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聚乙烯醇薄膜中茶多酚向水中释放的不同动力学模型比较分析 预览 被引量:1
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作者 陈晨伟 许哲玮 +4 位作者 马亚蕊 谢晶 张勤军 唐智鹏 杨福馨 《食品科学》 EI CAS CSCD 北大核心 2019年第3期24-29,共6页
研究聚乙烯醇薄膜中茶多酚向水中释放的不同动力学模型表征。通过释放实验研究了薄膜中茶多酚向水中的释放规律,基于4种动力学模型对实验数据进行拟合表征,比较分析了不同模型的拟合效果。结果表明:茶多酚释放率随薄膜中茶多酚质量浓度... 研究聚乙烯醇薄膜中茶多酚向水中释放的不同动力学模型表征。通过释放实验研究了薄膜中茶多酚向水中的释放规律,基于4种动力学模型对实验数据进行拟合表征,比较分析了不同模型的拟合效果。结果表明:茶多酚释放率随薄膜中茶多酚质量浓度的增加而降低。对比不同模型的拟合效果,Fickian模型和Fickian+一级动力学模型可以很好地模拟茶多酚的释放(R^2≥97.27),后者更优;Weibull模型的拟合效果较前两个模型差(R^2≥85.21),但是该模型可以很好地模拟从释放开始到平衡初期茶多酚的释放(R^2≥92.20);短期释放模型的拟合效果较好(R^2≥91.32),但其扩散系数与由Fickian模型和Fickian+一级动力学模型得到的扩散系数相差较大。总的来看,Fickian+一级动力学模型模拟效果最好,Fickian模型次之,Weibull模型模拟从释放开始到平衡初期过程的效果较好,短期释放模型不适合用于模拟评估聚乙烯醇薄膜中茶多酚整个释放过程中的释放性能。 展开更多
关键词 聚乙烯醇 茶多酚 释放 释放动力学 动力学模型
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Photo-controlled release of paclitaxel and model drugs from RNA pyramids
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作者 Congcong Xu Hui Li +4 位作者 Kaiming Zhang Daniel W.Binzel Hongran Yin Wah Chiu Peixuan Guo 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第1期41-48,共8页
Stimuli-resp on sive release of drugs from a nano carrier in spatial-,temporal-,and dosage-controlled fashi ons is of great interest in the pharmaceutical industry.Paclitaxel is one of the most effective and popular c... Stimuli-resp on sive release of drugs from a nano carrier in spatial-,temporal-,and dosage-controlled fashi ons is of great interest in the pharmaceutical industry.Paclitaxel is one of the most effective and popular chemotherapeutic drugs against a number of cancers such as metastatic or non metastatic breast can cer,non-small cell lung can cer,refractory ovaria n cancer,AIDS-related Kaposi's sarcoma,and head and neck can cers.Here,by taki ng the adva ntage of RNA nanotechno logy in biomedical and material scie nee,we developed a three-dime nsional pyramid-shaped RNA nanocage for a photocontrolled release of cargo,using paclitaxel as a model drug.The light-triggered release of paclitaxel or fluorophore Cy5 was achieved by incorporation of photocleavable spacers into the RNA nanoparticles.Upon irradiation with ultraviolet light,cargos were rapidly released(within 5 min).In vitro treatment of breast can cer cells with the RNA nano particles harbori ng photocleavable paclitaxel showed higher cytotoxicity as compared to RNA nanoparticles without the photocleavable spacer.The methodology provides proof of con cept for the applicati on of the light-triggered con trolled release of drugs from RNA nano cages. 展开更多
关键词 RNA NANOTECHNOLOGY controlled release PACLITAXEL DRUG delivery RNA nanoparticles Phi29 three-way JUNCTION
RTTS安全接头脱手解卡技术 预览
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作者 赵宇光 《油气井测试》 2019年第3期21-25,共5页
APR测试施工过程中,由于井筒质量、井下工具、施工工艺等因素造成管柱被卡,尝试管柱整体解卡不成功时,优选采取将RTTS封隔器以上的RTTS安全接头进行脱手解卡措施,提出安全接头以上管柱,使留在井筒内的管柱工具最少,以便后续处理。结合... APR测试施工过程中,由于井筒质量、井下工具、施工工艺等因素造成管柱被卡,尝试管柱整体解卡不成功时,优选采取将RTTS封隔器以上的RTTS安全接头进行脱手解卡措施,提出安全接头以上管柱,使留在井筒内的管柱工具最少,以便后续处理。结合工作原理和现场案例,完善了RTTS安全接头脱手作业操作程序,现场2口井按照此操作程序实现了RTTS安全接头脱手,施工成功率100%,为同类APR测试管柱解卡作业提供了技术借鉴。 展开更多
