24 resultados para 1236


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采用示差扫描量热仪研究了稀土顺式聚丁二烯(PB)等温过程的结晶及其熔融行为。结果表明,在等温结晶的后期存在晶型完善的过程,而且随着等温结晶温度的提高,结晶速率均下降。PB的熔融总是在比等温结晶温度高约2℃处开始,而且在10℃/min的升温速率下,DSC曲线不仅显示出很宽的熔融温度范围,而且在低温处还出现了小肩峰,说明等温结晶后体系中具有在该升温速率下不同稳定性的晶体。

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The crystalline modifications alpha and beta of polypropylene (PP) were studied by using polarized light microscopy (PLM), wide-angle X-ray diffraction (WAXD), and differential scanning calorimetry (DSC). Typically beta crystals surrounded by alpha spherulites were observed at low temperature. With increasing temperature the beta crystals melted and a new crystal appeared. More interestingly, the melting temperature of the new crystal was about 5degrees higher than that of alpha spherulites originally present in the sample formed isothermally. It was assumed that this new crystal was the recrystalline alpha crystal. This assumption was supported by the DSC results. Furthermore, the crystallization kinetics of the PP used was studied on the basis of the traditional Avrami analysis. As a result, the Avrami exponents of crystallization temperature from 120 to 130degreesC ranged between 4.21 and 3.60, indicating that the crystallization mechanism of PP order melt was spherulitic growth and random nucleation.

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Tridentate ligand[(2,6-ArN=C(Me))(2)C5H3N](Ar=4-allyl-2,6-(i-Pr)(2)C6H3)(4)which contains allyl groups on each aryl ring was ready prepared and reacted with FeCl2. 4H(2)O to give the precatalyst [(2,6-ArN=C(CH3))(2)C5H3N]. FeCl2 (5). Compounds 2-5 were characterized by H-1 NMR, EI-MS,and IR. The complex 5 which was actived by methylaluminoxane(MAO) exhibits high activity for ethylene polymerization [1.9 x 10(6) g pE.(mol Fe . h)(-1) at 0 degreesC]. It was showed that the activity was decreased with increasing temperature and the polymer product was highly linear PE with (M) over bar (eta) varying from 50000 to 260000.

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合成了烯丙基取代的含氮中性配体 [( p-C3H5) C12 H16]2 N3C9H9,然后与 Fe Cl2 反应合成含烯丙基取代的三齿“茂后”烯烃聚合催化剂 [( p-C3H5) ( C12 H16) ]2 N3C9H9Fe Cl2 ,通过 IR,1H NHR,EI-MS对化合物进行了表征 .研究了它催化乙烯聚合的能力 ,这种催化剂与 MAO组成的催化体系可在常压下催化乙烯聚合 ,活性最高达 1 .9× 1 0 6g PE/ ( mol Fe· h) .所得聚乙烯粘均分子量在 5× 1 0 4 ~ 2 .6× 1 0 5之间

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The convolution between co-polarization amplitude only data is studied to improve ship detection performance. The different statistical behaviors of ships and surrounding ocean are characterized a by two-dimensional convolution function (2D-CF) between different polarization channels. The convolution value of the ocean decreases relative to initial data, while that of ships increases. Therefore the contrast of ships to ocean is increased. The opposite variation trend of ocean and ships can distinguish the high intensity ocean clutter from ships' signatures. The new criterion can generally avoid mistaken detection by a constant false alarm rate detector. Our new ship detector is compared with other polarimetric approaches, and the results confirm the robustness of the proposed method.

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在本研究所中,我们想建立一维的温度预报模式,在这个模式中,拟采用湍能和混合长度来求湍粘性系数。其中混合长度分和不稳定两种情况。这比 A。OM STEDT (1983)计算湍粘性系数的工作量要少生些。因而对于业务预报有应用前景。在这个工作中,我们把中性情况下的混合长度理论推广应用于非中性状态的湍粘性系数计算,并进一步用于温度预报。

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A new phenyl glycoside, 2-(3'-O-beta-D-glucopyranosyl) benzoyloxygentisic acid (1), along with seven known glycosides 2-8 was isolated from Tibetan herbal medicine Lomatogonium rotatum. The structures of the compounds were elucidated by spectroscopic methods including 1D and 2D NMR techniques and MS data.

