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水热合成和冷冻干燥相结合制备超轻三维多孔γ-MnOOH材料(英文)
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作者 汪艳秋 陈璐 +3 位作者 陈敏 仲兆祥 孟庆伟 邢卫红 《中国科学:材料科学(英文版)》 CSCD 2019年第4期527-535,共9页
超轻三维多孔金属氧化物材料在许多应用中起着重要作用,因此采用低成本的材料和简便的方法制备它们显得非常重要.本文以高锰酸钾、氯化锰和氢氧化钠为原料,结合水热合成法和冷冻干燥法首次制备出超低密度(<0.078 g cm-3)、形状可控... 超轻三维多孔金属氧化物材料在许多应用中起着重要作用,因此采用低成本的材料和简便的方法制备它们显得非常重要.本文以高锰酸钾、氯化锰和氢氧化钠为原料,结合水热合成法和冷冻干燥法首次制备出超低密度(<0.078 g cm-3)、形状可控和连续多孔的三维氢氧化氧锰(3D-γ-MnOOH).系统地研究了反应物添加量和水热反应时间对3D-γ-MnOOH合成过程的影响,得出制备3D-γ-MnOOH的最优工艺条件:NaOH/KMnO4和MnCl2/KMnO4的摩尔比分别为5.0和3.5,水热温度和时间分别为180°C和10 h.由于γ-MnOOH具有低密度和充满空气的三维孔道结构,使其可以在水中漂浮4个月以上,并保持微结构不变.分析探讨了3D-γ-MnOOH的微结构形成机制和漂浮机理.超轻3D-γ-MnOOH的成功制备将促进其在吸油、储能、催化剂载体等领域的应用. 展开更多
关键词 LOW-DENSITY 3D-γ-MnOOH POROUS material FREEZE-DRYING
Metformin improved oxidized low-density lipoprotein-impaired mitochondrial function and increased glucose uptake involving Akt-AS160 pathway in raw264.7 macrophages
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作者 Xuan He Lei Wang +6 位作者 Xiu-Fang Chen Qiao Liang Wen-Qing Wang An-Qi Lin Long Yi Yong Wang Qian Gao 《中华医学杂志:英文版》 SCIE CAS CSCD 2019年第14期1713-1722,共10页
Background:Macrophage accumulation in the vascular wall is a hallmark of atherosclerosis.Studies showed that shifting of oxidized lipids-induced inflammatory macrophages towards an anti-inflammatory phenotype by promo... Background:Macrophage accumulation in the vascular wall is a hallmark of atherosclerosis.Studies showed that shifting of oxidized lipids-induced inflammatory macrophages towards an anti-inflammatory phenotype by promoting oxidative metabolism attenuated atherosclerosis progression.Therefore,this study aimed to investigate whether metformin,which has ameliorated atherosclerosis in animal models and clinical trials,modulated oxidized low-density lipoprotein (Ox-LDL) induced inflammatory status in macrophages by regulating cellular oxidative metabolism.Methods:Murine raw264.7 macrophages were incubated with Ox-LDL (50 μg/mL) in the presence or absence of metformin (15 μmol/L) for 24 h.Real-time polymerase chain reaction was used to quantify the transcription of classically activated (M1) proinflammatory and alternatively activated (M2) anti-inflammatory markers and mitochondrial DNA copy numbers.Cellular reactive oxygen species (ROS) production and mitochondrial membrane potential were detected by immunofluorescence.Cellular adenosine triphosphate (ATP) synthesis,glucose uptake,and lactic acid production were measured by commercial kit and normalized to cellular lysates.Western blotting analysis was performed to detect the expression of mitochondrial fusion/fission related proteins,enzymes mediating lipid metabolism and signaling pathway of glucose transport.Differences between groups were analyzed using one-way analysis of variance.Results:Metformin improved Ox-LDL-impaired anti-inflammatory phenotype in raw264.7 macrophages as shown by up-regulated transcription of anti-inflammatory markers including interleukin 10 (0.76 ± 0.04 vs.0.94 ± 0.01,P =0.003) and Resistin-like molecule alpha (0.67 ± 0.08 vs.1.78 ± 0.34,P =0.030).Conversely,Ox-LDL-diminished phosphorylation of Akt was up regulated by metformin treatment (0.47 ± 0.05 vs.1.02 ± 0.08,P =0.040),associated with an improvement of mitochondrial function,characterized by decreased ROS generation (2.50 ± 0.07 vs.2.15 ± 0.04,P =0.040),increased lipid oxid 展开更多
