Benzil bis(carbohydrazone)(BBC) is prepared and explored as new N N Schiff's base, which plays the role of an excellent ion carrier in the construction of a Cd(II) ion membrane sensor. The tris(2-ethylhexyl) phosp...Benzil bis(carbohydrazone)(BBC) is prepared and explored as new N N Schiff's base, which plays the role of an excellent ion carrier in the construction of a Cd(II) ion membrane sensor. The tris(2-ethylhexyl) phosphate best performance corresponds to a membrane composition of 30% poly(vinyl chloride), 65%(TEHP), 3.5% BBC and 1.5% tetradodecyl-ammoniumtetrakis(4-chlorophenyl) borate(ETH 500). This sensor shows very good selectivity and sensitivity towards cadmium ion over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The effect of membrane composition, selectivity, pH and influence of additive on the response properties of electrode were investigated. The response mechanism was discussed in the view of UV-spectroscopy. The electrode exhibits a Nernstian behavior(with slope of 29.7 mV per decade) over a very wide concentration range from 1.0×10?1 to 1.0×10?8 mol·L?1 with a detection limit of 3.2×10?8 mol·L?1. It shows rela-tively fast response time in whole concentration range(<8 s) and can be used for at least 10 weeks in the pH range of 2.0-9.0. The proposed sensor is successfully used for the determination of cadmium in different chocolate sam-ples and as indicator electrode in titration with ethylene diamine tetraacetate(EDTA).展开更多
The aim of this paper is to define the nature, present the possibilities, and discuss the problems of using human resource controlling in small and medium-sized building companies. This paper is based on the assumptio...The aim of this paper is to define the nature, present the possibilities, and discuss the problems of using human resource controlling in small and medium-sized building companies. This paper is based on the assumption that expedient human resource controlling is an effective human resource management tool that achieves the required performance of employees and expected competitiveness of a building company. This paper uses the results of a questionnaire survey conducted in November 2013 to analyze human resource management in building companies in the Czech Republic and specify the organization and conditions of human resource management. Some 81 small （less than 50 employees） and 66 medium-sized （50-249 employees） building companies operating in the Czech Republic took part in the questionnaire survey. The results of the questionnaire survey showed the lack of concept and random nature of human resource management in most small and medium-sized building companies. Of course, in terms of the present economic trend, it is above all important for small and medium-sized companies to develop their adaptability to the building market and to be able to deal with a variety of construction works. It is effective human resource management supported by expedient human resources that serves this purpose.展开更多
文摘Benzil bis(carbohydrazone)(BBC) is prepared and explored as new N N Schiff's base, which plays the role of an excellent ion carrier in the construction of a Cd(II) ion membrane sensor. The tris(2-ethylhexyl) phosphate best performance corresponds to a membrane composition of 30% poly(vinyl chloride), 65%(TEHP), 3.5% BBC and 1.5% tetradodecyl-ammoniumtetrakis(4-chlorophenyl) borate(ETH 500). This sensor shows very good selectivity and sensitivity towards cadmium ion over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The effect of membrane composition, selectivity, pH and influence of additive on the response properties of electrode were investigated. The response mechanism was discussed in the view of UV-spectroscopy. The electrode exhibits a Nernstian behavior(with slope of 29.7 mV per decade) over a very wide concentration range from 1.0×10?1 to 1.0×10?8 mol·L?1 with a detection limit of 3.2×10?8 mol·L?1. It shows rela-tively fast response time in whole concentration range(<8 s) and can be used for at least 10 weeks in the pH range of 2.0-9.0. The proposed sensor is successfully used for the determination of cadmium in different chocolate sam-ples and as indicator electrode in titration with ethylene diamine tetraacetate(EDTA).
文摘The aim of this paper is to define the nature, present the possibilities, and discuss the problems of using human resource controlling in small and medium-sized building companies. This paper is based on the assumption that expedient human resource controlling is an effective human resource management tool that achieves the required performance of employees and expected competitiveness of a building company. This paper uses the results of a questionnaire survey conducted in November 2013 to analyze human resource management in building companies in the Czech Republic and specify the organization and conditions of human resource management. Some 81 small （less than 50 employees） and 66 medium-sized （50-249 employees） building companies operating in the Czech Republic took part in the questionnaire survey. The results of the questionnaire survey showed the lack of concept and random nature of human resource management in most small and medium-sized building companies. Of course, in terms of the present economic trend, it is above all important for small and medium-sized companies to develop their adaptability to the building market and to be able to deal with a variety of construction works. It is effective human resource management supported by expedient human resources that serves this purpose.
