多纤维增强重型汽车制动器摩擦材料的摩擦磨损性能研究

采用芳纶浆粕、玻璃纤维、硅灰石纤维和钛酸钾晶须多纤维混杂增强制备重型汽车制动器摩擦材料。利用XD-MSM型定速摩擦试验机，考察了摩擦材料的摩擦系数和磨损率随温度变化的情况，并且通过扫描电镜观察了摩擦材料在不同温度下磨损后的表面形貌，分析其摩擦磨损机理。研究结果表明，所研制的摩擦材料具有足够的机械性能和优异的摩擦磨损性能，热衰退小、恢复性能好、耐磨损，可满足重型汽车制动性能的要求。材料在中高温下主要是磨粒磨损和热疲劳磨损，同时伴随着粘着磨损。

Fatigue reliability quantitative analysis of cement concrete for highway pavement under high stress ratio

In order to obtain the change law of the fatigue reliability of cement concrete for highway pavement under high stress ratios, first, the probability densities of monotonic random variables including concrete fatigue life are deduced. And then, the fatigue damage probability densities of the Miner and Chaboche-Zhao models are deduced. By virtue of laboratory fatigue test results, the fatigue damage probability density functions of the two models can be obtained, considering different stress ratios. Finally, substituting load cycles into them, the change law of cement concrete fatigue reliability about load cycles can be acquired. The results show that under the same stress ratio, with the increase in the load cycle, the fatigue reliability declines from almost 100% to 0% gradually. No matter under what stress ratio, during the initial stage of the load action, there is always a relatively stable phase for fatigue reliability. With the increase in the stress ratio, the stable phase gradually shortens and the load cycle corresponding to the reliability of 0% also decreases. In the descent phase of reliability, the higher the stress ratio is, the lower the concrete reliability is for the same load cycle. Besides, compared with the Chaboche-Zhao fatigue damage model, the Miner fatigue damage model is safer.

Corrosion behaviors and mechanism of electroless Ni-Cu-P/n-TiN composite coating

In the present investigation, electroless Ni-Cu-P/n-TiN composite coating was prepared using alkaline citrate-based bath. X-ray diffraction （XRD）, scanning electron microscopy（SEM）, energy-dispersive spectroscopy（EDS）, electrochemical measurements, weight loss tests and Raman spectrometer were used to character the properties of the coating. As the Cu content increased from 7.3 wt% to 24.8 wt%, the corrosion current density of the Ni-Cu-P/n-TiN coating decreased from 10.80 to 4.34 ~tA. And the inclusion of Cu in NiP alloy resulted in refinement and less porosity in microstructure. The addition of TiN resulted in a slight decline in anti-corrosion property of the coating. As the mass loss test showed, Ni-24.8%Cu-P exhibited perfect corrosion resistance. Studies by Raman spectroscopy on coatings proved that Cu（II）3（PO4）（OH）3, Cu（OH）2 and CuO were examined while no compound of nickel was found, and Cu exhibited preferred corrosion in saline solution, providing cathodic protection to Ni alloy.

Damage Identification in Beam-Type Structures Using Pseudo Strain Energy Density and Grey Relation Coefficient

Based on pseudo strain energy density (PSED) and grey relation coefficient (GRC), an index is proposed to locate the damage of beam-type structures in time-domain. The genetic algorithm (GA) is utilized to identify the structural damage severity of confirmed damaged locations. Furthermore, a systematic damage identification program based on GA is developed on MATLAB platform. ANSYS is employed to conduct the finite element analysis of complicated civil engineering structures, which is embedded with interface technique. The two-step damage identification is verified by a finite element model of Xinxingtang Highway Bridge and a laboratory beam model based on polyvinylidens fluoride (PVDF). The bridge model was constructed with 57 girder segments, and simulated with 58 measurement points. The damaged segments were located accurately by GRC index regardless of damage extents and noise levels. With stiffness reduction factors of detected segments as variables, the GA program evolved for 150 generations in 6 h and identified the damage extent with the maximum errors of 1% and 3% corresponding to the noise to signal ratios of 0 and 5%, respectively. In contrast, the common GA-based method without using GRC index evolved for 600 generations in 24 h, but failed to obtain satisfactory results. In the laboratory test, PVDF patches were used as dynamic strain sensors, and the damage locations were identified due to the fact that GRC indexes of points near damaged elements were smaller than 0.6 while those of others were larger than 0.6. The GA-based damage quantification was also consistent with the value of crack depth in the beam model.

