230 research outputs found

    Ultrafast giant magnetic cooling effect in ferromagnetic Co/Pt multilayers

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    The magnetic cooling effect originates from a large change in entropy by the forced magnetization alignment, which has long been considered to be utilized as an alternative environment-friendly cooling technology compared to conventional refrigeration. However, an ultimate timescale of the magnetic cooling effect has never been studied yet. Here, we report that a giant magnetic cooling (up to 200 K) phenomenon exists in the Co/Pt nanomultilayers on a femtosecond timescale during the photoinduced demagnetization and remagnetization, where the disordered spins are more rapidly aligned, and thus magnetically cooled, by the external magnetic field via the lattice-spin interaction in the multilayer system. These findings were obtained by the extensive analysis of time-resolved magneto-optical responses with systematic variation of laser fluence as well as external field strength and direction. Ultrafast giant magnetic cooling observed in the present study can enable a new avenue to the realization of ultrafast magnetic devices.111Ysciescopu

    Hepatic Parasitic Abscess Caused by Clonorchiasis: Unusual CT Findings of Clonorchiasis

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    Clonorchiasis is caused by a chronic infestation of liver flukes, Clonorchis sinensis, and these reside mainly in the medium- and small-sized intrahepatic bile ducts. Therefore, diffuse, uniform, minimal or mild dilatation of these bile ducts, particularly in the periphery, without dilatation of the extrahepatic bile duct is the typical finding on several imaging modalities. We report here on the CT findings of an unusual case of hepatic parasitic abscess that was caused by clonorchiasis; this malady mimicked cholangiocarcinoma, and there was no dilatation of the intrahepatic bile ducts

    A Comparison of the Intrinsic Shapes of Two Different Types of Dwarf Galaxies: Blues Compact Dwarfs and Dwarf Ellipticals

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    We measure the apparent shapes for a sample of 62 blue compact dwarf galaxies (BCDs), and compare them with the apparent shapes for a sample of 80 dwarf elliptical galaxies (dEs). The BCDs are flatter, on average, than the dEs, but the difference is only marginally significant. We then use both non-parametric and parametric techniques to determine possible distributions of intrinsic shapes for the BCDs. The hypothesis that BCDs are oblate spheroids can be ruled out with a high confidence level (>99> 99%), but the hypothesis that they are prolate spheroids cannot be excluded. The apparent shapes of BCDs are totally consistent with the hypothesis that they are triaxial ellipsoids. If the intrinsic axis ratios, β\beta and γ\gamma, are distributed according to a Gaussian with means β0\beta_0 and γ0\gamma_0 and standard deviation σ\sigma, we find the best-fitting distribution for BCDs has (β0,γ0,σ)=(0.66,0.55,0.16)(\beta_0,\gamma_0,\sigma)= (0.66,0.55,0.16), while that for dEs has (β0,γ0,σ)=(0.85,0.64,0.24)(\beta_0,\gamma_0,\sigma)= (0.85,0.64,0.24). Our results are consistent with the hypothesis that BCDs have a close evolutionary relation with dEs.Comment: total 23 pages, 9 figures, and 1 Table, submitted to ApJ on Sep 19 1997. Email addresses: [email protected], [email protected], [email protected], [email protected], [email protected]

    Hypofractionated High-Dose Intensity-Modulated Radiotherapy (60 Gy at 2.5 Gy per Fraction) for Recurrent Renal Cell Carcinoma: A Case Report

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    A patient with renal cell carcinoma (RCC) developed synchronous bone metastasis with metachronous relapses to the bone and renal fossa. The primary lesion was initially removed surgically, and the metastatic bone lesions and locally recurrent tumours were treated by a high-fractional dose and high-total-dose intensity-modulated radiotherapy (IMRT, 60 Gy at 2.5 Gy per fraction) without significant side effects. All the grossly relapsed tumors underwent complete remission (CR) within a short time after IMRT. To date, CR has been maintained for more than two years. This case study reports the successful treatment of radioresistant RCC using a new scheme that involves a fractionation regimen with a high precision radiotherapy

    Pattern of Failure in Bladder Cancer Patients Treated with Radical Cystectomy: Rationale for Adjuvant Radiotherapy

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    Thus far, the role of adjuvant radiotherapy (RT) after radical cystectomy (RC) in urinary bladder cancer patients has yet to be defined. The purpose of this study is to analyze patterns of failure, and suggest the rationale for RT. Between 1986 and 2005, a total of 259 patients treated with RC and pelvic lymph node dissection was enrolled. The age range was 27-82 yr (median, 62 yr). Node positivity increased according to tumor staging. Patients were divided into the following two groups based on pathologic analysis: organ-confined disease group (n=135) and extravesical/lymph node-positive disease group (n=80). Pelvic failures (PF) were observed in 8 (4.9%) in organ-confined disease group, and 21 (21.7%) in extravesical/lymph node-positive disease group. Five-year PF-free survival rates were 91.2% in organ-confined disease group and 68.0% in extravesical/lymph node-positive disease group. Five-year cancer-specific survival rates were 86.2% in organ-confined disease group and 53.9% in extravesical/lymph node-positive disease group. In conclusion, a relatively high PF rate was observed in extravesical lymph node-negative and lymph node-positive disease patients in this study. Adjuvant pelvic RT may be considered to reduce pelvic failures in extravesical lymph node-positive bladder cancer. Future prospective trials are required to test the clinical benefit of adjuvant RT

