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1 – 10 of 306Qijing Lin, Zirong Wu, Na Zhao, Zhuangde Jiang, Qidong Zhang, Bian Tian and Peng Shi
The Fabry-Perot sapphire optical fiber sensor is an excellent choice for high-temperature sensing in civil and military fields, such as oil exploitation, engine and turbine. The…
Abstract
Purpose
The Fabry-Perot sapphire optical fiber sensor is an excellent choice for high-temperature sensing in civil and military fields, such as oil exploitation, engine and turbine. The purpose of this paper is to study the high-reflective film system withstanding high temperature in Fabry-Perot sapphire optical fiber high-temperature sensor. To improve the performance of the sensor and reduce the difficulty of signal acquisition, one of the key ways is to enhance the normalized light intensity of F-P sensor, which can be achieved by coating the high-reflective film system on the fiber end.
Design/methodology/approach
The high-reflective film system can be achieved by a multilayer film with alternating ZrO2 and Al2O3 film layers whose refractive indexes are different. In addition, the optimum film alternating sequences and the influence of the number of film layers, incident angle and temperature should be obtained by numerical analysis.
Findings
With the increase of the number of film layers, the reflectivity rises gradually and the change trend is more and more gentle. A minimum of the spectral reflectivity will occur at a certain incident angle depending on the design of the periodic multilayer system. Temperature affects the reflectivity of high-reflective film system. The normalized light intensity of the F-P sensor coated with high-reflective film system enhances greatly which is helpful to the signal demodulation. The temperature response of the F-P sensor is mainly determined by the characteristics of the F-P cavity.
Originality/value
Higher reflectivity, lower cost and easy signal acquisition are the most important features of the introduced high-reflective film system for the Fabry-Perot sapphire optical fiber high-temperature sensor.
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Bian Tian, Huafeng Li, Ning Yang, Yulong Zhao, Pei Chen and Hanyue Liu
It is significant to know the real-time indexes about the turbulence flow of the ocean system, which has a deep influence on ocean productivity, distribution of the ocean…
Abstract
Purpose
It is significant to know the real-time indexes about the turbulence flow of the ocean system, which has a deep influence on ocean productivity, distribution of the ocean populations and transmission of the ocean energy, especially the measurement of turbulence flow velocity. So, it is particularly urgent to provide a high-sensitivity, low-cost and reliable fluid flow sensor for industry and consumer product application. This paper aims to design a micro fluid flow sensor with a cross beam membrane structure. The designed sensor can detect the fluid flow velocity and has a low kinetic energy dissipation rate.
Design/methodology/approach
In this paper, a micro fluid flow sensor with a cross beam membrane structure is designed to measure the ocean turbulence flow velocity. The design, simulation, fabrication and measurement of the designed sensor are discussed. By testing the simply packaged sensor in the fluid flow and analyzing the experiments data, the results show that the designed sensor has favorable performance.
Findings
The paper describes the tests of the designed sensor, and the experimental results show that the designed sensor can measure the fluid flow velocity and has a sensitivity of 11.12 mV/V/(m/s)2 and a low kinetic energy dissipation rate in the range of 10-6-10-4 W/kg.
Originality/value
This paper provides a micro-electro-mechanical systems fluid flow sensor used to measure ocean turbulence flow velocity.
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This chapter presents systematic evidence on the persistent power of guanxi, the Chinese phrase for informal social relations and networks, in transitional China. I draw heavily…
Abstract
This chapter presents systematic evidence on the persistent power of guanxi, the Chinese phrase for informal social relations and networks, in transitional China. I draw heavily on my previous publications reporting findings from a series of probability sample surveys of the Job-Search Network (thereafter JSNET) project in Chinese cities, and job histories of the survey respondents combined cover a span of 37 years from 1978, the beginning year of China's market-oriented reforms, to 2014, the year of last JSNET survey completed.
