掺镁氧化铁电极光响应n-p型转换的研究

热形成氧化铁一般为n型光响应,掺Mg后有可能为p型。本文作者之一曾报导用涂敷方法制备的以Pt为基底的氧化铁膜随电极电势向负向移动,光响应由n型转为p型,但末作进一步研究。我们用工业纯铁制成的氧化铁电极则始终表现为n型光响应,原因可能是含Si0.005％所致。在本文中我们将工业纯铁片和分析纯MgO粉末直接接触,加热。在一定条件下可以得到具有n、p型双重光响应。溶液为硼酸、硼砂缓     

萃取色层梯度淋洗和柱后反应光度法连续检测装置

用普通材料自制和组装一套能梯度淋洗和柱后反应光度法连续检测萃取色层柱的流出曲线的设备。详细叙述了淋洗液切换阀、六通样样阀、四通混合器、盘管反应器的制作和将国产原子吸分光光度计改装流动光度计。     

YSC型阳离子色谱分离柱的研制及其性能测定

继Small提出双柱阳离子色谱法(IC)之后,Fritz又提出了不用抑制柱的单柱阳离子色谱法(SCIC),后者所用仪器较为简单。至今,两种方法都已成功地应用于碱金属、碱土金属、铵离子及各种有机胺类的分析。阳离子色谱法的核心是阳离子色谱柱及其填料,我们研制的薄壳磺酸型高效阳离子交换树脂填料,其柱效达到15000片/米,已用于双柱和单柱阳离子色谱分析。     

异丙基膦酸单正辛基酯负载树脂分离稀土元素

以吸着有异丙基膦酸单正辛基酯的大孔聚异丁烯酸甲酯的负载树脂分离１５种稀土元素，研究基分配系数，分离因素。结果表明采用梯度淋洗，可使Ｌａ＾３＋，Ｃｅ＾４＋，Ｎｄ＾３＋；Ｎｄ＾３＋，Ｓｍ＾３＋，Ｅｒ＾３＋，Ｇｄ＾３＋；Ｔｂ＾３＋，Ｄｙ＾３＋，Ｅｒ＾３＋，Ｔｍ＾３＋，Ｙｂ＾３＋，Ｌｕ＾３＋以不同程度得以分离，并呈现明显的四分组效应。     

异丙基膦酸单异辛酯负载树脂用萃取色层以分离稀土元素

本文报道异丙基膦酸单异辛酯负载树脂分离稀土（Ⅲ）的性能。实验结果表明采用不同浓度的稀盐酸淋洗可依次分离１５种稀土（Ⅲ）。除钇（Ⅲ）／铒（Ⅲ）对（Ｒｓ１．０）外，其余各相邻稀土（Ⅲ）均达到基线分离。所用酸度不超过２．０ｍｏｌ／Ｌ，低于常用的磷酸双（２－乙已基）酯和２－乙已基磷酸单２－乙基酯所需酸度。     

异丙基膦酸单异辛酯负载树脂用于萃取色层以分离稀土元素

本文报道异丙基膦酸单异辛酯负载树脂分离稀土(Ⅲ)的性能。实验结果表明采用不同浓度的稀盐酸淋洗可依次分离15种稀土(Ⅲ)。除钇(Ⅲ)/铒(Ⅲ)对(R.1.0)外,其余各相邻稀土(Ⅲ)均达到基线分离(R_a≥1.5)。所用酸度不超过2.0mol/L,低于常用的磷酸双(2-乙己基)酯(HDEHP)和2-乙已基膦酸单2-乙己基酯(HEHEHP)所需酸度。     

掺镁氧化铁电极光响应n-p型转换的研究

Electrodes were prepared with heating commercial pure iron chips buried in Mgo powder and showe dboth n-and p-type photoresponses.The photoresponses were so weak that in fact they were totally buried inthe noise.Hence asignal averager was used. After 1000 cycles'summation the signal to noise ratio was greatly improved and we obtained a wave form series showing the conversion of n-type, p-type photoresponses for the first time. Fig.1(a): E=0.261V. The absolute peak-to-peak photovoltagevalue (ΔV_(ph)) equals 13.4 mV and shows a typical n-type photoresponse. (b); E=-0.04 V, ΔV_(ph)=1.24 mV, still an -n-type response, but when light is chopped off, the electrode potential reaches its stable value much faster than in (a). (c): When E=-0.076 V, which is only 0.036 V more negative than in (b), in the latter 85% part of illuminating period, electrode potential tends to increase, demonstrating some p-type character. (d): As E=-0.09 V, the magnitude of p-type response almost equals that of n-type. (e): As E=-0.12 V, the main response belongs to p-type, and ΔV_(ph) is only 0.634 mV. This electrode potential is much more positive than the flat band potential of the undoped iron oxide electrode (E_(fb) is about -0.5 V). (f): E=-0.17 V. There is still a small n-type response at the beginning of every illuminating period, and the whole curve appears to be p-type responnse. (g): E=-0.36 V. Typical p-type response appears. ΔV_(ph)=2.05 mV. (h) and (i): E=-0.40 V and -0.45 V. ΔV_(ph) drop to 1.55 mV and 1.05 mV respectively. the above data were reproducible, no retardation of photoresponse was observed when potential was changed.An XPS surface analysis was performed thereafter on the same electrode. A peak of Mg1S at 1305 eV(BE) is apparent. Huge amount of Mg exists on the surface layer. the relative atomic concentration (s compared with Fe) reaches 15-20 AT%. After Ar~+ etching, the amount of Mg decreases. Fig.2 is the result after 9 minutes′ Ar~+ etching. A possible explanation of these experimental facts based on model of energy band of semiconductors was given.