Constrained neural network learning algorithm for estimating advertising effectiveness

This paper proposes a neural network algorithm for estimating advertising effectiveness. The basic premise under this algorithm is that the relationship between input and output monotonically increases. The algorithm is useful for domains such as estimation of advertising effectiveness, for which only deficient data are available. The experimental simulation shows that the algorithm builds a reasonable model for estimating advertising effectiveness. © 1998 Scripta Techinca, Electr Eng Jpn, 126(1): 34–41, 1999     

Rotor oscillation damping of a stepping motor by sliding mode control

Stepping motors are used mainly in OA and FA systems due to the merits of their digital driving behavior using switching devices. They are driven by closed‐loop control in systems where special performance such as prevention of out‐of‐synchronism or a high‐speed drive is required. It is well known that rotor oscillation is one of the principal problems in the switched drive of a stepping motor, and nowadays several methods for damping this oscillation have been suggested in which the switching sequence is changed in some manner. In such methods, the excitation time of the stator windings must be tuned appropriately, or the effect of damping is insufficient and oscillation may be even amplified in some circumstances. To resolve this problem, adaptive methods for tuning of the excitation time have been developed. However, they suffer the disadvantage that they require a tuning period for the excitation time to attain the optimal value at the beginning of control or when the machine parameters are varied by changing the driving condition. The authors have developed a new method for rotor oscillation damping of a stepping motor in a closed‐loop system. It is based on a sliding mode control technique and is designed to be robust to variation of rotor inertia which significantly affects the oscillatory characteristic. In this method, a lower‐order dynamical model, obtained by reaching a sliding mode where the angle‐torque characteristic of the motor is bound to a certain linear function, is made non‐oscillatory by pole assignment over a certain region of varying rotor inertia. Applying this method to an experimental system, rotor oscillation is damped excellently in the cases of single‐step and low‐speed multi‐step drive. On the other hand, it is shown deceleration is needed near the last step in the case of a high‐speed drive. © 1998 Scripta Technica, Electr Eng Jpn, 126(1): 42–51, 1999     

Fracture behaviour and numerical study of resistance spot welded joints in high-strength steel sheet

Cross tension tests of resistance spot welded joints with varying nugget diameter were carried out using 980 MPa high strength steel sheet of 1.6 mm thickness. In proportion, as nugget diameter increased from 3√t to 5√t (where t is thickness), cross tension strength (CTS) increased while fracture morphology simultaneously transferred from interface fracture to full plug fracture. In cases of interface fracture, circumferential crack initiation due to separation of the corona bond arose at an early stage of loading. The crack opening process without propagation was recognized until just before fracture and then the crack propagated to the nugget immediately in a brittle manner around CTS. In full plug fracture, main ductile crack initiation from the notch-like part at the end of sheet separation occurred with the sub-crack initiated at an early stage. The ductile crack propagated toward the HAZ and base material to form full plug fracture. The mode I stress intensity factor was considered as a suitable fracture parameter because the circumferential crack behaved pre-crack for brittle fracture in the nugget region at the final stage. Based on the FE analysis, the mode I stress intensity factor was calculated as 116 MPa √m at CTS as fracture toughness for the nugget. With respect to full plug fracture, ductile crack initiation behaviour from the notch-like part was expressed by concentration of equivalent plastic strain. On the assumption that the ductile crack arose in critical value of equivalent plastic strain, the value was calculated as 0.34 by FE analysis. Reasonable interpretation for interface fracture and full plug fracture in the resistance spot welded joint was proposed due to first crack initiation by stress concentration, brittle fracture by using mode I stress intensity factor, and ductile crack initiation by using equivalent plastic strain.     

Preparation of Fe-based monodisperse spherical particles with fully glassy phase

In this study, we prepared monodisperse spherical particles of a desired diameter using [(Fe_0.5Co_0.5)_0.75B_0.2Si_0.05]₉₆Nb₄ alloy; the particles were prepared by using an atomization process developed by us. The particles have perfect sphericity and narrow size distribution along with a homogeneous composition. The phase transitions of particles from the fully glassy phase to the crystalline phase via mixed phase structures occurred as the particle diameter was increased; the particles produced in the fully glassy phase in an argon atmosphere had a diameter of less than 300 μm. This allowed the estimation of the intrinsic critical cooling rate for the particles with a fully glassy phase, R_c:R_c varied in the range of 700-900 K/s and depended only on the initial temperature of the alloy melt.     

Formation of Small-Sized CdSxSe1-x Crystals in Sol-Gel-Derived SiO2 Glasses

Silica glasses doped with small-sized CdS_x-Se_1-x crystals were prepared by the sol-gel method. Gels synthesized by the hydrolysis of Si(OC₂H₅)₄, in the presence of CdSeO₄ with NH₄SCN dissolved in HNO₃ or NH₄OH, were heated in H₂-N₂ atmosphere. The pH value of solutions for CdSeO⁴ and NH⁴SCN primarily determined the fraction of anions in CdS^xSe^1-x crystals. The anion content in crystals was dependent on the pH value of the solvent and/or heat-treatment temperature, and the sulfur fraction changed from 0.1 to 0.6. The optical absorption spectra were red-shifted as the selenium content and the crystal size increased, and the emission spectra showed a sharp band near the absorption edge position and a broad tail extending into the long wavelength. The optical band gap energies increased reciprocally proportional to the square of the crystal size.     

