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Operational feasibility study of stagnation pressure reaction control for a mid-caliber non-spinning projectile
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作者 F.Bouquet 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第6期109-121,共13页
Controlled,guided munitions can reduce dispersion in the shot,while providing the capability of engaging both stationary and maneuvering targets.The Netherlands Organisation for Applied Scientific Research has develop... Controlled,guided munitions can reduce dispersion in the shot,while providing the capability of engaging both stationary and maneuvering targets.The Netherlands Organisation for Applied Scientific Research has developed a fin-less control technology called Stagnation Pressure Reaction Control(SPRC)that takes stagnation pressure air and directs it sideways to control non-spinning projectiles.In a previous study,this technology was demonstrated at Mach 2 wind-tunnel conditions to achieve up to 1.5°controllable angle of incidence for a non-spinning,aerodynamically unstable projectile-like test object.In an operational scenario,the decelerating projectile will experience a decline in control force while the simultaneous forward shift of the center of pressure increases the need for control force.Furthermore,angles of incidence exceeding 1.5°will be experienced under realistic flight conditions,especially against maneuvering targets.This work addresses these challenges and presents an operational feasibility study for a practical application of SPRC in a non-spinning mid-caliber gun-launched projectile,using experiment data on control latency and force of the earlier study.It illustrates the combined effect of the control-and stability dynamics and underlines the potential of an SPRC projectile as a precisionoperation ammunition.This research revealed that SPRC technology can stabilize and control the hypothesized projectile in a direct fire scenario against stationary and maneuvering targets. 展开更多
关键词 Supersonic projectile Feasibility study Ram air Stagnation pressure reaction control Simulation Attitude control
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Reentry Attitude Tracking Control for Hypersonic Vehicle with Reaction Control Systems via Improved Model Predictive Control Approach 被引量:4
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作者 Kai Liu Zheng Hou +2 位作者 Zhiyong She Jian Guo 《Computer Modeling in Engineering & Sciences》 SCIE EI 2020年第1期131-148,共18页
This paper studies the reentry attitude tracking control problem for hypersonic vehicles(HSV)equipped with reaction control systems(RCS)and aerodynamic surfaces.The attitude dynamical model of the hypersonic vehicles ... This paper studies the reentry attitude tracking control problem for hypersonic vehicles(HSV)equipped with reaction control systems(RCS)and aerodynamic surfaces.The attitude dynamical model of the hypersonic vehicles is established,and the simplified longitudinal and lateral dynamic models are obtained,respectively.Then,the compound control allocation strategy is provided and the model predictive controller is designed for the pitch channel.Furthermore,considering the complicated jet interaction effect of HSV during RCS is working,an improved model predictive control approach is presented by introducing the online parameter estimation of the jet interaction coefficient for dealing with the uncertainty and disturbance.Moreover,considering the strong coupling effect between the yaw channel and roll channel,a coupled model predictive controller is designed by introducing the feedback of sideslip angle into the roll control channel to eliminate the coupling effect.Finally,the comparison simulations using the classical control method,MPC and IMPC approach are given to demonstrate the effectiveness and efficiency of the presented IMPC scheme. 展开更多
关键词 Hypersonic vehicle reentry attitude control mode predictive control jet interference factor reaction control systems
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Experimental studies of water hammer in propellant feed system of reaction control system 被引量:4
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作者 Avanish Kumar P.Satya Prasad M.Raghavendra Rao 《Propulsion and Power Research》 SCIE 2018年第1期52-59,共8页
