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Chiang WY, Wu MH, Wu KL, Lin MH, Teng HH, Tsai YF, Ko CC, Yang EC, Jiang JA, Barnett LR, Chu KR. A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber. Rev Sci Instrum 2014; 85:084703. [PMID: 25173291 DOI: 10.1063/1.4891616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system.
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Affiliation(s)
- W Y Chiang
- Department of Physics, National Taiwan University, Taipei, Taiwan
| | - M H Wu
- Department of Physics, National Taiwan University, Taipei, Taiwan
| | - K L Wu
- Department of Physics, National Taiwan University, Taipei, Taiwan
| | - M H Lin
- Department of Physics, National Taiwan University, Taipei, Taiwan
| | - H H Teng
- Department of Physics, National Taiwan University, Taipei, Taiwan
| | - Y F Tsai
- Department of Entomology, National Taiwan University, Taipei, Taiwan
| | - C C Ko
- Department of Entomology, National Taiwan University, Taipei, Taiwan
| | - E C Yang
- Department of Entomology, National Taiwan University, Taipei, Taiwan
| | - J A Jiang
- Department of Bio-Industrial Mechatronics Engineering, National Taiwan University, Taipei, Taiwan
| | - L R Barnett
- Department of Physics, National Taiwan University, Taipei, Taiwan
| | - K R Chu
- Department of Physics, National Taiwan University, Taipei, Taiwan
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Chang TH, Chen SH, Barnett LR, Chu KR. Characterization of stationary and nonstationary behavior in gyrotron oscillators. Phys Rev Lett 2001; 87:064802. [PMID: 11497832 DOI: 10.1103/physrevlett.87.064802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2001] [Indexed: 05/23/2023]
Abstract
The transition from the stationary state to a sequence of nonstationary states in the gyromonotron oscillator is experimentally characterized for the first time. We have also demonstrated the stationary operation of a gyrotron backward-wave oscillator at a beam current far in excess of the generally predicted nonstationary threshold. This difference in nonlinear behavior has been investigated and shown to be fundamental with a comparative analysis of the feedback mechanisms, energy deposition profiles, and field shaping processes involved in these two types of oscillations.
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Affiliation(s)
- T H Chang
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
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Abstract
To evaluate the health effects of role overload, the relationship between multiple role (i.e., worker, spouse, caretaker) strain and current cigarette smoking was examined. A cross-sectional survey of women veterans, aged 36-85 years, was performed measuring home and job strain and health behaviors. Of the 275 women who rated both their work and home strains, 25% (n = 69) currently smoke cigarettes. Higher work strain, but not higher home strain, was associated with smoking adjusting for age, education, income, weight, and marital status. A stressful work environment may trigger persistent smoking and should be addressed during smoking cessation counseling.
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Affiliation(s)
- L A Bastian
- Center for Health Services Research in Primary Care, Durham Veterans Affairs Medical Center, Durham, North Carolina, USA
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Chu KR, Barnett LR, Chen HY, Chen SH, Wang C, Yeh YS, Tsai YC, Yang TT, Dawn TY. Stabilization of absolute instabilities in the gyrotron traveling wave amplifier. Phys Rev Lett 1995; 74:1103-1106. [PMID: 10058935 DOI: 10.1103/physrevlett.74.1103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Kou CS, Chen SH, Barnett LR, Chen HY, Chu KR. Experimental study of an injection-locked gyrotron backward-wave oscillator. Phys Rev Lett 1993; 70:924-927. [PMID: 10054239 DOI: 10.1103/physrevlett.70.924] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Barnett LR, Chang LH, Chen HY, Chu KR, Lau WK, Tu CC. Absolute instability competition and suppression in a millimeter-wave gyrotron traveling-wave tube. Phys Rev Lett 1989; 63:1062-1065. [PMID: 10040455 DOI: 10.1103/physrevlett.63.1062] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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