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As a kind of strategic resource,petroleum play an very important role in current social stability, economic development and state safety. Since 1993 China has turned from a net oil exporter into a net oil importer, the figure of imported oil increased from then on. In 2004 China's total energy consumption exceeded Japan’s, and ranked in the second place, just inferior to America. Today China is the world’s third-largest importing nation, accounting for 6% of world imports and 8% of world consumption. Comparing with other strategic petroleum reserve schemes, underground oil storage possess many advantages, such as security, economy, less pollution, save land, suited for strategic reserve and so on, so it is the most ideal form for strategic petroleum reserve. In the background of China Strategic Petroleum Reserve Program started just now, this paper choose Circum-Bo sea region as a study area, and do some system study on the underground oil storage caverns constructed in inter-large granite rock masses in Circum-Bo sea region. On the foundation of a great amount of information come from both home and abroad, firstly this paper analysed the principle, economy, cavern shape, profile dimension, and gain some cognizances and logos, as follows: ①Hard rock mass such as granite is the major rock, in which underground oil storage are constructed; ②Unlined underground oil storage caverns had been wide spread used as a sort of oil storage form abroad, there already exist a suit of skilled experience and technologies to prevent oil product from leaking; ③Compared with surface tanks, underground oil storage cavern possess predominance in economy clearly. In general, it will be more economical when the storage capacity exceed 50000m3. The quality of rock mass is the most important factor for underground storage cost, however such as hydrogeology, storage capacity, the number of storage galleries, the length, storage product, mechanical equipments, geographic location also influent the cost. In designed depth of the underground storage, the rock mass of Jinzhou mainly belong to class Ⅱ, but parts with dykes, clayization alteration, and dense joints are Ⅲ, Ⅳ; ④Now, there are few underground oil storages span more than 25m in both abroad and home. The examples of some ancient underground works and modern underground excavation with wide span surely give us many precious elicitations to construct more great unlined storage caverns, when the rock mass quality is good, cavern shape and construction method also are proper, it is quite possible to construct underground oil storage cavern with span more than 30m . The main axis orientation of Jinzhou underground oil storage cavern is NW direction, the cavern's elevation locate between -53msl and -76msl. The storage's total volume is about 3×106m3, composed of 8 parallel galleries with 950m length, the pillars between them are 45m, and every two of galleries form one unit, which can deposit 75×104m3 for each unit. The product will be stored are Saudi light and Saudi medium crude oil, the main cavern's section is 411.5m2, with 23m height and 19m width. According to the principle and technique of engineering geomechanics, this study supply a sort of system scientific thinking and method for sitting location of underground oil storage in granite region: ① On the foundation of the earth crust stability sub-zone appraise of Circum-Bo sea region, farther research concerning granite distribution, genesis, geological period and fault structure are conducted in stable areas, generally, this paper select Liaoxi, east shore of Liaotung peninsula and Jiaotung peninsula as target areas for underground oil storage regions, where Mesozoic granite is magnitude; ②After roundly comparison in facts of geologic structure, engineering geology, hydrogeology, topography, transportation and so on of three granite distributed areas, at last, selecting Jingzhou granite zone in Liaoxi out as an ideal construction area; ③ Detailed investigation is conducted in the southeast of Baimashi in Jingzhou development district, the final field. Ultrasonic Borehole Television, as a major way to collect original information of borehole rock mass were used, which is very effective to appraise the quality of deep rock mass; ④ According to the field data of tectonic stress, rock mass quality, the spatial distribution of fracture water, some optimum designs in cross section, axial direction and cavern span have been designed for the underground oil storage cavern layout in Jinzhou. To understand the characteristics of swelling alteration rock in Jinzhou granite mass, collected abundant swelling alteration rock engineering examples in granite, which study them in detail, concluded the swelling alteration rock distribute nearly everywhere in China, intruded medium-basic dykes alteration, along discontinuities and mineral hydrothermal alteration with genesis of granite are three main forms clayization alteration rock in granite rock mass. In Jinzhou field, from macro to micro studied the swelling rock which induced by mid-basic dyke intrusion, with weak swelling. In conclusion, this paper conclude the distribution rule and features of expansion alteration rock in filed, and advise some technical suggestions for excavation at swelling alteration rock part. The main features of this paper: ①In the process of site selection, investigation and design, a suit of technique and method of engineering geomechanics metasynthesis were formed, which is significative to guide the large scale underground oil storage cavern sitting location, investigation and design in granite rock mass; ②The detailed discussion on the engineering geology problems in granite mass, such as weathering crust, faults, dykes and clayization alteration rock, are useful for other projects in aspects of site selection, engineering geology evaluation and stability estimation; ③The summary and integration of the genesis, type, countermeasure relate to swelling alteration rock, also is likely to be used for other underground oil storage caverns constructed in swelling alteration granite. In conclusion, this study is meaningful for guiding the large scale underground oil storage for site selection, investigation and design in granite rock mass.

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The protein binding constant, binding sites of the Strychnos alkaloid-strychnine and bovine serum albumin (BSA) was determined by capillary electrophoretic frontal analysis (CE-FA) for the first time. The experiment was carried out in a polyacrylamide-coated fused silica capillary (48.4 cmx50 mu m i.d., 38.1 cm effective length) with 20 mmol/L citrate/MES buffer (pH 6.0, ionic strength 0.17). The applied voltage was 12 kV and detection wavelength was set at 257 nm. The plateau height of the peak was employed to determine the unbound concentration of drug in BSA equilibrated sample solution based on the external drug standard in the absence of protein. The present method provides a convenient, accurate technique for the early stage of drug screening.