Water hammer pressure transient produces large dynamic forces which can damage the pipes and other assemblies in the feed line of a reaction control system(RCS).It has led to the failure of pressure transducers monito... Water hammer pressure transient produces large dynamic forces which can damage the pipes and other assemblies in the feed line of a reaction control system(RCS).It has led to the failure of pressure transducers monitoring the manifold pressure in the feed line of RCS.Therefore,water hammer studies have been carried out to understand its effect in feed line.Feedline system has been simplified to develop a mathematical model and experiments have been carried out at extensive levels.The mathematical model was developed considering pipe of uniform c/s and moving liquid-gas interface.The experimental studies have been done using water as working medium instead of actual propellant.The studies showed that rate of pressurization have a very critical role on the water hammer amplitude.Sensitivity studies have been also carried out to study the effect of density,friction and initial liquid column length on water hammer amplitude. 展开更多
关键词 Water hammer reaction control system(RCS) Propellant feed system Experimental study TESTING
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Efficient oxidation of benzyl alcohol with heteropolytungstate as reaction-controlled phase-transfer catalyst 被引量:5
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作者 Zhi Huan Weng Jin Yan Wang Xi Gao Jian 《Chinese Chemical Letters》 SCIE CAS CSCD 2007年第8期936-938,共3页
A series of heteropolytungstates has been synthesized and utilized as catalysts to catalyze oxidation of benzyl alcohol with aqueous hydrogen peroxide. The results indicated that three of these catalysts showed the pr... A series of heteropolytungstates has been synthesized and utilized as catalysts to catalyze oxidation of benzyl alcohol with aqueous hydrogen peroxide. The results indicated that three of these catalysts showed the properties of reaction-controlled phasetransfer catalysis, and they had excellent catalytic ability to the oxidation of benzyl alcohol. No other by-products were detected by gas chromatography. Once the hydrogen peroxide was consumed completely, the catalyst precipitated from solvent, and the results of the catalyst recycle showed that the catalyst had high stability. 展开更多
关键词 HETEROPOLYTUNGSTATE reaction-controlled phase-transfer Benzyl alcohol BENZALDEHYDE Hydrogen peroxide
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Precisely Controlled Synthesis of Pt-Pd Octahedral Nanoframes as a Superior Catalyst towards Oxygen Reduction Reaction 被引量:1
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作者 叶春苗 黄宏文 曾杰 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2017年第5期581-587,I0002,共8页
Pt-based nanoframes represent a class of promising catalysts towards oxygen reduction reaction. Herein, we, for the first time, successfully prepared Pt-Pd octahedral nanoframes with ultrathin ridges less than 2 nm in... Pt-based nanoframes represent a class of promising catalysts towards oxygen reduction reaction. Herein, we, for the first time, successfully prepared Pt-Pd octahedral nanoframes with ultrathin ridges less than 2 nm in thickness. The Pt-Pd octahedral nanoframes were obtained through site-selected deposition of Pt atoms onto the edge sites of Pd octahedral seeds, followed by selective removal of the Pd octahedral cores via chemical etching. Due to that a combination of three-dimensional opens geometrical structure and Pt-skin surface compositional structure, the Pt-Pd octahedral nanoframes/C catalyst shows a mass activity of 1.15 A/mgPt towards oxygen reduction reaction, 5.8 times enhancement in mass activity relative to commercial Pt/C catalyst (0.20 A/mgPt). Moreover, even after 8000 cycles of accelerated durability test, the Pt-Pd octahedral nanoframes/C catalyst still exhibits a mass activity which is more than three times higher than that of pristine Pt/C catalyst. 展开更多
关键词 Pt-based nanoframes controlled synthesis Oxygen reduction reaction Mass activity
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A New Reaction-controlled Phase-transfer Catalyst System 被引量:1
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作者 MingQiangLI XiGaoJIAN GuiMeiWANG YanYU 《Chinese Chemical Letters》 SCIE CAS CSCD 2004年第3期350-352,共3页
A new reaction-controlled phase-transfer catalyst system was designed and synthesized. In this system, heteropolytungstate [C7H7N(CH3)3]9PW9O34 was used for catalytic epoxidation of cyclohexene with H2O2 as the oxida... A new reaction-controlled phase-transfer catalyst system was designed and synthesized. In this system, heteropolytungstate [C7H7N(CH3)3]9PW9O34 was used for catalytic epoxidation of cyclohexene with H2O2 as the oxidant. The conversion of H2O2 was 100% and the yield of cyclohexene oxide was 87.1% based on cyclohexene. Infrared spectra showed that both fresh catalyst and the recovered catalyst do have completely same absorption peak, indicating the structure of catalyst is very stability and can be recycled. 展开更多
关键词 reaction-controlled phase-transfer catalyst CYCLOHEXENE epoxidation.
