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“完全学分制”下分析化学实验的“多维”教学设计与思政挖掘
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作者 张盛 王明玉 +1 位作者 王小红 冯建成 《大学化学》 CAS 2024年第2期189-195,共7页
基于理工科、农学、海洋等专业人才培养方案和“完全学分制”下人才培养要求,提出“线上线下结合式教学模式”“翻转课堂教学模式”“单道双轨型教学模式”结合的“多维”实验教学法。基于“以成果为导向”“以不同专业为导向”以及“... 基于理工科、农学、海洋等专业人才培养方案和“完全学分制”下人才培养要求,提出“线上线下结合式教学模式”“翻转课堂教学模式”“单道双轨型教学模式”结合的“多维”实验教学法。基于“以成果为导向”“以不同专业为导向”以及“以学生为中心”的思政挖掘理念,运用“自上而下”和“问卷调查”的方法,提炼出七大思政元素,将专业知识传授与思政育人元素有机结合,渗透性地贯穿于课程教学全过程。采用实践性评价、过程性评价与终结性评价相结合的多元化评价方法,注重学生全面能力考核。以开放创新实验与科普性实验设计为抓手,注重竞赛能力提升,强化实践与创新能力,符合“完全学分制”背景下,以成果导向(OBE)为基础的人才培养目标。 展开更多
关键词 完全学分制 分析化学实验 人才培养 “多维”教学法 课程思政
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Ruxolitinib improves the inflammatory microenvironment,restores glutamate homeostasis,and promotes functional recovery after spinal cord injury 被引量:1
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作者 Jiang Cao Xiao Yu +10 位作者 Jingcheng Liu Jiaju Fu Binyu Wang Chaoqin Wu sheng zhang Hongtao Chen Zi Wang Yinyang Xu Tao Sui Jie Chang Xiaojian Cao 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第11期2499-2512,共14页
The inflammatory microenvironment and neurotoxicity can hinder neuronal regeneration and functional recovery after spinal cord injury.Ruxolitinib,a JAK-STAT inhibitor,exhibits effectiveness in autoimmune diseases,arth... The inflammatory microenvironment and neurotoxicity can hinder neuronal regeneration and functional recovery after spinal cord injury.Ruxolitinib,a JAK-STAT inhibitor,exhibits effectiveness in autoimmune diseases,arthritis,and managing inflammatory cytokine storms.Although studies have shown the neuroprotective potential of ruxolitinib in neurological trauma,the exact mechanism by which it enhances functional recovery after spinal cord injury,particularly its effect on astrocytes,remains unclear.To address this gap,we established a mouse model of T10 spinal cord contusion and found that ruxolitinib effectively improved hindlimb motor function and reduced the area of spinal cord injury.Transcriptome sequencing analysis showed that ruxolitinib alleviated inflammation and immune response after spinal cord injury,restored EAAT2 expression,reduced glutamate levels,and alleviated excitatory toxicity.Furthermore,ruxolitinib inhibited the phosphorylation of JAK2 and STAT3 in the injured spinal cord and decreased the phosphorylation level of nuclear factor kappa-B and the expression of inflammatory factors interleukin-1β,interleukin-6,and tumor necrosis factor-α.Additionally,in glutamate-induced excitotoxicity astrocytes,ruxolitinib restored EAAT2 expression and increased glutamate uptake by inhibiting the activation of STAT3,thereby reducing glutamate-induced neurotoxicity,calcium influx,oxidative stress,and cell apoptosis,and increasing the complexity of dendritic branching.Collectively,these results indicate that ruxolitinib restores glutamate homeostasis by rescuing the expression of EAAT2 in astrocytes,reduces neurotoxicity,and effectively alleviates inflammatory and immune responses after spinal cord injury,thereby promoting functional recovery after spinal cord injury. 展开更多
关键词 astrocytes EAAT2 EXCITOTOXICITY glutamate homeostasis JAK-STAT pathway locomotor function NEUROTOXICITY RUXOLITINIB spinal cord injury transcriptome analysis
