Eventhough Fe-6.5 wt.% Si alloy shows excellent magnetic properties, magnetic components made of the alloy are not totally because of its extremely low ductility. In order to overcome this demerit of alloy, 6.7 wt.% Si alloy powders were produced by gas atomization and then post-processed to form magnetic cores. By doing so, the total core loss could be minimized by reducing both hysteresis and eddy current loss. From our experiments, we were able to achive a core loss of at 0.1 T and 50 kHz through proper processes and a permeability of 68 at low frequency.

Magnetic powder core is considered to be one of the essential parts in modern electronic devices such as power supplies, digital telecommunication equipments and automotive electronics. To satisfy the recent requirement for the miniaturization of micro-systems and portable devices, the inductors or magnetic powder cores should have reduced compact volume and high universality both in magnetic and geometric aspects. In contrast, in some application areas such as power converters, the price is also one of the important aspects to be considered. To comply with such stringent technical requirements in modern electronic industry, it is highly required to develop magnetic materials with increased frequency stability, higher saturation magnetic flux density, higher permeability and higher quality factor (Q). The magnetic alloy powders which are currently being used in PM industry are permalloy (Ni-Fe), sendust (Fe-Si-Al), iron (Fe), silicon steel (Fe-Si) and ferrous amorphous alloy powders. Recent research trends for the industrial application of soft magnetic material and magnetic powder core will be introduced in the present paper. Emphasis will be placed on the newly required properties and corresponding new PM technologies for newly emerging application fields such as hybrid electric vehicle, alternative and renewable energy systems for next generation.

In this paper, we mainly analyze the performance of two ultra wideband communication systems, the classical Time Hopping Binary Pulse Position Modulation (TH-BPPM) UWB system and the Time Hopping Bipolar Pulse Amplitude Modulation (TH-BPAM) UWB system. The performance of TH-BPPM and TH-BPAM is analyzed in detail under an ideal AWGN channel and a correlation receiver. We use the power spectral density function to get the expression of BER of these two UWB systems. It yields simple and exact formulas relating the performance to the system parameters. The analysis shows that TH-BPPM suffers performance degradation with respect to TH-BPAM. Furthermore, we give the computer simulation of both data and image transmission and our simulation results also prove our theoretical analysis.

Ascorbic acid is a great antioxidant and helps protect the body against pollutants. GDP-mannose pyrophosphorylase (GMPase) is a key enzyme in manufacturing GDP-mannose, a glycosyl donor for ascorbate and cell wall biosynthesis as well as for protein glycosylation. In this study, we described molecular cloning of a full-length cDNA from Potato (Solanum tuberosum L. cv. Jasim), using tuber. The cDNA isolated encoded a GDP-mannose pyrophosphrylase. The nucleotide sequence of pGMPC showed about 95%, 89% and 80% homology with S. tuberosum (AF022716), N. tabacum (AB066279) and A. thaliana (AF076484) cDNAs clone known as GMPase, respectively. We detected the expression of GMPase using RT-PCR. The highest expression of GMPase was found in stems, and the largest amount of ascorbic acid was also presented in stems. In contrast, the leaf showed minimal level of GMPase transcript and ascorbic acid content. We propose that GMPase expression patterns were similar to the changes of ascorbic acid content in the leaves treated with diverse stresses.