Agricultural development and the opportunities for aquatic resources research in China

China is a large and rapidly developing country. Fisheries and aquaculture have been prominent sectors in the contribution to GDP and the provision of food security, export revenue, and livelihoods for the poor. The rapid development has come at some cost to the environment and the sustainability of natural resources. Levels of marine fisheries catches are stagnant. Some of the rivers and major lakes are polluted and the restoration of the productivity of these lakes is of key concern. These Proceedings, made up of four papers that leading Chinese experts presented to WorldFish Center in 2002, review four aspects of these trends: agricultural development, environmental issues and the contribution of aquaculture and fisheries to development in China.Agricultural development, Aquaculture development, Living resources, Research, WorldFish Center, WorldFish Center Contrib. No. 1668, China,

Dynamic Stress Intensity Factor for Interfacial Cracks of Mode III Emanating from Circular Cavities in Piezoelectric Bimaterials

This paper investigates dynamic stress intensity factors in piezoelectric bimaterials with interfacial cracks emanating from the circular cavities under steady SH-waves. The interfacial cracks are assumed to be permeable. Green functions for the experiment were constructed through complex variable and wave function expansion methods. Based on the crack-division and conjunction techniques, a series of Fredholm integral equations of the first kind were established to calculate the stress intensity of the crack tips. Direct numerical integration was used to solve the equations. Some numerical results were plotted to indicate the influence of the defect geometry, material constants, and SH-wave frequencies on dynamic stress intensity factors

Novel water insoluble (NaxAg2-x) MoO4 (0 <= x <= 2) microwave dielectric ceramics with spinel structure sintered at 410 degrees

In the present work, a novel series of water insoluble ultra-low temperature firing (Na,Ag)2MoO4 microwave dielectrics were prepared via the traditional solid state reaction method. A spinel structured solid solution was formed in the full composition range in the (NaxAg2−x)MoO4 (0 ≤ x ≤ 2). As x increased from 0 to 2.0, cell volume decreased linearly from 9.32 Å to 9.10 Å. Sintering behavior were described using a so-called ‘bowing’ effect and densification was achieved below 420 °C for 0.5 ≤ x ≤ 1.2 with grain size, 1 to 5 μm. Optimum microwave dielectric properties were obtained for (Na1.2Ag0.8)MoO4 ceramics sintered at 410 °C with a permittivity ∼8.1, a microwave quality factor ∼44 800 GHz and the temperature coefficient of the resonant frequency ∼−82 ppm °C−1 at 13.9 GHz. Silver within the solid solution inhibited hydrolyzation of ceramics and also reduced their sintering temperature. Compared with the sintering temperatures of traditional microwave dielectric ceramic (Al2O3, >1400 °C) and normal low temperature co-fired ceramics (<960 °C), this system will save lots of energy during processing and accelerate developments of sustainable electronic materials and devices

Polarization of AGN in UV Spectral Range

We present the review of some new problems in cosmology and physics of stars in connection with future launching of WSO. We discuss three problems. UV observations of distant z > 6 quasars allow to obtain information on the soft < 1 KeV X-ray radiation of the accretion disk around a supermassive black hole because of its cosmological redshift. Really the region of X-ray radiation is insufficiently investigated because of high galactic absorption. In a result one will get important information on the reionization zone of the Universe. Astronomers from ESO revealed the effect of alignment of electric vectors of polarized QSOs. One of the probable mechanism of such alignment is the conversion of QSO radiation into low mass pseudoscalar particles (axions) in the extragalactic magnetic field. These boson like particles have been predicted by new SUSY particle physics theory. Since the probability of such conversion is increasing namely in UV spectral range one can expect the strong correlation between UV spectral energy distribution of QSO radiation and polarimetric data in the optical range. In the stellar physics one of the interesting problems is the origin of the X-ray sources with super Eddington luminosities. The results of UV observations of these X-ray sources will allow to find the origin of these sources as accreting intermediate mass black holes.Comment: 6 pages, 3 figure

Non-Archimedean character of quantum buoyancy and the generalized second law of thermodynamics

Quantum buoyancy has been proposed as the mechanism protecting the generalized second law when an entropy--bearing object is slowly lowered towards a black hole and then dropped in. We point out that the original derivation of the buoyant force from a fluid picture of the acceleration radiation is invalid unless the object is almost at the horizon, because otherwise typical wavelengths in the radiation are larger than the object. The buoyant force is here calculated from the diffractive scattering of waves off the object, and found to be weaker than in the original theory. As a consequence, the argument justifying the generalized second law from buoyancy cannot be completed unless the optimal drop point is next to the horizon. The universal bound on entropy is always a sufficient condition for operation of the generalized second law, and can be derived from that law when the optimal drop point is close to the horizon. We also compute the quantum buoyancy of an elementary charged particle; it turns out to be negligible for energetic considerations. Finally, we speculate on the significance of the absence from the bound of any mention of the number of particle species in nature.Comment: RevTeX, 16 page

High permittivity and low loss microwave dielectrics suitable for 5G resonators and low temperature co-fired ceramic architecture

Bi 2 (Li 0.5 Ta 1.5 )O 7 + xBi 2 O 3 (x = 0, 0.01 and 0.02) ceramics were prepared using a solid state reaction method. All compositions were crystallized in a single Bi 2 (Li 0.5 Ta 1.5 )O 7 phase without secondary peaks in X-ray diffraction patterns. Bi 2 (Li 0.5 Ta 1.5 )O 7 ceramics were densified at 1025 °C with a permittivity (ϵ r ) of ∼ 65.1, Q f ∼ 15500 GHz (Q ∼ microwave quality factor; f ∼ resonant frequency; 16780 GHz when annealed in O 2 ) and the temperature coefficient of resonant frequency (TCF) was ∼ -17.5 ppm °C -1 . The sintering temperature was lowered to ∼920 °C by the addition of 2 mol% excess Bi 2 O 3 (ϵ r ∼ 64.1, a Q f ∼ 11200 GHz/11650 GHz when annealed in O 2 and at a TCF of ∼ -19 ppm °C -1 ) with compositions chemically compatible with Ag electrodes. Bi 2 (Li 0.5 Ta 1.5 )O 7 + xBi 2 O 3 are ideal for application as dielectric resonators in 5G mobile base station technology for which ceramics with 60 < ϵ r < 70, high Q f and close to zero TCF are commercially unavailable. They may additionally prove to be useful as high ϵ r and high Q f materials in low temperature co-fired ceramic (LTCC) technology