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KINETIC MODEL FOR DIFFUSION-CONTROLLED INTERMOLECULAR REACTION OF HOMOGENOUS POLYMER UNDER STEADY SHEAR 被引量:1
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作者 周持兴 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2006年第2期135-138,共4页
The kinetic model for diffusion-controlled intermolecular reaction of homogenous polymer under steady shear was theoretically studied. The classic formalism and the concept of conformation ellipsoids were integrated t... The kinetic model for diffusion-controlled intermolecular reaction of homogenous polymer under steady shear was theoretically studied. The classic formalism and the concept of conformation ellipsoids were integrated to get a new equation, which directly correlates the rate constant with shear rate. It was found that the rate constant is not monotonic with shear rate. The scale of rate constant is N^-1.5 (N is the length of chains), which is in consistent with de Gennes's result. 展开更多
关键词 Kinetic model Diffusion-controlled reaction Flow field Intermolecular reaction
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Heteropolymolybdate as a New Reaction-controlled Phase-transfer Catalyst for Efficient Alcohol Oxidation with Hydrogen Peroxide
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作者 Zhi Huan WENG Jin Yan WANG Xi Gao JIAN 《Chinese Chemical Letters》 SCIE CAS CSCD 2006年第6期848-850,共3页
A new catalytic process for the synthesis of aldehyde from alcohol by oxidation with H202 with high selectivity, was studied. In this system, heteropolymolybdate [C7H7N(CH3)3]3 {PO4[MoO(O2)2]4} was utilized as the... A new catalytic process for the synthesis of aldehyde from alcohol by oxidation with H202 with high selectivity, was studied. In this system, heteropolymolybdate [C7H7N(CH3)3]3 {PO4[MoO(O2)2]4} was utilized as the reaction-controlled phase-transfer catalyst to catalyze oxidation of benzyl and aliphatic alcohols. The molar ratio of H2O2 and alcohol was 0.75, no other by-products were detected by gas chromatography, the results of oxidation reaction indicated that the catalyst has high activity and stability. 展开更多
关键词 Heteropolymolybdate reaction-controlled phase-transfer ALCOHOL oxidation.
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THE SOLID STATE CONTROLLED PHOTOCHEMICAL REACTION OF NITROBENZALDEHYDE WITH INDOLE
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作者 Ji Ben MENG Da Ming DU +2 位作者 Guo Xiang XIONG Wen Guang WANG Yong Mei WANG 《Chinese Chemical Letters》 SCIE CAS CSCD 1992年第11期865-868,共4页
The solid state photochemical reaction of nitrobenzaldehyde with indole was investigated. Seven hey products were identified by IR, MS,^(1)H HMR and elemental analysis.
