Inland free-living nematodes in China: A historical review of taxonomic studies with descriptions of Aphanonchus orientalis sp nov (Chromadorida : Leptolaimidae) and Daptonema limnobia sp nov (Monhysterida : Xyalidae)

The study of inland free-living nematodes is relatively imperfect in China, only seventeen papers were previously published. Since the early researches in 20-30s, few works have been accomplished until 80s. Altogether 171 taxa were formerly recorded, among which, over eighty species have been re-combined. A checklist of the former records with notes on their distribution is presented in this paper. Recently, the function of free-living nematodes has received much attention from Chinese zoologists. Hence, the present authors carried out their studies with emphasis on taxonomy of inland nematodes. During the survey of freshwater lakes, two species are found to be nem to science. Aphanonchus orientalis sp. nov. is characterized by having sclerotized vagina, the presence of 10-11 tubular supplements and 42-62 alveoli supplements in males, but no alveoli in females. Daptonema limnobia sp, nov. is distinguished from other species of the genus in the presence of larger and more anteriorly located amphids, shorter bifurcated spicules, smaller apophysis of gubernaculum, shorter terminal setae, and postvulval uterine sac in females.

Photoluminescence and optical quenching of photoconductivity studies on undoped GaN grown by molecular beam epitaxy

Deep levels in undoped GaN materials grown by modified molecular beam epitaxy (MBE) are investigated by photoluminescence (PL) and optical quenching of photoconductivity measurements. A broad band which extends from 2.1 to 3.0 eV with a maximum at about 2.7 eV is observed, and four prominent quenching bands were found located at 2.18, 2.40, 2.71, and 2.78 eV above the valence band, respectively. These levels are attributed to four holes trap levels existence in the material. The defects cannot be firmly identified at present. (C) 2000 Elsevier Science B.V, All rights reserved.

Self-assembly of a water chain with tetrameric and decameric clusters in the channel of a mixed-valence (CuCuII)-Cu-I complex

The reaction of Cu(BF4)(2) with pyridine-2,6-dicarboxylic acid (H(2)pydc) and trans-1,2-bis(4-pyridyl)ethylene (bpe) under hydrothermal conditions afforded a porous mixed-valence (CuCuII)-Cu-I coordination polymer. Coexistence of tetrameric and decameric water clusters within the channels of the complex leads to a novel water chain. The metal-organic framework provides both hydrophilic and hydrophobic environments for stabilizing the clusters and retains its integrity upon dehydration and rehydration.

Distribution of uranium isotopes in the main channel of Yellow river (Huanghe), China

Uranium isotopes were measured in waters and suspended particulate matters (SPM) of the main channel of Yellow River, China that were sampled during four field trips between August 2005 and July 2006. The results show that the concentration of dissolved U (2.04-7.83 mu g/l) and the activity ratio of U-234/U-238 (1.36-1.67) are much higher than the average U concentrations and activity ratios of global major rivers. Mass balance calculations using the results of simulated experiments and measurement data show that the section of the Yellow River between Lanzhou and Sanmenxia has its dissolved U derived from two sources: suspended sediments (68%) and groundwater/runoff from loess deposits (32%). Both sources are related to the heavy erosion of the Chinese Loess Plateau. (C) 2008 Elsevier Ltd. All rights reserved.

Two-dimensional numerical simulation of the channel electron in an In0.52Al0.48As/In0.53Ga0.48As HEMT

A two-dimensional quantum model based on the solution of Schrodinger and Poisson equations is first presented for In0.52Al0.48As/In0.53Ga0.47As/InP HEMT. According to the model, the two-dimensional distributions of electron density and transverse electric field in the channel of InAlAs/InGaAs HEMT are discussed.

Experimental study of the U-238(S-36,3-5n)(269-271)Hs reaction leading to the observation of (270)Hs

The deformed doubly magic nucleus (270)Hs has so far only been observed as the four-neutron (4n) evaporation residue of the reaction Mg-26+Cm-248, where a maximum cross section of 3 pb was measured. Theoretical studies on the formation of (270)Hs in the 4n evaporation channel of fusion reactions with different entrance channel asymmetry in the framework of a two-parameter Smoluchowski equation predict that the reactions Ca-48+Ra-226 and S-36+U-238 result in higher cross sections due to lower reaction Q values, in contrast to simple arguments based on the reaction asymmetry, which predict opposite trends. Calculations using HIVAP predict cross sections for the reaction S-36+U-238 that are similar to those of the Mg-26+Cm-248 reaction. Here, we report on the first measurement of evaporation residues formed in the complete nuclear fusion reaction S-36+U-238 and the observation of (270)Hs, which is produced in the 4n evaporation channel, with a measured cross section of 0.8(-0.7)(+2.6) pb at 51-MeV excitation energy. The one-event cross-section limits (68% confidence level) for the 3n, 4n, and 5n evaporation channels at 39-MeV excitation energy are 2.9 pb, while the cross-section limits of the 3n and 5n channel at 51 MeV are 1.5 pb. This is significantly lower than the 5n cross section of the Mg-26+Cm-248 reaction at similar excitation energy.

Study of the ion channel behavior of didodecyldimethylammonium bromide formed bilayer lipid membrane stimulated by PF6-

Bilayer lipid membranes ( BLM) formed from didode-cyldimethylammonium bromide were made on the freshly exposed surface of a glassy carbon (GC) and were demonstrated by the ac impedance spectroscopy. The ion channels of membrane properties induced by PF6- were studied by the cyclic voltammetric methods. Experimental results indicated that the ion channel of BLM was open in the presence of the PF6- due to the interaction of PF6- with the BLM, while it was switched off in the absence of PF6-. Because the ion channel behavior was affected by the concentration of PF6-, a sensor for PF6- can be developed.

Induction effect of Ca2+ on ion-channel behavior of supported phospholipid membranes

As a kind of supported bilayer lipid membranes, hybrid bilayer membrane (HBM) was applied to the interaction between Ca2+ and lipid for the first time. By using Fe(CN)(6)(3-) as a probe, we found that Ca2+ could induce the ion channel of HBM to be in open state. STM images study proved this phenomenon.

SYNTHESIS AND CRYSTAL-STRUCTURES OF THE BIMETALLIC RARE-EARTH COMPLEXES AND STUDIES ON INSERTION MECHANISM OF DIENES POLYMERIZATION

The deepening of the studies on essentials of rare earth coordination catalyst brings about more and more reports on model compounds as active centre of the catalyst. Among them the most significant researches are those with identification of the crystal structures of compounds.