Real-time output voltage control method of quasi-ZCS seriesresonant HF-linked DC-AC converter

This paper proposes a real-time control method of a series resonant high-frequency linked DC-AC converter employing quasi-zero current switching (quasi-ZCS) and a feedback control method for sinusoidal output voltage. An approximate analysis of the converter is performed, and then simplified equations and an equivalent circuit similar to the conventional PWM inverters/inverters are obtained. A real-time feedback control of the converter is realized using the equivalent circuit without detecting HF link current. The usefulness of the proposed control algorithm is confirmed by experimental results     

Highly specific enzyme immunoassay for human chorionic gonadotropin

A highly specific enzyme immunoassay for determining hCG was established by using beta-D-galactosidase as label. In order to increase the specificity of the assay, an antiserum against whole hCG was purified on a column of hCG beta carboxyl-terminal peptide (residues 123-145) covalently linked to Sepharose 4B. The antibody (N101S) thus prepared showed a weak cross-reactivity with human LH in an assay using hCG-enzyme conjugate, but the slight cross-reactivity was virtually avoided when an hCG beta carboxyl-terminal peptide was used as a peptide in the enzyme conjugate. N101S antibody was compared with antiserum (B1B) directed against a carboxyl-terminal peptide (123-145). In hCG measurement N101S gave about 30 times higher sensitivity than B1B, although the former antibody was less sensitive to carboxyl-terminal peptides of hCG beta. The enzyme immunoassay using a combination of N101S antibody and a carboxyl-terminal peptide (130-145)-enzyme conjugate was able to detect as little as 0.25 mIU of hCG without the interference of LH. The performance and validity of this assay were comparable to those of conventional radioimmunoassay.     

Traditional Japanese architecture blends beauty and rationale[lessons for software engineering]

It's hard to find a good instance of harmonization of beauty and rationale in the field of software engineering. We can, however, find it in ancient Japanese architecture which is where we might find the clues we need to achieve our goal. Unfortunately, the software community is relatively young, so there are few such secrets or literatures to use as a basis for our communications. Moreover, because the structure of software is not obvious yet architectural structures are clearly visible-the difficulty we face might be larger and deeper than that of other disciplinary fields. However, by carefully examining ancient architectural methods, we believe that we are stepping in the right direction in our pursuit of the patterns that will realize the harmony of beauty and rationale     

Noncontact Operational Modal Analysis of Structural Members by Laser Doppler Vibrometer

Abstract:   A system that uses ambient vibration and two laser Doppler vibrometer (LDV) is developed for noncontact operational modal analysis of structural members. The system employs natural excitation technique (NExT) to generate the cross-correlation functions from laser signals, and the eigensystem realization algorithm (ERA) to identify modal parameters of structural members. To facilitate simultaneous modal identification, time-synchronization technique and construction of cross-correlation functions from ambient response of laser signals are proposed. Performance of the proposed system is verified experimentally by evaluating the consistency and accuracy of identification results in different measurement conditions. The work presented here is an extension of the previous study, where a modal-based damage detection method using LDV was formulated. In the present study, application of LDV for structural parameters identification of a combined dynamical system is proposed. A model that represents the connection properties in terms of additional stiffness and damping is developed, and its importance for structural damage detection is discussed. The study shows that the presence of simulated damage in a steel connection can be detected by tracking the modal phase difference and by quantifying the additional stiffness and damping .     

Damage Analysis of Hanshin Expressway Viaducts during 1995 Kobe Earthquake. III: Three-Span Continuous Girder Bridges

Almost all the single reinforced concrete (RC) piers from P35 to P350 received consistently severe damage, considering the large residual inclination of piers included in earthquake-induced severe damage. However, some of the piers in the section from P35 to P350 remained lightly damaged, and this phenomenon is observed especially in many piers under fixed bearings in continuous girder bridges. In this study, using experimentally based models for metal bearings and installing them to an existing FEM code, a nonlinear dynamic response analysis of a continuous girder bridge system is conducted. It is shown that the results depend on the ground motion, but the fuse effect of the breaking of the bearings could have been a reason for the phenomenon.     

Graded glass coatings for Co-Cr implant alloys

A graded glass coating for Vitallium®, a Co-Cr alloy, has been prepared using a simple enameling technique. The composition of the glasses has been tailored to match the thermal expansion of the alloys. The optimum glass composition and firing conditions (temperature and time) needed to fabricate homogeneous coatings with good adhesion to the alloy were determined. The final coating thickness ranged between 25 and 60 μm. Coatings fired under optimum conditions do not delaminate during indentation tests of adhesion. Excellent adhesion to the alloy has been achieved through the formation of 100 nm thick interfacial chromium-oxide (CrOx) layers. The graded glass (consisting of BIG and 6P50 layers) can be successfully coated to a Co-Cr alloy, and forms hydroxyapatite (HA) on the coating surface when immersed in a simulated body fluid (SBF) for 30 days.     

Enhancement of low density lipoprotein binding to both low density lipoprotein receptor-positive and- negative cells by tetracycline antibiotics

Some tetracycline (TC) antibiotics, including TC and anhydrotetracycline, have been found to enhance specific binding of low density lipoprotein (LDL) to both LDL receptor-positive and-negative cells at relatively higher concentrations. When incubated at 37°C, the ability of LDL receptor-negative human fibroblasts to bind ¹²⁵I-LDL was increased from<2 to 45 ng/mg by 170 μM TC. In normal human fibroblasts and Hep G2 cells, ¹²⁵I-LDL binding was elevated 1.4- to 2-fold by 113 μM TC. The ¹²⁵I-LDL binding in the presence of TC was diminished by both heparin and EDTA. The enhancement by TC was not observed when ¹²⁵I-LDL binding was assayed at 4°C. TC enhanced LDL binding to paraformaldehyde-fixed Hep G2 cells, excluding LDL receptor induction in the mechanism. These results demonstrated that TC enhanced cellular LDL binding through a process not involving functional LDL receptors.     

An attempt to add biological functions by genetic engineering in order to produce high-performance bioreactor cells for hybrid artificial liver: transfection of glutamine synthetase into Chinese hamster ovary (CHO) cell

Ureteral triplication is a rare congenital anomaly of the upper urinary tract. It is reported to be associated with an increased incidence of congenital anomalies as well as a predisposition to infection and calculus formation. We report a case of type 1 variant of ureteral triplication associated with vesicoureteral reflux into lower and mid pole ureters in a solitary kidney. To our knowledge ureteral triplication in a solitary kidney has not been described previously.     

Study of Passive Deck-Flaps Flutter Control System on Full Bridge Model. I: Theory

A passive aerodynamic control method for suppression of the wind-induced instabilities of a very long span bridge is presented in this paper. The control system consists of additional control flaps attached to the edges of the bridge deck. Control flap rotations are governed by prestressed springs and additional cables spanned between the control flaps and an auxiliary transverse beam supported by the main cables of the bridge. The rotational movement of the flaps is used to modify the aerodynamic forces acting on the deck and provides aerodynamic forces on the flaps used to stabilize the bridge. A time-domain formulation of self-excited forces for the whole three-dimensional suspension bridge model is obtained through a rational function approximation of the generalized Theodorsen function and implemented in the FEM formulation. This paper lays the theoretical groundwork for the one that follows.