Some aspects of freezing and frozen storage of pomfrets

It has been observed that a better frozen product can be obtained by freezing good quality pomfrets transported in insulated containers with sufficient quantity of ice. To enhance the keeping quality and to prevent dehydration and discoloration, a dip in B H A (0.005%) for 15 minutes and subsequent storage in polythene lined gunny bag at -15°c to -I8°c can be recommended. The products treated in the above manner can be stored well over six months. Periodical glazing at an interval of 3 weeks will also prevent the dehydration to a greater extent.

Durability study of eleven years old cement-bentonite cut-off wall material

Comprehensive understanding of the long-term performance of cement-bentonite slurry trench cut-off walls is essential as these mixes may degrade when exposed to aggressive environments or when subjected to prolonged drying. A series of wetting-drying and immersion experiments was carried out to evaluate the durability characteristics of laboratory mixed samples and block field samples from 40 days to 11 years of age. For the wetting-drying tests, the samples buried in medium graded sand were subjected to periodical flooding and drying cycles. They were then used for permeability testing and unconfined compressive strength (UCS) testing. For the immersion tests, the samples confined in perforated molds were submerged in magnesium sulfate solution for 16 weeks and their microstructures were then analyzed using X-ray diffraction (XRD) technique. This paper identifies the effects of contaminant exposure on durability of cement-bentonite and the effects of aging by comparing 11 years old samples to younger samples. Test results showed that young or previously contaminated cement-bentonite mixes are more susceptible to sulfate attack than old or less contaminated mixes. Copyright ASCE 2008.

Fish sauce from two species of unexploited deep sea fish Peristedion adeni and Peristedion weberi

Two species of unexploited deep sea fish Peristedion adeni and Peristedion weberi caught from the Exclusive Economic Zone of India were subjected to fermentation at ambient temperature (30 ± 2°C) in the presence of salt in 4:1 ratio. Periodical analysis of the fermented product was carried out up to one year. The sauces had brownish yellow colour and conformed to special grade of the standards prescribed by the Food and Drug Administration. Further solubilization of protein after 9 month's maturation was not appreciable.

Magnetization of bulk superconductors using thermally actuated magnetic waves

A novel technique is proposed to magnetize bulk superconductors, which has the potential to build up strong superconducting magnets. Instead of conventionally using strong magnetic pulses, periodical magnetic waves with strength as low as that of rare-earth magnets are applied. These magnetic waves travel from the periphery to the center of a bulk superconductor and become trapped little by little. In this way, bulk superconductors can gradually be magnetized. To generate these magnetic waves, a thermally actuated magnet was developed, which is constructed by a heating/cooling switch system, a rare-earth bulk magnet, and a Gadolinium (Gd) bulk. The heating/cooling switch system controls the temperature of the Gd bulk, which, along with the rare-earth magnet underneath, can transform thermal signals into magnetic waves. The modeling results of the thermally actuated magnet show that periodical magnetic waves can effectively be generated by applying heating and cooling pulses in turn. A YBCO bulk was tested in liquid nitrogen under the magnetic waves, and a notable accumulation of magnetic flux density was observed. © 2006 IEEE.

Computer generated holograms for carbon nanotube arrays.

Multiwalled carbon nanotubes are highly diffractive structures in the optical regime. Their metallic character and large scattering cross-section allow their usage as diffractive elements in Fraunhofer holograms. This work elaborates some important features of the far field diffraction patterns produced from periodic arrays of nanotubes. A theoretical approach for the interaction of arrays of nanotubes with light is presented and a computer generated hologram is calculated by means of periodical patterns. Based on the results, fabrication of carbon nanotube arrays (in holographic patterns) was performed. Experimentally measured diffraction patterns were in good agreement with the calculations.

