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11.
Multiparticle production data on proton-nucleus collisions have been analyzed taking the number of ‘created’ charged particles
instead of the observed number of shower particles as the variable. The mean normalized multiplicity,R
A
, has been found to be independent of energy in the energy range (7–8000) GeV and its mass number dependence has been obtained.
The modified analysis introduces some more regularities in the experimental results onp-nucleus collisions like the invariance with respect to energy of the relationshipR
A
= α + βN
h
and the KNO-like scaling of the multiplicity distributions of the created charged particles. The functional form of the scaling
function has been calculated. 相似文献
12.
Shafi KV Ulman A Lai J Yang NL Cui MH 《Journal of the American Chemical Society》2003,125(14):4010-4011
We present a new route for the preparation of gamma-alumina and YAG nanoparticles. Metal salts of ethylhexanoic acids provide good solubility in hydrocarbon solvents and allow efficient ultrasonication. The sonication product is an alumioxane gel, which can reversibly collapse and reform, depending on the solvent used. The dried gel nanoparticles are calcined at temperatures significantly lower than those used in conventional syntheses, resulting in gamma-alumina nanoparticles. This is due to the complete mixing of elements at the atomic level and the small size of the formed nanoparticles. 相似文献
13.
Oded Goldreich Shafi Goldwasser Eric Lehman Dana Ron Alex Samorodnitsky 《Combinatorica》2000,20(3):301-337
at arguments of its choice, the test always accepts a monotone f, and rejects f with high probability if it is ε-far from being monotone (i.e., every monotone function differs from f on more than an ε fraction of the domain). The complexity of the test is O(n/ε).
The analysis of our algorithm relates two natural combinatorial quantities that can be measured with respect to a Boolean
function; one being global to the function and the other being local to it. A key ingredient is the use of a switching (or sorting) operator on functions.
Received March 29, 1999 相似文献
14.
Six fish species-Cirrhinus mrigala (Morakhi), Labeo rohita (Danbhro), Catla catla (Thalli), Wallago attu (Jarko), Ctenopharyngodon idella (Grass), and Cyprimus carpio (Gulfam)--commonly found in the Pakistani Indus river, were selected for fat and cholesterol evaluation. Fat content was quantified by the Folch method and cholesterol content was determined by a simple GC method. The application of the proposed method to quantify cholesterol content revealed variations among the six breeds evaluated. The breeds studied contained 0.80-1.95% fat, indicating that all investigated fishes were lean; significant variation was found in cholesterol content, and ranged between 72 and 392 mg/100 g. Standard addition analyses showed that the method was accurate, as the recovery of cholesterol varied from 95 to 103%, with a coefficient of variance not more than 5.6%. The results showed that, after the development of suitable calibration, within 11 min, the cholesterol could be accurately determined by GC. 相似文献
15.
Nusrat Lubna Gregory AunerRahul Patwa Hans HerfurthGolam Newaz 《Applied Surface Science》2011,257(10):4749-4753
Thin film materials are widely used in the fabrication of semiconductor microelectronic devices. In thin film deposition, cleanliness of substrate surface have become critically important as over 50% of yield losses in integrated circuit fabrication are caused by microcontamination [1]. There are many wafer cleaning techniques. The most successful approach for silicon wafer cleaning technique is RCA clean [2]. But for glass substrate it is still not known which procedure of cleaning is the best. This paper provides an understanding of the right way of glass wafer cleaning method, with a focus towards identifying good bond strength. Two wafer cleaning techniques have been used for cleaning glass substrates in the context of laser micro-joining of dissimilar substrates. First cleaning procedure involves two steps, first cleaning in acetone solution and then in DI water solution. After each step dried with N2. Second cleaning procedure involves four steps, first cleaning with 1% Alconox solution, second in DI water, third in acetone solution and finally in a methanol solution and dried with N2 after each step. Deposition of Ti thin film on top of these two types of substrate using DC magnetron sputtering method also showed better adhesion of Ti film on glass for the second type of cleaning method. Scanning electron microscopy (SEM) analyses of the lap shear tested failed surfaces for these two kinds of samples revealed strong bond for samples prepared by second cleaning method compared to first cleaning method. Characterization of these two sets of samples using X-ray photoelectron spectroscopy (XPS) has shown excellent contamination removal for the second cleaning method. This modification is believed to be due to reduction of carbon contamination. 相似文献
16.
