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71.
陇2井为长庆油田在陇东区块部署的一口高温气探井, 完钻井深4960m,生产套管固井要求全井段封固, 固井施工存在井底温度高(井底静止温度130℃),水泥浆体系需要具备抗高温性能;上下温差大(80℃),低密度水泥浆体系易发生超缓凝现象; 一次性封固段长, 防漏压稳难度大等技术难题,通过高温降失水剂G411-GFL及高温缓凝剂G410-GHN研发,形成了抗高 温低密度/ 常规密度水泥浆体系及配套固井工艺技术,并在陇2井进行了现场施工,产层段固井优质率95%,低密度封固段优质率75%,满足了后期储层改造的需要,为长庆油田陇东区块高温气井开发提供了有力的技术支撑。 相似文献
72.
Qi-Yan Zhang Qin-Fu Zhao Xi-Min Liang Xiao-Li Wang Feng-Xian Ma Bing-Bing Suo Wen-Li Zou Hui-Xian Han Qi Song Qi Wu Ya-Wei Li Hai-Yan Zhu 《International Journal of Hydrogen Energy》2018,43(21):9935-9942
By use of the theoretical method of density functional theory (DFT), we systemically investigate the chalcogen doped Cu4 metal clusters (Cu4O, Cu4S, and Cu4Se) as catalysts for the electrochemical CO2 reduction with toluene as solvent. These doped clusters have efficient catalytic properties which can reduce CO2 to CH4 and a small amount of CH3OH. In the case of CO2 hydrogenation to CH4, the reaction barrier of the Cu4O cluster and Cu4S cluster are reduced by 0.37 eV and 0.15 eV, respectively, compared with the pristine Cu4 cluster. The calculation results also show the overpotentials for the CO2 hydrogenation to CH4 in the order of Cu4S < Cu4O < Cu4Se. In?addition, the geometry structures, the electronic properties, and the reaction free energies on the chalcogen doped Cu4 clusters are also discussed to further reveal the reaction mechanism in the CO2 electroreduction process. We hope that our present work will enlighten extensive studies on the modified electrode to decrease the limiting potential and provide a reference for the subsequent studies. 相似文献
73.
P modification has been widely used in Al-Si piston industry, but trace of Ca element has great influence on the P modification efficiency. In this work, it is found that primary Si can be heterogeneously nucleated by AlP in near eutectic Al-12.6Si alloy, but Ca element may destroy the P modification efficiency, whereas the addition of B can recover the P modification efficiency in near eutectic Al-12.6Si alloy with high Ca containing. The microstructure transformation was related to the reaction of Ca, B, and AlP. According to the thermodynamic calculation, Ca may react with AlP and form Ca3P2 compound in Al-Si alloy, whereas, when B was added into the melt, AlP could be reformed. The reaction of Ca, B, and AlP can be shown as follows: 2AlP +3Ca→Ca3P2+2Al; Ca3P2+18B+2Al→3CaB6+2AlP. In addition, with B added into the Al-12.6Si alloy with Ca and P addition, the mechanical properties were improved compared with single Ca and/or P addition. 相似文献
74.
75.
目的 为了评价稻田养殖中华绒螯蟹体内砷的污染水平和膳食风险。方法 本研究中从辽宁省盘锦市和鞍山市采集了560份样本,采用电感耦合等离子体质谱仪和高效液相色谱-原子荧光法测定了肌肉、肝胰腺及性腺总砷和总无机砷(AsⅢ和AsⅤ)的含量,并利用目标危险商数(THQ)和致癌风险(CR)来评价对人体的健康风险。结果 中华绒螯蟹中总砷均值呈现雌蟹肝胰腺与性腺>雄蟹肝胰腺与性腺>雄蟹肌肉>雌蟹肌肉的趋势,其中雄蟹肌肉与雌蟹肝胰腺及性腺总砷均值之间有显著性差异(P<0.05),而雌蟹肌肉与肝胰腺及性腺总砷均值之间具有显著差异(P<0.05);总无机砷均值呈现雌蟹肝胰腺与性腺>雄蟹肝胰腺与性腺>雌蟹肌肉>雄蟹肌肉的趋势,总无机砷含量仅占总砷含量的5.014%-6.250%;盘锦市盘山县大洼区和胡家镇梁家村几个采样点的总砷和总无机砷含量相较于其他地区偏高,而其余的采样点总砷和总无机砷含量处在一个相对较低的水平;稻田养殖中华绒螯蟹所有样品的THQ值远低于1,CR值在10-6和10-4之间,经判别仅具有低致癌风险(level Ⅱ)。结论 稻田养殖中华绒螯蟹不会对消费者造成潜在的健康危害。 相似文献
76.
