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1.
碳是构成生命的重要元素,环境中的碳不仅是生命元素,也是植物的营养和调节元素,是自然界中生命及其有机物的重要组分,并在有机物的合成、转化和调节植物体内的生理现象以及对环境的影响等方面起着重要作用。硫是构成含硫氨基酸和蛋白质的基本元素,  相似文献   

2.
药物分析课程与家庭环境致癌因素教育的结合   总被引:2,自引:0,他引:2  
对于现代人而言,对生命构成最大威胁的是心血管病,脑血管病和恶性肿瘤,而癌症将取代心脏病成为威胁人类生命的头号杀手[1]。癌症发病因素虽比较复杂,但环境因素是重要诱因,特别是室内空气污染以及不良生活习惯。因此医学院校学生(特别是药学专业学生)应适当增加家庭致癌因素方面教育。药物分析是一门研究与发展药品质量控制的方法学科,药品质量控制的方法都是《中国药典》所规范的方法,内容较为枯燥、乏味。且本课程是在学生学完药物化学、分析化学、仪器分析等课程之后开设的,所以部分内容有些与上述课程重复,可在授课时适当略过。另外,为…  相似文献   

3.
元素医学里有它,因它是生命科学的前沿阵地;现代医学里有它,因它是细胞学及酶学的基础物质;传统医学里有它,因它是五行学说及阴阳学说的理论基础;营养科学里有它,因它是人体不能合成的重要营养素;保健科学里有它,因它是人体养生保健的重要物质基础;环境科学里有它,因它是环境评价和环境监测的有力指标;农业科学里有它,因它能使农作物增产,又能使农产品有保健功能。  相似文献   

4.
氨基甲酸酯类是一类广谱杀虫剂,是以甲酸酯为前体化合物发展而来的,多数品种是高效、低毒、低残留的,对环境的危害相对较小,被认为是取代六六六、滴滴涕的优良药剂品种。虽然氨基甲酸酯危害较小,但其在生物体、农产品和环境中的残留是不可忽视的。氨基甲酸酯类农药在弱酸性条件下可与  相似文献   

5.
吴军 《化学教育》2021,42(7):55-55
1没有证据的推理通过推理可以得出重要的结论,但是没有证据的推理往往是一种猜测,可能是臆造事实上不成立的问题;即使猜测的是事实,没有证据也不具有说服力。所以,中学化学中没有证据的推理学生难以理解,难以接受,甚至苍白无力。2没有推理的证据没有推理的证据是不借助理论思维、没有逻辑推理的事实或材料,是一些孤立的事实或材料,把握不了证据和结论之间的关系。在中学化学教学中缺少原理推导,使得化学知识之间难以组织,感觉是化学知识点较为零散,学习化学需要死记硬背。  相似文献   

6.
王伟群  龚魏魏 《化学教育》2007,28(10):8-10,25
高中化学新课程的一个基本理念是要"在人类文化背景下构建化学课程体系",为了彰显化学的文化特点,从科学是一种文化入手,分析了化学也是一种文化,化学的文化特征是科学和人文的统一;文化视野下的化学教育也应该是科学教育和人文教育的统一,是一种全面的化学教育。  相似文献   

7.
将创新理念融入化学教学是学科特点,也是时代的要求,更是军队院校改革的要求。在军事后勤专业化学教学中,一是利用PBL教学法培养创新意识,二是融入团队的科研成果和学术前沿,三是利用第二课堂提升学员创新能力,培育具有创新思维和组织能力的后勤专业人才。  相似文献   

8.
高校教学改革一直是高校教师关心的热点,也是高等学校教学工作的重要组成部分,实验教学是高等学校理科教学特别是化学教学中必不可少的一门课程,是培养学生动手能力、实际工作能力的重要环节。如何改革实验教学一直是教师们在不断探讨的问题。该文从学生兴趣的角度出发,提出一种以兴趣为中心的教学模式,就如何改革有机化学实验教学模式进行了初步探讨。  相似文献   