关键词 Atherosclerosis MACROPHAGES OXIDIZED LOW-DENSITY LIPOPROTEIN Mitochondria Metabolism
Biomarkers and subtypes of deranged lipid metabolism in nonalcoholic fatty liver disease 预览
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作者 José M Mato Cristina Alonso +1 位作者 Mazen Noureddin Shelly C Lu 《世界胃肠病学杂志:英文版》 SCIE CAS 2019年第24期3009-3020,共12页
Nonalcoholic fatty liver disease(NAFLD)is a heterogeneous and complex disease that is imprecisely diagnosed by liver biopsy.NAFLD covers a spectrum that ranges from simple steatosis,nonalcoholic steatohepatitis(NASH)w... Nonalcoholic fatty liver disease(NAFLD)is a heterogeneous and complex disease that is imprecisely diagnosed by liver biopsy.NAFLD covers a spectrum that ranges from simple steatosis,nonalcoholic steatohepatitis(NASH)with varying degrees of fibrosis,to cirrhosis,which is a major risk factor for hepatocellular carcinoma.Lifestyle and eating habit changes during the last century have made NAFLD the most common liver disease linked to obesity,type 2 diabetes mellitus and dyslipidemia,with a global prevalence of 25%.NAFLD arises when the uptake of fatty acids(FA)and triglycerides(TG)from circulation and de novo lipogenesis saturate the rate of FAβ-oxidation and verylow density lipoprotein(VLDL)-TG export.Deranged lipid metabolism is also associated with NAFLD progression from steatosis to NASH,and therefore,alterations in liver and serum lipidomic signatures are good indicators of the disease’s development and progression.This review focuses on the importance of the classification of NAFLD patients into different subtypes,corresponding to the main alteration(s)in the major pathways that regulate FA homeostasis leading,in each case,to the initiation and progression of NASH.This concept also supports the targeted intervention as a key approach to maximize therapeutic efficacy and opens the door to the development of precise NASH treatments. 展开更多
关键词 S-ADENOSYLMETHIONINE Methionine adenosyltransferase Lipid METABOLISM Multiomics LIPIDOMICS Nonalcoholic steatohepatitis One-carbon METABOLISM Very LOW-DENSITY LIPOPROTEINS STEATOSIS Precision medicine
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低密度高熵合金的研究进展 预览
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作者 赵海朝 梁秀兵 +4 位作者 乔玉林 柳建 胡振峰 陈永雄 张志彬 《航空材料学报》 CAS CSCD 北大核心 2019年第5期61-81,共21页
高熵合金是一种新型合金,其优异的物理化学性能吸引了研究者的广泛关注。然而,传统高熵合金的密度普遍较大,极大地限制了其工程应用。为了降低合金密度,Al、Ti、Mg、Li、C等低密度元素被用于制备高熵合金,系列等摩尔或非等摩尔比的低密... 高熵合金是一种新型合金,其优异的物理化学性能吸引了研究者的广泛关注。然而,传统高熵合金的密度普遍较大,极大地限制了其工程应用。为了降低合金密度,Al、Ti、Mg、Li、C等低密度元素被用于制备高熵合金,系列等摩尔或非等摩尔比的低密度高熵合金成功制备,在航空航天、能源交通等领域显示出巨大的应用潜力。本文综述了低密度高熵合金的研究现状,分析了合金组元的设计指导原则、制备工艺,并根据其体系特性介绍了高熵合金的相结构以及性能,对低密度高熵合金未来研究方向提出了展望。 展开更多
关键词 高熵合金 低密度 组元设计 制备技术 性能
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Design of Irregular QC-LDPC Code Based Multi-Level Coded Modulation Scheme for High Speed Optical Communication Systems 预览
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作者 Liqian Wang Dongdong Wang +3 位作者 Yongjing Ni Xue Chen Midou Cui Fu Yang 《中国通信:英文版》 SCIE CSCD 2019年第5期106-120,共15页
