Browsing by Author "Huang, Yu-Fang"

Now showing 1 - 5 of 5

Blue Laser Diode Based Free-space Optical Data Transmission elevated to 18 Gbps over 16 m
(2017-09-05)
Huang, Yu-Fang
;
Chi, Yu-Chieh
;
Kao, Hsuan-Yun
;
Tsai, Chen-Ting
;
Wang, Huai-Yung
Up to 18-Gbps direct encoding of blue laser diode (BLD) is demonstrated for free-space data transmission. By reshaping the orthogonal frequency multiplexed (16-QAM OFDM) stream with sidelobe filtering, the raw data rate expedites from 17.2 to 18.4 Gbps. Employing an ultrafast p-i-n photodiode with smaller active area diameter and lower noise equivalent power significantly enlarges the data rate by 1.6 Gbps or upgrades the signal-to-noise ratio (SNR) by 0.2 dB. Replacing the 80-mW BLD with the 120-mW one essentially increases the received SNR by 0.4 dB under enhanced modulation throughput. Reinforcing the beam collimation and collection by increasing the numerical aperture with a plano-convex hyper-hemispherical lens further improves the SNR by 0.6 dB. After optimization, the 16-QAM OFDM data with and without sidelobe filtering are respectively delivered at raw data rates of 16.4 and 18 Gbps with spectral-density usage efficiency as high as 4 bit/s/Hz over 16 m in free space, wherein the BLD carried QAM-OFDM data stream remains its capacity after reformation with sidelobe filtering as the superior inter-carrier-interference immunity reinforces.
Comparing PI3K/Akt Inhibitors Used in Ovarian Cancer Treatment
(2020-03-03)
Wu, Yi-Hui
;
Huang, Yu-Fang
;
Chen, Chien-Chin
;
Huang, Chia-Yen
;
Chou, Cheng-Yang
Epithelial ovarian carcinoma (EOC) is the most lethal gynecological malignancy. Herein, we sought to determine the efficacy of phosphoinositide 3-kinase (PI3K)/Akt inhibition using three AZD compounds in a NOD-SCID xenograft mouse model and Akt regulation in a panel of eight ovarian cancer cell lines. Elevated Akt phosphorylation on Ser473 but not on Thr308 in cancerous tissues correlated with short progression-free survival (PFS), overall survival (OS), and death. AZD8835 and AZD8186 inhibited Akt phosphorylation while AZD5363 augmented its phosphorylation on Ser473. To add, all compounds inhibited the Akt downstream effectors 4E-BP1 and p70S6 kinase. AZD8835 and AZD5363 sensitized chemoresistant ovarian cancer cells to cisplatin and paclitaxel treatment. Only AZD5363 could inhibit COL11A1 mRNA and promoter activity, which are important factors in Akt regulation and chemoresistance in ovarian cancer. By using a mouse xenograft model, AZD8835 and AZD5363, but not AZD8186, caused a significant reduction in tumor formation. AZD compounds did not change the mRNA expression of BRCA1/BRCA in ovarian cancer cells, but AZD8835 inhibited BRCA1/BRCA2 mRNA expression and p-ERK protein expression in OVCAR-8 cells with the KRAS mutation. This study highlights the importance of PI3K/Akt in ovarian tumor progression and chemoresistance and the potential application of AZD compounds, especially AZD8835 and AZD5363, as therapeutic agents for the treatment of ovarian cancer.
Impedance Matched GaN LD Package for Direct OFDM Communication at 14 Gbps
(2016)
Huang, Yu-Fang
;
Wu, Tsai-Chen
;
Chi, Yu-Chieh
;
Tsai, Cheng-Ting
;
Wang, Wei
A transmission line aided impedance matching package for 450-nm GaN laser diode is employed to increase the directly encoded 16-QAM OFDM transmission up to 14-Gbps over 7 m in free-space after modulation throughput intensity optimization.
Panel data analyses of the pecking order theory and the market timing theory of capital structure in Taiwan
(2013-06-01)
Chen, Dar-Hsin
;
Chen, Chun-Da
;
Chen, Jianguo
;
Huang, Yu-Fang
;
資訊管理與財務金融系註：原資管所+財金所
We exploit panel data of publicly-traded Taiwanese firms to test the pecking order theory the market timing theory over 1990-2005. On the one hand, the results indicate no support for pecking order behavior (consistent with Frank & Goyal, 2003), as net equity issues track the financing deficit much more closely than net debt issues do. The adverse selection also demonstrates that the pecking order theory is not supported by our empirical results. On the other hand, the evidence of the market timing theory is favorable for the Taiwan stock market especially for the period 1990 to 2001, suggesting that the results of this theory provide an explanation when our results do not support the pecking order hypothesis. However, the market timing theory does not apply in the period of 2002-2005. In other words, firms in Taiwan prefer issuing more debt rather than equity under low market performance. (C) 2012 Elsevier Inc. All rights reserved.
Violet Laser Diode Enables Lighting Communication
(2017-09-05)
Chi, Yu-Chieh
;
Huang, Yu-Fang
;
Wu, Tsai-Chen
;
Tsai, Cheng-Ting
;
Chen, Li-Yin
Violet laser diode (VLD) based white-light source with high color rendering index (CRI) for lighting communication is implemented by covering with Y3Al5O12:Ce3+ (YAG:Ce) or Lu3Al5O12:Ce3+/CaAlSiN3: Eu2+ (LuAG: Ce/CASN: Eu) phosphorous diffuser plates. After passing the beam of VLD biased at 70 mA (similar to 2I(th)) through the YAG: Ce phosphorous diffuser, a daylight with a correlated color temperature (CCT) of 5068 K and a CRI of 65 is acquired to provide a forward error correction (FEC) certified data rate of 4.4 Gbit/s. By using the VLD biased at 122 mA (similar to 3.5I(th)) to excite the LuAG: Ce/CASN: Eu phosphorous diffuser with 0.85-mm thickness, a warm white-light source with a CCT of 2700 K and a CRI of 87.9 is obtained at a cost of decreasing transmission capacity to 2.4 Gbit/s. Thinning the phosphor thickness to 0.75 mm effectively reduces the required bias current by 32 mA to achieve the same CCT for the delivered white light, which offers an enlarged CRI of 89.1 and an increased data rate of 4.4 Gbit/s. Further enlarging the bias current to 105 mA remains the white-light transmission capacity at 4.4 Gbit/s but reveals an increased CCT of 3023 K and an upgraded CRI of 91.5.