9.
孙玉婷  林丹 《化学教育》2009,30(8):1-2,5
膨松剂是常见的食品添加剂之一,一般分为生物膨松剂和化学膨松剂,不同膨松剂的使用原理是一致的.常用的的膨松剂是含铝的泡打粉,而饮食中铝的含量过多会减退人的记忆力和抑制免疫功能,所以无铝膨松剂将是膨松剂新的发展趋势.  相似文献   

10.
白欣  胡佳  冯晓颖 《化学通报》2012,(4):379-384
奥托·哈恩是德国著名化学家、物理学家,一生致力于放射性化学的研究,是原子核裂变的奠基人,是科学史上的重要人物。因发现"原子核裂变"而获得1944年诺贝尔化学奖。  相似文献   

11.
本实验采用溶胶-凝胶燃烧的方法,将Co掺入到CeFeO3(CFO)钙钛矿晶格中制备了具有晶格缺陷的CeFe0.8Co0.2O3(CFCO)纳米颗粒催化剂。通过扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)等表征技术对CFCO催化剂进行表征分析,结果表明在CFCO上形成了表面氧空位(VO)。同时,还研究了过硫酸氢钾(PMS)用量、不同pH值对CFCO降解噻虫胺(CTD)的影响。结果表明,在CFCO投加量为0.6 g?L-1,PMS用量为0.8 mmol?L-1,pH为7时,20 mg?L-1的噻虫胺在30分钟内完全降解。并且经过4次循环使用后,噻虫胺降解率仍能达到91.2%。CFCO对于PMS的高效活化能力,主要归功于晶格缺陷所产生的电位差促使自由电子顺着氧空位快速定向传导到PMS上。为了模拟在天然水体环境中CFCO光催化活化PMS去除CTD,进行阴离子和有机酸的对比实验,分析了不同环境因素对CFCO降解噻虫胺的影响;此外,本文通过自由基淬灭实验与电子自旋共振(ESR)检测确定了CFCO光催化活化PMS降解噻虫胺实验中起主要作用的活性物种为单线态氧(1O2)与羟基自由基(?OH),并分析推测了自由基的产生机理。最后采用高效液相色谱-质谱联用仪(LC-MS)检测分析了CTD降解过程中可能产生的代谢产物,并基于代谢产物的产生顺序归纳出了三条可能的降解路径。  相似文献   

12.
A series of polyaniline-anatase TiO2 (PANI-TiO2) nanocomposite powders with different PANI:TiO2 ratios were prepared by ‘in-situ’ deposition oxidative polymerization of aniline hydrochloride using ammonium persulfate (APS) as oxidant in the presence of ultrafine grade powder of anatase TiO2 cooled in an ice bath. And the solid-phase photocatalytic degradation of PANI-TiO2 nanocomposites was investigated under the ambient air in order to assess the feasibility of developing photodegradable polymers. The photodegradation of the composite powders was compared with that of pure PANI powders by performing weight loss monitoring, elemental analysis, FT-IR and UV-vis spectroscopy and X-ray photoelectron spectroscopy (XPS). The PANI-TiO2 nanocomposite powders showed highly enhanced photodegradation and the photodegradation increased with decreasing ratios of PANI:TiO2. A weight loss of about 6.8% was found for the PANI-TiO2 (1:3) nanocomposite; however, the weight loss of the PANI-HCl powder was only 0.3% after being irradiated for 60 h under air. The photocatalytic degradation of the nanocomposite powders accompanied the peak intensity decrease in the FT-IR spectra at 1235 cm−1, attributed to C-N stretching mode for benzenoid unit, and the depigmentation of the powders due to the visible light scattering from growing cavities. The elemental analysis and XPS analysis of the composite showed that the bulk and surface concentrations of N decreased with irradiation. A possible mechanism for the photocatalytical oxidative degradation was also mentioned.  相似文献   

13.
The photocatalytic degradation of polyvinyl chloride (PVC) films by tungstophosphoric acid (HPW) was investigated. The main reason for highly enhanced photodegradation of HPW-doped PVC film was studied and discussed.  相似文献   

