Studies on the reliability of the polarcardiographic records (author's transl)

Reliability of the polarcardiogram obtained by the newly constructed polarcardiograph, in which the vector sum circuit applying absolute value operations were used for the computation of the magnitude curve, were examined in fifty normal subjects. There was no statistically significant difference between the means of the measured values of the polarcardiogram and of the corresponding polar components calculated from the three scalar ECG concerning all twenty items, namely spatial magnitude, magnitudes in each plane, each longitude and latitude at the time of the spatial maximum QRS and T vectors, except alpha-longitude. Highly significant positive correlations were observed between these two sets of values in all twenty items. Configurations of the pattern obtained by plotting the instantaneous polar components, which were calculated from the three scalar ECG, on the linear time scale were very similar with those of the polarcardiographic records. These findings showed that the records obtained by the newly constructed polarcardiograph were reliable.     

An X-ray photo-electron spectroscopic study of surface treatments of stainless steels

The effects of surface treatments on the surface composition and structure of Type 304 and 316 stainless steels were studied by X-ray photo-electron spectroscopy. The content of chromium and iron in the surface film depends considerably on the surface treatment method, while the nickel content in the film is significantly lowered compared to bulk composition regardless of the method. Some surface treatments which result in a significant enrichment of chromium in the surface film on the steels give the highest pitting potential. When the specimens were left for at least a day in contact with air, a certain amount of a magnetite-like compound was formed in the surface film. This fact is responsible for the ennoblement of the pitting potential by ageing after treatment.     

Effects of early cyclophosphamide treatment on lymphoid organs and its immune response in ducks

Cyclophosphamide treatment of newly hatched White Pekin ducks significantly reduced the weight of their lymphoid organs and almost completely eliminated the formation of bursal lymphoid follicles at one week of age. There after the thymus and spleen of these ducks completely recovered in weight at 7 weeks of age. The bursa, however, retained its light weight and morphological defects, such as the absence of lymphoid follicles. The specific antibody producing-capability to Salmonella pullorum was also eliminated. The total dosage of cyclophosphamide was smaller than that employed in chickens, which makes effective chemical bursectomy in ducks possible.     

Third-order nonlinear optical properties of sol-gel-derived V(2)O(5), Nb(2)O(5), and Ta(2)O(5) thin films

The third-order nonlinear optical properties of sol-gel-derived V(2)O(5), Nb(2)O(5), and Ta(2)O(5) thin films have been investigated by the third-harmonic-generation method, and the effect of the metal-oxygen bond length on the third-order nonlinear optical susceptibility χ((3)) has been examined. The χ((3)) values of V(2)O(5), Nb(2)O(5), and Ta(2)O(5) thin films were 1.1 × 10(-11), 1.3 × 10(-12), and 6.1 × 10(-13) esu, respectively, which corresponds to an increase in the average bond length I(b) of the order of V-O (I(b) = 0.183 nm), Nb-O (I(b) = 0.200 nm), and Ta-O (I(b) = 0.204 nm). The current and previous results indicate that χ((3)) of these transition metal oxides with the empty d orbitals is dominated mainly by the metal-oxygen bond length rather than the valence of the metal cation. It is predicted on the basis of Lines' model that transition metal oxides with the shortest I(b) exhibit the highest χ((3)), whereas nontransition metal oxides with the longest I(b) exhibit the highest χ((3)).     

Development of a pulse programmer for magnetic resonance imaging using a personal computer and a high-speed digital input-output board

We have developed a pulse programmer for magnetic resonance imaging (MRI) using a personal computer and a commercially available high-speed digital input-output board. The software for the pulse programmer was developed using C∕C++ and .NET Framework 2.0 running under the Windows 7 operating system. The pulse programmer was connected to a digital MRI transceiver using a 32-bit parallel interface, and 128-bit data (16 bits × 8 words) for the pulse sequence and the digitally detected MRI signal were transferred bi-directionally every 1 μs. The performance of the pulse programmer was evaluated using a 1.0 T permanent magnet MRI system. The acquired MR images demonstrated the usefulness of the pulse programmer. Although our pulse programmer was developed for a specially designed digital MRI transceiver, our approach can be used for any MRI system if the interface for the transceiver is properly designed. Therefore, we have concluded that our approach is promising for MRI pulse programmers.     

A tight approximation ratio of a list scheduling algorithm for a single-machine scheduling problem with a non-renewable resource

Journal of Scheduling - In this paper, we investigate an open problem by Györgyi and Kis for a single-machine scheduling problem with a non-renewable resource (NR-SSP) and total weighted...     

A Combinatorial Optimization Technique for the Sequential Decomposition of Erosions and Dilations

This paper presents a general algorithm for the automatic proof that an erosion (respectively, dilation) has a sequential decomposition or not. If the decomposition exists, an optimum decomposition is presented. The algorithm is based on a branch and bound search, with pruning strategies and bounds based on algebraic and geometrical properties deduced formally. This technique generalizes classical results as Zhuang and Haralick, Xu, and Park and Chin, with equivalent or improved performance. Finally, theoretical analysis of the proposed algorithm and experimental results are presented.     

Effect of reduction of slider pitch-mode vibration on magnetic-recording performance at low-clearance head–disk interface

Aiming at improvements of both stability of slider flying and magnetic-recording performance under a low-clearance condition, a “narrow-grooved slider” was constructed and demonstrated at drive level. The proposed slider has narrow grooves on its center pad of an air-bearing surface for attaining a high-damping effect on pitch-mode resonant vibration of the air bearing. The relationship between the high-damping effect and the pitch-mode resonant vibration was studied, and the magnetic-recording performance at the lube/slider interaction regime was improved. In this study, first, flying-height modulation (FHM) of the slider was analyzed in the frequency domain by using a fast Fourier transform. Compared with the narrow-grooved slider, a non-grooved slider showed a larger increase in high-frequency modulation of gap flying height when the clearance was reduced to near “zero” at which the slider is starting to interact with lube. Furthermore, by means of drive-level experiments, sector error rate (SER) as a function of flying clearance was investigated. Under a low gap flying height condition, HDDs with the non-grooved slider showed slight SER degradation during slider/lube interaction. However, the narrow-grooved slider did not show any SER degradation at the same gap flying height; the damping effect of the narrow-grooved slider suppressed high-frequency FHM, thereby preventing SER degradation in the slider/lube interaction region.