关键词 钻柱地层测试 RTTS安全接头 封隔器遇卡 脱手 解卡 操作方法
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Theranostic nanoparticles with tumor-specific enzyme-triggered size reduction and drug release to perform photothermal therapy for breast cancer treatment
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作者 Rui Liu Chuan Hu +2 位作者 Yuanyuan Yang Jingqing Zhang Huile Gao 《药学学报:英文版》 CSCD 2019年第2期410-420,共11页
Although progress has been indeed made by nanomedicines, their efficacies for cancer treatment remain low, consequently leading to failures in translation to clinic. To improve the drug delivery efficiency,nanoparticl... Although progress has been indeed made by nanomedicines, their efficacies for cancer treatment remain low, consequently leading to failures in translation to clinic. To improve the drug delivery efficiency,nanoparticles need to change size so as to fully utilize the enhanced permeability and retention(EPR) effect of solid tumor, which is the golden principle of nanoparticles used for cancer treatment. Herein, we employed cationic small-sized red emission bovine serum albumin(BSA) protected gold nanocluster(Au NC@CBSA,21.06 nm) to both load indocyanine green(ICG) and act as imaging probe to realize theranostic. Then Au NC@CBSA-ICG was fabricated with negatively charged hyaluronic acid(HA) to form Au NC@CBSAICG@HA, which was about 200 nm to easily retain at tumor site and could be degraded by tumor-specific hyaluronidase into small nanoparticles for deep tumor penetration. The HA shell also endowed Au NC@CBSA-ICG@HA with actively targeting ability and hyaluronidase-dependent drug release. Furthermore, the quenching and recovery of fluorescence revealed the interaction between ICG and carrier, which was essential for the investigation of pharmacokinetic profiles. No matter in vitro or in vivo, Au NC@CBSAICG@HA showed markedly anti-tumor effect, and could suppress 95.0% of tumor growth on mice breast cancer model. All results demonstrated Au NC@CBSA-ICG@HA was potential for breast cancer therapy. 展开更多
关键词 Size-shrinkage Drug release PHOTOTHERMAL therapy THERANOSTIC BREAST cancer
玫瑰茄花色苷微胶囊的制备及其稳定性与释放性的评价 预览
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作者 孟翔宇 赵彦巧 +4 位作者 李钰琨 李亚琴 肖红 肖瑶 杨梦龙 《食品工业科技》 CAS 北大核心 2019年第14期174-181,共8页
为了避免花色苷物质直接受热、光的影响而引起氧化质变,有效控制花色苷的释放和稳定性,本研究以壳聚糖-海藻酸钠为壁材,玫瑰茄花色苷为芯材,研究锐孔法制备玫瑰茄花色苷微胶囊的工艺及其微胶囊化花色苷红外光谱、贮藏条件和体外释放性... 为了避免花色苷物质直接受热、光的影响而引起氧化质变,有效控制花色苷的释放和稳定性,本研究以壳聚糖-海藻酸钠为壁材,玫瑰茄花色苷为芯材,研究锐孔法制备玫瑰茄花色苷微胶囊的工艺及其微胶囊化花色苷红外光谱、贮藏条件和体外释放性。通过单因素实验和响应面法确定玫瑰茄花色苷微胶囊制备的最佳工艺条件,利用红外光谱仪分析花色苷微胶囊的结构和成分,考察不同温度和光照条件下花色苷微胶囊的稳定性,模拟体外人工胃、肠液来评价花色苷微胶囊释放性。结果表明,花色苷微胶囊制备的最佳工艺参数为海藻酸钠质量分数2.0%,CaCl2质量分数2.0%,壁芯比2∶1g/g,壳聚糖质量分数0.1%,玫瑰茄花色苷包埋率为99.2%±0.16%。红外谱图结果表明,微胶囊前后的花色苷特征吸收峰发生了变化。玫瑰茄花色苷微胶囊在4或25℃时能稳定贮藏,并在体外释放实验中均体现较好的缓释性。 展开更多
关键词 锐孔法 玫瑰茄花色苷 微胶囊 红外光谱 稳定性 释放性
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内嵌混合乳化剂微球的海藻酸钠食品抗菌包装膜的机械和释放性能研究 预览
