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1.
张新 《大学化学》2017,32(4):68-75
在客观分析色谱现象的基础上对色谱分离机理的传统解释提出了质疑和否定,并对色谱分离机理作出了新的解释。通过对色谱现象的研究和分析,不仅确定了一条流体运动的基本规律,还对固定相赋予了新的内涵,提出了能量场固定相的设想。由于对色谱分离原理进行了新的解释,因此对色谱现象提出了一个新的定义。  相似文献   

2.
乙酰乙酸乙酯-BR化学振荡反应的研究   总被引:2,自引:0,他引:2  
本文首次报道了乙酰乙酸乙酯-IO-3-H2O2-Mn2+-H2SO4体系的化学振荡反应。研究了各种因素对振荡反应的影响,测定了最佳反应条件及振荡反应的浓度范围。研究了温度变化对振荡反应的影响,并计算了振荡反应的表观活化能,对振荡反应产物进行了分析,并测定了体系主要反应的计量关系,采用UV法对金属离子的作用和催化机理作了研究,探索了BR反应中I2的产生机理及消耗机理,对体系中有关反应物的作用作了说明。在FKN机理的基础上,对BR反应的自催化反应步骤和控制机理进行了初步的探索,并对有关实验现象作了说明。  相似文献   

3.
本文采用热力学与Gouy-chapmann理论相结合的方法, 考察了离子对试剂浓度对反相离子对色谱保留值的影响, 获得了反相离子对色谱ink'与离子对试剂浓度间的近似线性关系。同时考察了溶质疏水性和熔质电荷数对线性关系式中斜率和截距的影响。  相似文献   

4.
碳纳米管的纯化──电化学氧化法   总被引:13,自引:0,他引:13  
用电化学氧化法对碳纳米管进行纯化,从稳态极化曲线出发,对反应的可行性进行了分析,考察了支持电解质、电流密度、时间等因素对反应的影响,确定了最佳实验条件,同时对纯化机理进行了解释.  相似文献   

5.
报道了以235名健康小儿的血清锌、铜正常参考值及铜/锌比值作依据,对538名本地区集体儿童进行了调查.对240例不同病种患儿的血清锌、铜含量测定,并进行了分析;对G6PD、GSH-PX、AKP醇活性与微量元素含量的关系进行了相关性比较;对微量元素锌缺乏症的患儿进行了临床治疗观察;对微量元素缺乏症的防治进行了讨论.  相似文献   

6.
张伟  杨占胜 《化学教育》2006,27(6):9-11
针对工业实际对提高防护层防腐、耐磨性能的要求,对化学镀镍磷镀层的方法,镀敷液配方等进行了分析,对其腐蚀率进行了测定,并对镀层性能进行了表征;讨论了影响腐蚀率的若干重要因素;对有关工艺进行了优化,从而在多种基质上获得了抗腐蚀性较好的镍磷镀层,初步研究证明,其性能优于电镀方法所获得的镀层.  相似文献   

7.
张秋彦 《化学教育》2017,38(17):25-30
对化学课堂教学发展性评价指标制定了操作性定义,并设计了具体观测点和测量表,拟对化学课堂教学做一个全面的、综合的发展性评价。并用该测量表对本校高二年级学生和教师做了调查,及时反馈给了教师,对本校教师的课堂教学提出了发展性的意见和建议。  相似文献   

8.
纳米纤维素(NCC)由于其大量、可再生、可生物降解以及优良的力学性能,成为纳米技术领域研究的热点。文章综述了NCC的制备方法,对化学和机械法制备NCC纤维素做了重点介绍,同时,对NCC的表面改性进行了综述。并对NCC在制备纳米复合材料领域的应用进行了总结,对其在增强复合材料中的应用做了较详细的介绍。最后对NCC未来的发展进行了展望。  相似文献   

9.
李伟王锐  刘守新 《化学进展》2010,22(10):2060-2070
纳米微晶纤维素(NCC)由于其大量、可再生、可生物降解以及优良的力学性能,成为纳米技术领域研究的热点。文章综述了NCC的制备方法,并对化学和机械法制备NCC纤维素作了重点介绍。同时对NCC的表面改性进行了综述。并对NCC在制备纳米复合材料领域的应用进行了总结,对其在增强复合材料中的应用作了较详细的介绍。最后对NCC未来的发展进行了展望。  相似文献   