Separation of isorhamnetin 3‐sulphate and astragalin from Flaveria bidentis (L.) Kuntze using macroporous resin and followed by high‐speed countercurrent chromatography 下载免费PDF全文
Nusrat Shaheen Li Yin Yanxiang Gu Eric Rwigimba Qianqian Xie Yun Wei 《Journal of separation science》2015,38(11):1933-1941
D4020 resin offered the best dynamic adsorption and desorption capacity for total flavonoids based on the research results from ten kinds of macroporous resin. A column packed with D4020 resin was used to optimize the separation of total flavonoids from Flaveria bidentis (L.) Kuntze extracts. The content of flavonoids in the product was increased from 4.3 to 30.1% with a recovery yield of 90%. After the treatment with gradient elution on D4020 resin, the contents of isorhamnetin 3‐sulfate and astragalin were increased from 0.49 to 8.70% with a recovery yield of 74.1% and 1.16 to 30.8%, with a recovery yield of 92.2%, respectively. Further purification was carried out by one‐run high‐speed countercurrent chromatography yielding 4.5 mg of isorhamnetin 3‐sulfate at a high purity of 96.48% and yielding 24.4 mg of astragalin at a high purity of over 98.46%. 相似文献
17.
Castillo-Martínez E Bieringer M Shafi SP Cranswick LM Alario-Franco MÁ 《Journal of the American Chemical Society》2011,133(22):8552-8563
A novel ScVO(3) perovskite phase has been synthesized at 8 GPa and 1073 K from the cation-disordered bixbyite-type ScVO(3). The new perovskite has orthorhombic symmetry at room temperature, space group Pnma, and lattice parameters a = 5.4006(2) ?, b = 7.5011(2) ?, and c = 5.0706(1) ? with Sc(3+) and V(3+) ions fully ordered on the A and B sites of the perovskite cell. The vanadium oxygen octahedra [V-O(6)] display cooperative Jahn-Teller (JT) type distortions, with predominance of the tetragonal Q(3) over the orthorhombic Q(2) JT modes. The orthorhombic perovskite shows Arrhenius-type electrical conductivity and undergoes a transition to triclinic symmetry space group P-1 close to 90 K. Below 60 K, the magnetic moments of the 4 nonequivalent vanadium ions undergo magnetic long-range ordering, resulting in a magnetic superstructure of the perovskite cell with propagation vector (0.5, 0, 0.5). The magnetic moments are confined to the xz plane and establish a close to zigzag antiferromagnetic mode. 相似文献
18.
T. Aziz S. Ahmad H. Ahrar S. B. Beri V. S. Bhatia S. N. Ganguli S. K. Gupta V. K. Gupta A. Gurtu G. L. Kaul Manjit Kaur A. R. Khan S. Kumar P. K. Malhotra L. K. Mangotra I. S. Mittra Y. Prakash N. K. Rao M. Shafi M. Shyam G. Singh S. K. Tuli Aligharh Collaboration Bombay Collaboration Chandigarh Collaboration Jammu Collaboration Varanasi Collaboration 《Zeitschrift fur Physik C Particles and Fields》1985,27(3):325-328
19.
Q. Shafi 《Physics letters. [Part B]》1977,69(4):473-476
We discuss, within the framework of the basic Pati-Salam model, the feasibility of the hypothesis that quarks are unconfined, integer-charged, relatively light (mass ~2?3 GeV) and short-lived (τq?10?12s). Our estimates for the quark life-times vary between 10?12s and 10+11 s for the white and blue quarks and between 10?12 s and 10+16 s for the red quarks. The life-times depend very sensitively, and it is shown why, on the values of the Salam-Weinberg mixing angle and the quark-gluon coupling constant. 相似文献
20.
The crystal structure of 3β-hydroxy-4-(1,4-oxazin-4-yl)-androstane (C31H54NO2) has been determined by X-ray crystallographic techniques. The compound crystallizes in the orthorhombic space group P21212 with the following unit-cell parameters: a = 7.124(1) Å, b = 10.127(1) Å, c = 40.660(1) Å, V = 2933.4(1) Å3, and Z = 4. The structure has been solved by direct methods and refined to an R factor of 0.067. Three six-membered rings, A, C, and E, exist in the chair conformation, while the ring B adopts a distorted half-chair conformation. The five-membered ring, D, has a distorted envelope conformation. The crystal structure is stabilized by strong intermolecular O-H...O hydrogen bonds. 相似文献