initial resistance
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Xiao-Fang Wang ◽  
Pao-An Lin ◽  
Xue-miao Wen ◽  
Bing-Yuh Lu ◽  
Tian-Le Li ◽  

Abstract This study examined the phase-change Ge12Sb88 films that are fabricated through radio-frequency reactive magnetron sputtering to substrates with varying thermal conductivity. The in situ resistance was measured, and X-ray diffraction was conducted to investigate the phase-change behavior of the films under adjustments to the heating and annealing temperature. Differences in the films’ band gaps were determined by a spectrometer. The results were as follows: (1) The initial resistance levels of the films on low-thermal-conductivity substrates were higher than those on high-thermal-conductivity substrates. Resistance ratios were in the range of 102 to 103. The substantial changes in resistance influenced the characteristics of accelerating switching time and reduced the power consumption of the investigated materials. (2) Because of the partial crystallization of the films, an additional phase transition (from FCC1 to FCC2) was observed among thin films on low-thermal-conductivity substrates. This phase transition can be leveraged in the development of data storage devices.

2021 ◽  
Alexandru Dascaliuc

Several morphological and functional mechanisms determine the resistance of plants to extreme temperatures. Depending on the specificity of mechanisms of action, we divided them into two groups: (1) the mechanisms that ensure the avoidance/reduction of the exposure dose; (2) functional mechanisms which increase plant resistance and ability to recover damages caused by stress through regulation metabolic and genes expression activity. We developed theoretical and practical methods to appreciate the contribution of parameters from both groups on the primary and adaptive resistance of different wheat genotypes. This problem became more complicated because some properties are epigenetically inherited and can influence genotypes’ primary (initial) resistance to stressors. The article describes results obtained by the accelerated determination of the initial resistance of wheat (Triticum aestivum L.) genotypes to temperature stress and the prospects for their implementation in the selection and development of methods for rational choosing wheat varieties for cultivation under specific environmental conditions.

Dimitri Anastasopoulos ◽  
Lysandros Anastasopoulos ◽  
Thomas Mergner

Normal subjects can completely eliminate resistance upon imposed head-on-trunk rotations when they are asked to relax. It is not, however, clear how neck reflexes to stretch can be voluntarily suppressed. Reflexive responses might be modified by adjusting the gain of the reflex loop through descending control. Theoretically, necessary corrections upon interfering disturbances during coordinated motor performace requiring the interplay of relaxation/activation may be missing if muscle relaxation is taking place exclusively by this mechanism. It has been alternatively proposed, that sensory information from the periphery may be allowed to "neutralize" neck reflexes if it is fed back with opposite sign to the structures driving the reflexes. Six healthy subjects were asked to relax while subjected to head-on-trunk rotations generated by a head motor. After any initial resistance had completely subsided, the head was unexpectedly exposed to "ramp-and-hold" perturbations of up to 2○ amplitude and 0.7 s duration. Resistance to stretch consistently reappeared thereupon suggesting that stretch reflex gain had not been set to zero during the previously achieved complete relaxation. Resistance to perturbations under these circumstaces was compared to the forces generated when the same "ramp-and-hold" displacements were delivered unpredictably to the head held stationary. A quantitative model of neck proprioceptive reflexes suppression has been thus constructed. Gain scheduling or "motor set" cannot sufficiently account for the voluntary reflex suppression during slow passive head rotations. Instead, we propose as underlying mechanism the "neutralization" of the controlling servo by means of continuous feedback tracking displacement and force signals from the periphery.

Hyunjoo Cho ◽  
Seungjun Chung ◽  
Jaewook Jeong

Abstract Stretchable electrodes with high stretching capability and low sheet resistance were developed using a metal/silver nanowires (AgNWs)/metal hybrid structure on a poly-dimethylsiloxane (PDMS) substrate. A low sheet resistance around 100 mΩ/square was achieved using the hybrid structures of Ag/AgNWs/Ag and Cu/AgNWs/Cu electrodes. The stretching capability under single and multi-cycling strain conditions was greatly improved due the AgNWs in-between top and bottom metal electrodes. The random connection of AgNWs generates new current path over the various cracks and wavy structures of the metal electrodes, which improve the initial resistance, the stretching capability of single strain up to 16 % and the resistance stability of 100 times cycling strain for the electrodes. Using a simple resistor model, it was shown that the hybrid structure is effective to improve the stretching capability of the stretchable metal electrodes due to random connection of AgNWs in-between the metal electrodes.

2021 ◽  
Vol 7 (3) ◽  
pp. 49-61
D. P. Zverev ◽  
A. A. Myasnikov ◽  
A. Yu. Shitov ◽  
A. N. Andrusenko ◽  
V. I. Chernov ◽  

Aim: using oral stress kidney tests to reveal changes in renal function and water-electrolyte metabolism in divers with different initial resistance to hypoxic hypoxia.Materials and methods. 44 men were studied. All subjects were evaluated for their initial resistance to hypoxic hypoxia. Oral renal stress tests were performed to determine the status of kidney function.Results and their discussion. For the selection of divers, it is necessary to carry out oral stress tests with water, 10% potassium chloride solution and 7.5% calcium lactate solution. In divers with low and medium resistance to hypoxic hypoxia, there is a deterioration in the calcium and potassium uretic function of the kidneys after oral stress renal tests. The method for determining the resistance of divers to hypoxic hypoxia should be supplemented by the regularity developed by us.

