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31.
This paper is based on the research we have done in recent years of the constitute law of gas seepage in rock fractures. Both
experiments and theoretical derivations will be discussed. The gases used in our experiments include methane and CO2, both of which are highly adsorptive. The experiments were conducted mainly in coal fractures. The results reveal that the
permeability coefficient of gas in rock fractures varies parabolically with respect to fracture pore pressure. When the pore
pressure is below a certain value, the permeability coefficient decreases while the pore pressure increases. It is different
from the water seepage law in fractures. Analysis shows that this abnormality is caused by adsorption. It is also concluded
that the tangent deformation has the same effects as normal deformation on gas seepage law. The permeability of gas in fractures
has a negative exponent relationship with both normal deformation and tangent deformation. 相似文献
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Yangsheng Yuan Yahong Chen Chunhao Liang Yangjian Cai Yahya Baykal 《Applied physics. B, Lasers and optics》2013,110(4):519-529
With the help of a tensor method, we derive an explicit expression for the on-axis scintillation index of a circular partially coherent dark hollow (DH) beam in weakly turbulent atmosphere. The derived formula can be applied to study the scintillation properties of a partially coherent Gaussian beam and a partially coherent flat-topped (FT) beam. The effect of spatial coherence on the scintillation properties of DH beam, FT beam and Gaussian beam is studied numerically and comparatively. Our results show that the advantage of a DH beam over a FT beam and a Gaussian beam for reducing turbulence-induced scintillation increases particularly at long propagation distances with the decrease of spatial coherence or the increase of the atmospheric turbulence, which will be useful for long-distance free-space optical communications. 相似文献
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In order to quantitatively study the jasmonate biosynthetic pathway, we chemically synthesized a pair of isotope mass probes and established a labeling protocol. The pair of mass probes used in our work were ω-bromoacetonylpyridinium bromide (BPB) and d(5)-ω-bromoacetonylpyridinium bromide (d(5)-BPB), which contain carboxylic acid reactive groups, isotopically labeled groups and permanent positive charges. High performance liquid chromatography (HPLC) and electrospray ionization quadrupole-time of flight mass spectrometry (ESI-QTOF-MS) were used for the detection of labeled standard mixtures and plant samples. In comparison to negative mode electrospray ionization detection of unlabeled analytes, the ESI signal of reverse charge labeled compounds was shown to improve by 20- to 80-fold. Accurate relative quantification was achieved as no isotopic effects of the different isotope labeled phytohormones during RP/SCX mixed-mode liquid chromatographic separation were observed. A data analysis method was established for analyzing metabolic pathways using our labeling strategy. We then applied our method and examined the jasmonate biosynthetic pathway of rice under salt stress and the premature senescence mutant. Here we found that under salt stress conditions, rice showed up-regulation in (13S)-hydroperoxyoctadecatrienoic acid (HOPT), cis-(+)-12-oxophytodienoic acid (OPDA), 3-oxo-2-(2'-pentenyl)-cyclopentane-1-octanoic acid (OPC-8) and jasmonoyl-valine (JA-Val) levels, while α-linolenic acid (LA) and jasmonic acid (JA) showed down-regulation, and three components (HPOT, OPC-8 and JA-Val) were accumulated. The premature senescence mutant showed up-regulation in all major components of the jasmonate biosynthetic pathway with the exception of LA, and an accumulation of HPOT, OPC-6 and JA-Val. This study demonstrates that our chemical stable isotope labeling strategy can be used as a powerful tool for metabolic pathway analysis of phytohormones in plants. 相似文献
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高温高压花岗岩钻孔实验表明,温度低于500℃,静水应力低于150MPa 状态下,岩体的钻孔变形均属于稳态蠕变变形阶段. 该文选取了广义开尔文模型来反映其特征,通过拉普拉斯变换及逆变换,详细推演出了钻孔径向位移解析解,并且考虑温度-应力的耦合效应,给出了模型参数随温度及应力变化的关系式. 利用该关系进行拟合计算,说明广义开尔文模型来表达高温高压环境中的花岗岩稳态蠕变变形特性,寻求蠕变参数是合理可靠的. 该文对于高温岩体地热资源开发中的钻孔施工与维护、钻孔变形量预测等方面,具有实际的指导意义. 相似文献
35.
Bin Zhu Nan Chen Denghua Zhu Yangsheng Li Wei Sun Guihua Liu Guoping Du 《Journal of Sol-Gel Science and Technology》2013,66(1):126-132
In this work, we used a low temperature solvothermal method to synthesize Eu3+-doped LaF3 (LaF3:Eu3+) nanocrystals. The effect of thermal annealing on their phase structures and luminescence properties was studied. Transformation from LaF3 to LaOF was observed after the annealing, and the initial transformation process was studied using a rapid thermal annealing technique. It was found that a sufficiently high annealing temperature is required for the transformation of LaF3 to LaOF. LaOF phase started to be formed after annealing at 500 °C for as short as 5 min, and higher annealing temperatures and longer annealing time led to a larger amount of LaOF formed. With the increase of the formation of LaOF, the luminescence was greatly enhanced. Strong O2? → Eu3+ charge transfer band was present in these samples annealed at 500 °C and higher temperatures, and greatly enhanced 7F0 → 5D2 transition of Eu3+ was also observed. 相似文献
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PBT溶于甲基磺酸(MSA)和多聚磷酸(PPA)等强酸溶剂中时能形成液晶。用TGA法测定了PBT在氮气和空气中的热分解温度,分别高达690℃和585℃。计算了PBT在氮气中的分解活化能为161 kJ/mol。测定了PBT-MSA体系液晶的退偏振光强度-温度谱和浓度-温度二元液晶区域相图,并发现8%的PBT-PPA体系表现出特殊的退偏光强度-温度特性。液晶和PBT固体的X-衍射图表明液晶状态下沉积的薄膜保持了液晶态的结构,固体小角光散射的H_v图表明非液晶态下沉积的PBT薄膜有球晶结构。 相似文献
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The worldwide primary demand of energy will keep rising over the coming decades. It becomes essential and desirable to exploit lignite, 23 % reservation of the whole coal energy, by a suitable and effective technique. However, the current technology limitations of the exploiting and utilizing of lignite have caused low exploiting rate and high pollution situation. Owing to the development of the in situ gasification techniques, the lignite has become more attractive in the energy field than ever. The permeability of coal is a crucial factor in determining the tars (liquid phases) and gases production during the in situ gasification process. And the transport properties of the coal will in turn affect the thermal and chemical-mechanical reactions. Here, in this work, the permeability of lignite has been tested from room temperature (25 $^{\circ }$ C) up to as high as 650 $^{\circ }$ C through a triaxial rock permeability testing system under different pore pressures. A remarkable decrease of permeability can be observed during the whole temperature zone (25–650 $^{\circ }$ C) as the pore pressure increasing. The permeability curve versus temperature up to 650 $^{\circ }$ C has been divided into four stages based on the three peak values of the permeability. The competition between the strength of the frame structure with the shrinkage due to pyrolysis determines the significant fluctuation of the permeability versus temperature. Furthermore, the combined effect of temperature and pressure shows that the valleys and peaks in stage II will shift to higher temperature zone, while the valleys and peaks stay in the same temperature place in stage III and IV. The current investigation results of the permeability property of lignite will provide essential and valuable information for the exploiting and utilizing of lignite, especially by the in situ pyrolysis technique. 相似文献