In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC compon... In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC component code. Firstly, the sub-channel capacities of MLCM systems is analyzed and discussed, based on which the optimal component code rate can be obtained. Secondly, an extrinsic information transfer chart based two-stage searching algorithm is proposed to find the good irregular QC-LDPC code ensembles with optimal component code rates for their corresponding sub-channels. Finally, by constructing the irregular QC-LDPC component codes from the designed ensembles with the aim of possibly enlarging the girth and reducing the number of the shortest cycles, the designed irregular QC-LDPC code based 16QAM and 64QAM MLCM systems can achieve 0.4 dB and 1.2 dB net coding gain, respectively, compared with the recently proposed regular QC-LDPC code based 16QAM and 64QAM MLCM systems. 展开更多
关键词 quasi-cyclic LOW-DENSITY parity check (QC-LDPC) code irregular EXTRINSIC INFORMATION transfer(EXIT) chart generalized mutual information(GMI) MULTI-LEVEL coded modulation(MLCM)
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The rate of patients at high risk for cardiovascular disease with an optimal low-density cholesterol level: a multicenter study from Thailand 预览
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作者 Rungroj Krittayaphong Arintaya Phrommintikul +4 位作者 Smonporn Boonyaratvej Rapeephon Kunjara Na Ayudhya Pyatat Tatsanavivat Chulaluk Komoltri Piyamitr Sritara 《老年心脏病学杂志:英文版》 SCIE CAS CSCD 2019年第4期344-353,共10页
Background Hypercholesterolemia is a major risk factor for cardiovascular events in patients with established atherosclerotic disease (EAD) and in those with multiple risk factors (MRFs). This study aimed to investiga... Background Hypercholesterolemia is a major risk factor for cardiovascular events in patients with established atherosclerotic disease (EAD) and in those with multiple risk factors (MRFs). This study aimed to investigate the rate of optimal low-density lipoprotein (LDL) cholesterol level in a multicenter registry of patients at high risk for cardiovascular events. Methods A multicenter registry of EAD and MRF patients was conducted. Demographic data,medical history,cardiovascular risk factors,anthropometric data,laboratory data,and medications were recorded and analyzed. We classified patients according to target LDL levels based on recommendation by the European Society of Cardiology (ESC) 2011 into Group 1 which is EAD and diabetes or chronic kidney disease (CKD)–target LDL below 70 mg/dL,and Group 2 which is MRF without diabetes or CKD–target LDL below 100 mg/dL. The rate of optimal LDL level in patients with Group 1 and Group 2 was analyzed and stratified according to the treatment pattern of lipid-lowering medications. Results A total of 3100 patients were included. Of those,51.7% were male. Average age was 65.8 ± 9.7 years. Average LDL level was 96.3 ± 32.6 mg/dL. A vast majority (92.7%) received statin and 9.3% received ezetimibe. Optimal LDL level was achieved in 20.3% of patients in Group 1 (LDL < 70 mg/dL),and in 46.6% in Group 2 (LDL < 100 mg/dL). The overall rate of optimal LDL control was 23% since 89.6% of study population belongs to Group 1. The rate of optimal LDL was not different between high and low potency statin. Factors that were associated with optimal LDL control were older age,the presence of coronary artery disease or peripheral artery disease. Conclusions The rates of optimal LDL level were unacceptably low in this study population. As such,a strategy to improve LDL control in high-risk population should be implemented. 展开更多