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Zhongliang Yu, Yulong Zhao, Lili Li, Cun Li, Xiawei Meng and Bian Tian
The purpose of this study is to develop a piezoresistive absolute micro-pressure sensor for altimetry. For this application, both high sensitivity and high overload resistance are…
Abstract
Purpose
The purpose of this study is to develop a piezoresistive absolute micro-pressure sensor for altimetry. For this application, both high sensitivity and high overload resistance are required. To develop a piezoresistive absolute micro-pressure sensor for altimetry, both high sensitivity and high-overload resistance are required. The structure design and optimization are critical for achieving the purpose. Besides, the study of dynamic performances is important for providing a solution to improve the accuracy under vibration environments.
Design/methodology/approach
An improved structure is studied through incorporating sensitive beams into the twin-island-diaphragm structure. Equations about surface stress and deflection of the sensor are established by multivariate fittings based on the ANSYS simulation results. Structure dimensions are determined by MATLAB optimization. The silicon bulk micromachining technology is utilized to fabricate the sensor prototype. The performances under both static and dynamic conditions are tested.
Findings
Compared with flat diaphragm and twin-island-diaphragm structures, the sensor features a relatively high sensitivity with the capacity of suffering atmosphere due to the introduction of sensitive beams and the optimization method used.
Originality/value
An improved sensor prototype is raised and optimized for achieving the high sensitivity and the capacity of suffering atmosphere simultaneously. A general optimization method is proposed based on the multivariate fitting results. To simplify the calculation, a method to linearize the nonlinear fitting and optimization problems is presented. Moreover, a differential readout scheme attempting to decrease the dynamic interference is designed.
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Bian Tian, Yulong Zhao, Zhe Niu and Jiang Zhuangde
The purpose of this paper is to report on a piezoresistive pressure sensor for micro-pressure measurement with a cross-beam membrane (CBM) structure. This study analyzes the…
Abstract
Purpose
The purpose of this paper is to report on a piezoresistive pressure sensor for micro-pressure measurement with a cross-beam membrane (CBM) structure. This study analyzes the dynamic characteristics of the proposed device.
Design/methodology/approach
This CBM sensor possesses high stiffness and sensitivity, measuring dynamic pressure more effectively in a high-frequency environment compared with other piezoresistive structures. The dynamic characteristics are derived using the finite element method to analyze the dynamic responses of the new structure, including natural frequency and lateral effect performances. The CBM dynamic performances are compared with traditional structures.
Findings
The pressure sensor performance was evaluated, and the experimental results indicate that they all exhibit similar dynamic characteristics as the designed model. Compared with traditional structures such as the single island, the CBM proves to be superior in evaluating the dynamic performances of pressure sensors at high frequencies of > 30 kHz.
Originality/value
Most studies of this micro pressure sensors attempt to promote the sensitivity or focus on the static performance of pressure sensor with micro gauge. This study is concerned with analyze the dynamic characterism of micro pressure sensor and compared with the traditional structures, that prove the CBM structure has stable dynamic performance and is a better option for measuring dynamic micro pressure in biomedical applications.
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Bian Tian, Yulong Zhao and Zhuangde Jiang
The purpose of this paper is to investigate the disadvantages of traditional sensors and establish a new structure for pressure measurement.
Abstract
Purpose
The purpose of this paper is to investigate the disadvantages of traditional sensors and establish a new structure for pressure measurement.
Design/methodology/approach
A kind of novel piezoresistive micro‐pressure sensor with a cross‐beam membrane (CBM) structure is designed based on the silicon substrate. Through analyzing the stress distribution of the new structure by finite element method, the model of structure is established and compared with traditional structures. The fabrication is operated on silicon wafer, which applies the technology of anisotropy chemical etching and inductively coupled plasma.
Findings
Compared to the traditional C‐ and E‐type structures, this new CBM structure has the advantages of low nonlinearity and high sensitivities by the cross‐beam on the membrane, which cause the stress is more concentrated in sensitive area and the deflections that relate to the linearity are decreased.
Originality/value
The paper provides the first empirical reports on the new piezoresistive structure for the pressure measurement by fabricating a cross‐beam on the membrane and resolving the conflict of nonlinearity and sensitivity of the piezoresistive sensors.