关键词 WANG THE SOLID STATE controlLED PHOTOCHEMICAL reaction OF NITROBENZALDEHYDE WITH INDOLE HIGH
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Balance recovery control for biped robot based on reaction null space method
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作者 Baoping WANG Renxi HU +1 位作者 Jinming ZHANG Chuangfeng HUAI 《控制理论与应用(英文版)》 EI 2009年第1期87-91,共5页
A biped walking robot should be able to keep balance even in the presence of disturbing forces. This paper presents a step strategy concept of biped walking robot that is stabilized by using reaction null space method... A biped walking robot should be able to keep balance even in the presence of disturbing forces. This paper presents a step strategy concept of biped walking robot that is stabilized by using reaction null space method. The called "step strategy" can be modeled by means of the reaction null space method that introduced earlier to tackle dynamic interaction problems of free-floating robots, or moving base robots in general. 6-DOF biped robot model simulations are used to confirm the validity. 展开更多
关键词 Biped robot Balance recovery control reaction null space Step strategy
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Mixed Reaction to Proposed Dual Standards for Birth Control
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《China Population Today》 2002年第Z1期19-20,共2页
关键词 Mixed reaction to Proposed Dual Standards for Birth control
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Implementation of Process Reaction Curve for Tuning of Temperature Control Parameters in a 10 L Stirred Tank Heater
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作者 Yulius Deddy Hermawan 《材料科学与工程(中英文A版)》 2011年第4X期572-577,共6页
关键词 电加热器 温度上升 反应曲线 调整参数 控制参数 搅拌槽 积分时间常数 PID控制
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质量控制和精细化管理在PIVAS的应用效果分析
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作者 方永 《中国卫生产业》 2024年第3期1-5,共5页
目的探究质量控制和精细化管理在医院静脉用药调配中心(Pharmacy Intravenous Admixture Service,PIVAS)应用中的效果。方法济南市第三人民医院于2020年1月—2022年12月实施质量控制和精细化管理方案,将此时段内设定为研究组,与2018年1... 目的探究质量控制和精细化管理在医院静脉用药调配中心(Pharmacy Intravenous Admixture Service,PIVAS)应用中的效果。方法济南市第三人民医院于2020年1月—2022年12月实施质量控制和精细化管理方案,将此时段内设定为研究组,与2018年1月—2019年12月采用传统输液管理方式的对照组进行对比。两个阶段的医护人员均为同一批,共计20名医护人员,记录两组医护人员的正负性情绪评分、情绪智力以及工作质量。结果研究组正性情绪评分高于对照组,研究组管理后的负性情绪评分低于对照组,差异有统计学意义(P均<0.05);研究组各项情绪智力高于对照组,差异有统计学意义(P均<0.05);与对照组相比,研究组医护人员审方排药、核对、配置操作、环境卫生、清场、设备使用及维护评分更高,差异有统计学意义(P均<0.05)。结论质量控制和精细化管理的引入,使得PIVAS在患者用药过程中更加安全可靠,医护人员的情绪得到改善,并且护理质量大大提升,在提高医疗质量方面具有显著优势。 展开更多