关键词 CARDIOVASCULAR EVENT Established ATHEROSCLEROTIC disease LOW-DENSITY LIPOPROTEIN CHOLESTEROL Risk factors Thailand
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深水表层固井水泥浆体系的优选 预览
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作者 廖易波 李望军 +3 位作者 范鹏 刘玉杰 陆永伟 闫许峰 《科技视界》 2019年第23期5-7,4共4页
最近几年中,深水油气发现占全球油气发现总量逐步增大,深水油气资源已成为未来全球石油战略接替的重点,为更好地促进我国深水固井技术的发展,笔者团队结合室内研究与现场实际应用,总结了一套适用于超水表层固井的低密全液早强水泥浆体系... 最近几年中,深水油气发现占全球油气发现总量逐步增大,深水油气资源已成为未来全球石油战略接替的重点,为更好地促进我国深水固井技术的发展,笔者团队结合室内研究与现场实际应用,总结了一套适用于超水表层固井的低密全液早强水泥浆体系.该水泥浆体系配方简单,采用全液体添加剂,成本低,具有良好的流变性能、防气窜性能及沉降稳定性.该体系低温下水泥石强度发展好,具有较高的抗压强度,控失水性能强.目前该低密全液早强水泥浆体系成功应用于南海多口深水井中,现场应用表明:该体系现场易配浆,浆体流动性良好,水泥浆气泡少,现场操作方便,固井作业时未发现浅层气窜漏,满足后续施工要求. 展开更多
关键词 深水 低密度 全液体 早强 水泥浆体系
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低密度支撑剂研究进展 预览
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作者 杨双春 佟双鱼 +3 位作者 李东胜 KHISAYNOV Umed 郭明哲 徐明磊 《化工进展》 EI CAS CSCD 北大核心 2019年第9期4264-4274,共11页
低密度支撑剂是通过化学改性、物理改性等方法制备得到的高性能支撑剂,具有密度低、沉降速度低等特性。本文在调研大量文献基础上,根据改性方法不同将低密度支撑剂分为多孔无包覆陶瓷低密度支撑剂、多孔无机物包覆低密度支撑剂、多孔树... 低密度支撑剂是通过化学改性、物理改性等方法制备得到的高性能支撑剂,具有密度低、沉降速度低等特性。本文在调研大量文献基础上,根据改性方法不同将低密度支撑剂分为多孔无包覆陶瓷低密度支撑剂、多孔无机物包覆低密度支撑剂、多孔树脂包覆低密度支撑剂,对比了不同类型低密度支撑剂制备体系组成、密度以及承压性能,总结了制备不同类型低密度支撑剂的机理、主要影响因素及应用情况。根据制备方式不同将超低密度支撑剂(ultra-light weight proppants, ULWP)分为常规方法制备、新技术制备两类。提出未来可通过结合使用多种添加剂、优化烧制工艺等方式探索莫来石相、刚玉相等晶体结构,实现支撑剂超低密度与高强度的有效结合,利用疏水改性、结构改性等方式向多功能、高性能发展,为相关研究提供借鉴和参考。 展开更多
关键词 支撑剂 制备 低密度 高强度 超低密度
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Implementation of encoder and decoder for LDPC codes based on FPGA 预览
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作者 CHENG Kun SHEN Qi +1 位作者 LIAO Shengkai PENG Chengzhi 《系统工程与电子技术:英文版》 SCIE EI CSCD 2019年第4期642-650,共9页
This paper proposes a parallel cyclic shift structure of address decoder to realize a high-throughput encoding and decoding method for irregular-quasi-cyclic low-density parity-check(IR-QC-LDPC)codes,with a dual-diago... This paper proposes a parallel cyclic shift structure of address decoder to realize a high-throughput encoding and decoding method for irregular-quasi-cyclic low-density parity-check(IR-QC-LDPC)codes,with a dual-diagonal parity structure.A normalized min-sum algorithm(NMSA)is employed for decoding.The whole verification of the encoding and decoding algorithm is simulated with Matlab,and the code rates of 5/6 and 2/3 are selected respectively for the initial bit error ratio as 6%and 1.04%.Based on the results of simulation,multi-code rates are compatible with different basis matrices.Then the simulated algorithms of encoder and decoder are migrated and implemented on the field programmable gate array(FPGA).The 183.36 Mbps throughput of encoder and the average 27.85 Mbps decoding throughput with the initial bit error ratio 6%are realized based on FPGA. 展开更多
关键词 low-density parity-check(LDPC) field programmable gate array(FPGA) normalized min-sum algorithm(NMSA).
