Template-free fabrication of hexagonal ZnO microprism with an interior space

Well-faceted hexagonal ZnO microprisms with regular interior space have been successfully prepared by a template-free hydrothermal synthetic route. The morphologies of the products depend on the experimental conditions such as the solvent, the concentration of ammonia aqueous solution, and the reaction temperature. Through manipulation of the aging time, the as-prepared ZnO can be controlled as a monodispersed hexagonal twinning solid or as hollow microprisms. Moreover, the evolution process of the hollow ZnO nanoarchitecture after reaction for 2, 6, 12, and 24 h has been investigated by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). A possible growth mechanism has also been proposed and discussed. Furthermore, the photoluminescence (PL) measurement exhibits the unique emitting characteristic of hollow ZnO nanostructures.

Peripheries of molecular projection in three-dimensional space and studies of quantitative structure-activity relationships

A new index, i.e., the periphery representation of the projection of a molecule from 3D space to a 2D plane is described. The results, correlation with toxicity of substituted nitrobenzenes, obtained by using periphery descriptors are much better than that obtained by using the areas (i.e., shadows) of projections of the compounds. Even better results were achieved by using the combination of periphery descriptors and the projections areas as well as the indicated variable K reflecting the action of group NO position on the benzene ring.

Crystallization behaviors of n-nonadecane in confined space: Observation of metastable phase induced by surface freezing

Crystallization and phase transition behaviors of n-nonadecane in microcapsules with a diameter of about 5 mu m were studied with the combination of differential scanning calorimetry ( DSC) and synchrotron radiation X-ray diffraction ( XRD). As evident from the DSC measurement, a surface freezing monolayer, which is formed in the microcapsules before the bulk crystallization, induces a novel metastable rotator phase ( RII), which has not been reported anywhere else. We argue that the existence of the surface freezing monolayer decreases the nucleating potential barrier of the RII phase and induces its appearance, while the lower free energy in the confined geometry turns the transient RII phase to a " long- lived" metastable phase.

Atom space distance and computing of molecular similarity

A mathematical model on computation of molecular similarity was suggested, The algorithmic techniques for measuring the degree of similarity between pairs of three-dimensional chemical molecules was represented by modified interatomic distance matrices. Current work was carried out on Indigo 2 work station with Sybyl software. Four groups of molecules were used to compute the molecules similarity to testing the mathematical model with satisfactory results.

Synthesis and properties of two novel Ru(phen)(3)(2+)-based probes for electrochemiluminescent immunoassay

Two novel Ru(phen)(3)(2+)-based probes for electrochemiluminescent immunoassay, Ru(phen)(2)(phen-NHCOCH2CH2COOH)(PF6)(2) and Ru(phen)(2) (phen-NHCOCH2CH2CH2COOH) (PF6)(2), were designed, synthesized and characterized. Electrochemistry, Fluorescence, and electrochemiluminescence of the two complexed are also reported.

Determination of electron mobility in a blue-emitting alternating block copolymer by space-charge-limited current measurements

In this communication we analyse current versus voltage data obtained using one carrier injection at metal/polymer/metal structures, The used polymer is a soluble blue-emitting alternating block copolymer, Our experimental results demonstrate that the electron current is limited by a large amount of traps with exponential energy distribution in the copolymer. The electron ;mobility of 5.1 x 10(-10) cm(2)/V s is directly determined by space-charge-limited current measurements. The electron mobility is at least three orders of magnitude smaller than that for holes in the copolymer. (C) 1999 Elsevier Science Ltd. All rights reserved.

The intermolecular coupling through space for stacked high spin molecules

Intermolecular ferromagnetic interactions in two stacking models for the dimer of high spin molecules are investigated by means of AM1-CI approach. It is shown that the stability of high spin ground state versus low spin state can be simply traced back to the number and the extent of atoms with reversed signs of pi-spin density in neighboring molecules coupled to each other in shortest distance.

