different Initial Processing Methods on Atractylodin Content of Atractylodes chinensis

[Objectives]The paper was to compare the effects of different initial processing methods on atractylodin content of Atractylodes chinensis.[Methods]The atractylodin content of A.chinensis obtained by different initial processing methods was determined by HPLC.The loss rate on drying was determined by weighing.[Results]In the study of drying methods,the atractylodin content varied significantly among different thicknesses of slices,and the overall content of the product with the slice thickness of 5 mm was higher.Among different drying methods,constant temperature vacuum drying and shade drying of 5 mm slice resulted in the highest content of atractylodin.In the experiment of root impacting,root impacting twice received the best effect,and there was no significant difference in the atractylosin content of A.chinensis between drying in the sun and drying in the shade after root impacting twice(P>0.05).[Conclusions]Constant temperature vacuum drying or drying in the shade with the slice thickness of 5 mm,and root impacting twice is the best initial processing method,which leads to high atractylodin content of A.chinensis and good quality of medicinal materials.

Effect of variety and drying method on the nutritive value of corn for growing pigs

Background：This experiment was conducted to determine the nutritive value of corn from the north of China for growing pigs.The experiment examined corn variety（LS1,LS2,LS3 and LS4）grown in one location,drying method（sun dried and artificially dried）and different drying temperatures.Corn harvested at 20-25%moisture was dried to about 12%moisture by sun drying and artificially drying at 80,100,or 120℃ in a fluidized bed dryer.Ninety-six barrows（average BW of 33.4 ± 2.7 kg）were housed in individual metabolism crates to facilitate separate collection of feces and urine.A five-day collection period followed a seven-day diet acclimation period.Results：The results indicated that variety significantly influenced（P〈0.01）the 1,000 kernel weight of corn but not the bulk weight.Variety also influenced the available energy content（digestible energy of dry matter,P〈0.01;metabolisable energy of dry matter,P〈0.01）and digestibility of organic matter（P〈0.01）,as well as dry matter（P〈0.01）and gross energy（GE）content（P〈0.02）.The drying method of corn significantly influenced the 1,000 kernel weight（P〈0.01）,bulk weight（P〈0.01）and digestibility of ether extract（EE）（P〈0.01）.No effect of drying temperature on the digestibility of organic matter,dry matter（DM）,crude protein（CP）,neutral detergent fiber（NDF）,acid detergent fiber（ADF）and gross energy was observed,but gelatinization（P〈0.05）and test weight（P〈0.01）decreased with an increase in temperature.Conclusions：Variety has a significant impact on the nutritive value of corn for growing pigs,and greater attention needs to be paid to these influences in the assignment of the nutritive value of corn given to growing pigs.

Effects of drying method on preparation of nanometer α-Al_2O_3

Ammonium aluminum carbonate hydroxide (AACH) precursor was synthesized by the precipitation reaction of aluminum sulfate and ammonium carbonate. Then the precursor was dealt with five drying methods including ordinary drying, alcohol exchange, vacuum freeze-drying, glycol distillation, n-butanol azeotropic distillation respectively and calcined at 1 200 ℃ for 2 h to get α-Al2O3. The effects of drying methods on preparation of nanometer α-Al2O3 were discussed, and the optimal drying method was confirmed. The structural properties of powders were characterized by XRD, SEM and BET measurements. The results show that vacuum freeze-drying, glycol distillation and n-butanol azeotropic distillation can prevent the powders from aggregating, and among them the n-butanol azeotropic distillation is the best method. The nanometer α-Al2O3 powder with non-aggregation can be manufactured using n-butanol azeotropic distillation and the average particle size is about 40 nm.

A Multi-harmonic Method for Studying Effects of Mistuning on Resonant Features of Bladed Disks with Dry Friction Damping

An efficient multi-harmonic method is proposed for studying the effects of mistuning on resonant features of bladed disks with blade-to-blade dry friction damping. This method is able to predict accurately the forced response of bladed disks in frequency domain, which is validated by numerical integration method in time domain. The resonant features of both tuned and mistuned systems are investigated by using this method under various system coupling strengths, viscous dampings, and dry friction darnpings, etc. The results demonstrate that the proposed multi-harmonic method is very efficient for studying the mistuning effects on the resonant response of bladed disks with blade-to-blade dry friction damping, especially considering the combined effects of various system parameters.

Immersed Interface Method for Fokker-Planck Equation with Discontinuous Drift

The Immersed Interface Method (IIM) is derived to solve the corresponding Fokker-Planck equation of Brownian motion with pure dry friction, which is one of the simplest models of piecewise-smooth stochastic systems. The IIM is capable of treating a discontinuity in the drift of Fokker-Planck equation and it is readily extended to the dry and viscous friction model. Analytic results of the considered model are used to confirm the effectiveness and design accuracy of the scheme.

