A simple prediction model for asphalt surface texture incorporating mix gradation and air voids

This paper presents the results of a preliminary study that seeks to show how asphalt grading and air voids are related to the texture depth of asphalt. The fiftieth percentile particle size (D50) is shown to be a good predictor of texture depth measurements from a collected database of field and laboratory studies. The D50 is used to normalise collected texture data and this 'relative texture' is shown to correlate with air voids. Regression analyses confirm that air voids should be included along with a measure of gradation in the interpretation of asphalt surface texture.The derived formulae are used to develop correlation charts.

Re-examination of the coefficient of determination (r2) using road materials engineering case studies

The analysis of scientific data is integral to materials engineering and science. The correlation between measured variables is often quantified by estimating the coefficient of determination or the r2 value. This is the recognised procedure for determining linear relationships. The authors review the derivation of the r2 value and derive an associated quantity, termed the relative deviation (RD), which is the ratio of the root mean square of the deviations about the fitted line to the root mean square of the deviations about the y bar line expressed as a percentage. The relative deviation has an advantage over the coefficient of determination in that it has greater numerical sensitivity to changes in the spread of data about the fitted line, especially when the scatter is small. In addition, the relative deviation is able to define, in percentage terms, the reduction in scatter when different independent variables are correlated with a common dependent variable. Four case studies in the materials field (aggregate crushing value, Atterberg limits, permeability and creep of asphalt) from work carried out at the Queensland Main Roads Department are presented to show the use of the new parameter RD.

病毒感染草鱼胸腺的EST分析和免疫相关基因的鉴定

以感染草鱼(Ctenopharyngodon idellus)出血病病毒(GCHV)的草鱼胸腺为材料,构建了草鱼胸腺的SMARTcDNA文库。筛选文库获得到1933条有效EST序列。BLASTX分析显示,583条序列在公共数据库中能找到同源基因(E-value≤1.00E10-3,Identities≥30%),另外1350条序列则找不到显著同源性。已知基因按具体功能可划分为6类,大部分与细胞内的各种生理过程、细胞结构以及免疫防御相关。研究结果从分子水平上表明鱼类的胸腺在机体感染病毒的免疫反应中发挥重要作

对虾白斑综合症病毒结构蛋白60B的原核表达和其基本氨基酸序列的初步分析

VP60B是对虾白斑综合症病毒(WSSV)中含量很少的一个结构蛋白。VP60B的一段序列与腺病毒纤维蛋白(Adenovirus type 5 fiber protein)的knob domain的一段序列具有同源性。本试验将VP60B基因克隆到原核表达系统中,在低温条件下,诱导了VP60B蛋白的表达。结果显示VP60B在该系统主要是以包含体的形式存在。原核表达的VP60B不能被鼠抗WSSV多克隆血清所识别,预示该蛋白的免疫原性较弱。通过对VP60B氨基酸序列的分析,发现有一个跨膜区,这预示着该蛋白可能位于

微囊藻毒素RR的制备及鉴定

以野外收集的水华蓝藻为原料,建立了以75%甲醇溶液提取、快速色谱和半制备色谱分离为主要步骤的微囊藻毒素分离纯化方法,并用HPLC、分光光度计和电喷雾质谱对所得毒素的纯度和结构进行了鉴定.结果表明,所得毒素为MCRR,纯度大于95%,其紫外吸收光谱在239nm处有特征吸收,分子组成为环(Ala-Arg-MeAsp-Arg-Adda-Glu-Mdha),分子量为1037.

饲料质量对丰鲤和奥尼罗非鱼氮及能量收支的影响

实验比较了丰鲤与奥尼罗非鱼摄食低质和高质两种等能饲料时的氮收支和能量收支。低质饲料的蛋白质含量为 34.2 5 %、蛋白质主要来源为豆粕 ,高质饲料的蛋白质含量为 4 5 .4 4 %、蛋白质主要来源为鱼粉。 5 3d的生长结果显示 :摄食低质饲料时 ,奥尼罗非鱼通过降低排泄氮、排泄能和代谢能的比例 ,使生长氮和生长能的比例显著高于丰鲤 ,摄食高质饲料时 ,则通过降低粪氮和粪能的比例取得快速生长的效果 ;丰鲤生长氮和生长能比例不受饲料质量的显著影响 ,但高质饲料使排泄氮和代谢能比例显著降低 ;奥尼罗非鱼的

建鲤和异育银鲫摄食不同质量饲料时的氮收支和能量收支比较

实验探讨了建鲤和异育银鲫摄食低质和高质饲料时氮和能量的收支情况。低质饲料以豆粕为主要蛋白源 ,饲料蛋白含量为 33 91% ,高质饲料以鱼粉为主要蛋白源 ,饲料蛋白含量为 4 5 5 9%。 5 5d的生长结果显示 ,氮收支和能量收支受到饲料质量和鱼类种类的显著影响 :摄食低质饲料时 ,建鲤的生长氮和生长能比例显著低于异育银鲫 ,排泄氮、排泄能和代谢能比例显著高于异育银鲫 ;摄食高质饲料时 ,两种鱼的氮收支和能量收支无显著差异 ;建鲤的氮收支和能量收支受饲料质量的显著影响 ,摄食低质饲料时 ,其生长氮和生

Changes in biomechanical properties of the coronary artery wall contribute to maintained contractile responses to endothelin-1 in atherosclerosis.