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Hua Ke and Xingyue Chen
In this paper, the authors aim to consider the manufacturer's battery research and development (R&D) decision under subsidy. The supply chain includes two manufacturers, which…
Abstract
Purpose
In this paper, the authors aim to consider the manufacturer's battery research and development (R&D) decision under subsidy. The supply chain includes two manufacturers, which produce substitutable electric vehicles, and a battery supplier. One of the manufacturers can choose to develop batteries or buy batteries. The authors assume consumers do not have enough trust in the manufacturer-made battery.
Design/methodology/approach
Stackelberg game is made use of to study the battery R&D strategy of the manufacturer under the incentive of government subsidies. This paper makes a comparative analysis on six situations, then the authors get some conclusions and give some managerial insights.
Findings
The results show that subsidy strategies do not necessarily reduce actual payments when the manufacturer does not research and develop batteries. The retail prices and actual payments are closely related to the substitutability and total cost advantage of product. The authors also find consumer trust positively affects the demand of the electric vehicles using the manufacturer-made batteries and then affects the manufacturer's battery R&D decision. When consumers have low trust in manufacturer-made battery, subsidy can bring greater sales and make R&D more profitable than procurement, so that the manufacturer chooses R&D. This study's findings also suggest consumer subsidy is always better for the government.
Originality/value
Distinguished from previous studies, the authors discuss the decision-making of component research, and introduce various government subsidy strategies and consumer trust to study their roles in the manufacturer's battery R&D choice.
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Chetan Kumar, K.B. Rangappa, S. Suchitra and Huchhe Gowda
Many studies have illustrated the vast advantages which blended learning has to offer to the learning community. However, when a learner accesses a digital platform, one cannot…
Abstract
Purpose
Many studies have illustrated the vast advantages which blended learning has to offer to the learning community. However, when a learner accesses a digital platform, one cannot ignore the negative repercussions which the learner would be subjected to in the process. Our study tries to analyze the negative repercussions of digital media distractions on their wholistic development.
Design/methodology/approach
Information pertaining to the use of digital media among students for blended learning and the consequent distractions faced by them in the process was elicited through a well-structured questionnaire from pre-university and university students. The PLS-SEM model was constructed to identify the effect of digital distractions on students' academic performance, outlook of life and health, keeping counseling and spiritual inclination as moderating variables.
Findings
From our research, we inferred that the students' time spent on a digital platform was directly related with their time spent on blended learning and their tendency to get distracted. However, they were more prone to e-distractions than e-learning. Furthermore, e-learning did not enhance their academic performance. However, distractions had significant negative repercussions on their mental health. Counseling that the students were getting in their educational institutions did not play any significant role in improving their mental health.
Originality/value
Studies which have been undertaken to analyze the negative repercussions of blended learning on the wholistic development of students are scarce. Given the increasing popularity of blended learning among South Asian students in recent times, our study has tried to bridge this gap.
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Man has been seeking an ideal existence for a very long time. In this existence, justice, love, and peace are no longer words, but actual experiences. How ever, with the American…
Abstract
Man has been seeking an ideal existence for a very long time. In this existence, justice, love, and peace are no longer words, but actual experiences. How ever, with the American preemptive invasion and occupation of Afghanistan and Iraq and the subsequent prisoner abuse, such an existence seems to be farther and farther away from reality. The purpose of this work is to stop this dangerous trend by promoting justice, love, and peace through a change of the paradigm that is inconsistent with justice, love, and peace. The strong paradigm that created the strong nation like the U.S. and the strong man like George W. Bush have been the culprit, rather than the contributor, of the above three universal ideals. Thus, rather than justice, love, and peace, the strong paradigm resulted in in justice, hatred, and violence. In order to remove these three and related evils, what the world needs in the beginning of the third millenium is the weak paradigm. Through the acceptance of the latter paradigm, the golden mean or middle paradigm can be formulated, which is a synergy of the weak and the strong paradigm. In order to understand properly the meaning of these paradigms, however, some digression appears necessary.
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