Photoreduction of mercuric salt in UV/Fe (III)-oxalate complex system

In this paper, the photochemical reduction process of Hg (II) in aqueous solution containing ferric iron and oxalate (Ox) has been studied. Under the radiation of a low-pressure mercury lamp (lambda = 253.7 nm, 8W), Fe(III)-oxalate complexes undergo photolysis to produce ferrous ions and other organic reductive species, which reduce Hg(II) subsequently. For 0.1 mg/L Hg (II), the photoreduction efficiency is comparatively higher in the solution at pH 5.0 than that over the range of 3.0 similar to 8.0. The photoreduction efficiency of Ho (II) in aqueous solution increases with increasing, initial concentration of ferric ions from 0.02 mmol/L to 0.2 mmol/L and initial concentration of oxalate from 0.96 mmol/L to 4.8 mmol/L and then gradually approaches to a steady state. CH3OH also contributes the reduction of Hg (II). We investigate the increase of the ferric, oxalate and CH3OH concentrations resulting from the increase of reduction efficiency of Hg (II). It can be seen that ferrous ions and other reactive species are reductants of Hg (II), and the reaction product with oxalate is mainly volatile metallic mercury.

Study on fluorescence emission and synchronous-scan fluorescence spectrea of Nitzschia hantzschiana solution with FE(III)

The characterization of the algal Nitzschia hantzschiana solution with (or without) Fe(III) was carried out using fluorescence emission and synchronous-scan spectroscopy. An emission peak (excited at 440 nm) was observed at 675 nm for Nitzschia hantzschiana solution. The effective characterization method used was synchronous-scan fluorescence spectroscopy (SFS). A wavelength difference (Delta lambda) of 90 nm was maintained between excitation and emission wavelengths. The peak was observed at about 236(ex) nm (326(em) nm) for synchronous fluorescence spectroscopy. Fe(III) was an effective quencher. The relationship between I-0/I (quenching efficiency) and c (concentration of Fe (III) added) was a linear correlation for the algal solution with Fe(III). Effects of pH on synchronous-scan fluorescence intensity were evident.

Preliminary study on the photoproduction of hydroxyl radicals in aqueous solution with Aldrich humic acid, algae and Fe(III) under high-pressure mercury lamp irradiation

Under a high-pressure mercury lamp (HPML) and using an exposure time of 4 h, the photoproduction of hydroxyl radicals ((OH)-O-.) could be induced in an aqueous solution containing humic acid (HA). Hydroxyl radicals were determined by high-performance liquid chromatography using benzene as a probe. The results showed that (OH)-O-. photoproduction increased from 1.80 to 2.74 muM by increasing the HA concentration from 10 to 40 mg L-1 at an exposure time of 4 h (pH 6.5). Hydroxyl radical photoproduction in aqueous solutions of HA containing algae was greater than that in the aqueous solutions of HA without algae. The photoproduction of (OH)-O-. in the HA solution with Fe(111) was greater than that of the solution without Fe(III) at pH ranging from 4.0 to 8.0. The photoproduction of (OH)-O-. in HA solution with algae with or without Fe(111) under a 250 W HPML was greater than that under a 125 W HPML. The photoproduction of (OH)-O-. in irradiated samples was influenced by the pH. The results showed that HPML exposure for 4 h in the 4-8 pH range led to the highest (OH)-O-. photoproduction at pH 4.0.

Taxonomic studies of parasitic nyctotherans from chinese Anura amphibians III. Wichtermania

Wu-Han Xiao, Jian-Guo Wang and Lian-Xiang Li (2002) Taxonomic studies of parasitic nyctotherans from Chinese Anura amphibians III. Wichtermania. Zoological Studies 41(1): 69-76. This paper describes 6 new species belonging to the genus Wichtermania from Anura amphibians distributed in southern China. The 6 species are Wichtermania multigranularis sp. nov., W. oviformis sp. nov., W vesiformis sp. nov., W. reticulatis sp. nov., W granuliformis sp. nov., and W obliquoides sp. nov. The characteristics for diagnosis of the 6 new species are described in this paper.

Four new terrestrial species of Marionina (Clitellata, Enchytraeidae) from China and re-examination of M. hoVbaueri Moller

Enchytraeid surveys were made in China, mainly along the Changjiang (Yangtze) River Basin, during the period 1991-1999. Among the findings, four terrestrial species of Marionina are new to science and well illustrate the taxonomic complexity of the genus as currently defined. Marionina sinica sp. n. is characterized by a specific chaetal distribution, the marionine pattern of the dorsal blood vessel, and elongate, fusiform, spermathecal ectal ducts. Marionina sacculata sp. n. is distinguished by the possession of a pair of pouch-like oesophageal appendages in IV, the lack of lateral chaetae in VII-XI, a marionine pattern of the dorsal blood vessel, and short spermathecal ectal ducts gradually expanding into spherical ampullae. Both M. sinica and M. sacculata have minute bodies (2-3 mm long in vivo) and lack spermathecal accessory glands. The former species shows its closest aYnities with the European M. brendae Rota, 1995, whereas the latter is closest to the German M. hoVbaueri Moller, 1971, for which an amended diagnosis is provided. Marionina seminuda sp. n. has only ventral chaetal bundles, distributed from III onwards and bisetose. It is similar to the Holarctic M. subterranea (Knollner, 1935) in lacking entirely the lateral chaetae and in having the brain incised posteriorly, the dorsal vessel bifurcating behind the pharynx, and coelomocytes containing opaque granules, but diVers from it in having the longest chaetae in preclitellar segments and gland cells distributed all over the spermathecal ectal ducts. Marionina righiana sp. n. is diagnosed by the location of the head pore on the prostomium, the absence of lateral chaetae from VIII ( VII or IX) onwards, the possession of free spermathecae extending backwards through one to four segments, the brain deeply incised posteriorly, the lumbricilline pattern of the dorsal blood vessel, and the opacity of coelomocytes in vivo. Prior to this study, members of the genus so atypical as M. righiana with respect to the position of the head pore and the structure of the spermathecae were known only from South American soils. Until the taxonomy of Marionina has been more thoroughly assessed and revised, the assignment of the four species to this large assemblage should be regarded as tentative.

LSIS-III VLSI CAD 系统集成的研究

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气态源分子束外延III-V族可见光半导体材料及其性质研究

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III-V半导体低维结构材料分子束外延生长及其性质的研究

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III-V族可见光半导体材料生长及其性质研究

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III-V族和碳杂质对硅中热施主的影响

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III-V族半导体的喇曼散射研究

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六角III-V氮化物量子阱的电子结构和光学性质

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III-V族半导体低维结构材料的平面光学各向异性

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III－V族氮化物的生长及其光学性质

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III族氮化物材料的性质研究

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