Papers by Keyword: Quartz

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Authors: Bing Tao Lin, Jian Hua Zhao, Wen Yun Li, Qian Zhou, Xin Man, Ri Le Lin, Bang Ying Weng, Hong Kui Dong, Zhou Xu, Qiao Yun Zhang
Abstract: A digital closed-loop control quartz accelerometer with new structures is performed, which overcomes the disadvantages of restriction of measurement range and sensitivity of QVBA (quartz vibrating beam accelerometer). It has not only the same precision as QVBA in theory, but also large measurement range without reducing the sensitivity. The accelerometer is proposed to be used in large range and high-precision measurement of acceleration.
Authors: Un Chung Cho
Abstract: V-grooved quartz substrates are manufactured by glass molding press and the pitch errors of the molded quartz fiber array blocks are statistically investigated. The V-grooved carbon molds of 8 and 16 channels and 250 μm in pitch are machined and then quartz substrates are molded on the V-grooved carbon molds by glass molding press. The pitch errors of X, Y and diagonal axis are measured and then statically analyzed. It is demonstrated that the V-grooved quartz fiber array blocks of 8 and 16 channels and 250 μm in pitch can be manufactured by glass molding technology without significant pitch errors.
Authors: Sasha J. Kweskin, Larry W. Shive
Abstract: RCA clean has evolved since 1965 [1]. Typically used before critical thermal steps, depositions/etches, or after strip operations, these solutions are robust and reliable. Stringent semiconductor demands of shrinking feature size, increased contamination sensitivity and cost pressure have led to cleaning projects that improve performance and reduce chemical usage. One of the sources of contamination is the process chemicals themselves, where wafers are exposed to chemicals for etching or cleaning. Concerns over contamination are compounded in wet benches where chemical baths are re-circulated for periods up to 24 hours. Metal impurities can arise from insufficiently pure chemicals or water, tanks, carriers, plumbing components, chemical containers, incoming wafers and handling equipment. Strict chemical, DIW and material specifications as well as dilute chemistry and reduced temperature have benefited the industry as a whole. Trends such as lower temperature/concentration SC1, and higher temperature/concentration SC2 have reached a point of diminishing returns for metal contamination reduction. In the same way, chemical and water purity are well below detection, so improvements are difficult to quantify.[2]
Authors: Hua Jiang, Wen Ke Lu, Yuan Yuan Li, Shi Gen Shen
Abstract: In order to improve the signal-noise rate (SNR) of the acceleration sensor system, this article analysis of the design principles of a novel surface acoustic wave (SAW) acceleration sensor with cantilever beam using ST-X quartz. The main structure of the novel SAW acceleration sensor is composed of two oscillator, a mixer and a low pass filter to get the difference frequency structure, which can inhibit temperature drift and lateral acceleration impact. The two oscillator have the same structure, which is constitute of a low insertion loss SAW delay line and a feedback amplifier. This article shows the simulation results of the force analysis of the cantilever beam free end using ANSYS finite element analysis software. The novel acceleration sensor has potential applications in portable mobile devices or automotive airbags fields.
Authors: S. Karaoğlu, M. Çolak, İ. Işık
Authors: Kun Ling Wu, Hsin Min Lee, Kuan Hwa Chin
Abstract: Electrochemical discharge machining (ECDM) is the preferred non-traditional process technology in recent years, The main processing is applied to machining non-conductive hard brittle materials. This study investigated the precision and stability of quartz fabricated by ECDM and explored the optimal processing parameters including size of electrode, machining speed as well as pulse-on and pulse-off duration. Microgrooves machined under the optimal processing parameters with adjusted rotational speed and feed rate were examined to understand the effect of different ECDM parameters on machining performance. The results indicate that micro-holes of better morphology could be obtained under pulse voltage of 40 V, electrolyte concentration of 5 M, electrode size of 125 μm. Moreover, rotational speed of 1500 rpm and pulse-on/pulse-off (ms) ratio of 1:0.6 gave higher machining accuracy with smaller hole diameter and shorter machining time. Finally, microgrooves machined under the optimal processing parameters showed the best accuracy in dimension and cross-sectional morphology at rotational speed of 2500 rpm, pulse-on /pulse-off (ms) ratio of 1:1.6, and feed rate of 3000 μm/min.
Authors: J. David van Horn, Fei Wu, Gerald Corsiglia, Yan Ching Jean
Abstract: We have studied the interaction of the positron with chiral left-or right-handed quartz crystals. In Doppler-broadening experiments, using a mono-energetic positron beam there is a differential depth profile for positrons implanted in LH or RH z-cut quartz as identified by a shape parameter (S). Further, in bulk positron annihilation lifetime spectroscopy (PALS) experiments, the lifetime (τ 2) attributed to free annihilation of the positron interacting with the chiral lattice exhibits a larger value for the LH quartz, and the associated intensity (I2) is also significantly different—RH quartz is consistently 10% greater than the LH crystal. The τ 3 lifetime and its intensity, I3, attributed to positronium interacting with defects in the quartz, also appears to exhibit differences between the enantiomeric sets of crystals. These observations may demonstrate chiral recognition using a positron annihilation technique, pave the way for a broad range of positron experiments, and may help inform hypotheses of chirality recognition, selection, or induction by beta radiation.
Authors: Siti Khodijah Chaerun, Frideni Yushandiana Putri, Mohammad Zaki Mubarok, Wahyudin Prawira Minwal, Zela Tanlega Ichlas
Abstract: Environmentally friendly mining technologies have to be developed extensively to avoid the impact of mining activities with respect to environmental concern. One example of such technology is bioleaching which has been developed worldwide and is regarded as an appropriate technology for the extraction of metals from polymetallic ores such as supergene porphyry copper ores, mainly consisting of secondary copper sulfides, including chalcocite (Cu2S), covellite (CuS), or oxide minerals, i.e., cuprite (Cu2O) and tenorite (CuO). The extraction process for this complex ore generally requires high temperature, high pressure and/or high acid concentration. For the economic extraction of valuable copper from such ores, the bioleaching of supergene porphyry copper ore from Sungai Max in Southeast Sulawesi of Indonesia was investigated in shake-flask experiments at room temperature (28 °C) for 14 days using an iron- and sulfur-oxidizing bacterium (Alicyclobacillus sp.) indigenous to an Indonesian mine site. The main mineralogical composition of gangue minerals contained in this ore sample included quartz, muscovite, kaolinite and alunite. The relatively high copper extraction efficiencies were obtained over a 14-day period of the bioleaching experiments as a function of pH, pulp density and NaCl concentration. Therefore, the findings of this study provide the first information of bioleaching process of supergene porphyry copper ores in Indonesia that may highly be useful for developing an economical and environmentally friendly extraction process of such complex ores.
Authors: De Si Sun, Hong Bao, Hao Chen, Xian Zhen Zhang, Ji Han Nie
Abstract: The effects of biosorption time and cell concentration on adsorption amount on the surface of diaspore, kaolinite and quartz were studied by using two kinds of silicate bacteria ____Bacillus circulans and Bacillus mucilaginosus, and three kinds of silicate minerals . the experimental results show that two kinds of silicate bacteria absorb more easily on the surface of diaspore than on that of kaolinite and quartz, and the adsorption amount of the strain of B•M is always higher than that of the strain of B•C on the surface of diaspore, kaolinite and quartz .The possible reason is that the pHPZC of diaspore is higher than that of kaolinite and quartz, and the strain of B•M probably produce more metabolites charged negatively than that of B•C in incubation process.
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