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作者 陈曦 卢立新 +1 位作者 丘晓琳 唐亚丽 《中国食品学报》 EI CAS CSCD 北大核心 2019年第8期166-172,共7页
研究制备了内嵌混合乳化剂包裹肉桂精油微球的海藻酸钠食品包装膜,并表征其乳液的形貌,膜的机械性能和膜中肉桂精油的单侧释放性能。混合乳化剂由明胶/阿拉伯胶(GA)、明胶/吐温80(GT)和明胶/阿拉伯胶/吐温80(GAT)3种组合组成,以单一乳... 研究制备了内嵌混合乳化剂包裹肉桂精油微球的海藻酸钠食品包装膜,并表征其乳液的形貌,膜的机械性能和膜中肉桂精油的单侧释放性能。混合乳化剂由明胶/阿拉伯胶(GA)、明胶/吐温80(GT)和明胶/阿拉伯胶/吐温80(GAT)3种组合组成,以单一乳化剂明胶(G)作为对照。乳液形貌与粒径分布结果表明,乳液中形成大量微球,吐温80的加入使微球大量聚集,并显著降低了乳液的中值粒径。膜的机械性能表明,混合乳化剂膜GAT的机械性能显著优于对照膜G,吐温80的加入对膜的机械性能有提升的趋势。膜中肉桂精油的释放性能表明,混合乳化剂显著降低了肉桂精油的释放速率,吐温80的加入显著降低了肉桂精油的释放速率。 展开更多
关键词 海藻酸钠 肉桂精油 混合乳化剂 吐温80 微球 释放
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脱扣器执行元件的动态仿真和试验验证 预览
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作者 耿立新 江镇伟 《电器与能效管理技术》 2019年第10期31-35,共5页
针对一种脱扣器执行元件进行了动态仿真和试验验证。应用Maxwell电磁仿真软件,计算动铁心在不同激励电压作用下磁力随气隙的变化情况;采用Maxwell和ADAMS联合仿真方法,模拟了脱扣器执行元件的动态运动过程。最后,试验验证了执行机构释... 针对一种脱扣器执行元件进行了动态仿真和试验验证。应用Maxwell电磁仿真软件,计算动铁心在不同激励电压作用下磁力随气隙的变化情况;采用Maxwell和ADAMS联合仿真方法,模拟了脱扣器执行元件的动态运动过程。最后,试验验证了执行机构释放力值与释放行程的关系,为脱扣器执行元件的优化设计提供了理论依据和数据支撑。 展开更多
关键词 脱扣器 执行元件 MAXWELL ADAMS 动态运动过程
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宅基地“三权分置”的实施路径探析 预览
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作者 孙辉 陈子虹 《广东土地科学》 2019年第2期24-28,共5页
探索农村宅基地“三权分置”,首先要明确三权的具体内涵,即所有权重在强化落实,资格权重在对“户”的界定,使用权重在权能的丰富和规范。在此基础上,探索通过强化管理权能、管理主体和管理手段落实所有权,通过对集体经济组织成员和宅基... 探索农村宅基地“三权分置”,首先要明确三权的具体内涵,即所有权重在强化落实,资格权重在对“户”的界定,使用权重在权能的丰富和规范。在此基础上,探索通过强化管理权能、管理主体和管理手段落实所有权,通过对集体经济组织成员和宅基地农户的界定管理保障资格权,通过丰富使用权权能、规范使用权管理适度放活使用权,并结合各地的实践经验,形成系统的宅基地“三权分置”实施路径,从而更有效促成农村宅基地改革工作的完成。 展开更多
关键词 “三权分置” 落实 认定 放活 规范
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天铁高炉电动鼓风机应用效能的提升 预览
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作者 王岳峰 《天津冶金》 CAS 2019年第3期34-37,共4页
通过分析高炉配套的AV-90电动鼓风机的工作参数、老区三座高炉所需风量和风压,制定了以一台AV-90电动鼓风机代替老区三台小鼓风机为老区三座高炉提供冷风的供风方案,实施后解决了旧风机风压不足、风量过大、无法升级、防喘振保护不全、... 通过分析高炉配套的AV-90电动鼓风机的工作参数、老区三座高炉所需风量和风压,制定了以一台AV-90电动鼓风机代替老区三台小鼓风机为老区三座高炉提供冷风的供风方案,实施后解决了旧风机风压不足、风量过大、无法升级、防喘振保护不全、调节功能不完善等问题。 展开更多
关键词 电动鼓风机 风量 风压 放散 高炉 喘振
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Interleukin-6 secretion is limited by self-signaling in endosomes
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作者 Danielle R.J.Verboogen Natalia H.Revelo +1 位作者 Martin ter Beest Geert van den Bogaart 《分子细胞生物学报:英文版》 SCIE CAS CSCD 2019年第2期144-157,共14页
Cells producing cytokines often express the receptor for the same cytokine, which makes them prone to autocrine signaling. How cytokine release and signaling are regulated in the same cell is not understood? In this s... Cells producing cytokines often express the receptor for the same cytokine, which makes them prone to autocrine signaling. How cytokine release and signaling are regulated in the same cell is not understood? In this study, we demonstrate that signaling by exogenous and self-synthesized inflammatory cytokine interleukin-6 (IL-6) within endosomal compartments acts as a cellular brake that limits the synthesis of IL-6. Our data show that