Studies on plant calmodulin and its interaction with antagonist W-7 by Ln(3+) luminescence probes

Plant calmodulin (CaM) has been extracted from cauliflower, and the purified CaM has been identified with the activation of NAD kinase (NADK) and the inhibition effect of CaM antagonist W-7. CaM's intrinsic fluorescence and Tb3+ fluorescence showed that there was one tyrosine residue and four metal-binding sites in cauliflower CaM. Based on Forster-type nonradiative energy theory, the distances of Tyr --> site III, IV have been determined, and these are 1.23 nm (Tyr --> site III ) and 1.18 nm(Tyr --> site IV). The Eu3+ and Tb3+ fluorescence probes showed that the combination of CaM with W-7 resulted in significant change on CaM's conformation, but did not affect coordination environment of metal-binding sites.

Development of rRNA and rDNA-targeted probes for fluorescence in situ hybridization to detect Heterosigma akashiwo (Raphidophyceae)

Heterosigma akashiwo (Hada) is a fragile, fish-killing alga. Efforts to understand and prevent blooms due to this harmful species to mitigate the impact on aquaculture require the development of methods for rapid and precise identification and quantification, so that adequate warning of a harmful algal bloom may be given. Here, we report the development and application of rRNA and rDNA-targeted oligonucleotide probes for fluorescence in situ hybridization (FISH) to aid in the detection and enumeration of H. akashiwo. The designed probes were species specific, showing no cross-reactivity with four common HAB causative species: Prorocentrum micans Ehrenberg, P. minimum (Pavillard) Schiller, Alexandrium tarmarense (Lebour) Balech, and Skeletonema costatum (Greville) Cleve, or with four other microalgae, including Gymnodinium sp. Stein, Platy-monas cordiformis (Karter) Korsch, Skeletonema sp.1 Greville and Skeletonema sp.2. The rRNA-targeted probe hybridized to cytoplasmic rRNA, showing strong green fluorescence throughout the whole cell, while cells labeled by rDNA-targeted probe exhibited exclusively fluorescent nucleus. The detection protocols were optimized and could be completed within an hour. For rRNA and rDNA probes, about a corresponding 80% and 70% of targeted cells could be identified and quantified during the whole growth circle, despite the inapparent variability in the average probe reactivity. The established FISH was proved promising for specific, rapid, precise, and quantitative detection of H. akashiwo. (C) 2008 Elsevier B.V. All rights reserved.

Transformation of accommodation space of the Cretaceous Qingshankou Formation, the Songliao Basin, NE China

Analysis of accommodation space variation during deposition of the Cretaceous Qingshankou Formation in the Songliao Basin, NE China, indicates that accommodation space changed both through time and across the basin as a seesaw movement. The mid-upper Qingshankou Formation is divided into three units. In each unit, changes of accommodation space differ in the southern and northern part of the basin. Increasing accommodation in the southern part is accompanied by a decrease in the northern part, and vice versa. Between the northern and southern basin, there was a neutral belt that is like a fulcrum, called the transformation belt here, where the accommodation did not change to any significant degree. We call this response 'accommodation transformation', whose characteristics are defined by tectonic subsidence analysis, palaeontological and sedimentary analyses. The accommodation increasing belt, decreasing belt, transformation belt and accommodation transformation boundary together constitute the accommodation transformation system. The recognition of accommodation transformation in the Songliao Basin provides a new insight into sequence stratigraphy and might be widely applicable.

Near-Space Wide-Swath Radar Imaging With Multiaperture Antenna

Near-space, defined as the altitude region between 20 and 100 km, offers many capabilities that are not accessible for low Earth-orbit (LEO) satellites or airplanes because it is above storm and not constrained by orbital mechanics and high fuel consumption. Hence, a high flying speed can be obtained for the maneuvering vehicles operating in near-space. This offers a promising solution to simultaneous high-resolution and wide-swath synthetic aperture radar (SAR) imaging. As such, one near-space wide-swath SAR imaging technique is presented in this letter. The system configuration, signal model, and imaging scheme are described. An example near-space SAR system is designed, and its imaging performance is analyzed. Simulation results show that near-space maneuvering vehicle SAR indeed seems to be a promising solution to wide-swath SAR imaging.

