矿物掺合料对低水胶比混凝土干缩和自收缩的影响

研究了粉煤灰(0%、10%、30%、50%)、矿粉(0%、10%、30%、50%)以及硅灰(0%、10%、20%)对水胶比为0.24的低水胶比混凝土干缩和自收缩性能的影响规律,并采用双曲线函数的收缩表达式对试验结果进行拟合,定量化地揭示了矿物掺合料对收缩随时间发展趋势的影响,分析了干缩与自收缩的关系.结果表明:粉煤灰有利于减少低水胶比混凝土的干缩,矿粉次之,硅灰略增大混凝土的干缩;粉煤灰有利于减少低水胶比混凝土的自收缩值,矿粉增大了自收缩,硅灰非常明显地增大混凝土自收缩;低水胶比混凝土的自收缩在所测试的干缩中占有很大的比重,而且随着粉煤灰、矿粉和硅灰掺量的增加所占的比重均逐渐增大.     

Effects of mineral oil spray additives on the distribution and dissipation kinetics of pyraclostrobin and azoxystrobin in banana leaves,fruits, and soil

Using LC–MS/MS, a rapid and sensitive method for the simultaneous determination of pyraclostrobin and azoxystrobin residues in banana matrices (leaf and whole banana) and soil was established. The samples were extracted using acetonitrile and purified through C₁₈ dispersive solid-phase extraction. The average recovery of the analytes in various matrices was in the range of 77.3%–103.9% with an RSD range of 0.9%–9.5%. The initial deposition amounts of pyraclostrobin and azoxystrobin at 2 h in the banana leaves of the mineral oil group were 1.43 and 1.31 times in Guangxi, and 2.10 and 1.81 times in Hainan for the water group, whereas those in the soil of the water group were 3.45 and 3.03 times in Guangxi, and 2.14 and 3.48 times in Hainan for the mineral oil group. The half-lives in the leaves and soil of the mineral oil group were not remarkably different from those of the water group. The terminal residue of the analytes on the whole banana was <0.02 mg/kg at 14 days after application from the two sites. The results of this work may indicate and promote the safety of using pyraclostrobin and azoxystrobin in banana production, especially with mineral oil spray adjuvants.     

2017年天然气水合物研发热点回眸

 2017年，天然气水合物研发领域散发出强劲活力，发生了一系列重大事件。本文回顾了2017年日本南海海槽天然气水合物试采、中国神狐海域天然气水合物试采、中国荔湾海域天然气水合物试采、天然气水合物作为新矿种等重大事件和进展，盘点了天然气水合物油气系统在中国南海神狐海域等主要地区的应用与研究、动力学抑制剂、开采方法、沉积物稳定性、环境效应等研究热点，部分展示了中国在天然气水合物领域作出的贡献，并进一步分析了天然气水合物未来研究热点。     

稠油蒸汽驱过程中储集层伤害模式分析——以辽河盆地西部凹陷齐40区块为例

蒸汽注采过程中的储集层伤害是导致稠油开发后期产量下降的重要因素之一,其伤害机理与伤害模式一直是油藏开发过程中的研究难点。以辽河油田齐40区块莲花油层为例,采用物理模拟实验的方法,分析了蒸汽驱过程中储集层的伤害机理,建立了研究区块蒸汽驱过程中储集层伤害模式。研究结果表明,高温强碱性蒸汽注入后,高温溶蚀区中的矿物溶解量增加,储集层物性明显变好;而中温低溶膨胀区至低温膨胀区中,蒸汽对储集层物性逐渐转为破坏作用,岩石颗粒的溶解量降低,生成的钠基蒙脱石等黏土矿物发生水化膨胀并堵塞孔隙喉道,致使储集层受到伤害。     

A system for measuring elastic wave velocity under high pressure and high temperature using a combination of ultrasonic measurement and the multi‐anvil apparatus at SPring‐8

An experimental system to measure the elastic wave velocities of hot‐pressed polycrystalline samples at high pressure and high temperature has been installed at SPring‐8. It uses a combination of the ultrasonic pulse‐echo‐overlap method and Kawai‐type multi‐anvil apparatus (SPEED‐1500). X‐ray radiographic imaging enables the sample length to be determined at high pressure and high temperature, which is indispensable for precise determination of elastic wave velocity. Precise measurements of the elastic wave velocities of various minerals have been determined at pressures up to 19 GPa and temperatures up to 1673 K. The experimental technique provides the precise elastic wave velocities of various materials corresponding to those in the Earth's mantle.     

非糖尿病绝经后女性胰岛素抵抗与骨代谢的相关性研究

为探讨胰岛素抵抗与骨代谢之间的相互关系,采用双能X线吸收仪测量了262名非糖尿病绝经后女性腰椎L1-4和股骨颈(Femoral Neck,FN)的骨密度(Bone Mineral Density,BMD),并检测了其外周血骨转换标志物和糖代谢指标以及雌激素水平.结果发现胰岛素和稳态模型评估的胰岛素抵抗(Homeosta...     

低渗透煤层提高瓦斯采收率技术现状及发展趋势

低渗透煤层压裂对于煤矿瓦斯防治以及降低煤矿事故发生率具有重要意义。详细阐述了四种低渗透煤层压裂技术的作用机理,分析了压裂技术以及压裂效果数值模拟上存在的问题,针对存在的问题,提出未来要研究适应中国煤层气储气特点的高效压裂液、支撑液及配套设施与装备;气体驱替发展应合理解决两种气体的协调关系;数值模拟应综合多种影响因素进行压裂效果模拟分析。     

不同地质条件及地层下煤矸石理化性质的试验研究

通过对不同地质条件和不同地层的煤矸石进行XRD(X-ray diffraction)试验及物理性能试验,分析其矿物组成与物理性能指标的内在规律。研究结果表明,煤矸石的化学成分以Si O2和Al2O3为主,但不同地质条件下的煤矸石矿物组成及化学成分差异较大。在物理性能方面,黄陇侏罗纪煤田煤矸石吸水率较高,表观密度较小,压碎指标较大,渭北石炭二叠纪煤田的煤矸石和陕北侏罗纪煤田的煤矸石的吸水率较小,表观密度较大和压碎指标较小。不同地层的煤矸石的矿物组成和化学成分含量相差不大,但地层越深的煤矸石吸水率越低、表观密度越大、压碎指标越小。研究成果可为不同地区煤矸石在混凝土资源化利用提供依据。     

水中矿物油的荧光分析

分析了市售柴油、机油、煤油、汽油及混合油水溶液的激发光和荧光光谱,研究了它们的光谱特性.在优化选择激发光波长和荧光波长下,对不同浓度的矿物油水混合液进行了荧光光谱分析,得到了荧光光谱强度与浓度的关系,并对实际环境的水样进行了测量分析.