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Cardiovascular risks of postmenopausal women with low-density lipoprotein-cholesterol<130 mg/dL in Chaoshan region of China
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作者 王莹 黄桢淳 何新界 《岭南心血管病杂志:英文版》 CAS 2019年第2期79-85,共7页
Background Many postmenopausal women with low-density lipoprotein-cholesterol(LDL-C)<130 mg/dL from Chaoshan region suffer from coronary artery diseases,especially severe coronary artery lesions.However,few studies... Background Many postmenopausal women with low-density lipoprotein-cholesterol(LDL-C)<130 mg/dL from Chaoshan region suffer from coronary artery diseases,especially severe coronary artery lesions.However,few studies specifically focused on the cardiovascular risks of this subgroup of postmenopausal women.Methods A total of 270 postmenopausal women with LDL-C<130 mg/dL from Chaoshan region were enrolled in this cohort study.Patients with angiographically proven coronary artery diseases(CAD)served as CAD group(n=174),while the ones with angiographically proven normal coronary arteries served as Control group(n=96).Results The age of CAD group(68.5±8.4 years)was older than that of Control group(60.0±6.9 years)(P<0.001).The prevalence rates of hypertension,diabetes mellitus(DM)and hyperuricemia in CAD group were significantly higher than those of Control group(P<0.05 for both comparisons).The serum level of uric acid(UA)in CAD group was significantly higher than that in Control group(P<0.001).Age,DM and UA were independent cardiovascular predictors of postmenopausal women with LDL-C<130 mg/dL from Chaoshan Region[ORAGE:1.140(95%CI:1.095-1.188),ORDM:2.740(95%CI:1.368-5.486),ORUA:1.003(95%CI:1.001-1.006),PAGE<00.001,PDM=0.004,PUA=0.019].Conclusions Postmenopausal women with LDL-C<130 mg/dL complicating CAD are elder with higher prevalence rates of hyperuricemia and DM.Age,DM and UA are considered as independent cardiovascular risk factors in the postmenopausal women with LDL-C<130 mg/dL from Chaoshan Region of China. 展开更多
关键词 CORONARY artery disease POSTMENOPAUSAL women LOW-DENSITY lipoprotein-cholesterol uric acid
低密度聚丙烯材料在商用车轻量化应用开发 预览
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作者 代玉堂 杨汐 《汽车实用技术》 2018年第12期145-147,共3页
文章主要介绍低密度聚丙烯(PP)材料开发的思路、原理、材料性能测试、零件注塑和零件性能评价。为内饰塑料件轻量化提供一种低成本、低风险的可行方案。
关键词 聚丙烯 低密度 轻量化
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Effect of a viscoelastic target on the impact response of a flat-nosed projectile 预览
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作者 Hu Liu Jialing Yang Hua Liu 《力学学报:英文版》 SCIE EI CAS CSCD 2018年第1期162-174,共13页
Taylor impact is a widely used strategy in which a flat-nosed projectile is fired onto a rigid anvil directly to determine the dynamic strength of rod specimens. Nowadays, the rigid anvil is often replaced by an outpu... Taylor impact is a widely used strategy in which a flat-nosed projectile is fired onto a rigid anvil directly to determine the dynamic strength of rod specimens. Nowadays, the rigid anvil is often replaced by an output target bar to ensure the accuracy of measurement via recording strain signals in the output bar. For testing the dynamic strength of low-density materials, a low-impedance target bar, which exhibits viscoelastic