Performance Analysis of Permanent Magnet Brushless Motors for Mobility Scooters

Yu-Chuan Lu,Ming-Yang Cheng,Chun-Hsien Wu,Wei-Chih Chen,Cheng-Hu Chen 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

Most modern commercial electric scooters are still equipped with the DC brush motor. This type of motor has mechanical structures such as permanent magnet, brush, and commutator. Therefore, it has attractive features, e.g., large start-up torque and easy to control. However, this kind of mechanical commutation often leads to drawbacks such as low power density, low reliability, and poor heat dissipation. In contrast, the Permanent Magnet Brushless Motors (PMBLMs) have advantages such as high efficiency and maintenance free, etc. Hence, the PMBLMs have great potential in becoming the actuators for electric scooters. In this paper, the performance of the PMBLMs with trapezoidal and sinusoidal back-emf waveforms driven by square wave commutation and sinusoidal commutation is investigated. To reduce the cost, low-resolution Hall sensors are used to implement sinusoidal commutation.

The back contact modification in high-efficiency Cu₂ZnSn(S,Se)₄ solar cells by a thin MoO₃ layer

Septia KHOLIMATUSSADIAH,Cheng-Ying CHEN,Wei-Chao CHEN,Yi-Rung LIN,Shao-Hung LU,Meng-Chia HSIEH,Jan-Kai CHANG,Chih-I WU,Ruei-San CHEN,Kuei-Hsien CHEN,Li-Chyong CHEN 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8

Biochemical Compositions of Follicular Fluid and the Effects of Culture Conditions on the In Vitro Development of Pig Oocytes

Huang, Wei-Tung,Lu, She-Ghi,Tang, Pin-Chi,Wu, Shinn-Chih,Cheng, San-Pao,Ju, Jyh-Cherng Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.10

The aims of this study were, firstly, to analyze the biochemical compositions of serum and follicular fluid (FF) from prepubertal gilts after PMSG (1,000 IU) treatment. The concentrations of total proteins, lipids, cholesterol, glucose and sex hormones (progesterone, $P_4$; estradiol-$17{\beta}$, $E_2$; testosterone, T) were measured. Secondary, the effects of porcine FF (pFF) addition (40% and 100%) in IVM media and different culture conditions [Exp. 1: mBMOC-2+20% porcine serum (PS), fresh IVM medium, filtered IVMconditioned medium, or rabbit oviducts; Exp. 2: mBMOC-2+20%PS or stepwise medium replacement procedures (SMRP) cocultured with or without cumulus cells] on the in vitro development (IVD) of porcine oocytes were also examined. Results showed that no significant differences were found in total protein levels between serum and pFF from different sizes (large, >7 mm; medium, ~5-7 mm; small, <3-5 mm) of follicles (75-85 and 49-90 mg/dl; p>0.05). Total lipid concentrations remained constant in serum (395-472 mg/dl), and reduced significantly in the pFF from large follicles (287 mg/dl) at 132 h after PMSG treatment when compared to those at other time points (441-480 mg/dl). Basal cholesterol levels in serum and pFF at 12 h were similar (153-161 mg/dl), but increased at 36 h (186-197 mg/dl). Basal P4 and E2 levels in serum (0.1 ng/ml and 5.5 pg/ml) were low, but increased from 0.34 ng/ml and 12.13 pg/ml at 24 h to 0.81 ng/ml and 61.70 pg/ml at 98 h, respectively, after PMSG treatment (p<0.05). P4 levels increased linearly in pFF from large follicles during 12 through 132 h (138-1,288 ng/ml). A similar increase was also observed in $E_2$ levels (22-730 pg/ml) before 60 h post PMSG treatment, and then dropped afterwards (730-121 pg/ml). The development of the oocytes fertilized in 40% pFF-medium was greater than that in 100% pFF-medium group without gonaodtropin addition (31% vs 10%, p<0.05). However, both were lower than those in mBMOC-2+20%PS and in rabbit oviducts (p<0.05). When cocultured with cumulus cell monolayers, a greater cleavage rate was observed in the group cultured in filtered IVM-conditioned medium than the SMRP group (36% vs 18%, p<0.05). A similar phenomenon was also observed in the culture without cumulus cell monolayers (33% vs 19%, p<0.05). It is concluded that neither the fresh IVM nor filtered IVM-conditioned medium has positive effect on the IVD of oocytes. Coculture with cumulus cell monolayers and the SMRP were not beneficial to the development of IVF pig oocytes.