Preparation of imprinted polymers at surface of magnetic nanoparticles for the selective extraction of tadalafil from medicines 总被引:1,自引:0,他引:1
Li Y Ding MJ Wang S Wang RY Wu XL Wen TT Yuan LH Dai P Lin YH Zhou XM 《ACS applied materials & interfaces》2011,3(9):3308-3315
In this paper, highly selective core-shell molecularly imprinted polymers (MIPs) of tadalafil on the surface of magnetic nanoparticles (MNPs) were prepared. Three widely used functional monomers 2-(trifluoromethyl) acrylic acid (TFMAA), acrylic acid (AA), and methacrylic acid (MAA) were compared theoretically as the candidates for MIP preparation. MIP-coated magnetic nanoparticles (MIP-coated MNPs) showed large adsorption capacity, high recognition ability, and fast binding kinetics for tadalafil. Furthermore, because of the good magnetic properties, MIP-coated MNPs can achieve rapid and efficient separation with an external magnetic field simply. The resulting MIP-coated MNPs were used as dispersive solid-phase extraction (DSPE) materials coupled with HPLC-UV for the selective extraction and detection of tadalafil from medicines (herbal sexual health products). Encouraging results were obtained. The amounts of tadalafil that were detected from the herbal sexual health product was 43.46 nmol g(-1), and the recoveries were in the range of 87.36-90.93% with the RSD < 6.55%. 相似文献
77.
目的 采用免疫亲和柱净化双壳类水产中的软骨藻酸,建立高效液相色谱-三重四级杆质谱串联(LC-MS/MS)方法检测双壳类水产中的软骨藻酸,为水产品中的软骨毒素检测提供方法依据。方法 选用InfinityLab Poroshell 120 EC-C18色谱柱,以10 mmol/L甲酸铵-0.1%甲酸-甲醇为流动相,采用梯度洗脱进行分离。样品用80%甲醇水提取,上清液加入PBS缓冲液后经免疫亲和柱净化,将洗脱液氮吹至干定容后上机测定。多重态反应监测(MRM)方式检测。结果 软骨藻酸的线性范围为20.0~200 ng/ml,检出限为0.002 μg/g,回收率在75.2% ~ 85.7%之间。结论 本方法特异性强、提取效果好、无基质抑制效应,适用于双壳类水产中软骨藻酸的痕量检测。 相似文献
78.
Li W Wang J Jiang HR Xu XL Zhang J Liu ML Zhai LY 《International journal of molecular sciences》2011,12(1):668-681
The present study was designed to investigate the combined effects of cyclooxygenase (COX)-1 and COX-2 selective inhibitors on human ovarian SKOV-3 carcinoma cells xenograft-bearing mice. The animals were treated with 3 mg/kg SC-560 (a COX-1 selective inhibitor) alone, 25 mg/kg celecoxib (a COX-2 selective inhibitor) alone, or SC-560/celecoxib by gavage, twice a day for three weeks. To test the mechanism of inhibition of tumor growth by COX selective inhibitors, the index of proliferating cells in tumor tissues was determined by immunostaining and the index of apoptotic cells by the terminal-deoxynucleotidyl-transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) method. The inhibitory rate on tumor growth in the combination group was 35.54% which is significant statistically compared with that of the control group (P < 0.05). In the combination group, the index of cell proliferation and apoptosis were 12.40% and 51.03% respectively, which are significant statistically compared with those of the control group (22.56%, 19.07%, all P < 0.05). These studies indicate that synergism between two COX inhibitors and inhibitor combination treatment has particular potential for chemoprevention of ovarian cancer growth. 相似文献
79.
蜂产品中氯霉素残留检测方法的研究进展 总被引:1,自引:1,他引:0
本文综述了近年来蜂产品中氯霉素残留的主要检测方法及其研究进展, 包括微生物法、免疫分析法、色谱分析法和生物传感器法。其中, 免疫分析法着重介绍了酶联免疫法, 色谱分析法则主要介绍了高压液相色谱和色谱-质谱联用技术。最后, 对现有检测方法进行了比较分析。 相似文献
80.