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Enhancing microseismic/acoustic emission source localization accuracy with an outlier-robust kernel density estimation approach 被引量:1
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作者 Jie Chen Huiqiong Huang +4 位作者 Yichao Rui Yuanyuan Pu sheng zhang Zheng Li Wenzhong Wang 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第7期943-956,共14页
Monitoring sensors in complex engineering environments often record abnormal data,leading to significant positioning errors.To reduce the influence of abnormal arrival times,we introduce an innovative,outlier-robust l... Monitoring sensors in complex engineering environments often record abnormal data,leading to significant positioning errors.To reduce the influence of abnormal arrival times,we introduce an innovative,outlier-robust localization method that integrates kernel density estimation(KDE)with damping linear correction to enhance the precision of microseismic/acoustic emission(MS/AE)source positioning.Our approach systematically addresses abnormal arrival times through a three-step process:initial location by 4-arrival combinations,elimination of outliers based on three-dimensional KDE,and refinement using a linear correction with an adaptive damping factor.We validate our method through lead-breaking experiments,demonstrating over a 23%improvement in positioning accuracy with a maximum error of 9.12 mm(relative error of 15.80%)—outperforming 4 existing methods.Simulations under various system errors,outlier scales,and ratios substantiate our method’s superior performance.Field blasting experiments also confirm the practical applicability,with an average positioning error of 11.71 m(relative error of 7.59%),compared to 23.56,66.09,16.95,and 28.52 m for other methods.This research is significant as it enhances the robustness of MS/AE source localization when confronted with data anomalies.It also provides a practical solution for real-world engineering and safety monitoring applications. 展开更多
关键词 Microseismic source/acoustic emission(MS/AE) Kernel density estimation(KDE) Damping linear correction Source location Abnormal arrivals
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Surrogate modeling for unsaturated infiltration via the physics and equality-constrained artificial neural networks 被引量:1
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作者 Peng Lan Jingjing Su sheng zhang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第6期2282-2295,共14页
Machine learning(ML)provides a new surrogate method for investigating groundwater flow dynamics in unsaturated soils.Traditional pure data-driven methods(e.g.deep neural network,DNN)can provide rapid predictions,but t... Machine learning(ML)provides a new surrogate method for investigating groundwater flow dynamics in unsaturated soils.Traditional pure data-driven methods(e.g.deep neural network,DNN)can provide rapid predictions,but they do require sufficient on-site data for accurate training,and lack interpretability to the physical processes within the data.In this paper,we provide a physics and equalityconstrained artificial neural network(PECANN),to derive unsaturated infiltration solutions with a small amount of initial and boundary data.PECANN takes the physics-informed neural network(PINN)as a foundation,encodes the unsaturated infiltration