Summary The temper embrittlement affecting the HAZ of 2 1/4Cr-1Mo steel subjected to SR treatment and subsequent reheating is investigated with synthetic HAZ specimens and compared with the embrittlement observed in specimens tempered in the same temperature range without SR treatment (direct tempering). The synthetic HAZ specimens are de-embrittled on application of suitable SR treatment (975 K × 5 hours). Subsequent reheating at 775 to 925 K, however, produces four different types of embrittlement in the specimens. These are the second, third, fourth, and fifth types of embrittlement already identified in the direct-tempered specimens. The first type of embrittlement which occurs during direct tempering in the shortest time range does not appear after SR treatment. The second type (the short-term type), which occurs over a wide time-temperature range during direct tempering, only appears in a narrow range after SR treatment. The third and fourth types (the long-term types) occur just as intensively as during direct tempering. The fifth type (the high-temperature type) also appears after SR treatment. This suggests that embrittlement in the short-term range is to some extent suppressed by SR treatment, but the types of embrittlement arising in the long-term range and high-temperature range occur after SR treatment as well. The ‘step cooling process’ can be applied for short-term detection of temper embrittlement in this steel. However, there is considered to be little or no embrittlement promotion effect due to step cooling per se.
This paper proposes a reference signal synchronization method for improving the performance of the maximum likelihood type synchronization method under the realistic environment accompanying frequency offset. In the proposed method, the search of correlation was carried out to not only the timing direction but also frequency offset direction. In this way, correlations were computed for time and frequency direction and two dimensional maximum correlation search has been done. In this way the reference signal synchronization has been achieved. Furthermore, a increase ratio of the computational complexity for the conventional method has been shown. We have made it clear that the increase is relatively small and this ratio decreases with increasing the number of antenna elements
Background: Reduced insulin secretion is linked to diabetes and cardiovascular disease (CVD), but its role in non-diabetic CVD patients is unclear. The homeostasis model assessment of β-cell function (HOMA-β) measures pancreatic β-cell function. This study investigated the association between HOMA-β and adverse cardiovascular events in non-diabetic CVD patients.
This paper focuses on an on-board computer (OBC) that evolves computer programs through bit inversion and targets analyzing robustness against bit inversion in registers. We also propose a new method that can change the number of computer programs dynamically. Intensive experiments revealed the following: (1) Correct programs can be maintained even in bit inversion in registers in addition to bit inversion in instructions. (2) Our proposal accelerates program evolution by increasing the population size, i.e., the number of programs, within fixed memory size.
In this paper, we propose a non-uniform subband adaptive filtering (SAF) method using a new objective. This objective uses the decrease in power in each subband error signal. Carrier frequencies, decimation rates (parameters in the analysis bank), lengths of each adaptive filter and FFT bin number are treated as time-varying parameters, and adjusted to ensure quick convergence of subbands with small power decrease, by sacrificing convergence of subbands in whose power decrease is large. The proposed method uses a delayless structure to avoid signal path delay. Simulation with colored noise shows that our method can achieve higher convergence rates and smaller MSE reductions than uniform SAF.
Unlike the basic adaptive array antenna (AAA) , a tapped delay line adaptive array antenna (TDL-AAA) is effective in mitigating interference from user signals or multipath waves which impinge on the array close to the direct wave. This is also useful for reducing the number of antenna elements under a multipath propagation environment. Furthermore, this adaptive antenna system is also effective for multi-input multi-output (MIMO) spatial multiplexing techniques under frequency selective fading channels. However, a method of designing the required number of antenna elements or tap stages has not been studied. We propose a design equation for TDL-AAA when a number of users and maximum delay time are given. We assume that multipath waves impinge on the array successively with symbol period interval and individual waves have a different direction of arrival (DoA). The influence of the roll-off factor of a cosine roll-off filter is also studied by computer simulation. Simulation results show that the proposed design equation is applicable in case of a roll-off factor of 1.0. On the other hand, simulation results of a roll-off factor of 0.5 show that one can determine the number of antenna elements.
In order to solve a problem of maximizing a directivity of a transmitting array antenna with nulls at specified directions, we intended to utilize an adaptive antenna algorithm which enables the SNR to be maximum under the incidence of interferences. However, we encountered the discrepancy between transmitting antenna patterns and receiving ones. We investigated why this discrepancy arises, although a reciprocity theorem is effective between the transmitting pattern and the receiving one. Through these investigations, we derived the equation which determines the matched load impedances of the array elements and solved it numerically up to five elements. We also derived an equation to evaluate output voltages which are summed up into an output of the array and confirmed the coincidence between the transmitting pattern and the receiving one.