Current Status of Population Density of Mediterranean Fruit Fly （Ceratitis capitata） in Fruit Orchards in Central Iraq

In the recent years The Mediterranean Fruit fly Ceratitis capitata is distributed in the orchards of central Iraq and caused highly economic losses. This study was conducted in orchards in central Iraq during 2009 and 2010 and made field survey of the insect in four types of orchards （Citrus, Apricot, Figs ＆ Citrus and A mixture of fruit trees） and used for this purpose Tephri Traps supplied with Q-Lure and dimethyl dichloroviny phosphate （DDVP）. The present preliminary study has shown that the Mediterranean fruit fly C. capitata has a year round presence in fruit orchards in central Iraq and reached its highest ntunerical density of the pest in citrus orchards during of November and December were 345 and 363 insect/trap per month in citrus orchards and the least numerical density during of January and February while the highest numerical density of the insect in orchards of Apricot in March 2010, Figs ＆ Citrus in August 2009 and a Mixture of fruit trees in November 2009 were 45, 116, 311 insect/trap per month respectively. The population density of the pest was highest is started 2010 compared with 2009, but the high temperature degree （46-51℃） in August 2010 caused decreasing the population density of this pest. C. capitata caused highly economic losses in citrus reached 68% and 71% of the Mandarin and Kaki fruits respectively Currently in Iraq to fight no control method to reduce the economic losses caused by this pest except the use of pesticides GF-120.

Effects of oxidation treatment on properties of SiO_(2f)/SiO_2-BN composites

The silica fiber reinforced silica and boron nitride-based composites （SiO2f/SiO2-BN） were prepared firstly via the sol-gel method and then the urea route, and the effects of oxidation treatment on the component, structure, mechanical and dielectric properties of the composites were investigated. The results show that the oxidation treatment at 450 ℃ will not impair the structure of boron nitride, and carbon is the main impurity with the excessive urea. The density of SiO2f/SiO2-BN composites is 1.81 g/cm3, and the flexural strength and elastic modulus are 113.9 MPa and 36.5 GPa, respectively. After oxidation treatment, the density varies to 1.80 g/cm3, and the flexural strength and elastic modulus are decreased to 58.9 MPa and 9.4 GPa, respectively. The mechanical properties of the composites are severely damaged, but they still exhibit a good toughness. The composites show excellent dielectric properties with the dielectric constant and loss tangent being 3.22 and 0.003 9, respectively, which indicates that the oxidation treatment is ineffective to improve the dielectric properties of SiOzf/SiO2-BN composites.

Effects of primary suture and fibrin sealant on hemostasis and liver regeneration in an experimental liver injury

AIM: To investigate the effects of fibrin sealant on hemostasis and liver regeneration and intra-abdominal adhesions in an experimental liver injury. METHODS: Thirty-six Wistar rats were randomly divided into primary suture group (n = 15), fibrin sealant group (n = 15) and control group (n = 6). A wedge resection was performed on the left lobe of the liver. In primary suture group, liver was sutured using polypropylene material, while fibrin glue was administrated on the liver surface in fibrin sealant group. RESULTS: More intra-abdominal adhesions were observed in the primary suture group compared to the fibrin sealant group on 3rd (2.50 ± 0.5 vs 0.25 ± 0.5, P = 0.015), 10th (2.75 ± 0.5 vs 0.50 ± 0.6, P = 0.06) and 20th (1.75 ± 0.5 vs 0.70 ± 0.5, P = 0.015) postoperative days. Histopathological scores were better in the fibrin sealant group in comparison with the primary suture group on 3rd (8.75 ± 0.5 vs 6.75 ± 0.5, P = 0.006), 10th (7.50 ± 1.0 vs 5.5 ± 0.6, P = 0.021) and 20th (6.40 ± 1.7 vs 3.20 ± 1.6, P = 0.025) postoperative days. CONCLUSION: Out data suggest that fibrin sealant is preferred over primary suture in appropriate cases including liver trauma since it causes less intra-abdominal adhesions while allowing shorter hemostasis time as assessed in experimental liver trauma.

Investigation of Different Characters of Stomata on Three Cocoa Clones with Resistance Level Difference to VSD （Vascular Streak dieback） Disease

The development of the science of cytology and genetics, particularly on cell structure and function provided a breakthrough for breeders and allowed for early selection. Character of stomata density on some commodities was reported as important factor to determine the disease resistance. The research was done for getting information about the differences in the stomata characters influenced on the level of Vascular Streak dieback （VSD） resistance on cocoa. The research was conducted in the Laboratory of Genetics, Gadjah Mada University and leaves samples were conducted in Kendeng Lembu Gardens, PTPN XII. The research used a split plot design with three factors included the type of clones with different levels of VSD disease resistance （PA 191, BL 703 and GS 29）, leaf position （top, middle and base） and leaf age （young and old）. Stomata characters included number of stomata, stomata opening width, stomata wide and stomata diameter were observed. The results showed that the stomata characters in three cacao genotypes with different resistance levels indicated a difference in number of stomata, stomata size, stomata opening width, stomata wide and stomata diameter. Stomata number, stomata opening width and stomata diameter on PA 191 （resistance clone） were lower than the susceptible clones （BL 703 dan GS 29）. The lowest of number and diameter stomata on the base position on the old leaves tissues. Number of stomata, stomata opening width and stomata diameter were estimated role in mechanism of VSD resistance and that were expected could be used as criteria selection to VSD resistance.

