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21.
Summary A nitrate-selective electrode based on precipitated nitron nitrate in an epoxy resin matrix has been prepared. The lower detection limit is 10–5
M, the optimum pH range is 2.0–8.5, and the response time is 1 min. The electrode is selective in presence of CH3COO–, SO4
2–, C2O4
2–, PO4
3–, NO2
–, Cl– and Br–, but I– interferes. Results for nitrate in soil samples were in agreement with values obtained spectrophotometrically.
Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980. 相似文献
Eine neue nitrat-spezifische Elektrode auf der Basis gefällten Nitronnitrats
Zusammenfassung Eine nitrat-spezifische Elektrode auf der Basis gefällten Nitronnitrats in einer Epoxyharz-Matrix wurde hergestellt. Die untere Nachweisgrenze ist 10–5 M, das pH-Optimum liegt zwischen 2,0 und 8,5, die Reaktionszeit beträgt 1 Minute. Die Elektrode ist selektiv in Gegenwart von Acetat, Sulfat, Oxalat, Phosphat, Nitrit, Chlorid und Bromid; aber Jodid stört. Ergebnisse der Nitratbestimmung in Bodenproben stimmen mit spektrophotometrischen Resultaten überein.
Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980. 相似文献
22.
A new glass electrolyte formed by constant amounts of titanium oxide (TiO2) and various amount of phosphotungstic acid (PWA) doped P2O5-SiO2 is prepared using the sol-gel process. The structural formation is confirmed by Fourier infrared spectroscopy (FTIR) and from thermogravimetric and differential thermal analysis (TG/DTA) measurements, the glasses display good thermal stability. Further characterisation is undertaken by N2 adsorption/desorption measurements, proton conductivity and hydrogen permeability analyses and a H2/O2 fuel cell test is also performed. The glass materials with large pores and specific surface area are suitable for use as the electrolyte in H2/O2 fuel cells. The effect of TiO2 processing with constant amount of PWA in phosphosilicate glasses, is investigated and discussed. The hydrogen permeability is 1.57x10(-11) mol cm(-1) s(-1) Pa(-1) at 110 degrees C for 0.8 mm thick glass; a power density of 46.3 mW cm(-2) at 125 mA cm(-2) and a current density of 175 mA cm(-2) is obtained (T=28 degrees C, relative humidity). 相似文献
23.
The kinetics of 2,2-bipyridyl catalyzed Cr(VI)–I– reaction has been studied. The order with respect to Cr(VI) is one and fractional with respect to bipyridyl. The order in [I–] changes from unity to zero. Plots of 1/kobs vs. 1/[bipy] and 1/kobs vs. 1/[I–] are straight lines with positive slopes and intercepts.
IICT Publication NO. 2586 相似文献
2,2-, Cr(VI)–I–. Cr(VI) , -. [I–] 1 0. 1/kobs 1/[bipy] 1/kobs 1/[I–] .
IICT Publication NO. 2586 相似文献
24.
25.
S. Krishna Prasad Yoji Maeda Corresponding author D. S. Shankar Rao S. Anitha Nagamani Uma S. Hiremath C. V. Yelamaggad 《Liquid crystals》2013,40(11):1277-1283
The phase behaviour of two achiral bent core banana-shaped compounds, the hexyloxy (compound I) and decyloxy (compound II) members of the 1,3-phenylene bis[N-(2-hydroxy-4-n-alkoxybenzylidene)-4′-aminobenzoate] series was investigated under hydrostatic pressures up to 300?MPa using high pressure differential thermal analysis and light transmission methods. The reversible transition sequence crystal (Cr1)–B1 phase–isotropic liquid (I), observed at room pressure for compound I, remains in the pressure region up to c 70?MPa. At higher pressures a pressure-induced crystalline phase (Cri) appears between the Cr1 and B1 phases, its temperature region becoming wider with increasing pressure. The temperature vs. pressure phase diagram shows a triple point of 72.9?MPa and 160.3°C for the Cr1, Cri and B1 phases, indicating the lower limit of pressure for the Cri phase. In compound II the reversible transition sequence crystal (Cr1)–B2 phase–I is seen over the whole pressure region, and the temperature range of the B2 phase remains unaltered. It is concluded that both the B1 and B2 banana phases are stable over the whole pressure region studied. 相似文献
26.
27.
Togapur Pavan Kumar Mohammad Abdul Sattar Vanka Uma Maheshwara Sarma 《Tetrahedron: Asymmetry》2013,24(24):1615-1619
An efficient protocol for the enantioselective Michael additions of ketones to chalcones catalyzed by a hydroxyphthalimide linked triazole–pyrrolidine derivative has been developed. The corresponding products, 1,5-dicarbonyl compounds, were obtained in good yields with high levels of stereoselectivities under mild reaction conditions employing benzoic acid as an additive. 相似文献
28.
Prof. Dr. Manabu Yamada Fumiya Uemura Dr. Uma Maheswara Rao Kunda Prof. Dr. Takenori Tanno Prof. Dr. Hiroshi Katagiri Prof. Dr. Fumio Hamada 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(38):8393-8399
Alkanes composed of C−C and C−H show a low electric polarization, and therefore, there is only very weak interaction between alkanes and adsorbents. Thus, it is difficult to separate a specific alkane from a mixture of alkanes by adsorption. Here, two activated “channel-like” crystals generated from brominated thiacalix[4]arene propyl ethers, which adopt 1,3-alternate and partial cone conformations, recognize specific alkane vapors depending on alkane-shape and -size, sorting in three-type alkane guests such as linear, branched, and cyclic alkanes. Two activated crystals, which are prepared by removal of solvent upon heating under reduced pressure, incorporate branched and/or cyclic alkane vapors by a unique “gate-opening” mechanism via a crystal transformation in the process. Linear alkane vapors do not trigger gate opening and are not taken up by the activated crystals. The shape and size molecular-recognition properties of the activated crystals promises considerable usefulness for the separation of linear, branched, and cyclic alkanes. 相似文献
29.
Venugopal D. V. R. Karteek Rao Amperayani Uma Devi Parimi Sastry Y. N. Aruna Lakshmi K. Tarak Ramji M. Shiralgi Y. 《Research on Chemical Intermediates》2017,43(10):5755-5778
Research on Chemical Intermediates - Antibiotic-resistant penicillin binding protein (PBPs) production is one of the reasons why bacteria develop resistance to β-lactam antibiotics, and this... 相似文献
30.