characteristics is often employed. In this paper, an extended Taylor model is proposed to improve the idealization of treating the target bar as perfectly rigid material in the classic Taylor model, and the viscoelastic effect of the target bar is incorporated. The viscoelastic target bar is depicted by two elastic springs and one dashpot.Based on the plastic shock wave theory in the flat-nosed projectile associated with the viscoelastic wave analysis in the target bar, the viscoelastic effect of the target bar on the impact response of the flat-nosed projectile is investigated. The finite element simulation is also carried out to verify the theoretical model, and good agreement is found. The present theoretical model is also called the Taylor-cylinder Hopkinson impact, which provides a more accurate way to identify the dynamic material parameters. The dynamic responses of the present model are further compared with previous elastic and rigid target bar models. It is found that the viscoelastic effect of the target bar should be taken into consideration in the Taylor-cylinder Hopkinson impact test for low-impedance materials. 展开更多
关键词 Dynamic RESPONSE TAYLOR impact VISCOELASTIC TARGET LOW-DENSITY material
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巢氏PCR检测血片中低密度间日疟原虫的研究 预览
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作者 尚婧晔 郁涛 +2 位作者 邹晏 李黎 刘阳 《西部医学》 2018年第6期798-802,共5页
目的 探讨巢式PCR应用于检测低密度疟原虫血片DNA的方法。方法 以健康人抗凝血为稀释液提取不同浓度梯度间日疟原虫血片DNA,测定其最低检出限,将一份含有高密度间日疟原虫的抗凝血样按照1:10、1:100、1:1000、1:2000、1:4000、1:8... 目的 探讨巢式PCR应用于检测低密度疟原虫血片DNA的方法。方法 以健康人抗凝血为稀释液提取不同浓度梯度间日疟原虫血片DNA,测定其最低检出限,将一份含有高密度间日疟原虫的抗凝血样按照1:10、1:100、1:1000、1:2000、1:4000、1:8000、1:16000、1:32000比例进行稀释,制成9个浓度梯度血样。每个浓度血样按照厚血膜5ul、薄血膜2ul同时制作2张血片,连续稀释(9个稀释度)一份含有高密度间日疟原虫的EDTA抗凝血样本,制作标准血片,同时进行所制得的血片中厚、薄血膜通过显微镜计数后,分别用以提取DNA,进行和巢式PCR检测。结果 间日疟原虫血片厚血膜的检出限为1:16000(0.8个虫/μl血),薄血膜检出限为1:100,与镜下计数水平一致。结论 巢式PCR适用于低密度血片中间日疟原虫DNA的检测,具有较高的检测意义。 展开更多
关键词 间日疟原虫 低密度 血片 巢氏PCR
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Oxidized phospholipids are ligands for LRP6 预览
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作者 Lei Wang Yu Chai +9 位作者 Changjun Li Haiyun Liu Weiping Su Xiaonan Liu Bing Yu Weiqi Lei Bin Yu Janet L.Crane Xu Cao Mei Wan 《骨研究:英文版》 SCIE CAS CSCD 2018年第3期266-279,共14页
Low-density lipoprotein receptor–related protein 6(LRP6)is a co-receptor for Wnt signaling and can be recruited by multiple growth factors/hormones to their receptors facilitating intracellular signaling activation.T... Low-density lipoprotein receptor–related protein 6(LRP6)is a co-receptor for Wnt signaling and can be recruited by multiple growth factors/hormones to their receptors facilitating intracellular signaling activation.The ligands that bind directly to LRP6 have not been identified.Here,we report that bioactive oxidized phospholipids(oxPLs)are native ligands of LRP6,but not the closely related LRP5.oxPLs are products of lipid oxidation involving in pathological conditions such as hyperlipidemia,atherosclerosis,and inflammation.We found that cell surface LRP6 in bone marrow mesenchymal stromal cells(MSCs)decreased rapidly in response to increased oxPLs in marrow microenvironment.LRP6 directly bound and mediated the uptake of oxPLs by MSCs.oxPL-LRP6 binding induced LRP6 endocytosis through a clathrin-mediated pathway,decreasing responses of MSCs to osteogenic factors and diminishing osteoblast differentiation ability.Thus,LRP6 functions as a receptor and molecular target of oxPLs for their adverse effect on MSCs,revealing a potential mechanism underlying atherosclerosis-associated bone loss. 展开更多