关键词 输液用药 不良反应 合理用药 质量控制 精细化管理
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3-羟基色酮的不对称Michael加成反应
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作者 黄敏 李文哲 +1 位作者 李敏 张晓梅 《合成化学》 CAS 2024年第9期769-778,786,共11页
3-羟基色酮骨架存在于大量天然产物中,其衍生物多具有重要的生理活性和潜在的药用价值,但目前对3-羟基色酮的不对称手性催化反应研究较少。为丰富3-羟基色酮的研究多样性,通过控制变量法对手性金鸡纳碱类催化剂、溶剂、温度、投料比、... 3-羟基色酮骨架存在于大量天然产物中,其衍生物多具有重要的生理活性和潜在的药用价值,但目前对3-羟基色酮的不对称手性催化反应研究较少。为丰富3-羟基色酮的研究多样性,通过控制变量法对手性金鸡纳碱类催化剂、溶剂、温度、投料比、底物浓度和催化剂用量进行筛选,确定了最佳的反应条件:以化合物1a和2a的反应为例,0.10 mmol的化合物1a与0.12 mmol的化合物2a在Cat*5(10%,物质的量分数)的催化下,在1.0 mL的甲基叔丁基醚(MTBE)中于0℃下反应24~48 h。对底物进行普适性研究,以中等至优异的收率(71%~99%)和较好的对映选择性(56%~89%)获得了2-芳基3-羟基色酮衍生物。将对映选择性最高的产物3al(89%)进行30倍放大反应,能够以99%的收率和76%的对映选择性获得目标产物。所有化合物的结构经1H NMR,13C NMR, HPLC以及HR-MS(ESI)确证。 展开更多
关键词 手性金鸡纳碱类 3-羟基色酮 (E)-(2-硝基乙烯基)苯 不对称Michale加成反应 控制变量法
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基于亚硫酸盐的高级氧化技术及其反应机制研究进展 被引量:1
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作者 袁杨春 董红钰 关小红 《环境化学》 CAS CSCD 北大核心 2024年第3期765-782,共18页
近年来,基于亚硫酸盐的高级氧化技术(S(Ⅳ)-AOPs)受到广泛关注,但活化S(Ⅳ)过程中涉及各种含硫自由基和非自由基物种的转化,使得S(Ⅳ)-AOPs的反应机制较为复杂,同一种S(Ⅳ)-AOP的反应机制常常存在争议.然而,鲜有研究对现有的S(Ⅳ)-AOPs... 近年来,基于亚硫酸盐的高级氧化技术(S(Ⅳ)-AOPs)受到广泛关注,但活化S(Ⅳ)过程中涉及各种含硫自由基和非自由基物种的转化,使得S(Ⅳ)-AOPs的反应机制较为复杂,同一种S(Ⅳ)-AOP的反应机制常常存在争议.然而,鲜有研究对现有的S(Ⅳ)-AOPs及其反应机制进行较为详细的分类与总结.基于此,总结了S(Ⅳ)的理化性质以及S(Ⅳ)-AOPs中含硫自由基的转化机制,综述了各类活化S(Ⅳ)的方法,系统阐述了S(Ⅳ)-AOPs的反应机制、活性氧化剂的产生及贡献,解析了影响S(Ⅳ)-AOPs氧化水中污染物效能的因素.针对目前S(Ⅳ)-AOPs的研究现状和需求进行展望,以期为S(Ⅳ)-AOPs在水污染控制领域的应用提供参考. 展开更多
关键词 高级氧化技术 亚硫酸盐 反应机制 影响因素 水污染控制
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基于嵌入式ARM的微流控PCR检测系统设计
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作者 张帅 胡志刚 +3 位作者 杜喆 祖向阳 王新征 马蓓蓓 《传感器与微系统》 CSCD 北大核心 2024年第1期76-79,83,共5页
为了实现微流控设备功能的集成化、提高交互系统的可操作性,提出一种基于嵌入式ARM的微流控聚合酶链式反应(PCR)控制系统及上位机软件的设计方案。系统硬件采用多个嵌入式ARM控制器与功能模块相互协调,制定可扩展的通信机制和协议,实现... 为了实现微流控设备功能的集成化、提高交互系统的可操作性,提出一种基于嵌入式ARM的微流控聚合酶链式反应(PCR)控制系统及上位机软件的设计方案。系统硬件采用多个嵌入式ARM控制器与功能模块相互协调,制定可扩展的通信机制和协议,实现微流控PCR检测过程中的流路运动、温度控制、荧光信号采集等功能的集成控制。采用Qt结合SQLite数据库设计了上位机软件,利用多线程和节点映射,实现对硬件模块的协调控制以及检测信息存储。实验表明:该系统运行稳定,人机交互效果好,可操作性高,满足微流控PCR的集成功能需求。 展开更多
关键词 嵌入式ARM 微流控聚合酶链式反应 控制系统 上位机软件 Qt软件
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Active disturbance rejected predictive functional control for space vehicles with RCS 被引量:2
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作者 TIAN Jiayi ZHANG Shifeng 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第5期1022-1035,共14页
