碳纳米管组装电极上计时电流法测定辣根过氧化物酶的研究

以多壁碳纳米管修饰玻碳电极为工作电极,研究了辣根过氧化物酶（HRP）一对苯二酚（HQ）-H2O2体系的电化学催化行为。比较碳纳米管修饰玻碳电极和玻碳电极,峰电位从64mV（vs．SCE）前移至116mV,催化电流提高了10倍。对工作电位、介质pH、H2O2和HQ浓度进行了选择。在优化的实验条件下,采用计时电流法测定HRP的线性范围为5．0×10-10～1．0×10-10g／mL。检出限为2．5x1×10-10g／mL。该法具有电极制作简单和灵敏度高等优点。     

对乙酰氨基酚在多壁碳纳米管修饰电极上的电化学行为

用循环伏安法研究了对乙酰氨基酚(ACOP)在多壁碳纳米管修饰玻碳电极(MCNT/GCE)上的电化学行为.结果表明ACOP在裸玻碳电极上表现为不可逆的电极过程,而在多壁碳纳米管修饰电极上ACOP的氧化过电位降低152 mV,电极反应的可逆性得到明显改善.在优化的条件下ACOP在1.0×10-7-2.0×10-5mol.L-1浓度范围内,氧化峰峰电流与浓度间成线性关系,其检出限为5.0×10-8mol.L-1.     

线性扫描伏安法测定维生素B2

运用循环伏安法(CV)、线性扫描伏安法(LSV)等方法研究维生素B2在多壁碳纳米管修饰电极上的电化学行为,建立一种直接测定维生素B2的电化学分析方法.与裸玻碳电极相比,多壁碳纳米管修饰电极显示出很好的催化作用,维生素B2在修饰电极上得到一对灵敏的氧化还原峰(Epa=-0.222 V,Epc=-0.317 V),且氧化还原峰电流显著增强.在优化实验条件下,还原峰电流与维生素B2浓度在3.0×10-6～2.0×10-5mol·L-1有良好的线性关系,检出限为1.0×10-6mol·L-1.对1.0×105mol·L-1维生素B2溶液平行测定10次的相对标准偏差(RSD)为4.2%.用此方法测定维生素B2片中维生素B2的含量,结果令人满意.     

铋膜修饰电极示差脉冲伏安法测定胞嘧啶

利用铋膜修饰电极对胞嘧啶的电化学行为进行了研究．结果表明,在0．1mol/L 的PBS 缓冲溶液（ pH6.64）中,胞嘧啶于-0．23 V电位处有一良好的氧化峰,峰电流与胞嘧啶在4．98×10-6～3．38×10-5 mol/L浓度范围内呈良好的线性关系,检出限为5．6×10-7 mol/L．实验显示,铋膜修饰电极性质稳定,对胞嘧啶的测定具有良好的选择性．     

多壁碳纳米管修饰电极对抗坏血酸的电催化作用

用循环伏安法研究了在不同的电解质溶液及不同扫速下,多壁碳纳米管修饰电极对抗坏血酸(AA)的电催化作用。实验表明在MWCNT电极上,AA的氧化峰电位负移,氧化峰电流显著增加,AA的电极过程呈现扩散控制的特征,且AA浓度在1.0×10-5-5.0×10-1moL·dm-3范围内,其浓度与峰电流有良好的线性关系,检测下限达1.0×10-6moL·dm-3,一些常见物质对其测定无干扰。     

对乙酰氨基酚在铁氰化铜修饰电极上的电化学行为研究

用循环伏安法制备了铁氰化铜修饰玻碳电极,并研究了对乙酰氨基酚在该修饰电极上的电化学行为。结果表明,在pH=6.86的磷酸缓冲溶液中,对乙酰氨基酚在铁氰化铜修饰电极上0.437V处出现一氧化峰,与裸玻碳电极相比氧化峰电位负移了81mV。对乙酰氨基酚浓度在4×10-5-1×10-3mol/L范围内,其氧化峰电流与浓度呈现很好的线性关系,其相关系数是0.9993,检出限为1×10-5mol/L。     

多壁碳纳米管修饰电极电化学传感器测定尿酸

基于羧基化多壁碳纳米管的催化作用,建立了一种测定体液中尿酸含量的新方法．通过扫描电子显微镜和电化学手段对传感器的表面形貌和性能进行了表征,并且优化了检测条件,研究了传感器对尿酸的响应．结果表明,多壁碳纳米管对尿酸的氧化有明显的催化作用．在最优实验条件下,尿酸在修饰电极表面的峰电流与其浓度在8．0×10^－7-8．0×10^－4 mol·L^－1内呈良好线性关系,检测限为5×10^－8 mol·L^－1,该传感器已经应用于实际样品中的测定,测定的回收率在94％-105％．     

一种测定污水中对苯二酚的新方法

用循环伏安法制备铜/聚对氨基苯甲酸复合修饰电极,并研究对苯二酚在该修饰电极上的电化学行为.在p H3.5磷酸盐缓冲溶液中,扫描速率为240 m V/s时,对苯二酚会在铜掺杂修饰电极上产生一对清晰的氧化还原峰,峰电位分别为Epa=0.376 V,Epa=0.293 V.对苯二酚氧化峰电流与其浓度在3.0×10-6~1.0×10-3mol/L范围内呈良好的线性关系,检出限为8.0×10-7mol/L.基于对苯二酚在修饰电极上的电化学特性,为我们建立一种新的测定方法.对对苯二酚样品的测定分析,结果满意.     

Nafion/MWCNT复合修饰电极测定痕量锡的伏安法

研究了利用Nafion/多壁碳纳米管(MWCNT)复合修饰玻碳电极测定痕量锡的阳极溶出伏安法。结果表明,在pH值为1.2的NH4Cl—HCl电解液中,当Sn(Ⅳ)在Nafion/MWCNT复合修饰电极表面富集时间为3min,电位扫描速度为200mV/s时,该修饰电极在伏安图上能出现一灵敏的氧化峰,峰电位约为-570mV,利用该峰可以进行痕量锡的检测;峰电流与Sn(Ⅳ)浓度在4.0×10-8~1.0×10-6mol/L的范围内呈良好线性关系,相关系数为0.997,检出限为1.0×10-8mol/L;该修饰电极稳定性较好,用于实际水样中锡含量的测定,平均回收率为97.48%,所得结果令人满意。     

槲皮素在碳纳米管修饰碳糊电极上的电化学行为及测定

本文研究了槲皮素在多壁碳纳米管修饰碳糊电极上的电化学行为.实验结果表明:槲皮素在多壁碳纳米管修饰碳糊电极上的电极过程为一受吸附控制的两电子、两质子参与的准可逆过程,电子传递系数α=0.53.槲皮素的氧化峰电流与槲皮素浓度在1.0×10-7～6.0×10-3mol/L范围内呈良好的线性关系,可应用于槐花米中槲皮素含量测定.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.