大港千米桥地区综合地质地球物理研究

Qianmiqiao buried hill, which is a high-yield burial hill pool, was discovered at Dagang oilfield in 1998. To employ the integrated geological and geophysical research at Qianmiqiao area, it is very valuable and meaningful for the petroleum exploration of Bohai Bay Basin and even the whole country. Based on the previous results, this paper is carried out from the research on Huanghua depression, following the law, i.e. the deep part constrains the shallow, the regional constrains the local, takes the geophysical research in Qianmiqiao oilfield, discusses the formation history of burial hills, burial history, thermal history, the generated and expelling history of hydrocarbon, and migration characteristics, probes into the formation of burial hill pool. This paper uses the gravity and magnetic methods which are based on potential field, with natural sources, configures the inner structure of the earth according to the difference in the density and magnetism of the rock. The geophysical characteristics of Dagang oil field is that it is an area with positive Buge gravity anomal. The upheaval of Moho boundary is in mirror symmetry with the depression of the basin's basement. The positive and negative anomaly distributein axis symmetry, and the orientation is NNE. The thickness of the crust gradually reduces from west to east, from land to sea. The depth gradient strip of Curie surface is similar to Moho boundary, whereas their local buried depth is different. Local fractures imply that the orientation of base rock fractures is NNE-NE, and the base rock is intersected by the fractures of the same/ later term, whose orientation is NW, so the base rock likes rhombic mosaic. The results of tomography show that there exists significant asymmetry in vertical and horizontal direction in the velocity configuration of Huanghua depression. From Dezhou to Tianjin, there exits high-speed block, which extends from south to north. The bottom of this high-speed block is in good agreement with the depth of Moho boundary. Hence we can conclude that the high-speed block is actually the crystal basement. According to seismic data, well data and outcrop data, Huanghua depression can be divided into four structure layers, i.e. Pi,2-T, Ji,2-K, E, N-Q. Qianmiqiao burial hills undergo many tectonic movement, where reverse faults in developed in inner burial hill from Indosinian stage to Yanshanian stage, the normal faults extended in Himalayan stage. Under the influence of tectonic movements, the burial hills show three layers, i.e. the reverse rushing faults in buried hills, paleo-residual hill, and extended horst block. The evolution of burial hills can be divided into four stages: steady raising period from Calenonian to early Hercynian, rushing brake drape period from Indosinian to middle Yanshanian, block tilting period in early Tertiary, and heating depression period from late Tertiary to Quaternary. The basin modeling softwares BasinMod 1-D and Basin 2-D, which are made by PRA corporation, are used in this paper, according to the requirement, corresponding geological model is designed. And we model the burial history, thermal history, hydrocarbon generation and hydrocarbon expelling history of Qianmiqiao area. The results show that present bury depth is the deepest in the geological history, the sedimentary rate of Tertiary is highest and its rising rate of temperature rate is higher. During sedimentary history, there is no large erosion, and in the Tertiary, the deeper sediment was deposited in large space, therefore it is in favor of the conservation and transformation of oil and gas. The thermal research shows that the heat primarily comes from basement of the basin, present geotherm is the highest temperature in the geological history. Major source rock is the strata of ES3, whose organic is abundant, good-typed, maturative and of high-expulsive efficiency. The organic evolution of source rock of O has come to the overmature stage, the evolving time is long and the source rock can be easily destroyed. Therefore it is more difficult for the O formation source rock to form the huge accumulation of oil and gas than Es3 formation. In the research of oil assembling, we first calculated the characteristics of the fluid pressure of single well, then analyzed the distribution of the surplus fluid pressure of each formation and profile, and probe the first hydrocarbon migration situation and the distribution of pressure system of buried hill pool. In every formation, the pressure system of each burial hill has its own characteristics, e.g. high pressure or low pressure. In the research of secondary migration, the fluid potential is calculated while the relative low potential area is figured out. In Qianmiqiao area, the west margin faults have the low potential, and hence is the favorable reconnoiter belt.