    Regulating the surface of anion-doped TiO2 nanorods by hydrogen annealing for superior photoelectrochemical water oxidation

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    Dedications to achieve the highly efficient metal oxide semiconductor for the photoelectrochemical water splitting system have been persisted to utilize the TiO2 as the promising photoanode material. Herein, we report notable progress for nanostructured TiO2 photoanodes using facile sequential one-pot hydrothermal synthesis and annealing in hydrogen. A photocurrent density of 3.04 mA·cm−2 at 1.23 V vs. reversible hydrogen electrode was achieved in TiO2 nanorod arrays annealed in hydrogen ambient, which is approximately 4.25 times higher than that of pristine TiO2 annealed in ambient air. 79.2% of incident photon-to-current efficiency at 380 nm wavelength demonstrates the prominence of the material at the near-UV spectral range region and 100 h chronoamperometric test exhibits the stability of the photoanode. Detailed studies regarding crystallinity, bandgap, and elemental analysis provide the importance of the optimized annealing condition for the TiO2-based photoanodes. Water contact angle measurement displays the effect of hydrogen annealing on the hydrophilicity of the material. This study clearly demonstrates the marked improvement using the optimized hydrogen annealing, providing the promising methodologies for eco-friendly mass production of water splitting photoelectrodes.The authors gratefully acknowledge the fnancial support from the Creative, Material Discovery Program (2016M3D1A1027666, 2017M3D1A1040834, 2018M3D1A1058793) through the National Research Foundation of Korea funded by Ministry of Science and ICT, the Basic Research Laboratory Program through an NRF grant funded by the Korean Ministry of Science, ICT and Future Planning (2021R1A4A302787811), the KRISS (Korea Research Institute of Standards and Science) MPI Lab. Program and the National Research Foundation of Korea (NRF) grant funded by the Korea Government MSIT (2021R1C1C2006142), and Nuclear Energy R&D Program(2020M2D8A206983012). The Inter-University Semiconductor Research Center and Institute of Engineering Research at Seoul National University provided research facilities for this work

    Direct Synthesis of Molybdenum Phosphide Nanorods on Silicon Using Graphene at the Heterointerface for Efficient Photoelectrochemical Water Reduction

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    MoP nanorod-array catalysts were directly synthesized on graphene passivated silicon photocathodes without secondary phase. Mo-O-C covalent bondings and energy band bending at heterointerfaces facilitate the electron transfer to the reaction sites. Numerous catalytic sites and drastically enhanced anti-reflectance of MoP nanorods contribute to the high solar energy conversion efficiency. Abstract Transition metal phosphides (TMPs) and transition metal dichalcogenides (TMDs) have been widely investigated as photoelectrochemical (PEC) catalysts for hydrogen evolution reaction (HER). Using high-temperature processes to get crystallized compounds with large-area uniformity, it is still challenging to directly synthesize these catalysts on silicon photocathodes due to chemical incompatibility at the heterointerface. Here, a graphene interlayer is applied between p-Si and MoP nanorods to enable fully engineered interfaces without forming a metallic secondary compound that absorbs a parasitic light and provides an inefficient electron path for hydrogen evolution. Furthermore, the graphene facilitates the photogenerated electrons to rapidly transfer by creating Mo-O-C covalent bondings and energetically favorable band bending. With a bridging role of graphene, numerous active sites and anti-reflectance of MoP nanorods lead to significantly improved PEC-HER performance with a high photocurrent density of 21.8 mA cm−2 at 0 V versus RHE and high stability. Besides, low dependence on pH and temperature is observed with MoP nanorods incorporated photocathodes, which is desirable for practical use as a part of PEC cells. These results indicate that the direct synthesis of TMPs and TMDs enabled by graphene interlayer is a new promising way to fabricate Si-based photocathodes with high-quality interfaces and superior HER performance. Graphic Abstrac

    Universal field-tunable terahertz emission by ultrafast photoinduced demagnetization in Fe, Ni, and Co ferromagnetic films

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    We report a universal terahertz (THz) emission behavior from simple Ni, Fe, and Co metallic ferromagnetic films, triggered by the femtosecond laser pulse and subsequent photoinduced demagnetization on an ultrafast time scale. THz emission behavior in ferromagnetic films is found to be consistent with initial magnetization states controlled by external fields, where the hysteresis of the maximal THz emission signal is observed to be well-matched with the magnetic hysteresis curve. It is experimentally demonstrated that the ultrafast THz emission by the photoinduced demagnetization is controllable in a simple way by external fields as well as pump fluences. © 2020, The Author(s).1
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