physical laws(i.e.Richards equation,RE)into the loss function,and uses the augmented Lagrangian method to constrain the learning process of the solutions of RE by adding stronger penalty for the initial and boundary conditions.Four unsaturated infiltration cases are designed to test the training performance of PECANN,i.e.one-dimensional(1D)steady-state unsaturated infiltration,1D transient-state infiltration,two-dimensional(2D)transient-state infiltration,and 1D coupled unsaturated infiltration and deformation.The predicted results of PECANN are compared with the finite difference solutions or analytical solutions.The results indicate that PECANN can accurately capture the variations of pressure head during the unsaturated infiltration,and present higher precision and robustness than DNN and PINN.It is also revealed that PECANN can achieve the same accuracy as the finite difference method with fewer initial and boundary training data.Additionally,we investigate the effect of the hyperparameters of PECANN on solving RE problem.PECANN provides an effective tool for simulating unsaturated infiltration. 展开更多
关键词 Richards equation(RE) Unsaturated infiltration Data-driven solutions Numerical modeling Machine learning(ML)
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Reliability analysis of slope stability by neural network,principal component analysis,and transfer learning techniques 被引量:1
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作者 sheng zhang Li Ding +3 位作者 Menglong Xie Xuzhen He Rui Yang Chenxi Tong 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第10期4034-4045,共12页
The prediction of slope stability is considered as one of the critical concerns in geotechnical engineering.Conventional stochastic analysis with spatially variable slopes is time-consuming and highly computation-dema... The prediction of slope stability is considered as one of the critical concerns in geotechnical engineering.Conventional stochastic analysis with spatially variable slopes is time-consuming and highly computation-demanding.To assess the slope stability problems with a more desirable computational effort,many machine learning(ML)algorithms have been proposed.However,most ML-based techniques require that the training data must be in the same feature space and have the same distribution,and the model may need to be rebuilt when the spatial distribution changes.This paper presents a new ML-based algorithm,which combines the principal component analysis(PCA)-based neural network(NN)and transfer learning(TL)techniques(i.e.PCAeNNeTL)to conduct the stability analysis of slopes with different spatial distributions.The Monte Carlo coupled with finite element simulation is first conducted for data acquisition considering the spatial variability of cohesive strength or friction angle of soils from eight slopes with the same geometry.The PCA method is incorporated into the neural network algorithm(i.e.PCA-NN)to increase the computational efficiency by reducing the input variables.It is found that the PCA-NN algorithm performs well in improving the prediction of slope stability for a given slope in terms of the computational accuracy and computational effort when compared with the other two algorithms(i.e.NN and decision trees,DT).Furthermore,the PCAeNNeTL algorithm shows great potential in assessing the stability of slope even with fewer training data. 展开更多