Sweet false stalk crusher

After finishing picking the banana, how to tackle banana pesudostem has long been a thorny problem. According to banana pesudostem＇s characteristics of more crassitude stem, high moisture content and heavy fiber density, this paper proposes a efficient, energy-saving and low-loss device for crushing banana pesudostems and returning field.

Density distribution in a heavy-medium cyclone

Heavy-medium cyclones are widely used to upgrade run-of-mine coal.But the understanding of flow in a cyclone containing a dense medium is still incomplete.By introducing turbulent diffusion into calculations of centrifugal settling a theoretical distribution function giving the density field can be deduced.Qualitative analysis of the density field in every part of a cylindrical cyclone suggests an optimum design that has exhibited good separation effectiveness and anti-wear performance when in commercial operation.

Influence of A Hyperons ^1S0 Superfluidity on the Direct Urca Processes with Hyperons

In the framework of the relativistic mean field theory （RMFT）, the relativistic energy losses of the direct Urea processes with hyperons （Y-DURCA ） for reactions A → p ＋ e ＋ υe and ≡^-→ A＋e＋υe are studied in neutron stars. We calculate the energy gap of A hyperons and investigate the effects of the ^1S0 superfluidity （SF） of A hyperons on the Y-DURCA processes. The calculated results are in line with the recent experimental data △ BAA ～ 1.01 ±0.20-0.11^＋0.18 MeV. The results indicate that the ^1S0 SF of A hyperons exists in most density ranges of happening the two reactions. The theoretical cooling curves are in agreement with observation data.

Use of Fractals Channels to Improve a Proton Exchange Membrane Fuel Cell Performance

One of the most important and effective hardware elements for improvement of efficiency and power density of proton exchange membrane fuel cells is the flow field plate. The design and the pattern of the flow field plate have a considerable effect on the effectiveness of mass transport as well as on the electrochemical reactions inside the cell. The configuration of the flow field plate aims at ensuring a low pressure-drop over all channels in the stack. In this work, a FPFFP （fractal parallel flow field plate）, with bio-inspired configuration by insertion of fractals in a classic PFFP （parallel flow field plate）, is proposed, increasing the flow area of the hydrogen at anode side without increasing the section＇s area of the flow field plate. By simulating was observed that, the use of channels in fractal shape can increase the hydrogen flow area without occuring pressure loss in the cell. The fluid dynamic behavior in the FPFFP at smaller scales was replicated in the same plate, with better advantage of the active area of the electrode. Increasing the hydrogen flow area without causing pressure loss could be a good tactic to increase the power density of fuel cells, and consequently improving the cell performance.

Bale Density and Moisture Content Effects on the Losses of Baled Alfalfa

In order to reduce alfalfa losses, the effect of bale density and alfalfa moisture content on the losses of baled alfalfa during the baling and transportation process was determined in this study. Three ranges of moisture content including 14%-17%, 17% -20%, and 20%-23% （wb） were considered in this study. Bale densities considered in this research were 110-120, 120-130, 130-140, and 140-150 kg/m3. The study was conducted in the form of a split-plot experimental design with three replications and a small rectangular baler was used to bale the second cut alfalfa. Alfalfa losses were measured in the pickup system and compression chamber of baler and losses were separated to stems and leaves. Alfalfa losses were also determined during the bale transportation process. Results showed that alfalfa moisture content had significant effect on the leaf and stem losses of the baler pickup system and alfalfa losses during the transportation process while; leaf and stem losses of baler compression chamber were not affected by alfalfa moisture content. Results also revealed that the bale density had no significant effect on the leaf and stem losses of the baler pickup system and alfalfa losses during the transportation process but leaf and stem losses of baler compression chamber were significantly affected by the bale density.

Practical Performance of High Bulk Modulus Oil

Although hydraulic drives have an advantage of high power density, volumetric shrinkage of hydraulic fluids due to pressure causes various disadvantages such as delay of hydraulic response and compression energy loss. Hydraulic fluids of new concept, high bulk modulus oils, have been developed as a new approach to improve the performance of a hydraulic servo system and verified. In this paper, practical performances of high bulk modulus oil, such as oil temperature rise during pump test, air bubbles generation by ultrasonic wave vibration, oxidation stability and anti-wear property, were studied. And the new oil was confirmed to have excellent practical performances besides advantages in pressure response and volumetric efficiency of pumps. Various new applications of the new oil are promising.

