979 resultados para Description of Grout


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Loaches of the genus Niwaella, family Cobitidae, are distributed only in East Asia. At present only in Japan and South Korea have fishes of the genus Niwaella been found. Herein we revise the genus Niwaella in China. Son and He ( 2001) transferred the species Cobitis laterimaculata to the genus Niwaella, but their specimens were not N. laterimaculata, but a new species, N. longibarba sp. n., collected from Cao'ejiang River, Huangzezhen, Chengxian County, Zhejiang Province. The new species is distinguished from N. laterimaculata by its colour pattern of a row of slightly large, and long, scattered dark brown vertical bars on the dorsolateral surface, two or three striations on the caudal fin, and long barbels and undeveloped mental lobes. In this paper we also describe another new species, N. xinjiangensis sp. n., collected from Xinjiang River, Guangfeng County, Jiangxi Province, May 1990, with diagnostic colour pattern of 17 - 20 large and long, dark brown vertical bars on the dorsolateral surface, a dark stripe or rounded black spots along the lateral midline and some blotches below the lateral midline; it is a large-sized species, with shorter barbels, and longer caudal peduncle. Thus five species of the genus Niwaella are known, three are endemic to eastern China and two are endemic to either Japan or South Korea.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Two new species of myxosporeans (Myxosporea: Myxidiidae), Myxidium tuanfengensis sp. n. and Zschokkella saurogobionis sp. n., Parasitic in freshwater fishes collected from the Yangtze River of China are described in this paper. M. tuanfengensis was found in the liver parenchyma and intestine lumen of Leptobotia taeniops Sauvage, 1878, while Z. saurogobionis was found in the gall bladder of Saurogobio dumerili Bleeker, 1871. The diagnostic characters of M. tuanfengensis are: round or elliptical polysporous plasmodia averaging 118 mum in size; spore oval in frontal view with smooth surface and nearly spindle-shape in sutural view with slightly sinuous sutural ridge, averaging 19.5 x 9.75 x 8.9 mum in size; two large spherical polar capsules 6.8 mum in diameter, with polar filament wound in 4 to 5 coils. The diagnostic characters of Z. saurogobionis are: spore elliptical in both frontal and sutural view measuring 18.3 x 9.8 x 10.8 mum in size; fine sutural ridge in S-form, spore shell marked with 10 to 12 distinct lines paralleled with the sutural line; two spherical polar capsules, 6.7 mum in diameter, with polar filament in 5 coils.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Placocheilus is re-diagnosed on the basis of oromandibular structures compared to those of closely related groups. It is represented in China by three species restricted to Yunnan, namely P. caudofasciatus from the Tengtiaohe River (Nam Na), P. cryptonemus from the Nujiang Rive ( upper Salween River basin), and P. robustus, herein described as a new species from the Yuanjiang River ( Red River basin). P. robustus n. sp. is differentiated from its congeners in having a stout caudal peduncle ( depth 72.4-82.5% of its length) and the medium-sized scaleless midventral region of belly extended slightly beyond halfway from the pectoral- to pelvic-fin origin. It is further distinguished from P. caudofasciatus in having a coarsely crenulated rostral fold with 18-23 indentations on its distal margin and a smaller mental adhesive disc ( length 66.7-71.4% of its width and 37.0-43.1% of the head length).

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Tylopharynx clariamphida sp. n. is described from muddy sand collected in Anhui Province, China. It can be distinguished from T foetida (Butschli, 1874), the type and only species of the genus, by numerous characters: having 24 to 26 prominent and clearly separated longitudinal ridges, a higher lip region with no hint of a cephalic framework, more prominent amphidial foveae in lateral view, wider and more posteriorly located amphidial apertures, smaller basal knobs of stoma, longer metacorpus, more enlarged phasmids, shorter spicules with shorter digitate terminus, shorter reflexed part of testis, and thicker gubernaculum with more angular shape. For comparison, an expanded description is given for T foetida from Belgium, and SEM photographs of both species are provided.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Fifth-order corrected expressions for the fields of a radially polarized Laguerre-Gauss (R-TEMn1) laser beams are derived based on perturbative Lax series expansion. When the order of Laguerre polynomial is equal to zero, the corresponding beam reduces to the lowest-order radially polarized beam (R-TEM01). Simulation results show that the accuracy of the fifth-order correction for R-TEMn1 depends not only on the diffraction angle of the beam as R-TEM01 does, but also on the order of the beam. (c) 2007 Optical Society of America.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Based on the perturbative series representation of a complex-source-point spherical wave an expression for cylindrically symmetrical complex-argument Laguerre-Gauss beams of radial order n is derived. This description acquires the accuracy up to any order of diffraction angle, and its first three corrected terms are in accordance with those given by Seshadri [Opt. Lett. 27, 1872 (2002)] based on the virtual source method. Numerical results show that on the beam axis the number of orders of nonvanishing nonparaxial corrections is equal to n. Meanwhile a higher radial mode number n leads to a smaller convergent domain of radius. (C) 2008 Optical Society of America.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

An accurate description of a radially polarized fundamental Gaussian beam is presented on the basis of complex-source-point spherical waves (CSPSWs). In contrast to other descriptions based on the perturbative Lax series, the expressions for the electromagnetic field components of this description have explicit and simple mathematical forms. Numerical calculations show that both paraxial and fifth-order corrected beam descriptions have large relative error when the diffraction angle is large, while the accurate description based on the CSPSW approach proposed here can give field expressions which satisfy Maxwell's equations with great accuracy.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A matrix formulation has been developed and applied to simulate large-angle convergent-beam electron diffraction (LACBED) patterns from the Si/GexSi1-x strained layer superlattice (SLS). Good quantitative agreement has been achieved between experimental and simulated patterns. By utilizing dynamical HOLZ line patterns, we demonstrate that an accuracy of better than 0.1% can be achieved in the determination of the averaged lattice constant of a SLS, and the averaged number of layers of atoms within one period of SLS can be determined up to a single monolayer.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A central challenge to the semiclassical description of quantum mechanics is the quantum phenomenon of "deep" tunneling. Here we show that real time classical trajectories suffice to account correctly even for deep quantum tunneling, using a recently formulated semiclassical initial value representation series of the quantum propagator and a prefactor free semiclassical propagator. Deep quantum tunneling is effected through what we term as coherent classical paths which are composed of one or more classical trajectories that lead from reactant to product but are discontinuous along the way. The end and initial phase space points of consecutive classical trajectories contributing to the coherent path are close to each other in the sense that the distance between them is weighted by a coherent state overlap matrix element. Results are presented for thermal and energy dependent tunneling through a symmetric Eckart barrier.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The parasitic isopod genus Gigantione is first recorded from China. Four species are reported infesting xanthid and goneplacid crabs, three are new to science, and one is a new record from China. Gigantione ishigakiensis Shiino, 1941, infesting Liagore rubromaculata (De Haan); G. hainanensis sp. nov., infesting Atergatis floridus (L.) and Atergatis sp., which differs from other recorded species in the shape of its barbula, first oostegite and subrectangular maxilliped; G. rhombos sp. nov., infesting Heteroplax dentata Stimpson, Eucrate alcocki Serene and Eucrate sp., its female distinguished from other species of Gigantione by having a prominent rhombic projection on the barbula; and G. tau sp. nov., infesting Carcinoplax longimanus (De Haan), the female of which differs from other species mainly by its T-shaped pigmentation on the head. Four brachyuran crabs are first reported as hosts of bopyrids. A list of all brachyuran species so far recorded as bopyrid hosts in China is provided.