关键词 Slope stability analysis Monte Carlo simulation Neural network(NN) Transfer learning(TL)
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刺激响应型可注射水凝胶在药物控释领域的研究进展
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作者 郑月丹 王晓玲 +2 位作者 冯俊峰 张晟 郭坤 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2024年第9期164-172,共9页
可注射水凝胶作为一种新兴的智能生物材料,由于其可以精准植入组织部位,实现高靶向性原位成形、原位给药、无需手术、创口小等特点,在生物医学领域显示出巨大的应用潜力。这类水凝胶可以通过物理或化学交联形成,具有良好的生物相容性和... 可注射水凝胶作为一种新兴的智能生物材料,由于其可以精准植入组织部位,实现高靶向性原位成形、原位给药、无需手术、创口小等特点,在生物医学领域显示出巨大的应用潜力。这类水凝胶可以通过物理或化学交联形成,具有良好的生物相容性和生物降解性,通过负载活性物质,在药物递送、组织工程等生物医用领域大有可为。刺激响应型水凝胶在感受到环境刺激时会改变形状或体积。当pH值、温度、光照、电磁场或酶等条件发生变化时,它们的体积会膨胀或收缩,甚至发生降解。文中从内源性刺激(如pH值、温度、酶和葡萄糖)和外源性刺激(如光、电、磁场)2个方面,综述了刺激响应型可注射水凝胶的研究进展,重点介绍了内源性刺激(如pH值、温度、酶和葡萄糖)和外源性刺激(如光、电、磁场)相变机理、设计和合成策略及释药行为,并对可注射水凝胶开发中需应对的挑战与问题和未来发展提出了建议。 展开更多
关键词 刺激响应 可注射水凝胶 药物控释
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临海地带浅埋隧洞地表注浆加固技术
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作者 相泽 邓世平 +3 位作者 盛章 周烨 王伟 裴亚兵 《中外公路》 2024年第6期233-239,共7页
针对某工程取水隧洞Ⅵ级围岩段地处临海地带、覆盖砂层厚、围岩破碎等特点,采用室内试验探讨水玻璃体积掺量对水泥-水玻璃(CS)双液浆终凝时间和强度的影响,并进行现场试验对注浆工法进行全面分析。最终确定采用约束-发散模式,将注浆区... 针对某工程取水隧洞Ⅵ级围岩段地处临海地带、覆盖砂层厚、围岩破碎等特点,采用室内试验探讨水玻璃体积掺量对水泥-水玻璃(CS)双液浆终凝时间和强度的影响,并进行现场试验对注浆工法进行全面分析。最终确定采用约束-发散模式,将注浆区域划分为若干个小的注浆单元,按照先最外圈孔间隔、后内部孔隔排间隔的注浆顺序进行塑料管超前地表注浆加固。岩芯取样和暗挖掘进效果表明:通过地表预注浆加固,岩体裂隙得到了有效的填充加固,减少了开挖过程中发生涌水和塌方现象,确保隧洞正常掘进,取得了较好的经济和社会效益。 展开更多
关键词 临海地带 取水隧洞 破碎围岩 塑料管注浆
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Recess-free enhancement-mode AlGaN/GaN RF HEMTs on Si substrate
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作者 Tiantian Luan Sen Huang +12 位作者 Guanjun Jing Jie Fan Haibo Yin Xinguo Gao sheng zhang Ke Wei Yankui Li Qimeng Jiang Xinhua Wang Bin Hou Ling Yang Xiaohua Ma Xinyu Liu 《Journal of Semiconductors》 EI CAS CSCD 2024年第6期81-86,共6页
Enhancement-mode(E-mode)GaN-on-Si radio-frequency(RF)high-electron-mobility transistors(HEMTs)were fabri-cated on an ultrathin-barrier(UTB)AlGaN(<6 nm)/GaN heterostructure featuring a naturally depleted 2-D electro... Enhancement-mode(E-mode)GaN-on-Si radio-frequency(RF)high-electron-mobility transistors(HEMTs)were fabri-cated on an ultrathin-barrier(UTB)AlGaN(<6 nm)/GaN heterostructure featuring a naturally depleted 2-D electron gas(2DEG)channel.The fabricated E-mode HEMTs exhibit a relatively high threshold voltage(VTH)of+1.1 V with good uniformity.A maxi-mum current/power gain cut-off frequency(fT/fMAX)of 31.3/99.6 GHz with a power added efficiency(PAE)of 52.47%and an out-put power density(Pout)of 1.0 W/mm at 3.5 GHz were achieved on the fabricated E-mode HEMTs with 1-μm gate and Au-free ohmic contact. 展开更多
关键词 AlGaN/GaN heterostructure ultrathin-barrier ENHANCEMENT-MODE RADIO-FREQUENCY power added efficiency silicon substrate
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Analysis and verification of electrodynamic force,thermal stress and current sharing for CRAFT converter structure design
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作者 王重马 石朝毅 +6 位作者 张秀青 卢文武 张胜 高先和 许涛 邵兴星 黄连生 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第8期104-111,共8页