新款森林王牌墙板挤出机获专家好评

3月23日，森林王牌无轨轻质隔墙条板挤出成型机专家研讨论证会在京举行，与会专家对款设备的功能性给予了很高评价。

Self-thinning Rules at Chinese Fir(Cunninghamia lanceolata) Plantations——Based on a Permanent Density Trial in Southern China

Data selection and methods for fitting coefficients were considered to test the self-thinning law. TheChinese fir (Cunninghamia lanceolata) in even-aged pure stands with 26 years of observation data were applied tofit Reineke's (1933) empirically derived stand density rule (No∝d^-1.605, N = numbers of stems, d= mean diameter),Yoda's (1963) self-thinning law based on Euclidian geometry (v ∝ N^-3/2, v= tree volume), and West, Brown andEnquist's (1997, 1999)(WBE) fractal geometry (w ∝ d^-8/3). OLS, RMA and SFF algorithms provided observedself-thinning exponents with the seven mortality rate intervals (2%--80%, 5%--80%, 10%- 80%, 15%--80%,20%- 80%, 25%--80% and 30%- 80%), which were tested against the exponents, and expected by the rules con-sidered. Hope for a consistent allometry law that ignores species-specific morphologic allometric and scale differ-ences faded. Exponents a of N ∝ d^α, were significantly different from -1.605 and -2, not expected by Euclidianfractal geometry;exponents β of w ∝ N^β varied around Yoda's self-thinning slope - 3/2, but was significantly differentfrom - 4/3;exponent Y of w ∝ d^γ tended to neither 8/3 nor 3.

Dimensional Analysis on Resistance Characteristics of Labyrinth Seals

Experimental investigation of stepped and straight-through labyrinth seals was designed to study the sealing performance of two different typical labyrinth seals.In order to facilitate dimensional analysis on the flow resistance characteristics of labyrinth seals,the variable cross-section of the flow channels are considered as constant cross-section flow.The mechanical energy loss of flow caused by throttle turbulence intensity is considered as caused by friction along the way.The friction coefficient of stepped labyrinth seals is bigger than that of straight-through labyrinth seals by more than 40% for the same Reynolds number and the ratio of equivalent diameter and the seal length.The expression of friction coefficient /and /Re are obtained from experimental data.The verifications indicate that the expressions are highly accurate.The contribution to the total pressure drop of each tooth cavity gradually becomes less along the flow direction.

Combination of vitamin C and zinc gluconate prevented vanadium-induced tight junction leakage of MDCK cell monolayer

The tight junction disorder plays an important role in the pathological process of many chronic diseases, and is becoming a major concern for the clinical application of metal drugs, i.e. anti-diabetic vanadium compounds. The development of novel tight junction protecting agents has thus been a major research focus. Since oxidative stress is the primary cause for vanadium toxicity, the present work tested the protective effects of zinc gluconate （Zn2＋） alone and when combined with vitamin C （VC） on the vanadium compound （VO（acac）z.）-mediated paracellular leakage of MDCK cells. The experimental results showed that VO（acac）2_ treatment significantly increased the paracellular permeability of MDCK monolayer. Zn2＋ alone showed no protective effects and VC ameliorated tight junction leakage of MDCK cells when given in the basal chamber. Interestingly, unilateral treatment with the combination of Zn2＋ and VC effectively prevented the increase of paracellular permeability. In addition, the combination of zinc and VC down-regulated the levels of reactive oxygen species in both the control and VO（acac）2-treated MDCK cells and caused the elevation of intracellular Ca2＋; both effects were beneficial for the maintenance of integrity of intercellular tight junction. Our results provided a simple but very effective method of preventing the metal toxicity for clinical aoNication of anti-diabetic vanadium compounds.

Application of the condenser lens in microwave hyperthermia

According to the aplanatism theory, lens can be used to focus the electromagnetic wave. A piano-convex hyperboloid of revo- lution lens made of low loss material is designed for combinatorial applications with the rectangle microstrip applicator in microwave hyperthermia. Results of the extensive simulations and experiments show that the introduction of the lens to the clinical used antenna can significantly improve the directivity and hence increase the microwave power density in near field. In microwave hyperthermia applications, the lens antenna will exhibit superior directivity, high gain and well thermal efficiency for tumor in superficial layer. Besides, it has small treatment area that is helpful for reducing the injury of the normal tissue around the tumor.