IL-6 is internalized by dendritic cells and signals from endosomal compartments containing the IL-6 receptor. Newly synthesized IL-6 also traffics via these endosomal compartments and signals in transit to the plasma membrane. This allows activation of STAT3 which in turn limits toll-like receptor 4 stimulant lipopolysaccharide (LPS) triggered transcription of IL-6. Long-term exposure to LPS removes this brake via inhibition of STAT3 by increased expression of suppressor of cytokine signaling 3 and results in fully fledged IL-6 production. This transient regulation could prevent excessive IL-6 production during early infections. 展开更多
关键词 membrane TRAFFICKING CYTOKINE release EXOCYTOSIS INTERLEUKIN-6 endosomal SIGNALING
丹参饮对气虚血瘀模型大鼠的血小板生物学 预览
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作者 张玉昆 冯月男 +2 位作者 卞敬琦 肖洪彬 牛雯颖 《世界中医药》 CAS 2019年第4期848-851,858共5页
目的:观察丹参饮对气虚血瘀模型大鼠血小板生物学的影响,从血小板动态变化上探讨丹参饮作用机制。方法:选取SD大鼠40只为研究对象,一次性向气管内注射博莱霉素生理盐水溶液复制气虚血瘀模型,将40只SD大鼠随机分为空白对照组、气虚血瘀... 目的:观察丹参饮对气虚血瘀模型大鼠血小板生物学的影响,从血小板动态变化上探讨丹参饮作用机制。方法:选取SD大鼠40只为研究对象,一次性向气管内注射博莱霉素生理盐水溶液复制气虚血瘀模型,将40只SD大鼠随机分为空白对照组、气虚血瘀模型组、丹参饮高剂量组(3.6g/kg)、低剂量组(0.9g/kg),每组10只。造模后第2天开始灌胃给药,连续21d,末次给药1h后5%水合氯醛麻醉,腹主动脉取血,检测全血黏度、血浆黏度、血小板参数、血小板活化黏附、聚集、释放以及纤溶相关指标。结果:丹参饮可显著降低模型大鼠中低切变率下的全血黏度和血浆黏度,差异有统计学意义(P<0.05),可显著降低PDW和MPV血小板相关参数,差异有统计学意义(P<0.05);可显著升高环磷酸腺苷(cAMP)水平,差异有统计学意义(P<0.05),降低环磷酸鸟苷(cGMP)、β-血小板球蛋白(β-TG)血小板第4因子(PF4)和纤溶酶原激活物抑制剂-1(PAI-1)水平,差异有统计学意义(P<0.05),延长凝血酶原时间(PT)和凝血酶时间(TT),差异有统计学意义(P<0.05)。结论:丹参饮可能主要通过改善血小板聚集、抑制凝血及血小板释放亢进的状态方面达到降低全血黏度,改善气虚血瘀状态。 展开更多
关键词 丹参饮 气虚血瘀 血液流变学 血小板 黏附 聚集 释放 纤溶
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Release mechanism of a novel slow-release nitrogen fertilizer
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作者 Xiaolong Yu Bogang Li 《颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第4期124-130,共7页
We developed a novel slow-release nitrogen fertilizer with the aim of increasing the efficiency of urea use,recycling phosphogypsum,and reducing related pollution.Phosphogypsum was used as a granulating agent and carr... We developed a novel slow-release nitrogen fertilizer with the aim of increasing the efficiency of urea use,recycling phosphogypsum,and reducing related pollution.Phosphogypsum was used as a granulating agent and carrier for urea to prepare a novel fertilizer core,which was coated with paraffin wax.SpanTM 80 was added to the paraffin to improve the wetting and adhesion between the paraffin coating and the fertilizer core.Paraffin-coated urea particles were prepared as a control sample using this method and their urea-release behavior was investigated.The results showed that less than 35% of urea from the paraffin-coated phosphogypsum-granulated urea was released over 28 days of submersion in water.The urea release was sustained much longer than that of paraffin-coated urea (only 7 days due to the expansion of brittle cracks in the coating).The release patterns of all coated fertilizers followed a logistic model.The release efficiency of paraffin-coated fertilizers could be improved by increasing the particle size of the fertilizer cores and improving adhesion between the paraffin coating and fertilizer core. 展开更多