10.
对异丙基甲苯的合成研究进展   总被引:6,自引:0,他引:6  
综述了对异丙基甲苯的合成研究进展。重点介绍了以萜烯类化合物为原料合成对异丙基甲苯的研究进展情况,并展望了对异丙基甲苯的应用前景。  相似文献   

11.
The widespread use of miniaturized chemical sensors to monitor clinically important analytes such as PO2, PCO2, pH, electrolytes, glucose and lactate in a continuous, real-time manner has been seriously hindered by the erratic analytical results often obtained when such devices are implanted in vivo. One major factor that has influenced the analytical performance of indwelling sensors is the biological response they elicit when in contact with blood or tissue (e.g. thrombus formation on the device surface, inflammatory response, encapsulation, etc.). Nitric oxide (NO) has been shown to be a potent inhibitor of platelet adhesion and activation as well as a promoter of wound healing in tissue. Herein, we review recent work aimed at the development of hydrophobic NO-releasing polymers that can be employed to coat catheter-type amperometric oxygen sensors without interfering with the analytical performance of these devices. Such modified sensors are shown to exhibit greatly enhanced hemocompatibility and improved analytical performance when implanted within porcine carotid and femoral arteries for up to 16 h. Further, results from preliminary studies also demonstrate that prototype fluorescent oxygen sensors, catheter-style potentiometric carbon dioxide sensors and subcutaneous needle-type enzyme-based amperometric glucose sensors can also be fabricated with new NO-release outer coatings without compromising the analytical response characteristics of these devices. The NO-release strategy may provide a solution to the lingering biocompatibility problems encountered when miniature chemical sensors are implanted in vivo.  相似文献   

12.
In this work, nitric oxide (NO) release coatings designed for intravenous amperometric glucose sensors are optimized through the use of a polylactic acid (PLA) layer doped with a lipophilic diazeniumdiolated species that releases NO through a proton-driven mechanism. An Elast-Eon E2As polyurethane coating is used to both moderate NO release from the sensor surface and increase the sensor''s linear detection range toward glucose. These sensors were evaluated for thromboresistance and in vivo glucose performance through implantation in rabbit veins. By maintaining NO flux on a similar scale to endogenous endothelial cells, implanted glucose sensors exhibited reduced surface clot formation which enables more accurate quantitative glucose measurements continuously. An in vivo time trace of implanted venous sensors demonstrated glucose values that correlated well with the discrete measurements of blood samples on a benchtop point-of-care sensor-based instrument. The raw measured currents from the implanted glucose sensors over 7 h time periods were converted to glucose concentration through use of both a one-point in vivo calibration and a calibration curve obtained in vitro within a bovine serum solution. Control sensors, assembled without NO release functionality, exhibit distinctive surface clotting over the 7 h in vivo implantation period.  相似文献   

13.
Implantable sensors offer a great opportunity to extract physiological information from inside the body by real-time monitoring. With the demand for personal healthcare and point-of-care treatment, a long-term stable sensor of excellent mechanical and biological compatibility with human organs is urgently required. In contrast to rigid electronic devices using silicon or metallic materials, soft sensors are realized by flexible polymers in a simple way, endowing the implantable sensor with a tissue-mimetic structure. In this article, we systematically review the development of implantable electronic sensors based on polymer materials. The unique properties of polymers are introduced, followed by their applications in implantable device fabrication. Strategies to integrate polymers with implantable sensors, encompassing device interface, geometry, and integration, are also summarized. Furthermore, biosensing applications of polymer-based implantable devices are described, ranging from physical stimulus monitoring to biochemical analysis in vivo. Finally, we envision how advances in polymer materials may facilitate the development of intelligent sensors with broader applications in vivo.  相似文献   

14.
The use of nanoparticles within living systems is a growing field, but the long‐term effects of introducing nanoparticles to a biological system are unknown. If nanoparticles remain localized after in vivo implantation unanticipated side effects due to unknown biodistribution can be avoided. Unfortunately, stabilization and retention of nanoparticles frequently alters their function.[1] In this work multiple hydrogel platforms are developed to look at long‐term localization of nanoparticle sensors with the goal of developing a sensor platform that will stabilize and localize the nanoparticles without altering their function. Two different hydrogel platforms are presented, one with a liquid core of sensors and another with sensors decorating the hydrogel's exterior, that are capable of localizing the nanoparticles without inhibiting their function. With the use of these new hydrogel platforms nanoparticle sensors can be easily implanted in vivo and utilized without concerns of nanoparticle impact on the animal.  相似文献   