Synthesis and characteristics of large-scale ZnO rods by wet chemical method

The large-scale ZnO rods of submicrometer were prepared on the bare glass using a wet chemical method under different experimental parameters,such as the reactant concentration and the growth time.The microstructure of the ZnO rods was characterized by X-ray diffractometry(XRD) and field emission scanning electron microscopy (FESEM) with the energy dispersive X-ray spectroscopy(EDX),and the optical property was investigated by the room-temperature photoluminescence (PL) spectra.XRD and FESEM results show that the wurtzite structure and rod-like ZnO is obtained.The length (3-8 μm) and the diameter (400 nm-3 μm) vary with the experimental parameters.A strong UV emission at 384 nm and a weak visible yellow-green emission around 570 nm are observed in the PL spectrum.After annealing at 600 ℃ in air,the UV peak intensity increases obviously and the yellow-green peak intensity decreases greatly.The near-band-edge UV emission is attributed to the exciton recombination; the yellow-green emission can be associated with the defect recombination; and some defect complexes may be responsible for the latter emission.

Elimination of hard aggregation of bismuth-doped tin dioxide nanometer powders prepared by wet chemical method

Bismuth-doped tin dioxide （BTO） nanometer powders were prepared by the wet chemical method using tin tetrachloride （SnCl4）, bismuth nitrate [Bi（NO3） 3 ] and ammonia as raw materials. Non-bridge hydroxides and capillary force between particles were found to be key factors causing hard aggregation of BTO through analyzing the formation mechanism of hard aggregation. The hard aggregation of BTO was eliminated effectively when the Bi-Sn precursor （BSP） was treated with post processing including dispersing with ultrasonic wave, refluxing and distilling with addition of n-butanol and benzene （DRD） and drying by microwave. Characterized with X-ray diffraction （XRD） and transmission electron microscopy （TEM）, BTO spherical particles with tetragonal phase structure are well crystallized, dispersed easily and the average size was less than 10 nm.

Preparation of microsized silver crystals with different morphologies by a wet-chemical method

A wet-chemical method was presented for preparation of spherical, flowerlike, hexagonal, and triangular microsized silver crystals. Well-defined particles were prepared by mixing of iron（II） sulfate heptahydrate solution with silver nitrate solution at the presence of different modifiers with high-speed stirring at 8-20℃. It is found that the diameters of resulting products are 0.6-6.0 um and the morphologies of the silver microcrystals are greatly affected by the introduced modifiers. It is concluded that the microsized silver crystals with different morphologies can be synthesized by introducing appropriate modifiers at appropriate experimental parameters. Scanning electron microscopy and X-ray diffraction were used to characterize the resulting products.

Effects of Different Drying Methods on the Quality of Micronized Chinese Wolfberry Powder

[Objectives] To study the effects of different drying methods on quality of Chinese wolfberry powder. [Methods] The physical properties and nutritional contents of Chinese wolfberry powder prepared by hot air drying,vacuum freeze drying,microwave vacuum drying,drum drying and spray drying were measured and analyzed to explore the effects of different drying methods on quality characteristics of Chinese wolfberry powder. [Results] The total sugar content and reducing sugar contents of product: vacuum freeze drying > spray drying > microwave vacuum drying > drum drying > hot air drying; carotene and total flavonoid contents: vacuum freeze drying > microwave vacuum drying > spray drying > drum drying > hot air drying; after drying process,the dietary fiber content of product obtained by drum drying and spray drying was relatively higher,while the Vc content of Chinese wolfberry powder prepared by vacuum freeze drying was the highest. a~*value( redness to greenness) of color: vacuum freeze drying > microwave vacuum drying > spray drying > drum drying > hot air drying; the Chinese wolfberry powder prepared by vacuum freeze drying had the best solubility,hygroscopicity and rehydration ratio. [Conclusions] Microwave vacuum drying was the best method to prepare Chinese wolfberry powder,in order to keep its quality and consider the cost of production.

A Damping Characteristics Calculation Method of Metal Dry Friction Isolators

The dry friction ring-type vibration isolator is considered as an isotropic continuous medium. A method of dry friction hysteresis loop calculation is proposed based on friction force analysis of contact beam. The friction force is modeled as an equivalent distributed moment to use the finite element method （FEM） to calculate the dry friction vibration isolator hysteresis loop, so the damping characteristics can be obtained. A comparison of the hysteresis loop calculation results and the experimental results shows the average relative error is 2.7 %, it proves the calculation method is feasible.