In the design realm of fusion power supplies,structural components play a pivotal role in ensuring the safety of fusion devices.To verify the reliability of the converter structure design at the Comprehensive Research... In the design realm of fusion power supplies,structural components play a pivotal role in ensuring the safety of fusion devices.To verify the reliability of the converter structure design at the Comprehensive Research Facility for Fusion Technology(CRAFT),meticulous analysis of the converter's dynamic impact is carefully performed based on the worst fault current(400k A),firstly.Subsequently,the thermal stress analysis based on the maximum allowable steadystate temperature is finished,and the equivalent thermal stress,thermal deformation,maximum shear stress of a single bridge arm and the whole converter are studied.Furthermore,a simple research method involving the current-sharing characteristics of a bridge arm with multithyristor parallel connection is proposed using a combination of Simplorer with Q3D in ANSYS.The results show that the current-sharing characteristics are excellent.Finally,the structural design has been meticulously tailored to meet the established requirements. 展开更多
关键词 electrodynamic analysis thermal stress current-sharing characteristics CRAFT
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PDZK1 protects against mechanical overload-induced chondrocyte senescence and osteoarthritis by targeting mitochondrial function
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作者 Yan Shao Hongbo zhang +13 位作者 Hong Guan Chunyu Wu Weizhong Qi Lingfeng Yang Jianbin Yin Haiyan zhang Liangliang Liu Yuheng Lu Yitao Zhao sheng zhang Chun Zeng Guiqing Wang Xiaochun Bai Daozhang Cai 《Bone Research》 SCIE CAS CSCD 2024年第3期621-633,共13页
Mechanical overloading and aging are two essential factors for osteoarthritis(OA)development.Mitochondria have been identified as a mechano-transducer situated between extracellular mechanical signals and chondrocyte ... Mechanical overloading and aging are two essential factors for osteoarthritis(OA)development.Mitochondria have been identified as a mechano-transducer situated between extracellular mechanical signals and chondrocyte biology,but their roles and the associated mechanisms in mechanical stress-associated chondrocyte senescence and OA have not been elucidated. 展开更多
关键词 OVERLOAD aging stress
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Intermittent melena and refractory anemia due to jejunal cavernous lymphangioma:A case report
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作者 Kai-Rui Liu sheng zhang +2 位作者 Wei-Run Chen You-Xing Huang Xu-Guang Li 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第4期1208-1214,共7页
BACKGROUND Lymphangiomas in the gastrointestinal tract are extremely rare in adults.As a benign lesion,small intestine lymphangiomas often remain asymptomatic and pose challenges for definitive diagnosis.However,lymph... BACKGROUND Lymphangiomas in the gastrointestinal tract are extremely rare in adults.As a benign lesion,small intestine lymphangiomas often remain asymptomatic and pose challenges for definitive diagnosis.However,lymphangiomas can give rise to complications such as abdominal pain,bleeding,volvulus,and intussusception.Here,we report a case of jejunal cavernous lymphangioma that presented with intermittent melena and refractory anemia in a male adult.CASE SUMMARY A 66-year-old man presented with intermittent melena,fatigue and refractory anemia nine months