关键词 COATED UREA PHOSPHOGYPSUM RELEASE rate Surface stress Coating ADHESION
Sustained co-delivery of gemcitabine and cis-platinum via biodegradable thermo-sensitive hydrogel for synergistic combination therapy of pancreatic cancer
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作者 Kun Shi Bingxin Xue +5 位作者 Yanpeng Jia Liping Yuan Ruxia Han Fan Yang Jinrong Peng Zhiyong Qian 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第6期1389-1399,共11页
Pancreatic cancer is one of the most devastating cancers with poor prognosis and no significant change in the survival rate over the past decades.Localized targeted drug delivery through interventional endoscopic ultr... Pancreatic cancer is one of the most devastating cancers with poor prognosis and no significant change in the survival rate over the past decades.Localized targeted drug delivery through interventional endoscopic ultrasonography-guided fine-needle injection (EUS-FNI) is an attractive and minimally invasive strategy for inoperable pancreatic cancer.An injectable in-situ formed long-lasting drug delivery system is a promising alternative for the localized treatment of pancreatic cancer via EUS-FNI.Here,a biodegradable thermo-sensitive copolymer hydrogel for the co-delivery of anticancer agents gemcitabine (GEM) and cis-platinum (DDP) was developed.This hydrogel is a free flowable liquid at room temperature that changes into a semi-solid hydrogel following injection in response to the physiological temperature.Both in vitro and in vivo drug release behaviors indicate sustained drug release of this delivery system.Synergistic cellular proliferation inhibition and desirable apoptosis promotion have been found when pancreatic cancer Bxpc-3 cells were co-cultured with this GEM-DDP/hydrogel system.After a single intratumoral injection,the dual-drug loaded hydrogel formulation exhibited superior anti-tumor efficacy and minimized systemic side effect on pancreatic cancer xenograft mouse model in comparison to the intravenously injected free GEM and DDP combination.In addition,a strong synergistic therapeutic effect of the GEM-DDP/hydrogel system against pancreatic cancer has been found in vitro and in vivo compared to the single-drug loaded hydrogel composites.The obtained findings suggest this developed thermo-sensitive copolymer hydrogel system as a potential universal carrier for the localized targeted delivery of multi-drugs,for use in a variety of inoperable solid tumors. 展开更多
关键词 localized drug delivery SUSTAINED release THERMO-SENSITIVE HYDROGEL combination therapy pancreatic cancer
Development and Application of Coated Fertilizer in Japan 预览
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作者 Hiroshi Aoki Yuichi Sekiguti 《食品科学与工程:英文版(美国)》 2019年第4期142-152,共11页