Photosynthetic recovery of desiccated intertidal seaweeds after rehydration

Intertidal seaweeds experience periodical desiccation and rehydration to different extents due to the tidal cycles and their vertical distributions. Their photosynthetic recovery process during the rehydration may show different patterns among the seaweeds from different zonations or depths at intertidal zone. In this study 12 species of seaweeds collected from the upper, middle, lower and sublittoral zones were examined. The relationship of the photosynthetic recovery to vertical distribution was assessed by comparing their patterns of photosynthetic and respiratory performances after rehydration following desiccation. Both the photosynthesis and dark respiration declined during emersion, showing certain degrees of recovery after re-immersion into seawater for most species, but the extents were markedly different from one species to the other. The species from upper intertidal zone after being rehydrated for 1 hour, following 2 hours of desiccation, achieved 100 % recovery of their initial physiological activity, while most of the lower or sublittoral species did not achieve full recovery. It is the ability to withstand desiccation stress (fast recovery during rehydration), but not that to avoid desiccation (water retaining ability) that determines the distribution of intertidal seaweeds. Such physiological behavior during rehydration after desiccation reflects the adaptive strategy of intertidal seaweeds against desiccation and their capability of primary production in the process of rehydration.

Ecophysiological characteristics of four intertidal marine macroalgae during emersion along Shantou coast of China, with a special reference to the relationship of photosynthesis and CO2

Intertidal marine macroalgae experience periodical exposures during low tide due to their zonational distribution. The duration of such emersion leads to different exposures of the plants to light and aerial CO2, which then affect the physiology of them to different extents. The ecophysiological responses to light and CO2 were investigated during emersion in two red algae Gloiopeltis furcata and Gigartina intermedia, and two brown algae Petalonia fascia and Sargassum hemiphyllum, growing along the Shantou coast of China. The light-saturated net photosynthesis in G. furcata and P. fascia showed an increase followed by slightly desiccation, whereas that in G. intermedia and S. hemiphyllum exhibited a continuous decrease with water loss. In addition, the upper-zonated G. furcata and P. fascia, exhibited higher photosynthetic tolerance to desiccation and required higher light level to saturate their photosynthesis than the lower-zonated G. intemedia and S. hemiphyllum. Desiccation had less effect on dark respiration in these four algae compared with photosynthesis. The light-saturated net photosynthesis increased with increased CO2 concentrations, being saturated at CO2 concentrations higher than the present atmospheric level in G. furcata, G. intermedia and S. hemiphyllum during emersion. It was evident that the relative enhancement of photosynthesis by elevated CO, in those three algae increased, though the absolute values of photosynthetic enhancement owing to CO2 increase were reduced when the desiccation statuses became more severe. However, in the case of desiccated P. fascia (water loss being greater than 20 %), light saturated net photosynthesis was saturated with current ambient atmospheric CO2 level. It is proposed that increasing atmospheric CO2 will enhance the daily photosynthetic production in intertidal macroalgae by varied extents that were related to the species and zonation.

Comparative mechanisms of photosynthetic carbon acquisition in Hizikia fusiforme under submersed and emersed conditions

The economic seaweed Hizikia fusiforme (Harv.) Okamura (Sargassaceae, Phaeophyta) usually experiences periodical exposures to air at low tide. Photosynthetic carbon acquisition mechanisms were comparatively studied under submersed and emersed conditions in order to establish a general understanding of its photosynthetic characteristics associated with tidal cycles. When submersed in seawater, H fusiforme was capable of acquiring HCO3- as a source of inorganic carbon (Ci) to drive photosynthesis, while emersed and exposed to air, it used atmospheric CO2 for photosynthesis. The pH changes surrounding the H fusiforme fronds had less influence on the photosynthetic rates under emersed condition than under submersed condition. When the pH was as high as 10.0, emersed H fusiforme could photosynthesize efficiently, but the submersed alga exhibited very poor photosynthesis. Extracellular carbonic anhydrase (CA) played an important role in the photosynthetic acquisitions of exogenous Ci in water as well as in air. Both the concentrations of dissolved inorganic carbon in general seawater and CO2 in air were demonstrated to limit the photosynthesis of H fusiforme, which was sensitive to O-2. It appeared that the exogenous carbon acquisition system, being dependent of external CA activity, operates in a way not enough to raise intracellular CO2 level to prevent photorespiration. The inability of H fusiforme to achieve its maximum photosynthetic rate at the current ambient Ci levels under both submersed and emersed conditions suggested that the yield of aquaculture for this economic species would respond profitably to future increases in CO2 concentration in the sea and air.

Analysis of the additional modulation of semiconductor lasers using optical heterodyne techniques

In this letter, the power spectrum of a cooled distributed feedback laser module is measured using the self-heterodyne technique. Periodical oscillation peaks have been observed in the measurement. Further investigation shows that the additional modulation signal is coupled from the thermal electric cooler (TEC) controller to the laser driver, and then applied to the laser diode. The additional modulation can be eliminated by properly isolating the laser driving source from the TEC controller.