prior.Esophagogastroduodenoscopy and colonoscopy were performed many times and revealed no apparent bleeding.Conservative management,including transfusion,hemostasis,gastric acid secretion inhibition and symptomatic treatment,was performed,but the lesions tended to recur shortly after surgery.Ultimately,the patient underwent capsule endoscopy,which revealed a more than 10 cm lesion accompanied by active bleeding.After singleballoon enteroscopy and biopsy,a diagnosis of jejunal cavernous lymphangioma was confirmed,and the patient underwent surgical resection.No complications or recurrences were observed postoperatively.CONCLUSION Jejunal cavernous lymphangioma should be considered a cause of obscure gastrointestinal bleeding.Capsule endoscopy and single-balloon enteroscopy can facilitate diagnosis.Surgical resection is an effective management method. 展开更多
关键词 Intermittent melena Refractory anemia Capsule endoscopy Single-balloon enteroscopy Jejunal cavernous lymphangioma Enterectomy Case report
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Inhibition of Propionibacterium acnes by refined bamboo vinegar and preparation of the slow-release system with bamboo charcoal as the carrier
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作者 Ziyi Li Yanan Wang sheng zhang 《Journal of Dermatologic Science and Cosmetic Technology》 2024年第2期17-25,共9页
Background:Acne vulgaris is one of the most common skin diseases that can significantly impact a considerable proportion of individuals over their lifetime.Objective:This study focuses on the exploration of the applic... Background:Acne vulgaris is one of the most common skin diseases that can significantly impact a considerable proportion of individuals over their lifetime.Objective:This study focuses on the exploration of the application potential of bamboo vinegar in cosmetics.Materials and Methods:The stock solution of bamboo vinegar is subjected to reduced-pressure distillation at different temperatures to obtain refined bamboo vinegar.Then,inhibition of Propionibacterium acnes(P.acnes)by refined bamboo vinegar is observed.Moreover,the refined bamboo vinegar is adsorbed and released with activated bamboo charcoal as the carrier.In all,this study aims to probe into the mechanism of the controlledrelease system of bamboo vinegar.Results:The results shows that the harmful substances(tar)in bamboo vinegar distilled at 70℃decreased by 94.44%,which is a more notable decrease compared with that in the stock solution.The total organic acid content in bamboo vinegar after reduced-pressure distillation is 11.840%,reaching the national standard for refined bamboo vinegar(GB/T 31734–2015).Additionally,the minimum inhibitory concentration of refined bamboo vinegar against P.acnes using the punch method is 7.90 mg/mL.This indicates that refined bamboo vinegar has the potential as a prospective raw material for formulations in anti-acne cosmetic products.Furthermore,the release rate of bamboo charcoal/bamboo vinegar in water for 15 min reaches 70.57%,which then slows down to a plateau.The slow-release behavior is agreed with the Ritger-Peppas model and is beneficial to relieve the irritation of bamboo vinegar to the skin and lengthen its bacteriostatic duration.Conclusion:The foregoing conclusions can serve as the theoretical foundation for the application of bamboo vinegar in anti-acne cosmetics. 展开更多
