Microfabrication of Three-Dimensional Structures in Polymer and Glass by Femtosecond Pulses

We report three-dimensional laser microfabrication, which enables microstructuring of materials on the scale of 0.2-1 micrometers. The two different types of microfabrication demonstrated and discussed in this work are based on holographic recording, and light-induced damage in transparent dielectric materials. Both techniques use nonlinear optical excitation of materials by ultrashort laser pulses (duration < 1 ps).Comment: This is a proceedings paper of bi-lateral Conf. (Republics of China & Lithuania) on Optoelectronics and Magnetic Materials, Taipei, May 25-26, 2002.

Viscoelastic and light scattering studies on thermally induced sol to gel phase transition in fish myosin solutions

Viscoelastic (VE) and dynamic light scattering (DLS) analyses of fish (white croaker) myosin solutions were performed at myosin concentrations of 30mg/ml for VE and 0.1mg/ml for DLS at 0.6 MKCl and pH 7.0 to clarify thermally induced gelation. The hydrodynamic radius Rh considerably decreased around 30-35oC. The shear modulus G was constant below 25oC and increased by incubating the sample at 30oC. G further increased as the temperature of the incubated sample decreased. The curves of G vs. T for different time courses showed a sharp peak around 35oC and a moderate peak around 60oC in the heating process, while a stepwise increase in G was observed around 30oC in the cooling process when the temperature was elevated to not more than 60oC. No distinct stepwise change was observed once the temperature of the sample exceeded 60oC. The absolute value of G strongly depended on the maximum elevated temperature and the incubation time at that temperature. The corresponding behavior of the viscosity h was observed for each time course. Based on these results, the mechanism of thermally induced gelation of myosin solutions is discussed in view of S-S bridge formation in the head and tail portions and unwinding/rewinding of coiled-coil a-helices in the tail portion

Role of additives for copper damascene electrodeposition experimental study on inhibition and acceleration effects

The role of copper Damascene additives is discussed based on electrodeposit morphology on a through-mask cathode, field emission-Auger (FE-Auger), quartz crystal microbalance (QCM), and electrochemical measurements. Adsorbed particles, several tens of nanometers in diameter were observed on copper-electrodeposited surfaces by field emission-scanning electron microscopy (FE-SEM). These particles show a stronger oxygen intensity peak by FE-Auger spectrum than bare electrodeposited surfaces. The QCM frequency deviation did not increase with time in the CuSO4 and H2SO4 bath without polyethylene glycol (PEG) and chloride ion (Cl-) additives. When the substrates were immersed in the bath with these additives, the deviation markedly increased with time. Numerous PEG molecules were observed by FE-SEM immersed after 1000 s. The current density remained constant at a low value for the bath with PEG and Cl- additives. The current density started to increase markedly with time just after adding 1 ppm of bis(3-sulfopropyl) disulfide (SPS). Numerous PEG molecules were present on the electrodeposits before adding SPS. No PEG molecules, however, remained on the surface once SPS was added to the bath. The current density increased with narrower opening widths of the through-mask cathode. Despite this increase, the deposit cross sections on narrower opening widths of 2 and 10 mum were flat and no curvatures were found. Hence, the deposit curvature is not the origin of the acceleration effect. (C) 2004 The Electrochemical Society.</p

A real-time hand segmentation method using background subtraction and color information

This paper presents a real-time hand segmentation method that is based on background subtraction and color information. A hand, as foreground, is extracted from an image by background subtraction where unit gradient vectors (UGVs) are used instead of image intensities. The UGV-based method is more stable under dynamic lighting conditions because the UGVs are invariant to changes in illumination. Meanwhile, the hand is also detected using color information. These two method results lead into the final hand segmentation. Experimental results show that the proposed method can segment a hand in an image robustly under various lighting conditions. We have implemented the proposed method using a low-cost embedded board Raspberry Pi

A drowsiness detection method based on displacement and gradient vectors

This paper presents a drowsiness detection method for drivers based on visual features in a video sequence. Image intensities are traditionally visual features. However, it is known that they are directly influenced by lighting conditions. We propose a human eye detection method using the normalized cross-correlation between displacement vectors and gradient vectors. Gradient vectors are dependent on lighting conditions but the normalization step makes them independent of illuminations. In this way, the proposed method can detect human eyes regardless of various lighting conditions. We have also found that normalized cross-correlation can be useful, not only for detecting eyes, but also for recognizing open and closed eye states. To overcome poor lighting conditions, we used infrared auxiliary illumination in order to make the proposed method work every moment. The computation speed of the proposed method is fast enough to perform at video rates

Clinical Application of Unidirectional Porous Hydroxyapatite to Bone Tumor Surgery and Other Orthopedic Surgery

Unidirectional porous hydroxyapatite (UDPHAp) was developed as a remarkable scaffold characterized by a distinct structure with unidirectional pores oriented in the horizontal direction and connected through interposes. We evaluated the radiographic changes, clinical outcomes, and complications following UDPHAp implantation for the treatment of bone tumors. Excellent bone formation within and around the implant was observed in all patients treated with intralesional resection and UDPHAp implantation for benign bone tumors. The absorption of UDPHAp and remodeling of the bone marrow space was observed in 45% of the patients at a mean of 17 months postoperatively and was significantly more common in younger patients. Preoperative cortical thinning was completely regenerated in 84% of patients at a mean of 10 months postoperatively. No complications related to the implanted UDPHAp were observed. In a pediatric patient with bone sarcoma, when the defect after fibular resection was filled with UDPHAp implants, radiography showed complete resorption of the implant and clear formation of cortex and marrow in the resected part of the fibula. The patient could walk well without crutches and participate in sports activities. UDPHAp is a useful bone graft substitute for the treatment of benign bone tumors, and the use of this material has a low complication rate. We also review and discuss the potential of UDPHAp as a bone graft substitute in the clinical setting of orthopedic surgery