Responsivity and Noise of the AC-Excited Giant-Magnetoresistance Magnetic Field Sensor

Jen-Tzong Jeng,Ting-Yu Hsu,Chih-Cheng Lu 한국자기학회 2010 한국자기학회 학술연구발표회 논문개요집 Vol.2010 No.12

Orthogonality Correction for Concentric Tri-axis Fluxgate Magnetometer

Xuan Thang Trinh,Jen-Tzong Jeng,Chih-Cheng Lu,Van Su Luong 한국자기학회 2019 Journal of Magnetics Vol.24 No.2

In this work, a compact tri-axis fluxgate magnetometer comprising a single magnetic core was implemented and the effectiveness of the orthogonality correction algorithm was demonstrated. The vector magnetometer consists of a tube-shaped soft magnetic flux chopper with a toroidal coil and three concentric pick-up coils. The tube-shaped flux chopper with magnet wires has the total dimension of 10 mm × 10 mm. The number of turns of the pick-up coils X-, Y-, and Z- are 110, 110 and 150, respectively. The center of flux chopper is also the geometric center of the three pick-up coils, of which the sensing directions are aligned along the Cartesian axes. The concentric design ensures a single field point for the three sensing axes. When using the tri-axis fluxgate magnetometer as an electronic compass, the geomagnetic field components converted from the demodulated outputs of the sensing coils shows high accuracy by using the voltage-to-field transfer matrix. The proposed fluxgate system is suitable for applications related to high-accuracy static magnetic field measurement, e.g. geomagnetic field monitoring, electronic compass, and magnetic field mapping.

Risk of Hepatitis B Virus (HBV) Reactivation in HBsAg-Negative, Anti-HBc-Negative Patients Receiving Rituximab for Autoimmune Diseases in HBV Endemic Areas

Lan Ting-Yuan,Lin Yen-Chun,Tseng Tai-Chung,Yang Hung-Chih,Kao Jui-Hung,Cheng Chiao-Feng,Lee Tai-Ju,Huang Shang-Chin,Lu Cheng-Hsun,Li Ko-Jen,Hsieh Song-Chou 거트앤리버 소화기연관학회협의회 2023 Gut and Liver Vol.17 No.2

Background/Aims: Rituximab is known to be associated with high hepatitis B virus (HBV) reactivation rate in patients with resolved HBV infection and hematologic malignancy. However, data regarding HBV reactivation (HBVr) in rheumatic patients receiving rituximab is limited. To assess the HBVr rate in hepatitis B surface antigen (HBsAg)-negative patients receiving rituximab for autoimmune diseases in a large real-world cohort. Methods: From March 2006 to December 2019, 900 patients with negative HBsAg receiving at least one cycle of rituximab for autoimmune diseases in a tertiary medical center in Taiwan were retrospectively reviewed. Clinical outcome and factors associated with HBVr were analyzed. Results: After a median follow-up period of 3.3 years, 21 patients developed HBVr, among whom 17 patients were positive for hepatitis B core antibody (anti-HBc) and four were negative. Thirteen patients had clinical hepatitis flare, while eight patients had HBsAg seroreversion without hepatitis. Old age, anti-HBc positivity, undetectable serum hepatitis B surface antibody level at rituximab initiation and a higher average rituximab dose were associated with a higher HBVr rate. There was no significant difference in the HBVr risk between rheumatoid arthritis and other autoimmune diseases. Among anti-HBc-negative patients, subjects without HBV vaccination at birth had an increased risk of HBVr (4/368, 1.1%) compared with those who received vaccination (0/126, 0%). Conclusions: In HBV endemic areas where occult HBV is prevalent, anti-HBc-negative patients, may still be at risk for HBVr after rituximab exposure. HBVr may still be considered in HBsAgnegative patients developing abnormal liver function after rituximab exposure, even in patients with negative anti-HBc.

Malignant transformation of ovarian mature cystic teratoma into squamous cell carcinoma: a Taiwanese Gynecologic Oncology Group (TGOG) study

An Jen Chiang,Min-Yu Chen,Chia-Sui Weng,Hao Lin,Chien-Hsing Lu,Peng-Hui Wang,Yu-Fang Huang,Ying-Cheng Chiang,Mu-Hsien Yu,Chih-Long Chang 대한부인종양학회 2017 Journal of Gynecologic Oncology Vol.28 No.5

Objective: The malignant transformation (MT) of ovarian mature cystic teratoma (MCT)to squamous cell carcinoma (SCC) is very rare. This study analyzed cases from multiplemedical centers in Taiwan to investigate the clinicopathologic characteristics, treatment, andprognostic factors of this disease and reviewed related literature. Methods: Pathological reports of 16,001 patients with primary ovarian cancer who weretreated at Taiwan medical centers from 1990 to 2011 were reviewed. In total, 52 patients withMT of MCT to SCC were identified. Results: Among all ovarian MCTs, the incidence of MT to SCC is 0.2%. The median age ofpatients was 52 years (range, 29–89 years), and the mean tumor size was 10.5 cm (range, 1–40cm). We analyzed the patients in our study and those in the literature and determined thatearly identification and complete surgical resection of the tumor are essential for long-termsurvival. In addition, adjuvant chemotherapy or concurrent chemoradiotherapy can be usedto treat this malignancy. Old age, large tumor size (≥15.0 cm), and solid components in MCTsare suitable indicators predicting the risk of MT of MCT to SCC. Conclusion: Similar to general epithelial ovarian cancers, the early detection of MT of MCTto SCC is critical to long-term survival. Therefore, older patients with a large tumor or those with a tumor containing a solid component in a clinically diagnosed MCT should beevaluated to exclude potential MT to SCC.