The fertilizer industry faces a continuing challenge to improve its products to increase the fertilizer use efficiency and to minimize any possible adverse environmental impact.For this purpose,studies on the developm... The fertilizer industry faces a continuing challenge to improve its products to increase the fertilizer use efficiency and to minimize any possible adverse environmental impact.For this purpose,studies on the development of coated fertilizers have been done all over the world.In this paper,we are to introduce our coated urea“MEISTER”as the sophisticated fertilizer,with explaining the features and applications in actual fields.“MEISTER”is the coated urea with a mixture of polyolefin and silicate mineral.“MEISTER”has two releasing types.One is the linear type.Another is the sigmoidal type.Release of nitrogen from“MEISTER”mainly depends on temperature which allows precise prediction of nutrient release.Application experiments for rice,Chinese cabbage and long onion are introduced in this paper.Every experiment shows single basal application is possible by using“MEISTER”with keeping yield and high nitrogen recovery.Coated fertilizers show accurate release control of nutrients.The use of coated fertilizers brings:(a)efficient use of fertilizer resources,(b)reduction of environmental load by fertilizer,(c)labor saving.Thus applying coated fertilizers is definitely smart fertilization technology in agriculture.Coated fertilizers seem to closely meet the requirements of an ideal fertilizer.The problem is its high price compared to the normal rapid soluble fertilizer.Unit price of coated fertilizer is expensive on the surface,though total application cost of coated fertilizers is often cheaper than the cost of rapid soluble fertilizers.This sometime disturbs the spread of coated fertilizers.So,we have been trying to make an effort to reduce production cost and doing application enlargement trials of coated fertilizers for becoming more widespread.Through those studies and development,we believe coated fertilizers will contribute to agriculture more in the world. 展开更多
关键词 Coated FERTILIZER release control rice Chinese CABBAGE LONG ONION co-situs NITROGEN use efficiency
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直升机外挂物投放安全性研究 预览
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作者 毛旭 牛嵩 张威 《航空科学技术》 2019年第6期10-18,共9页
以直升机投放外挂副油箱为例,基于计算流体力学(CFD)方法开展了直升机外挂物投放安全性计算研究。采用动态网格技术模拟外挂物副油箱与直升机的相对运动,计算研究了外挂副油箱空气舵、直升机旋翼下洗流和飞行状态对外挂副油箱投放安全... 以直升机投放外挂副油箱为例,基于计算流体力学(CFD)方法开展了直升机外挂物投放安全性计算研究。采用动态网格技术模拟外挂物副油箱与直升机的相对运动,计算研究了外挂副油箱空气舵、直升机旋翼下洗流和飞行状态对外挂副油箱投放安全性的影响规律。计算结果表明,增加空气舵有利于外挂副油箱的安全投放,但空气舵并不是越大越好;直升机旋翼下洗流对外挂副油箱投放的影响并不总是正面的,这取决于直升机飞行状态,故其影响不容忽视;而直升机的飞行速度越低、迎角越小、侧滑角绝对值越小,越有利于外挂副油箱的安全投放。 展开更多
关键词 外挂副油箱 投放 安全性 动态网格 直升机
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Online scheduling of jobs with kind release times and deadlines on a single machine 预览
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作者 LI Wen-jie MA Ran FENG Qi 《高校应用数学学报:英文版(B辑)》 SCIE CSCD 2019年第1期113-126,共14页
