Development of a Nanostructual Microwave Probe Based on GaAs

With the development of nanotechnology, the measurement of electrical properties in local area of materials and devices has become a great need. Although a lot kind of scanning probe microscope have been developed for satisfying the requirement of nanotechnology, a microscope technique which can determine electrical properties in local area of materials and devices is not yet developed. Recently, microwave microscope has been an interest to many researchers, due to its potential in the evaluation of electrical properties of materials and devices. The advance of microwave is that the response of materials is directly relative to the electromagnetic properties of materials. However, because of the problem of the structure of probes, nanometer-scale resolution has not been successful. To achieve the goal, a new structure microwave probe is required. In this paper, we report a nanostructural microwave probe. To restrain the attenuation of microwave in the probe, GaAs was used as the substrate of the probe. To obtain the desired structure, wet etching was used to fabricate the probe. Different with the dry etching, a side-etching will occur under the etching mask. Utilizing this property, a micro tip can be fabricated by etching a wafer, of which a small mask was introduced on the surface in advance.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing

A Nanostructual Microwave Probe Used for Atomic Force Microscope

In order to develop a new structure microwave probe, the fabrication of AFM probe on the GaAs wafer was studied. A waveguide was introduced by evaporating Au film on the top and bottom surfaces of the GaAs AFM probe. A tip having 8 μm high, and curvature radius about 50 nm was formed. The dimensions of the cantilever are 250×30×15 μm. The open structure of the waveguide at the tip of the probe was introduced by using FIB fabrication. AFM topography of a grating sample was measured by using the fabricated GaAs microwave probe. The fabricated probe was found having nanometer scale resolution, and microwave emission was detected successfully at the tip of the probe by approaching Cr-V steel and Au wire samples

Thermoluminescence studies of ordinary chondrites in the Japanese Antarctic meteorite collection, II: New measurements for thirty type 3 ordinary chondrites

We have measured the thermoluminescence (TL) properties of thirty type 3 ordinary chondrites from the Japanese Antarctic meteorite collection. This brings to 73 the total number of Japanese type 3 ordinary chondrites examined in this way by the Arkansas-Okayama collaboration. Fifteen pairing groups were found using TL and geographical criteria. Most of the new meteorites are of petrologic types 3.6-3.9,but fourteen are of petrologic type ≤3.4. Six of the 73 meteorites (Yamato (Y)-790448,Y-793596,Y-793565,Y-791324,Y-791558,Y-74660) have petrographic types 3.5) tend to have higher induced TL peak temperature and peak width than those with low TL sensitivity, in confirmation of earlier work and consistent with peak temperature and width as well as TL sensitivity, being independent parameters of thermal history. Samples not obeying these trends (Y-75029,Y-86706,Y-793567 and Y-790787), are either heavily weathered or experienced atypical thermal histories

Search for Λ6^6_\LambdaH hypernucleus by the 6^6Li(π−,K+)(\pi^-,K^+) reaction at pπ−p_{\pi^-} = 1.2 GeV/cc

We have carried out an experiment to search for a neutron-rich hypernucleus, $^6_{\Lambda}$H, by the $^6$Li($\pi^-,K^+$) reaction at $p_{\pi^-}$ =1.2 GeV/$c$. The obtained missing mass spectrum with an estimated energy resolution of 3.2 MeV (FWHM) showed no peak structure corresponding to the $^6_{\Lambda}$H hypernucleus neither below nor above the $^4_{\Lambda}$H$+2n$ particle decay threshold. An upper limit of the production cross section for the bound $^6_{\Lambda}$H hypernucleus was estimated to be 1.2 nb/sr at 90% confidence level.Comment: 6 pages, 5 figures, published versio

Predictor for Histological Microvascular Invasion of Hepatocellular Carcinoma: A Lesson from 229 Consecutive Cases of Curative Liver Resection.

BACKGROUND: Microscopic vascular invasion is an important risk factor for recurrent hepatocellular carcinoma (HCC), even after curative liver resection or orthotopic liver transplantation. To predict microscopic portal venous invasion, the following two questions were examined retrospectively: Is it possible to detect microvascular invasion preoperatively? What are the characteristics of a group of early HCC recurrences even with no microvascular invasion? METHODS: Study 1 included 229 patients with HCC who underwent curative liver resection between 1991 and 2008; 127 had HCC without microscopic portal venous invasion, and 52 had HCC with microscopic portal venous invasion (MPVI). These two distinct groups were analyzed with regard to various clinicopathologic factors. Subsequently, we specifically investigated if HCCs 5 cm, the macroscopic appearance of HCC, and high levels of preoperative des-gamma-carboxyprothrombin are significant prognostic factors in identifying microvascular invasion of HCC. The strongest predictor of early recurrence (within 2 years) was the serum alpha-fetoprotein level in patients without clear microvascular invasion. CONCLUSIONS: Tumor size, macroscopic appearance, and high tumor marker levels are important elements in identifying the group of patients with a low HCC recurrence rate after curative liver resection

Effective balloon-occluded retrograde transvenous obliteration of the superior mesenteric vein?inferior vena cava shunt in a patient with hepatic encephalopathy after living donor liver transplantation

Balloon-occluded retrograde transvenous obliteration (BRTO) has become a common and effective procedure for treating hepatic encephalopathy due to a portosystemic shunt related to cirrhosis of the liver. However, this method of treatment has rarely been reported in patients after liver transplantation. Here, we report the case of a 52-year-old patient who underwent living donor liver transplantation (LDLT) due to hepatitis C virus-infected hepatocellular carcinoma that was complicated with portal vein thrombosis and a large portosystemic shunt between the superior mesenteric vein (SMV) and inferior vena cava (IVC). The SMV-IVC shunt was not obliterated during LDLT because there was sufficient portal flow into the graft after reperfusion. However, the patient was postoperatively complicated with encephalopathy due to the portosystemic shunt. BRTO was performed and was demonstrated to have effectively managed the encephalopathy due to the SMV-IVC shunt, while preserving the hepatic function after LDLT

Compressive stenosis of the inferior vena cava due to localized ascites after living-donor liver transplantation.

A 54-year-old woman was admitted to our hospital following the diagnosis of decompensated liver cirrhosis with hepatitis C. She underwent living-donor liver transplantation, performed using the left hepatic lobe with the middle hepatic vein donated by her husband. After the transplantation, the patient suffered from massive ascites with liver dysfunction. Computed tomography demonstrated stenosis of the suprahepatic inferior vena cava (IVC) with focal collection of fluid. A second laparotomy was performed 19 days after the transplantation. When the encapsulated localized ascites on both sides of the IVC was opened, the ascites was flushed away. Subsequently, the grafted liver was easily mobilized and it was placed in the natural position without any tension, and the pressure gradient of the IVC was improved. Herein, we report a very rare case of compression stenosis of the IVC resulting in Budd-Chiari syndrome caused by localized encapsulated ascites