AIMS: Our aim was to determine whether alterations in biomechanical properties of human diseased compared to normal coronary artery contribute to changes in artery responsiveness to endothelin-1 in atherosclerosis. MAIN METHODS: Concentration-response curves were constructed to endothelin-1 in normal and diseased coronary artery. The passive mechanical properties of arteries were determined using tensile ring tests from which finite element models of passive mechanical properties of both groups were created. Finite element modelling of artery endothelin-1 responses was then performed. KEY FINDINGS: Maximum responses to endothelin-1 were significantly attenuated in diseased (27±3 mN, n=55) compared to normal (38±2 mN, n=68) artery, although this remained over 70% of control. There was no difference in potency (pD2 control=8.03±0.06; pD2 diseased=7.98±0.06). Finite element modelling of tensile ring tests resulted in hyperelastic shear modulus μ=2004±410 Pa and hardening exponent α=22.8±2.2 for normal wall and μ=2464±1075 Pa and α=38.3±6.7 for plaque tissue and distensibility of diseased vessels was decreased. Finite element modelling of active properties of both groups resulted in higher muscle contractile strain (represented by thermal reactivity) of the atherosclerotic artery model than the normal artery model. The models suggest that a change in muscle response to endothelin-1 occurs in atherosclerotic artery to increase its distensibility towards that seen in normal artery. SIGNIFICANCE: Our data suggest that an adaptation occurs in medial smooth muscle of atherosclerotic coronary artery to maintain distensibility of the vessel wall in the presence of endothelin-1. This may contribute to the vasospastic effect of locally increased endothelin-1 production that is reported in this condition.

Evolution of structural defects in SiOx films fabricated by electron cyclotron resonance plasma chemical vapour deposition upon annealing treatment

We study the structural defects in the SiOx film prepared by electron cyclotron resonance plasma chemical vapour deposition and annealing recovery evolution. The photoluminescence property is observed in the as-deposited and annealed samples. [-SiO3](2-) defects are the luminescence centres of the ultraviolet photoluminescence (PL) from the Fourier transform infrared spectroscopy and PL measurements. [-SiO3](2-) is observed by positron annihilation spectroscopy, and this defect can make the S parameters increase. After 1000 degrees C annealing, [-SiO3](2-) defects still exist in the films.

Mode characteristics of semiconductor equilateral triangle microcavities with side length of 5-20 mu m

Semiconductor equilateral triangle microresonators (ETRs) with side length of 5, 10, and 20 mum are fabricated by the two-step inductively coupled plasma (ICP) etching technique. The mode properties of fabricated InGaAsP ETRs are investigated experimentally by photoluminescence (PL) with the pumping source of a 980-nm semiconductor laser and distinct peaks are observed in the measured PL spectra. The wavelength spacings of the distinct peaks agree very well with the theoretical longitudinal mode intervals of the fundamental transverse modes in the ETRs, which verifies that the distinct peaks are corresponding to the enhancement of resonant modes. The mode quality factors are calculated from the width of the resonant peaks of the PL spectra, which are about 100 for the ETR with side length of 20 mum.

Near infrared photoluminescence from Yb,Al Co-implanted SiO2 films on silicon

Intense room-temperature near infrared (NIR) photoluminescence (980 nm and 1032 nm) is observed from Yb,Al co-implanted SiO2 films on silicon. The optical transitions occur between the F-2(5/2) and F-2(7/2) levels of Yb3+ in SiO2. The additional Al-implantation into SiO2 films can effectively improve the concentration quenching effect of Yb3+ in SiO2. Photoluminescence exitation sprectroscopy shows that the NIR photoluminescence is due to the non-radiative energy transfer from Al-implantation-induced non-bridging oxygen hole defects in SiO2 to Yb3+ in the Yb-related luminescent complexes. It is believed that the defect-mediated luminscence of rare-earth ions in SiO2 is very effective.

High-quality multiple quantum wells selectively grown with tapered masks by ultra-low-pressure MOCVD

An InGaAsP/InGaAsP multiple quantum wells (MQWs) selectively grown by ultra-low-pressure (22 mbar) metal-organic chemical vapor deposition was investigated in this article. A 46 nm photoluminescence peak wavelength shift was obtained with a small mask width variation (15-30 mu m). High-quality crystal layers with a photoluminescence (PL) ftill-width-at-half-maximum (FWHM) of less than 30 meV were achieved. Using novel tapered masks, the transition-effect of the tapered region was also studied. The energy detuning of the tapered region was observed to be saturated with the larger ratio of the mask width divided to the tapered region length. (C) 2005 Elsevier B.V. All rights reserved.