This paper studies online scheduling of jobs with kind release times on a single machine.Here“kind release time”means that in online setting,no jobs can be released when the machine is busy.Each job J has a kind rel... This paper studies online scheduling of jobs with kind release times on a single machine.Here“kind release time”means that in online setting,no jobs can be released when the machine is busy.Each job J has a kind release time r(J)≥0,a processing time p(J)>0 and a deadline d(J)>0.The goal is to determine a schedule which maximizes total processing time (∑p(J)E(J)) or total number (∑E(J)) of the accepted jobs.For the first objective function ∑p(J)E(J),we first present a lower bound √2,and then provide an online algorithm LEJ with a competitive ratio of 3.This is the first deterministic algorithm for the problem with a constant competitive ratio.When p(J)∈{1,k},k>1 is a real number,we first present a lower bound minf(1+k)/k,2k/(1+k)g,and then we show that LEJ has a competitive ratio of 1+┌k┐=k.In particular,when all the k length jobs have tight deadlines,we first present a lower bound max{4=(2+k),1}(for ∑p(J)E(J))and 4/3(for ∑E(J)).Then we prove that LEJ is┌k┐/k-competitive for ∑p(J)E(J) and we provide an online algorithm H with a competitive ratio of 2┌k┐/(┌k┐+1)for the second objective function ∑E(J). 展开更多
关键词 SCHEDULING ONLINE algorithm KIND RELEASE time DEADLINE
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智能卡通讯中干扰测试的经验和诀窍 预览
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作者 杨利华 《中国集成电路》 2019年第6期67-70,共4页
智能卡的使用环境差异很大,有的电磁兼容环境很恶劣,既有来自电源的传导干扰,也有来自空间的辐射干扰。智能卡在通讯过程中受到干扰后,除了出现通讯中断、延时、死机等异常外,还存在指令跑飞、写地址变化、写数据变化等造成数据破坏的情... 智能卡的使用环境差异很大,有的电磁兼容环境很恶劣,既有来自电源的传导干扰,也有来自空间的辐射干扰。智能卡在通讯过程中受到干扰后,除了出现通讯中断、延时、死机等异常外,还存在指令跑飞、写地址变化、写数据变化等造成数据破坏的情形,因此,智能卡必须具备一定的抗干扰能力。评估智能卡的抗干扰能力一般通过固定时间内再现数据破坏的数量来确定。再现智能卡数据破坏不是很容易的事情,不是简单地对智能卡施加外来干扰,其中有一些经验和诀窍。本文介绍了一些智能卡通讯中干扰的经验和诀窍。 展开更多
关键词 通讯干扰 指令 释放
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一种可释放维生素B2的聚乙烯醇口腔膜的制备及其性能研究 预览
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作者 李俊起 李文明 +5 位作者 王宪鹏 史建华 朱爱臣 李博 郈秀菊 王传栋 《生物医学工程研究》 2019年第2期227-231,共5页
本研究将维生素B2溶解于聚乙烯醇(PVA)的水溶液中,利用静电纺丝法制备了含有维生素B2的PVA口腔膜,并测定其理化性能及溶出度。结果表明,该PVA膜具有合适的力学强度,遇水浸泡3h后的维生素B2含量累计释放度约为85.75%,可以作为贴膜来治疗... 本研究将维生素B2溶解于聚乙烯醇(PVA)的水溶液中,利用静电纺丝法制备了含有维生素B2的PVA口腔膜,并测定其理化性能及溶出度。结果表明,该PVA膜具有合适的力学强度,遇水浸泡3h后的维生素B2含量累计释放度约为85.75%,可以作为贴膜来治疗口腔溃疡。 展开更多
关键词 维生素B2 口腔溃疡 聚乙烯醇 电纺 释放
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Mathematical modeling of drug release from biodegradable polymeric microneedles 预览
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作者 Sarvenaz Chavoshi Mohammad Rabiee +6 位作者 Mehdi Rafizadeh Navid Rabiee Alireza Shahin Shamsabadi Mojtaba Bagherzadeh Reza Salarian Mohammadreza Tahriri Lobat Tayebi 《生物设计与制造(英文)》 CSCD 2019年第2期96-107,共12页