Reaction control system(RCS) is a powerful and efficient actuator for space vehicles attitude control, which is typically characterized as a pulsed unilateral effector only with two states(off/on). Along with inevitab... Reaction control system(RCS) is a powerful and efficient actuator for space vehicles attitude control, which is typically characterized as a pulsed unilateral effector only with two states(off/on). Along with inevitable internal uncertainties and external disturbances in practice, this inherent nonlinear character always hinders space vehicles autopilot from pursuing precise tracking performance. Compared to most of pre-existing methodologies that passively suppress the uncertainties and disturbances, a design based on predictive functional control(PFC) and generalized extended state observer(GESO) is firstly proposed for three-axis RCS control system to actively reject that with no requirement for additional fuel consumption. To obtain a high fidelity predictive model on which the performance of PFC greatly depends, the nonlinear coupling multiple-input multiple-output(MIMO) flight dynamics model is parameterized as a state-dependent coefficient form. And based on that, a MIMO PFC algorithm in state space domain for a plant of arbitrary orders is deduced in this paper.The internal uncertainties and external disturbances are lumped as a total disturbance, which is estimated and cancelled timely to further enhance the robustness. The continuous control command synthesised by above controller-rejector tandem is finally modulated by pulse width pulse frequency modulator(PWPF) to on-off signals to meet RCS requirement. The robustness and feasibility of the proposed design are validated by a series of performance comparison simulations with some prominent methods in the presence of significant perturbations and disturbances, as well as measurement noise. 展开更多
关键词 reaction control system(RCS) predictive functional control(PFC) generalized extended state observer(GESO) pulse width pulse frequency(PWPF) multiple-input multiple-output(MIMO)
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2型糖尿病血糖控制中二甲双胍联合门冬胰岛素治疗的作用价值
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作者 谢立凯 孙亚东 《糖尿病新世界》 2024年第6期95-98,共4页