关键词 LOW-DENSITY LIPOPROTEIN receptor–related PROTEIN 6
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压裂用低密度支撑剂研究进展和发展趋势 预览 被引量:1
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作者 李小刚 廖梓佳 +3 位作者 杨兆中 唐方璇 朱利勇 刘觐瑄 《硅酸盐通报》 CSCD 北大核心 2018年第10期3132-3135,共4页
压裂支撑剂是油气增产改造中用来支撑地下压裂裂缝的一种关键材料。目前常规的支撑剂视密度基本都在2.0g/cm3以上,在压裂过程中,支撑剂的沉降速度快,压裂效果不理想。为了解决这个问题,国内外支撑剂行业一直致力于低密度支撑剂的研究。... 压裂支撑剂是油气增产改造中用来支撑地下压裂裂缝的一种关键材料。目前常规的支撑剂视密度基本都在2.0g/cm3以上,在压裂过程中,支撑剂的沉降速度快,压裂效果不理想。为了解决这个问题,国内外支撑剂行业一直致力于低密度支撑剂的研究。文章叙述了低密度支撑剂的研究进展,将低密度支撑剂分为了空心球类、多孔类、低密度材料类和自悬浮类四种类型,并讨论了未来低密度支撑剂的发展趋势,对压裂支撑剂研究和相关行业的技术进步具有一定的指导意义。 展开更多
关键词 水力压裂 支撑剂 低密度
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Therapeutic approach targeting apolipoprotein E binding region and low-density lipoprotein receptor for Alzheimer's disease
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作者 Michael Leon Darrell Sawmiller +1 位作者 Brian Giunta Jun Tan 《神经免疫与神经炎症(英文版)》 2018年第7期36-42,共7页
Approximately 13% of the population over the age of 65 years is estimated to have AD. The total number of cases is expected to increase over the coming decades. The apolipoprotein E (ApoE) genotype is the greatest gen... Approximately 13% of the population over the age of 65 years is estimated to have AD. The total number of cases is expected to increase over the coming decades. The apolipoprotein E (ApoE) genotype is the greatest genetic deter-minant for Alzheimer's disease (AD) development. The ApoE4 allele increases the risk of AD by 4 to 14 fold while the ApoE2 allele has an opposing effect;decreasing risk. Indeed many studies have demonstrated that carriers of the ApoE2 allele are associated with greater likelihood of survival to advanced age, superior verbal learning ability in advanced age, and reduced accumulation of amyloid pathology in the aged brain. In addition, it is known that ApoE proteins have different affinities for the low-density lipoprotein receptor (LDLR), with ApoE2 having the weakest binding to the LDL receptor at < 2% relative to ApoE3 and E4. Because ApoE2 has shown protective effects in re-gard to AD, a novel approach for ApoE4 carriers may be to create a peptide antagonist that blocks the ApoE inter-actions with LDLR at its 135-150 N-terminal binding domain. This peptide may create a more ApoE2-like structure by decreasing the affinity of ApoE4 for LDLR thereby reducing AD onset, memory impairment, and amyloid plaque formation. In this review, we will discuss the different detrimental effects that ApoE4 can cause. Most importantly, we will review how ApoE4 binding to LDLR promotes AD pathogenesis and how blocking ApoE4 binding may be a promising novel therapeutic approach for AD. 展开更多
关键词 Alzheimer's DISEASE LOW-DENSITY LIPOPROTEIN receptor APOLIPOPROTEIN E amyloid precursor protein late ONSET Alzheimer's DISEASE
Oxidative alterations in sickle cell disease:Possible involvement in disease pathogenesis 预览
