Browsing by Author "Chang, Kai-Ting"

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A 160-GHz Frequency-Translation Phase-Locked Loop With RSSI Assisted Frequency Acquisition
(2014-06-01)
Chen, Wei-Zen
;
Lu, Tai-You
;
Wang, Yan-Ting
;
Jian, Jhong-Ting
;
Yang, Yi-Hung
A 160-GHz frequency-translation PLL with tuning range from 156.4 GHz to 159.2 GHz is presented. Sub-THz 1/9 prescaler is replaced by a 3rd harmonic mixer incorporating a frequency tripler for frequency down conversion. A transformer-based VCO is utilized to alleviate capacitive and resistive load associated with varactor and succeeding buffer stages. Frequency acquisition is assisted by received signal strength indicator (RSSI) for automatic frequency sweeping and fast locking. Fabricated in 65 nm CMOS technology, the chip size is 0.92 mm(2). The PLL locking time is less than 3 mu s. This chip drains 24 mW from a 1.2 V power supply.
Detecting Breath Ammonia for Non-invasive Diagnostic based on Low-Cost Organic Diode with Vertical Nanojunctions
(2012)
Dai, Ming-Zhi
;
Lin, Yi-Lo
;
Lin, Hong-Cheng
;
Zan, Hsiao-Wen
;
Chang, Kai-Ting
We propose a novel solid-state electrical ammonia sensor based on a vertical organic diode with high-density nanopores in the top electrode. The proposed ammonia sensor has a detection limit of 20 ppb, a real-time response, sufficient selectivity, simple structure, high reproducibility, and a low production cost. In addition, we used the proposed sensor to detect the nasal breath of rats directly. After controlling the relative humidity and filtering out the CO2, we successfully obtained repeated real-time, reliable responses. This is the first demonstration of a solid-state sensor having reliable responses to the breath ammonia of an animal. The sensing response between normal and acute groups is significantly different (p < 0.05). These results demonstrated that the proposed ammonia sensor can detect liver that undergoes moderate hepatopathy.
Effects of Structural Strain and Rare-Earth Moments on Spin Cycloidal-Plane in Multiferroic Rare-Earth Manganites
(2016-05)
Hsiao, Yen-Fu
;
Kuo, Wei-Cheng
;
Mi, Chun-Wei
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Chang, Kai-Ting
;
Luo, Chih-Wei
A series of orthorhombic multiferroic manganites (o-ReMnO3) thin films with deliberately designed strain states and different rare-earth elements were prepared to unveil the roles played by the strain and 4f-electron moments in determining the magnetic ordering and associated polarizations. The results obtained from temperature-dependent magnetization, dielectric and ferroelectric measurements revealed that the orientations of magnetic reordering and polarization varied with the specific rare-earth element involved. Namely, with the increase of total angular momentum J of the 4f-electrons of rare-earth element the orientation of magnetic reordering was changed from the b-axis (sinusoidal state) for Yb3+ to the a-axis (ab-cycloidal) for Tm3+ and, eventually to the c-axis (bc-cycloidal) for Er3+ and Ho3+. These results indicate that the Re-Mn magnetic exchange interaction plays a more important role than the external strain does in determining the magnetic and hence polarization states in multiferroic o-ReMnO3 manganites. Our results also confirmed the coexistence of different magnetic spin states in o-ReMnO3 thin films.
Highly Sensitive Ammonia Sensor with Organic Vertical Nanojunctions for Noninvasive Detection of Hepatic Injury
(2013-03-19)
Dai, Ming-Zhi
;
Lin, Yi-Lo
;
Lin, Hung-Cheng
;
Zan, Hsiao-Wen
;
Chang, Kai-Ting
We successfully demonstrate the first solid-state sensor to have reliable responses to breath ammonia of rat. For thioacetamide (TAA)-induced hepatopathy rats, we observe that the proposed sensor can detect liver that undergoes acute-moderate hepatopathy with a p-value less than 0.05. The proposed sensor is an organic diode with vertical nanojunctions produced by using low-cost colloidal lithography. Its simple structure and low production cost facilitates the development of point-of-care technology. We also anticipate that the study is a starting point for investigating sophisticated breath-ammonia-related disease models.