14.
ZnO nanoparticles with and without 8 mol % Ce dopant were synthesized by precipitation method and the prepared samples were treated with various types of non-thermal plasma in order to study their effects on the morphology and photocatalytic activity of the samples. As-prepared Ce-doped ZnO has a hexagonal wurtzite structure and the crystal system was not changed by the plasma treatment. The morphology of Ce-doped ZnO was changed from spherical particle to flower and rod-like shapes by the plasma treatment. The particle size of the treated Ce-doped ZnO is smaller in comparison with that of untreated sample. The photodegradation of methylene blue by the plasma-treated Ce-doped ZnO in aqueous solution is higher than that of the untreated Ce-doped ZnO. The enhancement of the photocatalytic activity by the plasma-treated samples may come from the particle size reduction, enhancement in charge separation efficiency and increase of the surface area.  相似文献   

15.
用复合电沉积技术制备了Ag@AgBr/CNT/Ni表面等离子体薄膜催化剂,以扫描电镜(SEM)、X射线衍射(XRD)、拉曼光谱(Raman Spectra)、X射线光电子能谱(XPS)和紫外-可见漫反射光谱(UV-Vis DRS)对薄膜的表面形貌、晶体结构、化学组成和光谱特性进行了表征,在可见光照射下,用罗丹明B(RhB)作为模拟污染物对薄膜的光催化性质和稳定性进行测定,采用测定薄膜电化学阻抗谱(EIS)和向反应系统中加入活性物种捕获剂的方法对薄膜光催化机制进行探索。结果表明:最优工艺下制备的Ag@AgBr/CNT/Ni薄膜是由少量碳纳米管(CNT)和表面沉积纳米Ag粒子的AgBr晶体构成的复合薄膜。薄膜具有突出的表面等离子体共振效应、优异的光催化活性和良好的催化稳定性。光催化罗丹明B 20 min,Ag@AgBr/CNT/Ni薄膜的降解率是Ag@AgBr/Ni薄膜的1.32倍,是P25 TiO2/ITO多孔薄膜的21.6倍。在保持光催化性能基本不变的前提下可循环使用5次。CNT的存在使薄膜电荷传导性能和光催化还原溶解氧的性能大幅增加,是所制薄膜相对于Ag@AgBr/Ni薄膜光催化性能提高的主要原因。提出了薄膜光催化罗丹明B的反应机理。  相似文献   

16.
Polymethylmethacrylate (PMMA) films were modified by RF oxygen plasma with various powers applied for different periods, and the effects of these parameters on the surface properties such as hydrophilicity, surface free energy (SFE), chemistry, and topography were investigated by water contact angle, goniometer, X‐ray photoelectron spectroscopy (XPS), and atomic force microscopy, and the types of the created free radicals and their decay were detected by electron spin resonance spectroscopy (ESR). SFE and contact angle results varied depending on the plasma parameters. Oxygen plasma treatment (100 W–30 min) enhanced the hydrophilicity of PMMA surface as shown by decreasing the water contact angle from 70° to 26°. XPS analysis showed the change in the amounts of the present functionalities as well as formation of new groups as free carbonyl and carbonate groups. The roughness of the surface increased considerably from ~2 nm to ~75 nm after 100 W–30 min oxygen plasma treatment. ESR analysis indicated the introduction of peroxy radicals by oxygen plasma treatment, and the intensity of the radicals increased with increasing the applied power. Significant decrease in radical concentration was observed especially for the samples treated with higher powers when the samples were kept under the atmospheric conditions. As a conclusion, RF plasma, causes changes in the chemical and physical properties of the materials depending on the applied parameters, and can be used for the creation of specific groups or radicals to link or immobilize active molecules onto the surface of a material. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