2021 ◽  
Masako Seki ◽  
Mitsuru Abe ◽  
Tsunehisa Miki ◽  
Masakazu Nishida

Abstract In this study, we clarified the influence of lignin in wood on its plastic flow deformation due to shear sliding of wood cells. Wood samples were subjected to delignification, where the lignin structure gradually changed, and characterized for their chemical and physicochemical properties, and deformability by free compression testing. The delignified wood deformed by efficient stretching and maintained its cell structures at a lower pressure compared to the untreated wood. The deformability was evaluated from two viewpoints: the initial resistance to plastic flow and final stretchability. The deformability of the delignified and untreated wood increased with increasing compressive temperature, even though the changes in molecular motility associated with the glass transition of lignin contributed minimally to the improvement in deformability. In the early stages of delignification, the molecular mass of lignin in the compound middle lamella decreased, which reduced the initial resistance to plastic flow. However, during the early stages of delignification, the stretchability of delignified wood was scarcely affected by changes in lignin. As the amount of lignin was further reduced and delignification proceeded in the vicinity of the polysaccharides, the stretchability significantly improved. The correlation between chemical and physicochemical properties and plastic flow deformability presented in this paper will be helpful for low-energy and highly productive forming of solid-state wood.

2021 ◽  
Vol 11 (9) ◽  
pp. 460
Rosa-María Rodríguez-Jiménez ◽  
Manuel Carmona

This article presents an exploratory and interpretative study on the development of self-reflection and self-knowledge in university teachers by an embodied experience. Dance Movement Therapy and Body–Mind Centering share the fundamentals of the paradigm of embodied cognition through a first-person full-body experience. Using these principles, a training program was designed and implemented in a cohort of 22 university teachers. The article offers details of the program and the adaptations necessary to carry it out in a higher-education context. The results of the qualitative analysis that was conducted suggested that the transformative learning paradigm could be useful to explain the process carried out by the participants. With the necessary limitations, the incorporation of awareness and attentive participation in bodily states and actions manifests as a transformative element in the teacher. The participants, despite initial resistance, see possibilities for applying this knowledge in their teaching practice.

2021 ◽  
Vol 8 ◽  
Kirill Keller ◽  
David Grafinger ◽  
Francesco Greco

As printed electronics is evolving toward applications in biosensing and wearables, the need for novel routes to fabricate flat, lightweight, stretchable conductors is increasing in importance but still represents a challenge, limiting the actual adoption of ultrathin wearable devices in real scenarios. A suitable strategy for creating soft yet robust and stretchable interconnections in the aforementioned technological applications is to use print-related techniques to pattern conductors on top of elastomer substrates. In this study, some thin elastomeric sheets—two forms of medical grade thermoplastic polyurethanes and a medical grade silicone—are considered as suitable substrates. Their mechanical, surface, and moisture barrier properties—relevant for their application in soft and wearable electronics—are first investigated. Various approaches are tested to pattern conductors, based on screen printing of 1) conducting polymer [poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)] or 2) stretchable Ag ink and 3) laser scribing of laser-induced graphene (LIG). The electromechanical properties of these materials are investigated by means of tensile testing and concurrent electrical measurements up to a maximum strain of 100%. Performance of the different stretchable conductors is compared and rationalized, evidencing the differences in onset and propagation of failure. LIG conductors embedded into MPU have shown the best compromise in terms of electromechanical performance for the envisioned application. LIG/MPU showed full recovery of initial resistance after multiple stretching up to 30% strain and recovery of functionality even after 100% stretch. These have been then used in a proof-of-concept application as connectors for a wearable tattoo biosensor, providing a stable and lightweight connection for external wiring.

2021 ◽  
Vol 30 (2) ◽  
pp. 359-378
Jin-A Choi ◽  
Sejung Park

In the midst of the COVID-19 pandemic, there have been varied responses to public health officials' recommendations about wearing face masks as a means to slow the spread of the virus. This study, by using Twitter data, aims to explore the role of digital technology in facilitating public conversations and formulating public perception regarding face masks during the COVID-19 pandemic in two contrasting contexts: the U.S. and South Korea. From January 1, 2020 to April 14, 2020, a total of 22,928 users generated 27,501 tweets regarding face masks in the U.S. network, whereas 17,267 users produced 18,686 tweets in that of South Korea. The results of the semantic network analysis shed light on Americans' initial resistance to wearing masks as well as Koreans' willingness to comply. Details of the results are discussed further in the paper. With real-time data aggregation, this study gives insight into the rising controversy regarding wearing face masks during COVID-19 while providing implications for health officials designing strategic communication messages.

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