Transdermal drug delivery systems have overcome many limitations of other drug administration routes,such as injection pain and first-pass metabolism following oral route,although transdermal drug delivery systems are... Transdermal drug delivery systems have overcome many limitations of other drug administration routes,such as injection pain and first-pass metabolism following oral route,although transdermal drug delivery systems are limited to drugs with low molecular weight.Hence,new emerging technology allowing high molecular weight drug delivery across the skin—known as‘microneedles’—has been developed,which creates microchannels that facilitate drug delivery.In this report,drug-loaded degradable conic microneedles are modeled to characterize the degradation rate and drug release profile.Since a lot of data are available for polylactic acid-co-glycolic acid(PLGA)degradation in the literature,PLGA of various molecular weights-as a biodegradable polymer in the polyester family-is used for modeling and verification of the drug delivery in themicroneedles.The main reaction occurring during polyester degradation is hydrolysis of steric bonds,leading to molecular weight reduction.The acid produced in the degradation has a catalytic effect on the reaction.Changes in water,acid and steric bond concentrations over time and for different radii of microneedles are investigated.To solve the partial and ordinary differential equations simultaneously,finite difference and Runge–Kutta methods are employed,respectively,with the aid of MATLAB.Correlation of the polymer degradation rate with its molecular weight and molecular weight changes versus time are illustrated.Also,drug diffusivity is related to matrix molecular weight.The molecular weight reduction and accumulative drug release within the system are predicted.In order to validate and assess the proposed model,data series of the hydrolytic degradation of aspirin(180.16 Da)-and albumin(66,000 Da)-loaded PLGA(1:1 molar ratio)are used for comparison.The proposed model is in good agreement with experimental data from the literature.Considering diffusion as themain phenomena and autocatalytic effects in the reaction,the drug release profile is predicted.Based on our results for a 展开更多
关键词 MATHEMATICAL modeling MICRONEEDLE Polymer DEGRADATION Drug release Poly(lactic-co-glycolic acid) AUTOCATALYTIC effect
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水华微囊藻衰亡后营养盐释放过程研究 预览
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作者 高磊 《安徽农学通报》 2019年第14期12-17,37共7页
在构建的水-沉积物系统中加入死亡的水华微囊藻细胞(烘箱中杀死),研究其衰亡后营养盐的释放过程及迁移转化规律。结果表明:(1)实验期间,微囊藻碎屑迅速分解释放,上覆水中DO和沉积物中氧化还原电位迅速降低;(2)实验初期上覆水中TN、NH4+-... 在构建的水-沉积物系统中加入死亡的水华微囊藻细胞(烘箱中杀死),研究其衰亡后营养盐的释放过程及迁移转化规律。结果表明:(1)实验期间,微囊藻碎屑迅速分解释放,上覆水中DO和沉积物中氧化还原电位迅速降低;(2)实验初期上覆水中TN、NH4+-N、NO3--N大幅上升,第4d达到最高水平,分别升高了16.6、13.3、6.4倍;第4d以后TN、NO3^--N逐渐降低,主要由于厌氧反硝化作用、向间隙水中迁移及NO3-向NH4+转化,NH4^+-N平稳缓慢增加,后期N主要以NH4^+的形式存在;(3)由于藻体分解,上覆水中TP、DTP、SRP、DOP的增加较快,第1d即达到较高水平,分别为初始值的4.10、5.29、4.86、8.33倍;(4)沉积物间隙水中TN、NH4^+-N增幅较大,NO3^--N次之,且NH4^+-N持续升高,间隙水中N的形态也主要以NH4+的形式存在,整个实验阶段间隙水中TP、DTP、SRP一直有所升高,DOP先升高后降低;(5)沉积物成为微囊藻衰亡阶段营养盐释放的“汇”。 展开更多
关键词 水华微囊藻 衰亡 营养盐 释放
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