17.
用复合电沉积技术制备了Ag@AgBr/CNT/Ni表面等离子体薄膜催化剂,以扫描电镜(SEM)、X射线衍射(XRD)、拉曼光谱(Raman Spectra)、X射线光电子能谱(XPS)和紫外-可见漫反射光谱(UV-Vis DRS)对薄膜的表面形貌、晶体结构、化学组成和光谱特性进行了表征,在可见光照射下,用罗丹明B(RhB)作为模拟污染物对薄膜的光催化性质和稳定性进行测定,采用测定薄膜电化学阻抗谱(EIS)和向反应系统中加入活性物种捕获剂的方法对薄膜光催化机制进行探索。结果表明:最优工艺下制备的Ag@AgBr/CNT/Ni薄膜是由少量碳纳米管(CNT)和表面沉积纳米Ag粒子的AgBr晶体构成的复合薄膜。薄膜具有突出的表面等离子体共振效应、优异的光催化活性和良好的催化稳定性。光催化罗丹明B 20 min,Ag@AgBr/CNT/Ni薄膜的降解率是Ag@AgBr/Ni薄膜的1.32倍,是P25 TiO_2/ITO多孔薄膜的21.6倍。在保持光催化性能基本不变的前提下可循环使用5次。CNT的存在使薄膜电荷传导性能和光催化还原溶解氧的性能大幅增加,是所制薄膜相对于Ag@AgBr/Ni薄膜光催化性能提高的主要原因。提出了薄膜光催化罗丹明B的反应机理。  相似文献   

18.
氩等离子体后辉光区对聚四氟乙烯膜表面的优化改性   总被引:2,自引:0,他引:2  
在理想管式反应器中,采用Langmuir双电子探针和电子自旋共振(ESR)诊断技术分别定量测定了氩等离子体场中各活性物种的轴向分布,并利用氩等离子体放电区及后辉光区对聚四氟乙烯(PTFE)进行了表面改性.通过接触角测量、扫描电子显微镜和X射线光电子能谱分析比较了改性前后常规及后辉光氩等离子体对PTFE表面结构及性能的影响.结果表明,氩等离子体中电子及离子浓度随轴向距离的增大迅速降低,30cm后接近于0,而自由基浓度则降低缓慢,40cm处仍为初始浓度的96%.氩等离子体放电功率、处理时间和气体流量强烈影响着PTFE表面润湿性的改善效果.后辉光区因抑制电子和离子的刻蚀作用,强化自由基反应,使改性效果远优于常规氩等离子体.经氩等离子体后辉光区短时间(30s)处理后,PTFE表面化学成分发生了变化,F/C原子比从3.27降至2.30,O/C原子比从0.02增至0.09.脱氟作用和含氧基团(如C=O)的引入是有效改善PTFE表面润湿性的关键因素.  相似文献   

19.
《Analytical letters》2012,45(17):2569-2579
With the aim of obtaining stable antibody immobilization on the poly(methyl methacrylate), PMMA channel surface, PMMA substrates were activated with O2 plasma treatment to introduce surface polar groups on it. The plasma-treated PMMA surfaces were characterized using water contact angle measurement, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). It was observed that plasma treatment significantly improved the surface wettability with changing surface chemistry and topography. The strategy of immobilization of a model antibody, anti-goat IgG on plasma-treated PMMA involved two steps. First the plasma-treated PMMA was functionalized with (3-aminopropyl)thriethoxy silane, APTES off-chip which facilitated covalent capturing of antibody via a crosslinking agent in the inner surface of PMMA channel in the second step. The antibody immobilization on plasma-treated PMMA was also confirmed using AFM, XPS, and fluorescence microscopy. The anti-IgG covalently captured on channel surface was evaluated with sandwich ELISA protocol on-chip using fluorescence microscopy. The observed results demonstrate that this technique could be extended to integrate the current diagnostic techniques into the plastic chip for important biomarker diagnosis.  相似文献   

20.
The influence of tetrahydrofuran (THF) on photooxidative degradation of poly(vinyl chloride) in films cast from THF solution was studied. THF is partially retained in the polymer matrix in amounts of 6–8% after casting and drying the film. The last 2–3% is very difficult to remove. By use of thermogravimetric analysis, density measurements, and gas permeability measurements, it was shown that THF residues can be removed by preheating the PVC samples to 80°C. THF forms a charge-transfer complex with oxygen which is easily photolyzed. During this reaction hydroperoxide radicals are formed. Molecular weight distribution curves by gel-permeation chromatography (GPC) show that THF in the presence of air promotes the photodegradation of PVC. Attention has been given to the correct interpretation of the infrared absorption spectra of PVC films containing THF residues and ultraviolet-irradiated in air.  相似文献   

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