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作者 Yesim Oztas Ahmet Yalcinkaya 《世界血液学杂志》 2017年第3期55-61,共7页
Sickle cell disease(SCD)is the first molecular disease in the literature.Although the structural alteration and dysfunction of the sickle hemoglobin(HbS)are well understood,the many factors modifying the clinical sign... Sickle cell disease(SCD)is the first molecular disease in the literature.Although the structural alteration and dysfunction of the sickle hemoglobin(HbS)are well understood,the many factors modifying the clinical signs and symptoms of the disease are under investigation.Besides having an abnormal electrophoretic mobility and solubility,HbS is unstable.The autooxidation rate of the abnormal HbS has been reported to be almost two times of the normal.There are two more components of the oxidative damage in SCD:Free radical induced oxidative damage during vaso-occlusion induced ischemia-reperfusion injury and decreased antioxidant capacity in the erythrocyte and in the circulation.We will discuss the effects of oxidative alterations in the erythrocyte and in the plasma of SCD patients in this review. 展开更多
关键词 OXIDATIVE stress SICKLE cell DISEASE Iron Protein oxidation Carbonyl GROUP SULFHYDRYL GROUP Low-density LIPOPROTEIN High-density LIPOPROTEIN
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无固相低密度油基泡沫修井液性能评价与应用 预览
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作者 王广财 钱峰 +4 位作者 高利民 方卫荣 张云达 王小龙 刘万成 《油田化学》 CSCD 北大核心 2017年第4期711-716,共6页
为减少清水、地层水、水基泡沫等常规水基修井液对吐哈盆地胜北油气田喀拉扎组油气藏储层的伤害,研制了一种无固相低密度油基泡沫修井液,考察了该修井液的性能并在喀拉扎组5口井进行了现场应用。结果表明,由30%地层水+70%原油+0.25%... 为减少清水、地层水、水基泡沫等常规水基修井液对吐哈盆地胜北油气田喀拉扎组油气藏储层的伤害,研制了一种无固相低密度油基泡沫修井液,考察了该修井液的性能并在喀拉扎组5口井进行了现场应用。结果表明,由30%地层水+70%原油+0.25%油基泡沫转化剂+0.20%油基泡沫稳泡剂+0.45%油基发泡剂组成的无固相低密度油基泡沫修井液密度在0.34数0.90 g/cm3之间可调、泡沫强度高、泡沫稳定时间大于24 h、防漏封堵能力良好、污染岩心后的渗透率恢复率大于94%、抗温达120℃、抗压达10数11 MPa。根据油基泡沫流体特点,配套了修井工艺技术措施,该技术现场应用有效率为100%,平均每口井恢复期缩短3 d,对产层污染伤害较小,漏失量较少,修井液性能稳定,现场施工方便,成本较油基修井液低,可有效解决水敏和水锁严重的低压油气藏修井作业。 展开更多
关键词 无固相 低密度 油基泡沫修井液 低压油气藏 储层保护
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白云石对焦宝石陶粒晶粒发育及性能的影响 预览 被引量:3
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作者 武雅乔 王凯悦 +5 位作者 田玉明 梁丽萍 郝建英 周毅 力国民 邹欣伟 《硅酸盐通报》 CSCD 北大核心 2017年第5期1524-1529,共6页
以陶粒的新原料-焦宝石为主要原料,白云石为熔剂性辅料利用陶瓷烧结工艺成功制备了粒径425~850μm满足35 MPa闭合压力下使用的支撑剂。重点研究了助熔剂白云石的不同添加量对焦宝石陶粒支撑剂晶粒发育及性能的影响。利用SEM和XRD分别对... 以陶粒的新原料-焦宝石为主要原料,白云石为熔剂性辅料利用陶瓷烧结工艺成功制备了粒径425~850μm满足35 MPa闭合压力下使用的支撑剂。重点研究了助熔剂白云石的不同添加量对焦宝石陶粒支撑剂晶粒发育及性能的影响。利用SEM和XRD分别对含有不同添加量的白云石的陶粒支撑剂进行了显微形貌和物相结构的分析,并多次测试了陶粒支撑剂的体密、视密和破碎率,结果揭示了白云石的添加有助于促进棒状莫来石晶粒的发育,同时在保证破碎率低于9%的前提下具有降低陶粒支撑剂体密/视密的作用。 展开更多
关键词 焦宝石 白云石 压裂支撑剂 低密
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新型页岩气田压裂用低密度支撑剂的研制 预览
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作者 严思明 杨珅 +2 位作者 史素青 韩金井 汤俊 《广东化工》 CAS 2017年第11期9-11,21共4页
页岩气储层具有低孔隙度、低渗透率特点,需要使用低密度支撑剂以降低压裂液中聚合物用量,减小对页岩气储层的伤害。优选出一种低密度桃壳作为基材,采用酚醛树脂浸泡和环氧树脂二次覆膜的方法,研制出一种低密度支撑剂。支撑剂密度为1.19 ... 页岩气储层具有低孔隙度、低渗透率特点,需要使用低密度支撑剂以降低压裂液中聚合物用量,减小对页岩气储层的伤害。优选出一种低密度桃壳作为基材,采用酚醛树脂浸泡和环氧树脂二次覆膜的方法,研制出一种低密度支撑剂。支撑剂密度为1.19 g/cm3;在60 MPa压力下,支撑剂的形变量和破碎率仅为6.80%和2.68%,具有较强的抗压能力;支撑剂能够悬浮在0.15%胍胶压裂液中,降低了所需稠化剂的加量;热重分析表明,该支撑剂承受温度为280℃,具有良好的热稳定性;扫描电镜分析表明,环氧树脂二次覆膜能够覆盖酚醛树脂固化产生的气孔,降低了支撑剂吸水率。 展开更多
关键词 页岩气压裂 支撑剂 低密度 树脂覆膜
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