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Some vacuum chambers in particle accelerators perform a waveguide- or resonator-like behavior due to their unique geometries. Electron multipacting caused by such a structural property might be able to overwhelm the classical beam-induced multipacting. This article shows that the wakefields of particle beams could stimulate the resonant modes of a vacuum chamber with a near-rectangular waveguide shape and accordingly induce much stronger electron avalanche in the chamber. Especially, it has been believed that the multipacting is responsible for pressure rise in a vacuum chamber, where energetic secondary electrons with growing numbers collide with gas particles at the chamber wall. Based on numerical simulations, the electron multipacting mechanism with the mode resonance is proposed, which can explain the significant pressure variation measured in our cryogenic vacuum chamber.

This study was carried out in order to understand the early diagenetic redistribution of phosphorus and relevant mass balance in the sediments of the East Sea. In two cruises during May 1993 and October 1995, 11 box cores were collected in the southwestern part of the East Sea. Dissolved phosphorus and iron were analyzed in the porewater from the cores. Sediment samples were analyzed for solid-phase P species and solid-phase Fe oxyhydroxide by sequential extraction. Phosphorus speciation results show that organic P is the major chemical form of phosphorus in young sediments within the upper 50 cm of sediment. However, the authigenic fraction of total P increases with depth, indicating the precipitation of carbonate fluorapatite (CFA) in the sediments. The authigenic CFA (Ca5(PO4)2.6(CO3)0.4F) was formed and buried at rates of 11–110 μmol cm−2 kyr−1. The main source of dissolved phosphorus for the precipitation of CFA is organic P. Dissolved phosphorus, released from the decomposition of organic P, diffuses upward to return to bottom water, or is sorbed to iron oxides in the oxidized sediments. As sedimentation proceeds, the iron oxide-bound P is released in the reduced layer and enters the dissolved phase, which contributes P to the formation of CFA in addition to that contributed by the organic P. The burial flux of reactive P (iron oxide-bound P+authigenic P+organic P) is 0.09–0.53 g P m−2 yr−1 that accounts for 18–58% of the reactive P arriving at the sediment/water interface. The burial flux of reactive P is high in the upper and lower continental margin sediment. The burial flux of reactive P in the Ulleung Basin sediment is less than those in the continental margin sites by a factor of 6, indicating that the reactive P burial flux is mainly dependent on sedimentation rate.

In this paper, a new ride-through module for a matrix converter has been proposed. The proposed module has been shown to maintain the rotor flux and synchronization between the motor and matrix converter during momentary power interruption. The ride-through system for matrix converter consists of two parts they are conventional matrix converter module and add-on ride through module. The principle of operation and advantages of matrix converter-fed ASDs are discussed in this paper.

Simultaneous liver and kidney transplantation (SLKT) is now considered the treatment of choice for patients with concurrent end-stage liver and kidney diseases. Even though the early postoperative mortality rate following SLKT is reported to be high compared to that of liver transplantation alone, the liver graft from the same donor has been argued to induce better kidney graft acceptance as evidenced by a low rate of acute renal rejection episodes. There have been many reports of a low incidence of acute renal rejection following SLKT; however, only a few cases were proven by simultaneous biopsies. The authors experienced a case of biopsy-proven isolated acute cellular rejection of the liver graft following SLKT.

Huntington’s disease (HD) is a fatal neurodegenerative disease caused by expansion of a cytosine–adenine–guanosine trinucleotide repeat within the HD gene, encoding an abnormally long polyglutamine moiety within the huntingtin protein. Clinical symptoms include problems with movement, cognition, and behavior. Pathologically, HD is characterized by atrophy of the caudate-putamen. Theories of pathogenesis include glutamate excitoxicity and altered mitochondrial energetics. While the normal function of huntingtin is still undefined, mutant versions of the protein can be cleaved, and the fragments can form insoluble aggregates. Currently, there are no effective treatments, but discoveries in basic research have advanced into clinical trials.

Free electron laser (FEL) is the most powerful source in the THz range. The main task is to decrease its size and cost to a laboratory scale. An inexpensive and compact THz FEL has been developed at KAERI (Y.U. Jeong et al., 2001), (Y.U. Jeong et al., 2005) and it is expected to play an important role in encouraging advanced THz applications for biomedical imaging due to its higher power and spectral brightness when compared to the table-top sources.