Photooxidative degradation of polyethylene containing flame retardants by monochromatic light

Photodegradation of incombustible polymer materials [high-density (HD) and low-density (LD) polyethylene (PE) containing 0.5 to 2.0 phr of decabromodiphenyl ether (DBDE) or tetrabromobisphenol A (TBA) as a flame retardant] were studied using an Okazaki Large Spectrograph (OLS). Samples were irradiated in air at 23°C with monochromatic light of wavelengths at 260, 280, 300, 320, 340, and 360 nm. Ultraviolet and Fourier transform infrared (FTIR) spectra were taken to estimate the chemical changes caused by photoirradiation. Molecular weight change was followed by gel permeation chromatography (GPC) measurements. It was found that the photostability of PE samples was reduced by the addition of flame retardants. The threshold wavelengths of photodegradation are 320 nm and 360 nm for PE–TBA samples and PE–DBDE samples, respectively. Main-chain scission is favored when the irradiation was carried out with the light of wavelength 300 nm for HDPE–DBDE and HDPE–TBA samples. The most effective irradiation wavelengths for crosslinking are found to be 300 nm and 280 nm for LDPE–DBDE and LDPE–TBA samples, respectively. 1995 John Wiley & Sons, Inc.     

Solid-state characterization of polyethylene reactor powders and their structural changes upon annealing

Polyethylene reactor powders prepared under different conditions were characterized using transmission electron microscopy, ¹H nuclear magnetic resonance and X-ray diffraction techniques. The molecular weight of the polyethylene reactor powders was around 1 × 10⁵. A unique domain morphology, quite different from the usual melt- or solution-crystallized lamellar structure, was observed, independent of polymerization temperature (T_poly). Annealing of reactor powders caused the aggregation of these crystalline domains, due to the significant molecular motion of the amorphous chains, before melting. The critical temperature was 20 °C higher than each T_poly, and corresponded to the temperature at the active catalyst site producing the chain growth. The morphologies of powders prepared at the lower T_poly contained smaller crystals that exhibited a constrained monoclinic form. In contrast, only usual orthorhombic crystals of larger size were found within the powder prepared at the higher T_poly. These results suggest that the competitive processes of chain propagation and crystal growth upon polymerization may lead to unique variations of the crystalline and amorphous phases, but with similar intermediate components in the phase that connects them.     

Postnatal changes in activation of polyunsaturated fatty acid,acylation of lysophosphoglyceride,and phosphorylation of diacylglycerol in cortical gray matter of rat cerebrum

Activation of polyunsaturated fatty acid, acylation of lysophosphoglyceride, and phosphorylation of diacylglycerol in postnatal developing rat cerebrum were studiedin vitro, using cortical gray matter homogenates. The rate of n-3 and n-6 fatty acid activation was maximal at ten days after birth and minimal at adulthood. Acylation of lysophosphoglyceride was most active at the neonatal stage and gradually decreased with age. In addition, the amount of phosphatidic acid formed from 1, 2-dioleoyl-glycerol was also maximum at the neonatal stage, and then gradually decreased. These results suggest that the specific activity of glycerolipid synthesis in cortical gray matter declines during postnatal development.     

Specific hybrid liposomes composed of phosphatidylcholine and polyoxyethylenealkyl ether with markedly enhanced inhibitory effects on the growth of tumor cells in vitro

The hybrid liposomes (90mol% DMPC/10mol% C12(EO)8 and 90mol% DMPC/10mol% C12(EO)12) have a highly inhibitory action against the growth of tumor cells. The uniform and stable structure of the hybrid liposomes was revealed on the basis of electron microscopy and dynamic light scattering measurements.     

Preferential selection of specific rotavirus gene segments in coinfection and multiple passages with reassortant viruses and their parental strain

INTRODUCTION: The size of current implantable cardioverter defibrillators (ICD) is still large in comparison to pacemakers and thus not convenient for pectoral implantation. One way to reduce ICD size is to defibrillate with smaller capacitors. A trade-off exists, however, since smaller capacitors may generate a lower maximum energy output. METHODS AND RESULTS: In a prospective randomized cross-over study, the step-down defibrillation threshold (DFT) of an experimental 90-microF biphasic waveform was compared to a standard 125-microF biphasic waveform. The 90-microF capacitor delivered the same energy faster and with a higher peak voltage but provided only a maximum energy output of 20 instead of 34 J. DFTs were determined intraoperatively in 30 patients randomized to receive either an endocardial (n = 15) or an endocardial-subcutaneous array (n = 15) defibrillation lead system. Independent of the lead system used, energy requirements did not differ at DFT for the experimental and the standard waveforms (10.3 +/- 4.1 and 9.5 +/- 4.9 J, respectively), but peak voltages were higher for the experimental waveform than for the standard waveform (411 +/- 80 and 325 +/- 81 V, respectively). For the experimental waveform the DFT w as 10 J or less using an endocardial lead-alone system in 10 (67%) of 15 patients and in 12 (80%) of 15 patients using an endocardial-subcutaneous array lead system. CONCLUSIONS: A shorter duration waveform delivered by smaller capacitors does not increase defibrillation energy requirements and might reduce device size. However, the smaller capacitance reduces the maximum energy output. If a 10-J safety margin between DFT and maximum energy output of the ICD is required, only a subgroup of patients will benefit from 90-microF ICDs with DFTs feasible using current defibrillation lead systems.