关键词 Bamboo vinegar REFINEMENT Propionibacterium acne Bamboo charcoal
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重组人脑利钠肽联合左西孟旦对急性心力衰竭患者心功能、心肌纤维化及安全性的影响 被引量:5
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作者 张胜 朱锦 杨晓宇 《中国药师》 CAS 2023年第11期264-271,共8页
目的 探究重组人脑利钠肽联合左西孟旦对急性心力衰竭(AHF)患者心功能、心肌纤维化及安全性的影响。方法 纳入2021年5月至2023年4月在常州市第一人民医院就诊的AHF患者,随机分为干预组和对照组。干预组给予重组人脑利钠肽联合左西孟旦治... 目的 探究重组人脑利钠肽联合左西孟旦对急性心力衰竭(AHF)患者心功能、心肌纤维化及安全性的影响。方法 纳入2021年5月至2023年4月在常州市第一人民医院就诊的AHF患者,随机分为干预组和对照组。干预组给予重组人脑利钠肽联合左西孟旦治疗,对照组给予左西孟旦治疗,两组均治疗14 d。记录两组治疗前后左室射血分数(LVEF)、左室舒张末径(LVEDD)、心率(HR),计算平均动脉压(MAP)值;检测两组心肌肌钙蛋白T(cTnT)和心肌型肌酸激酶同工酶(CK-MB)水平;检测白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)和高敏C反应蛋白(hs-CRP)炎症因子水平评估两组炎症情况;检测血清可溶性基质裂解素2(sST2)和血清成纤维细胞生长因子-21(FGF-21)水平评估两组心肌纤维化水平,观察两组不良反应发生率并评估其用药安全性。结果 共纳入90例AHF患者,研究组和对照组各45例。治疗14 d后,干预组HR、CK-MB、IL-6、TNF-α、hs-CRP、sST2和FGF-21水平均低于对照组,LVEF、cTnT和MAP均高于对照组(P <0.05);LVEDD差异无统计学意义(P> 0.05)。两组不良反应发生率差异无统计学意义(P> 0.05)。结论 重组人脑利钠肽联合左西孟旦能有效改善AHF患者心功能及心肌纤维化,且安全性良好。 展开更多
关键词 重组人脑利钠肽 左西孟旦 急性心力衰竭 心功能
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一种基于主客体识别的长效无刺激驱避剂 被引量:2
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作者 吴迪 张小勤 +2 位作者 侯君波 张晟 李帮经 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2019年第8期144-149,158,共7页
蚊虫是多种传染病的传播媒介,并且蚊虫的叮咬常常使人难以忍受,但目前的驱蚊产品或多或少均对人体有毒性及刺激性作用,人类直接接触后有一定的危害性。文中制备了一种长效且无刺激的驱避剂,利用γ-环糊精(γ-CD)与乙基丁酰基氨基丙酸乙... 蚊虫是多种传染病的传播媒介,并且蚊虫的叮咬常常使人难以忍受,但目前的驱蚊产品或多或少均对人体有毒性及刺激性作用,人类直接接触后有一定的危害性。文中制备了一种长效且无刺激的驱避剂,利用γ-环糊精(γ-CD)与乙基丁酰基氨基丙酸乙酯(BAAPE)的包合作用,达到缓慢释放和稳定驱避的目的。研究表明,当BAAPE与γ-CD形成包合物后,对皮肤的刺激性下降,储藏稳定性增加,释放明显减缓,可长效驱蚊。涂抹7h后,包合物的驱蚊效果为市售花露水的数倍以上。 展开更多
关键词 Γ-环糊精 驱避剂 主客体识别
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政府连环抉择机制:行政委托第三方评估实践差异现象的一种解释 被引量:3
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作者 张圣 《公共行政评论》 CSSCI 北大核心 2022年第3期119-139,M0006,共22页
近年来,受行政委托的第三方评估已成为提升政府治理绩效的重要工具。对此,现有研究主要聚焦于探讨第三方评估实效及其内外部影响因素,却忽视了对第三方评估实践差异现象的对比分析,导致所得结论略显局限。基于对X市A区慈善超市和Y市文... 近年来,受行政委托的第三方评估已成为提升政府治理绩效的重要工具。对此,现有研究主要聚焦于探讨第三方评估实效及其内外部影响因素,却忽视了对第三方评估实践差异现象的对比分析,导致所得结论略显局限。基于对X市A区慈善超市和Y市文明城市测评过程的对比分析,可提炼出一种作用于行政委托第三方评估实效的政府连环抉择机制。研究发现,政府连环抉择机制是一种由行政委托逻辑、政社关系结构、政社合作模式和第三方评估实践类型等关联性选择构成的复杂运作过程。该机制始于“行政督导”与“同谋共治”两类行政委托逻辑。这两类逻辑又分别决定着“委托人-代理人”和“委托人-管家”两种政社关系结构。二分后的政社关系结构又相应决定了被动式和主动式两种政社合作模式。最终,被动式政社合作模式产生了形式化第三方评估,与之相对的主动式政社合作模式则形成了实质性第三方评估。立足政府连环抉择机制,政府应树立同谋共治型委托逻辑,科学对待第三方评估过程;第三方评估机构则需提升专业能力、增强责任意识,并以“管家”身份参与其中。在政社共同努力下,优化行政委托第三方评估的实践过程,从而提升其实效。 展开更多
关键词 行政委托 第三方评估 治理绩效 政社关系 政府连环抉择机制
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Visualization of Exact Invariant Solutions Associated with Atmospheric Waves in a Thin Circular Layer
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作者 Ranis N. Ibragimov Lauren D. Mongrain +5 位作者 Benjamin Stimmel Olga Trozkaya Guang Lin sheng zhang Vesselin Vatchev Daniel Stankiewicz 《Journal of Applied Mathematics and Physics》 2021年第5期901-919,共19页
The purpose of the research was to investigate the exact solutions of nonlinear shallow water equations associated with planetary equatorial waves corresponding to the Cauchy-Poisson free boundary problem describing t... The purpose of the research was to investigate the exact solutions of nonlinear shallow water equations associated with planetary equatorial waves corresponding to the Cauchy-Poisson free boundary problem describing the nonstationary motion of an incompressible perfect fluid propagating around a solid circle. We consider water waves for which the ratio of the depth of fluid above the circular bottom to the radius of the circle is small (shallow water). 展开更多
