Local Hardening Evaluation of Carbon Steels by Using Frequency Sweeping Excitation and Spectrogram Method

We use steel materials for a car, an industrial machine, a building and so on. The steel materials are used for the main parts of the machine. The steel materials have good mechanical characteristics, however, higher mechanical characteristics by special treatment are often demanded. In this case, some evaluation methods are also required to monitor and control the mechanical characteristics of steel materials. Normally, mechanical destructive testing is used for the evaluation of them, however, all products on line cannot be evaluated because destructing samples are needed by mechanical testing. Therefore, non-destructive evaluation by electromagnetic method is focused on in this paper. We have developed a non-destructive evaluation for hardening steel named as a frequency sweep excitation and spectrogram (FSES) method [1]. This proposed method can evaluate mechanical characteristics non-destructively by using several frequency components of magnetic flux depending on hardening conditions [1]. Figure 1 shows the measured magnetic coercive force Hc and maximum magnetic field strength Hmax. The sample were hardened by induction heating with the current of 80[A]. As shown in Figure 1, in the 8 - 12 [mm] and 16 - 22 [mm] sections, the spectrogram of the maximum magnetic field strength Hmax was changed locally in comparison of the one of the magnetic coercive force Hc. It has been made clear that the magnetic coercive force Hc could evaluate the hardening strength qualitatively and quantitatively [1]. Moreover, it is obvious that the local material changes can be evaluated by the maximum magnetic field strength Hmax as shown in Figure 1

The Evaluation of Fatigue Caused by Plane-Bending Stress on Stainless Steel Using the Stacked-Coil Type Magnetic Sensor

To prevent an accident due to the metal degradation of stainless steels, we have previously proposed fatigue evaluation methods (such as the remnant magnetization method using a thin-film flux-gate magnetic sensor [1] and the inductance method using a pan-cake type coil [2]). These two fatigue evaluation methods demonstrated a good correlation between the magnetic sensor output signal and the amount of plane-bending fatigue damage in stainless steels. We developed a stacked-coil type magnetic sensor shown in Fig. 1(a) in order to achieve a magnetic sensor for an accurate fatigue evaluation. This magnetic sensor was composed of two detection coils that are connected differentially, an excitation coil, and a ferrite core. Fig. 1(b) shows the connection of the excitation coil and the two detection coils. Fig. 2 shows the detection result of fatigue and crack using this magnetic sensor. The material used for this specimen was an austenitic stainless steel (SUS304), and plane-bending stress was applied. From Fig. 2, it can be seen that this magnetic sensor detected defects well. The evaluation results of plane-bending fatigue damage distribution will be shown in in detail the complete paper

Structure of Musashi1 in a complex with target RNA: the role of aromatic stacking interactions

Mammalian Musashi1 (Msi1) is an RNA-binding protein that regulates the translation of target mRNAs, and participates in the maintenance of cell ‘stemness’ and tumorigenesis. Msi1 reportedly binds to the 3′-untranslated region of mRNA of Numb, which encodes Notch inhibitor, and impedes initiation of its translation by competing with eIF4G for PABP binding, resulting in triggering of Notch signaling. Here, the mechanism by which Msi1 recognizes the target RNA sequence using its Ribonucleoprotein (RNP)-type RNA-binding domains (RBDs), RBD1 and RBD2 has been revealed on identification of the minimal binding RNA for each RBD and determination of the three-dimensional structure of the RBD1:RNA complex. Unique interactions were found for the recognition of the target sequence by Msi1 RBD1: adenine is sandwiched by two phenylalanines and guanine is stacked on the tryptophan in the loop between β1 and α1. The minimal recognition sequences that we have defined for Msi1 RBD1 and RBD2 have actually been found in many Msi1 target mRNAs reported to date. The present study provides molecular clues for understanding the biology involving Musashi family proteins