15.
柳玢竹  张国军  李玉桃 《化学通报》2021,84(12):1292-1299
酸碱度异常即pH值改变与机体的健康状况有密不可分的关系,活体实时pH检测不仅可以为临床诊疗提供支持信息,而且有助于一些疾病发病机理的研究。本综述详细介绍了pH的定义、pH检测的发展历史、活体实时pH生物传感器所需满足的条件,重点介绍了各类型活体实时pH生物传感器的原理与应用,包括电化学传感器、荧光传感器、光纤传感器以及超声传感器,并对活体实时pH生物传感器的未来发展方向做出展望。  相似文献   

16.
周奇  张立敏  田阳 《电化学》2019,25(2):160-171
发展非电活性分子的活体电化学分析方法,对于解析这些物质在生理过程和病理过程中的作用具有重要研究意义. 本综述从三种分析策略出发,简要介绍了最近活体电化学传感器的研究进展:1)设计和筛选高选择性配体,通过将特异性的化学反应转换成电化学信号,发展了新型的非电活性分子的活体分析;2)利用微型孔道里的整流效应,结合特异性配体,建立了非电活性分子的新型分析平台;3)结合微电极阵列技术及同时分析多种输出信号的新型分析模式,实现活体中的多种非电活性物质的同时分析.  相似文献   

17.
Shin JH  Schoenfisch MH 《The Analyst》2006,131(5):609-615
The continuous, real-time monitoring of clinically important analytes (e.g., PO2, PCO2, pH, K+, Na+, glucose, and lactate) is of great importance to human health care. Despite considerable efforts spanning several decades, the use of in vivo sensors clinically remains limited due to inadequate biocompatibility. The discovery of nitric oxide (NO) as an effective inhibitor of platelet and bacterial adhesion has opened a new direction of research related to designing the next generation of in vivo sensors. In this Highlight article, recent progress in designing more biocompatible in vivo sensors is described, with a particular focus on preparing interfaces that resist biofouling via controlled NO release.  相似文献   

18.
Nitric oxide (NO) plays an important role in physiological processes and it has been confirmed some human diseases are related to its biological function. Electrochemical sensors provide an efficient way to explore the NO function in biological processes. This review details different kinds of electrochemical sensors used for NO concentration detection between 2008 and 2013 together with their application in biological samples. Four commonly used electrodes and different assisted analysis membranes used for contributions towards the development of the novel sensors were summarized. Electrochemical sensors employed to measure NO concentration in a single cell, cell culture, tissue homogenate, organ, in vivo, human being, as well as in plant were also detailed. The trends of developing novel NO sensors were outlooked in the last part.  相似文献   

19.
The real-time monitoring of specific analytes in situ in the living body would greatly advance our understanding of physiology and the development of personalized medicine. Because they are continuous (wash-free and reagentless) and are able to work in complex media (e.g., undiluted serum), electrochemical aptamer-based (E-AB) sensors are promising candidates to fill this role. E-AB sensors suffer, however, from often-severe baseline drift when deployed in undiluted whole blood either in vitro or in vivo. We demonstrate that cell-membrane-mimicking phosphatidylcholine (PC)-terminated monolayers improve the performance of E-AB sensors, reducing the baseline drift from around 70 % to just a few percent after several hours in flowing whole blood in vitro. With this improvement comes the ability to deploy E-AB sensors directly in situ in the veins of live animals, achieving micromolar precision over many hours without the use of physical barriers or active drift-correction algorithms.  相似文献   

20.
Technology always has been an indispensible part in the development of biosensors. The performance of biosensors is being tremendously improved using new materials as transducer as well as binding material in their construction. The use of new materials allowed innovation on transduction technology in biosensor preparations. Because of the submicron dimensions of these sensors, simple and rapid analyses in vitro as well as in vivo are now possible. Portable instruments capable of analysing multiple components are becoming available, too. Sensors that provide excellent temporal and spatial resolution for in vivo monitoring such as for measurement of neurotransmitters have become prominent. The interest to improve the stability, sensitivity and selectivity of the sensors is paramount. This study tries to give an overview of the present status of the material-based biosensor design and new generation of choline/acetylcholine neurotransmitter biosensors.  相似文献   

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