关键词 Atmospheric Waves Shallow Water Theory Exact Solutions
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高强高韧聚乙烯醇导电水凝胶的结构与传感性能 被引量:3
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作者 张胜 查湘军 +2 位作者 包睿莹 柯凯 杨伟 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2022年第6期118-124,131,共8页
为了制备高强高韧导电水凝胶,采用能与聚乙烯醇(PVA)形成氢键相互作用的单宁酸(TA)为物理交联剂,以丙三醇和水为共溶剂制备得到具有纳米纤维网络结构的PVA/TA有机水凝胶;通过浸泡1 mol/L硝酸银溶液得到金属络合作用和氢键作用协同增强... 为了制备高强高韧导电水凝胶,采用能与聚乙烯醇(PVA)形成氢键相互作用的单宁酸(TA)为物理交联剂,以丙三醇和水为共溶剂制备得到具有纳米纤维网络结构的PVA/TA有机水凝胶;通过浸泡1 mol/L硝酸银溶液得到金属络合作用和氢键作用协同增强增韧的导电水凝胶。研究结果表明,当PVA和TA质量比为2:3时,水凝胶中TA与银离子能形成强烈的络合作用,进一步增强了TA与PVA分子链间形成的物理交联网络,凝胶内部形成了更为致密的网络结构,从而赋予导电水凝胶优异的力学性能,其强度、模量和韧性相较于未引入TA的PVA水凝胶分别提高了4.5倍、5倍和5倍。该导电水凝胶用于应变传感时,表现出优异的灵敏性(GF=99.4)、极高的线性度(R~2>0.99)和良好的循环稳定性(>500圈)。 展开更多
关键词 聚乙烯醇 单宁酸 金属络合作用 导电水凝胶 力学性能 传感性能
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超细聚四氟乙烯微粉改性聚甲醛复合材料的制备及性能 被引量:7
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作者 董振强 杜钦青 +4 位作者 郑豪 姚宏兵 张晟 吕亮 何明平 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2018年第6期156-160,共5页
利用聚四氟乙烯(PTFE)的耐磨性与自润滑性能,采用超细PTFE微粉与聚甲醛(POM)制备PTFE-POM耐磨复合材料,研究了PTFE微粉的含量对复合材料力学性能、加工流动性能、耐磨性能的影响,并通过扫描电镜测试分析了产生上述现象的原因。结果表明... 利用聚四氟乙烯(PTFE)的耐磨性与自润滑性能,采用超细PTFE微粉与聚甲醛(POM)制备PTFE-POM耐磨复合材料,研究了PTFE微粉的含量对复合材料力学性能、加工流动性能、耐磨性能的影响,并通过扫描电镜测试分析了产生上述现象的原因。结果表明,随着复合材料PTFE含量的增加,其力学性能出现一定程度的下降,但加工流动性和耐磨性能均有显著的提升。扫描电镜测试结果表明,PTFE微粉与POM部分相容,导致其力学性能较纯POM下降;由于PTFE微粉的隔离效应,使得复合材料加工流动性能显著改善;由于注塑成型过程中PTFE部分向材料表面迁移,使得复合材料耐磨性能得到显著提高。所制备的PTFE-POM复合材料其成本与杜邦已商品化的AF500相当,但性能尤其是耐磨性显著优于AF500,可代替AF500作为工程塑料耐磨结构件使用。 展开更多
关键词 聚四氟乙烯微粉 聚甲醛 复合材料 耐磨性能
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主客体胶束水凝胶的制备及对神经生长因子的包载 被引量:2
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作者 冯俊峰 张晟 +3 位作者 柯朵 李帮经 周先礼 黄帅 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2020年第3期140-148,共9页
通过可逆加成-断裂链转移聚合(RAFT)反应制备了一种亲水性两嵌段聚合物——聚乙二醇/聚N-异丙基丙烯酰胺(PEG-PNIPAM),利用α-环糊精(α-CD)与其中PEG链段的选择性包合形成了一种独特的主客体胶束,这种胶束由于具备中空结构,可对亲水性... 通过可逆加成-断裂链转移聚合(RAFT)反应制备了一种亲水性两嵌段聚合物——聚乙二醇/聚N-异丙基丙烯酰胺(PEG-PNIPAM),利用α-环糊精(α-CD)与其中PEG链段的选择性包合形成了一种独特的主客体胶束,这种胶束由于具备中空结构,可对亲水性药物起到很好的负载作用。其对神经生长因子的包载率为经典普朗尼克F127胶束的2倍。进一步利用主客体胶束为大分子交联剂制备丙烯酰胺水凝胶,可赋予水凝胶优异的力学性能,拉伸伸长率为化学交联对照组5倍,并且强度高于对照组2倍以上。循环拉伸测试表明,该水凝胶具有良好的应力耗散机制。 展开更多
关键词 主客体 胶束 神经生长因子 水凝胶
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基于湿法纺丝技术构建环糊精/聚乙烯醇纤维膜及其对空气污染物的移除性能 被引量:2
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作者 赵决波 邢程远 +5 位作者 姜猛进 李帮经 张晟 陈朝喜 代弢 汪露 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2021年第8期118-124,共7页
文中探索了一种制备稳定、长时、高效移除效率和透气性的空气过滤材料的新方法。通过湿法纺丝技术制备了含β-环糊精(β-CD)的空气过滤膜(CD/PVA纤维膜),该纤维膜对PM2.5的移除效率约高达99%,其最大压差为673 Pa,QF值为0.025 Pa^(-1)(而... 文中探索了一种制备稳定、长时、高效移除效率和透气性的空气过滤材料的新方法。通过湿法纺丝技术制备了含β-环糊精(β-CD)的空气过滤膜(CD/PVA纤维膜),该纤维膜对PM2.5的移除效率约高达99%,其最大压差为673 Pa,QF值为0.025 Pa^(-1)(而PVA的最大压差值高达943,QF值为0.005 Pa^(-1)),表明CD/PVA纤维膜具有良好的移除率和透气性能。与商用空气过滤膜相比,CD/PVA纤维膜的移除率可以与其媲美,而透气性能远优于商用空气过滤膜,吸附30 h后,商用空气过滤膜的压差值高达865 Pa, CD/PVA纤维膜仅为284 Pa。同时,CD/PVA纤维膜可以吸附空气中的气体污染物(例如SO2),75CD/PVA对SO2移除率达到69.6%,而PVA纤维膜对SO2的移除率仅为50%。 展开更多
关键词 环糊精 湿法纺丝技术 移除效率 透气性能
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