目的探究二甲双胍与门冬胰岛素联合治疗2型糖尿病(Diabetes Mellitus Type 2,T2DM)对血糖的控制效果。方法选取2021年6月—2023年6月吉林省人民医院收治的100例T2DM患者为研究对象,以投掷硬币法分为参照组(n=50,二甲双胍治疗)、观察组(n... 目的探究二甲双胍与门冬胰岛素联合治疗2型糖尿病(Diabetes Mellitus Type 2,T2DM)对血糖的控制效果。方法选取2021年6月—2023年6月吉林省人民医院收治的100例T2DM患者为研究对象,以投掷硬币法分为参照组(n=50,二甲双胍治疗)、观察组(n=50,二甲双胍与门冬胰岛素联合治疗)。比较两组临床治疗效果、不良反应总发生率、血糖控制情况及血清炎性因子水平。结果观察组治疗总有效率(96.00%)高于参照组(84.00%),差异有统计学意义(χ^(2)=4.000,P<0.05)。两组不良反应总发生率对比,差异无统计学意义(P>0.05)。与治疗前相比,两组治疗半年后血糖水平、白细胞介素-6、白细胞介素-12水平均降低、白细胞介素-10水平升高,且观察组上述指标优于参照组,差异有统计学意义(P均<0.05)。结论二甲双胍与门冬胰岛素联合治疗T2DM患者时可提高疗效,患者血糖控制情况更佳,血清炎性因子水平也得到明显改善,安全性较高。 展开更多
关键词 2型糖尿病 二甲双胍 门冬胰岛素 血糖控制 临床疗效 不良反应 血清炎性因子
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自主平衡恢复过程中姿势调控反应时与运动时的增龄性变化研究
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作者 王雨生 贾子善 +3 位作者 张攻孜 左秀芹 高岩 吴瑞宁 《中国康复医学杂志》 CAS CSCD 北大核心 2024年第5期675-680,686,共7页
目的:观察人体在失稳后的自主平衡恢复过程中姿势调控反应时间与运动时间的增龄趋势与年龄敏感性变化区。方法:使用DE-A体感平衡检测系统对20—79岁的健康成年受试者97例进行姿势调控时间测试,包括在静态平衡与动态平衡状态下的支撑面... 目的:观察人体在失稳后的自主平衡恢复过程中姿势调控反应时间与运动时间的增龄趋势与年龄敏感性变化区。方法:使用DE-A体感平衡检测系统对20—79岁的健康成年受试者97例进行姿势调控时间测试,包括在静态平衡与动态平衡状态下的支撑面前倾、后倾、左倾和右倾失稳应激时的姿势调控反应时与运动时测试,并记录所有测试的各姿势调控时间指标。按照10岁为一年龄分段将受试者依次分为6个年龄组,其中组1(20—29岁)为16例、组2(30—39岁)为10例、组3(40—49岁)为17例、组4(50—59岁)为18例、组5(60—69岁)为31例、组6(70—79岁)为5例,观察姿势调控反应时与运动时的增龄变化,并分析其年龄敏感变化区。结果:姿势调控反应时和运动时随年龄增长呈现延长趋势。静态平衡状态下,组6的各反应时和运动时均较组1—5长,与组1—4比较均具有显著性差异(P<0.05),与组5比较均无显著性差异(P>0.05);组5的各反应时和运动时均较组1—4长,且均具有显著性差异(P<0.05);组4的各反应时和运动时均较组1—3长,支撑面右倾时的反应时与组1比较具有显著性差异(P<0.05),其余指标组间比较均无显著性差异(P>0.05);组3的各反应时和运动时均较组1—2长,支撑面左倾时的运动时与组1比较具有显著性差异(P<0.05),其余指标组间比较均无显著性差异(P>0.05);组2的各反应时和运动时与组1比较均无显著性差异(P>0.05)。动态平衡状态下,组6的各反应时和运动时均较组1—5长,与组1—4比较均具有显著性差异(P<0.05),与组5比较均无显著性差异(P>0.05);组5的各反应时和运动时均较组1—4长,且均具有显著性差异(P<0.05);组4的各反应时和运动时均较组1—3长,支撑面左倾时的反应时与组1比较无显著性差异(P>0.05),其余指标组间比较均具有显著性差异(P<0.05),而支撑面后倾和左倾的运动时与组2比较具有显著性差异(P<0.05),其余指标组间比较均无显著性差异(P>0.05);组3的各反应时和运动时均较组1—2长,各运动时与组1比较均具有显著性差异(P<0.05),而各反应时与组1比较无显著性差异(P>0.05);组2的各反应时和运动时与组1比较均无显著性差异(P>0.05)。结论:人体在失稳后的自主平衡恢复过程中姿势调控反应时和运动时随年龄增长而逐渐延长。静态平衡恢复的姿势调控反应时和运动时可能在60岁左右开始出现明显恶化,而动态平衡恢复的姿势调控反应时与运动时可能分别在50岁左右和40岁左右便开始出现明显恶化。 展开更多
关键词 支撑面倾斜应激 自主平衡恢复 姿势调控 反应时 运动时
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MOFs衍生物在尿素氧化中的研究进展
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作者 张霞 吴瑛 +1 位作者 袁牧锋 王春栋 《材料导报》 EI CAS CSCD 北大核心 2024年第6期55-64,共10页
尿素氧化反应(UOR)在缓解现代氢能源制备和废水处理等压力中起着关键作用,引入性能优异的电催化剂有助于降低电化学能耗。金属-有机骨架(MOFs)衍生物因能克服MOFs原有导电性及稳定性差的固有缺陷备受关注,被认为是一种很有前途的电催化... 尿素氧化反应(UOR)在缓解现代氢能源制备和废水处理等压力中起着关键作用,引入性能优异的电催化剂有助于降低电化学能耗。金属-有机骨架(MOFs)衍生物因能克服MOFs原有导电性及稳定性差的固有缺陷备受关注,被认为是一种很有前途的电催化剂。本文回顾和总结了基于MOFs衍生物的设计和构建的相关研究:(i)基于镍基/非镍基的UOR的机理分析;(ii)概括了利用结构调控、形貌控制、界面工程和缺陷工程的手段提高电子电导率的策略,同时概括了材料物理特性改变与催化活性的相关性;(iii) MOFs衍生物基于UOR的应用研究。最后,对UOR的后期研究挑战和发展提出了合理的建议。 展开更多
关键词 MOFs衍生物 尿素氧化反应 结构调控 形貌控制 界面工程 缺陷工程
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