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The complex permeability and permittivity, the relationship between dynamic and static properties, and attenuation properties have been studied for BaZn2-xCoxFe16O27 composites with x=0.7–2.0. The results show that the resonance frequency fR is controlled by the out-of-plane anisotropy field Hθ, and the static permeability μ0′ is related to the in-plane anisotropy field H[lowercase_phi_synonym]. For appropriate resonance frequency and high complex permeability, the percentage bandwidths of ΔW=Δf/f0>90% for attenuation of 10 dB or more can be achieved by composites with x=0.7 and 1.0. Therefore, W-type barium ferrites with easy c-plane anisotropy are good candidates for electromagnetic materials with low reflectivity over broad frequency range at microwaves. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Investigates the colossal magnetoresistance (CMR), Mossbauer spectra, and phase compositions of iron-doped La1-xSnxMn0.985Fe0.015O3+... manganites. Effects of a small amount of iron doping on the CMR and magnetic properties of the manganites; Synthesizing of the manganites using conventional ceramic techniques; Results of the investigation.

Examines the structure and magnetic properties of R2Fe15Si2Cy, where R = Nd, Sm, Gd and Er. Curie temperatures; Saturation magnetization; Anisotropy fields.

Aims The goal was to investigate the dynamics of soil bacterial community in the chronosequence tea orchards. Method and Results In this study, soils from tea orchards with continuously cropping histories for 1, 10 and 20 years were collected for investigating rhizosphere bacterial communities using 454 pyrosequencing. The results indicated that Gammaproteobacteria, Alphaproteobacteria, Acidobacteria and Actinobacteria were the main phyla in the tea orchard soils and accounted for more than 60% of the bacterial sequences. At the genus level, the relative abundance of beneficial bacteria, such as Pseudomonas, Rhodanobacter, Bradyrhizobium, Mycobacterium and Sphingomonas, significantly decreased in the 20-year tea orchard soils. Similar patterns of bacterial community structure were observed between 1-year and 10-year tea orchards, which significantly differed from those of 20-year tea orchards. Redundancy analysis indicated that soil organic carbon and pH showed high correlations (positive or negative) with the majority of the taxa. Conclusion Long-term tea cultivation altered the composition and structure of soil bacterial community, which led to the reduction in the beneficial bacteria. Significance and Impact of the Study The results can provide clues on how to regulate the soil microbial community and maintain the health of soils in tea orchard systems. [ABSTRACT FROM AUTHOR]

Precipitates and solute enrich in aged ferritic steel containing copper were examined using high-resolution electron microscopy, high-angle annular dark-field scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy. Two ledgeswith one-atom and two-atom layers height in the 9R/3R interface were observed. The enrichment of copper into two successive closed-packed planes with an interval of Fe-rich close-packed plane was detected. The passage of the Shockley partial, or the shearing, changes the stacking sequence of closed-packed planes. Finally, 9R Cu variant transformed into 3R Cu variant. [ABSTRACT FROM AUTHOR]

As a structural object of Petri nets, siphons play a key role in the development of deadlock prevention policies for resource allocation systems. The siphon solution in Petri nets has been extensively investigated in the literature. Since the number of siphons in a net grows quickly and in the worst case grows exponentially with respect to the size of a net, their computation is expensive. This paper aims to find the strict minimal number of siphons in a class of Petri nets, called extended systems of linear simple sequential process with resources, which can model flexible manufacturing systems where there exist no flexible processing routings except for the idle state and each operation state may require more than one sort of resources. First, a relationship between structural properties and strict minimal siphons in the class of Petri net is verified. Second, we define the resource digraph of the class net. Finally, based on the obtained results, a method to find the set of strict minimal siphons is proposed. A running example is used to demonstrate the proposed methods. [ABSTRACT FROM PUBLISHER]

Measurement of the flame temperature in a micro combustor is essentially difficult due to the size constraint. A one-dimensional (1D) flame model coupled with the heat conduction in the solid wall is employed to analyze the heat transfer occurring in a cylindrical micro combustor. The flame temperature is given explicitly by taking into account the effects of the heat loss (from the flame to the wall) in the reaction zone and heat recirculation through the solid wall. With the data obtained from the simulation results of the 1D adiabatic freely propagating CH4-air laminar flames, the flame temperature in a cylindrical micro combustor can be solved iteratively. In order to validate the 1D model, the two-dimensional (2D) numerical simulations of premixed combustion of the CH4-air mixtures are carried out in a 0.5 mm radius cylindrical micro combustor. The comparisons of the flame temperature and heat recirculation between the 1D model and 2D numerical simulation indicate that despite the simplifications and assumptions made in the present study, the 1D theoretical model is able to predict the flame temperature to a reasonable accuracy. [ABSTRACT FROM AUTHOR]