Entanglement evolution of a spin-chain bath coupled to a quantum spin

For an electron spin in coupling with an interacting spin chain via hyperfine-type interaction, we investigate the dynamical evolutions of the pairwise entanglement of the spin chain, and a correlation function joined the electron spin with a pair of chain spins in correspondence to the electron-spin coherence evolution. Both quantities manifest a periodic and a decaying evolution. The entanglement of the spin bath is significant in distinguishing the zero-coherence status exhibited in periodic and decoherence evolutions of the electron spin. The periodical concurrence evolution of the spin bath characterizes the whole system in a coherence-preserving phase, particularly for the case that the associated periodic coherence evolution is predominated by zero value in the infinite chain-length limit, which was often regarded as the realization of decoherence.

Molecular beam epitaxy InAs dot arrays on InGaAs/GaAs

Periodical alignment of the InAs dots along the < 100 > and < 110 > directions was observed on an elastically relaxed InGaAs buffer layer grown at 500 and 450 degrees C, respectively, on the vicinal GaAs(001) substrate. Due to alignment along these directions, the InAs dots were arranged into a quasi-two-dimensional hexagonal lattice. Such a periodical arrangement of InAs dots may be explained in terms of modulation in strain as well as composition along [110] as observed by using cross-sectional transmission electron microscopy.

Photoluminescence study of CdSexS1-x quantum dots in a glass spherical microcavity

The photoluminescence (PL) of CdSexS1-x semiconductor quantum dots (QDs) in a glass spherical microcavity is investigated. The CdSexS1-x semiconductor clusters embedded in a glass matrix are fabricated by using the heat treatment method. Periodical structures consisting of sharp spectral lines are observed in the PL spectra of CdSexS1-x QDs, which can be well explained by the coupling with the whispering gallery modes of the spherical microcavity based on Mie scattering theory.

Defects and morphologies in In0.8Ga0.2As/InAlAs/InP(001) for high electron-mobility transistors

Defects and morphologies are presented in this paper as revealed with transmission electron microscope (TEM) in the In(0.8)G(0.2)As/InAlAs heterostructure on InP(001) for high-electron-mobility transistors application. Most of the misfit dislocation lines are 60 degrees type and they deviate < 110 > at some angles to either side according to their Burges vectors. The misfit dislocation lines deviating [-110] are divided into two types according to whether their edge component b(eg) of Burges vectors in [001] pointing up or down. If b(eg) points up in the growth direction, there is the local periodical strain modulation along the dislocation line. In addition, the periodical modulation in height along [-110] on the In(0.8)G(0.2)As surface is observed, this surface morphology is not associated with the relaxation of mismatch strain.

1994-2006年《水土保持研究》载文被引定量分析

利用中国知识资源总库的中国引文数据库检索《水土保持研究》在1994-2006年所载论文的被引用情况,采用文献计量学方法对该刊1994-2006年载文被《中国期刊文献引证数据库》来源期刊引用的情况进行统计分析及评价。从文献引证的角度透视《水土保持研究》的学术水平。该刊1994-2006年共载文2098篇,被引用2018篇,占载文总数的96.62%。2001-2006年该刊影响因子、即年指标等文献计量指标逐年上升,分析表明:《水土保持研究》载文质量较高,在该学科有较大的学术影响力。

Wide-band underwater acoustic absorption based on locally resonant unit and interpenetrating network structure

The interpenetrating network structure provides an interesting avenue to novel materials. Locally resonant phononic crystal (LRPC) exhibits excellent sound attenuation performance based on the periodical arrangement of sound wave scatters. Combining the LRPC concept and interpenetrating network glassy structure, this paper has developed a new material which can achieve a wide band underwater strong acoustic absorption. Underwater absorption coefficients of different samples were measured by the pulse tube. Measurement results show that the new material possesses excellent underwater acoustic effects in a wide frequency range. Moreover, in order to investigate impacts of locally resonant units, some defects are introduced into the sample. The experimental result and the theoretical calculation both show that locally resonant units being connected to a network structure play an important role in achieving a wide band strong acoustic absorption.