An analysis model of plasma flow and electromagnetic waves around a reentry vehicle for radio frequency blackout prediction during aerodynamic heating was developed in this study. The model was ...validated based on experimental results from the radio attenuation measurement program. The plasma flow properties, such as electron number density, in the shock layer and wake region were obtained using a newly developed unstructured grid solver that incorporated real gas effect models and could treat thermochemically non-equilibrium flow. To predict the electromagnetic waves in plasma, a frequency-dependent finite-difference time-domain method was used. Moreover, the complicated behaviour of electromagnetic waves in the plasma layer during atmospheric reentry was clarified at several altitudes. The prediction performance of the combined model was evaluated with profiles and peak values of the electron number density in the plasma layer. In addition, to validate the models, the signal losses measured during communication with the reentry vehicle were directly compared with the predicted results. Based on the study, it was suggested that the present analysis model accurately predicts the radio frequency blackout and plasma attenuation of electromagnetic waves in plasma in communication.
The objective of this paper is to clarify the influence of the structural characteristics of organizations in Japanese enterprises on market-oriented behavior, starting from a study to grasp the ...market orientation of organizations represented by Kohli and Jaworski (1990) from the behavioral perspective. This paper focuses on the centrality of the influence of marketing decision-making, formulation of strategy, and task conflict among departments as precedent factors affecting market-oriented behavior, which are strongly related to management of marketing strategies. The paper takes an empirical approach using structural equation modeling based on a survey of marketers in the Japanese manufacturing industry on how the combination of preceding factors affect each other, after segmenting the process of market-oriented behavior into the generation and diffusion of market information and the reaction. The results showed that (1) the market-oriented behavior process does not persist as a seamless process, and (2) it is difficult to design an optimal organizational structure that satisfies all conditions in improving market-oriented behavior, and it is necessary to adjust the organizational structure according to the situation.
This study aimed to analyze long- and short-term longitudinal data sets (first wave N＝1,448 and 91, respectively) to identify profiles of change in depression during adolescence and adulthood using a ...group-based trajectory approach and investigate the extent to which two personality traits (Behavioral Activation and Inhibition Systems; BAS and BIS) measured at the first wave predicted these trajectories. Three distinct trajectories, low, moderate, and high depression, were identified via group-based trajectory modeling . Multinomial regression analysis revealed that the two personality traits contributed to the development of depression, with lower BAS and higher BIS sensitivity leading to greater levels of depression in both longitudinal data sets. These results indicate that there is heterogeneity in longitudinal profiles of change in depression and that personality traits are predictive of the patterns in the development of depression. These findings may facilitate the early identification of those at greater risk of following the higher-depression trajectory.
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A catalytic system for regioselective C–H azidation of inactive anilines was developed. In the presence of CuSO4·5H2O, simultaneous addition of NaN3 and Na2S2O8 to aq. CH3CN solution of free anilines ...under weakly acidic conditions (pH 4.5) smoothly underwent C–H azidation to provide corresponding α-azidated products in high yields. Methyl α-azidoanthranilate obtained by this method was readily transformed via simple reduction followed by cyclization to methyl 2-ethoxybenzimidazol-7-carboxylate, a key intermediate for antihypertensive Candesartan Cilexetil.
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The Finkelstein reaction of organic halides was found to proceed smoothly in non-polar organic solvents other than acetone when operated in the presence of a catalytic amount of tetra-n-butylammonium ...bromide and water. The new protocol was successfully applied to a preparation of ethyl 5-iodopentanoate from the corresponding bromide which was used directly for zinc reagent formation and Fukuyama coupling to enable the formation of the (+)-biotin side chain in a streamlined manner. Rate acceleration by microwave irradiation and an application to the synthesis of trimethylsilyl iodide will be described as well.
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An expedient synthesis of a key intermediate for (+)-biotin has been accomplished through high-yielding reduction of chiral imide with calcium borohydride and efficient isolation of the desired ...isomer by crystallization at a specific temperature where only undesired isomer was converted to soluble anhydrate while the desired isomer kept unchanged as a less soluble monohydrate.
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Abstract
The reentry blackout phenomenon, which is the communication cut-off between the re-entry vehicle and ground station, is a crucial problem that needs to be addressed. To improve safety during ...reentry, a new mitigation method was proposed using the surface catalysis effect. However, this method has not been investigated extensively by experimental methods. In this study, we experimentally demonstrated the mitigation method using a 1 MW arc-heated wind tunnel and numerically clarified the mitigation mechanism. As a demonstration experiment, communication tests were conducted to compare the two cases. In the first case, a ceramic surface was used as a low catalytic wall, whereas in the second case, a copper surface was used as a high catalytic wall in the arc-heated wind tunnel. The experimental results indicated that the blackout occurred when alumina was used as the low catalytic wall. On the other hand, for the high catalytic wall using copper, blackout was avoided. The tests were reproduced in the wind tunnel using a numerical simulation technique. From the simulation results, the mitigation mechanism suggested that: (a) the number of nitrogen and oxygen atoms decreased due to catalysis; (b) forward reactions of electron impact ionization were suppressed due to the decrease in the number of atoms; and (c) the suppression of reactions decreased the number of electrons, thereby mitigating the reentry blackout. In addition, the numerical simulations performed on the reentry plasma around the re-entry capsule suggested that the mitigation mechanisms between the arc-heated wind flow and reentry plasma were similar despite the different airflow conditions.
Intracranial carotid artery dissection causing cerebral ischemia is a rare but important cause of cerebral infarction in children and adolescents. Although endovascular therapy has been reported to ...be effective, questions regarding the indications for intervention are yet to be addressed. Therefore, this study aimed to evaluate factors related to clinical outcomes through a nationwide survey. Overall, 35 neurosurgical centers reported patients within 2 weeks after ischemic onset due to intracranial carotid artery dissection causing cerebral ischemia treated between January 2015 and December 2020. Data on clinical and radiological findings were statistically analyzed. Twenty-eight patients met the inclusion criteria. The median age was 36 years (range, 7-59 years), without sex differences. Headache at onset was documented in 60.7% of the patients. Dissection findings were categorized into stenosis (71.4%) or occlusion (28.6%). Initial treatments, including various antithrombotic agent combinations in 23 (82.1%) patients, effectively improved or prevented aggravation in half of the patients. The patients with stenotic dissection were significantly more likely to experience aggravation during the initial treatment than did those with occlusive dissection (P = 0.03). In addition, the patients with moderate to severe neurological deficits on admission had poorer outcomes at discharge more frequently than did those with mild neurological deficits on admission. Eight patients undergoing endovascular therapy had no procedural complications or further aggravation after intervention. In conclusion, patients with intracranial carotid dissection causing cerebral ischemia who had a stenotic dissection were at risk of further aggravation, and endovascular therapy effectively improved or prevented aggravation.
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