Ground settlement has long been a problem in Hong Kong, as most usable land in Hong Kong was reclaimed from the sea. Ground settlement may affect building structures and underground facilities such as water supply and sewage systems built on the land. Measurements of ground settlement can provide valuable data for assessing the impacts of ground settlement and for improving designs of future land reclamation projects. Experiments have been carried out to assess the performance of INSAR in the environment of Hong Kong especially the temporal decorrelations of SAR images and the potential atmospheric effects on INSAR measurements, and to use INSAR to study the ground settlement problem in Hong Kong. This study finds that the temporal decorrelation is an important problem in the heavily vegetated rugged areas as usually expected, and that the atmospheric effects can be very significant at times. Ground settlements measured over the airport and a residential area are presented. It can be seen from the results that both of the areas are still settling significantly many years after the reclamation. [ABSTRACT FROM AUTHOR]

We present determinations of fundamental parameters and lithium abundances in eleven solar-type stars through observations of the Li I λ6707.8Å. The correlations between the abundance of lithium and that of other elements (Ca, K and Fe) are also discussed. The analysis of our data indicates that the maximum lithium abundance decreases with decreasing Teff, and also decreases with increasing age. The sun is just one of the stars with low lithium abundance. One of the sample stars shows a high lithium abundance of as much as 2.34 dex. The plot of lithium abundance versus [Ca/H] is similar to that versus [Fe/H]. Lithium seems depleted more quickly than potassium in the cool solar-type stars. The correlation between the lithium abundance and the other stellar characteristics, such as absolute visual magnitude, does not seem very strong. The large scatter present at each color cannot be uniquely attributed to different initial compositions or to pure age effect. Other complex mechanisms may exist to provide different amounts of lithium depletion for stars with properties similar to the sun. [ABSTRACT FROM AUTHOR]

The bones of chicken play an important role in supporting and protecting the body. The growth and development of bones have a substantial influence on the health and production performance in chickens. However, genetic architecture underlying chicken bone traits is not well understood. The objectives of this study are to dissect the genetic basis of bone traits in chickens and to identify valuable genes and genetic markers for chicken breeding. We performed a combination of genome-wide association study (GWAS) and selection signature analysis (fixation index values and nucleotide diversity ratios) in an F 2 crossbred experimental population with different genetic backgrounds (broiler × layer) to identify candidate genes and significant variants related to femur, shank, keel length, chest width, metatarsal claw weight, metatarsal length, and metatarsal circumference. A total of 545 individuals were genotyped based on the whole genome re-sequencing method (26 F 0 individuals were re-sequenced at 10 × coverage; 519 F 2 individuals were re-sequenced at 3 × coverage). A total of 2 028 112 single-nucleotide polymorphisms (SNPs) remained to carry out analysis after quality control and imputation. The integration of GWAS and selection signature analysis indicated that all significant SNPs responsible for bone traits were mainly localized on chicken chromosomes 1, 4, and 27. Finally, we identified 21 positional candidate genes that might regulate chicken bone growth and development, including LRCH1 , RB1 , FNDC3A , MLNR , CAB39L , FOXO1 , LHFP , TRPC4 , POSTN , SMAD9 , RBPJ , PPARGC1A , SLIT2 , NCAPG , NKX3-2 , CPZ , SPOP , NGFR , SOST , ZNF652 , and HOXB3. Additionally, an array of uncharacterized genes was identified. The findings provide an in-depth understanding of the genetic architecture of chicken bone traits and offer a molecular basis for applying genomics in practical chicken breeding. [ABSTRACT FROM AUTHOR]

Mössbauer spectra of (La1-xSnx)2(Mn0.985Fe0.015)2Oy ( x=0.2, 0.3, 0.4 and 0.5) from room temperature to 4.2 K have been studied; in addition X ray diffraction patterns at room temperature have been obtained. The results show that the phase compositions of (La1-xSnx)2(Mn0.985Fe0.015)2Oy are strongly dependent on the Sn concentrations and on the heat treatment. The manganites with x=0.2, 0.3 and 0.4 after annealing in air at 1200°C appear to consist of two phases, ABO3 and A2B2O7. Their Mössbauer spectra are paramagnetic doublets at room temperature that become sextets at T ∼ 230 K and ∼ 60 K. The ABO3 phase appears to be the source of the CMR in manganite (La0.7Sn0.3)2(Mn0.985Fe0.015)2Oy [ABSTRACT FROM AUTHOR]

A controllability condition of a siphon composed of three elementary ones in a class of Petri nets, namely S3PR, is developed. Under the condition, a maximally permissive liveness‐enforcing supervisor expressed by a set of monitors (control places) can be decided by an algorithm with polynomial complexity for an S3PR if every dependent siphon is m‐composed with m ≤ 3. [ABSTRACT FROM AUTHOR]

A prototype microthermophotovoltaic (micro-TPV) power generator is described in this letter. The system is made of a SiC (silicon carbide) emitter, a simple nine-layer dielectric filter, and a GaSb (gallium antimony) photovoltaic cell array. In a microcombustor of 0.113 cm³ in volume, when the flow rate of hydrogen is 4.20 g/h, the micro-TPV system is able to deliver an electrical power output of 1.02 W, corresponding to an open-circuit electrical voltage of 2.28 V and a short-circuit current of 0.59 A. The prototype of the micro-TPV system will make it possible for us to substitute batteries with micropower generators in micromechanical devices in the near future. [ABSTRACT FROM AUTHOR]