Hybrid current loop timing control method for permanent magnet AC servo systems

Zhe Song,Jun Yang,Xuesong Mei,Tao Tao,Muxun Xu 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.12

The relationship between current loop bandwidth and time delay was analyzed on the basis of the mathematical model of a current loop. The time delays generated by double sampling and pulse-width modulation (PWM) duty cycle double update (DSDU) and immediate sampling and PWM duty cycle immediate update (ISIU) and their effects on the current loop bandwidth were compared. Combining DSDU and ISIU, a novel hybrid current loop timing control method was proposed to solve the problems of insufficient bandwidth expansion and low voltage output capability. ISIU was used when calculation delay is less than or equal to the action time of the zero voltage vector to expand the bandwidth. Meanwhile, DSDU was adopted when calculation delay is greater than the action time of the zero voltage vector to improve voltage output capability. Experimental results proved that the proposed method can reduce current loop delay to increase bandwidth without changing switching frequency and limiting output voltage.

Expression of stromal cell-derived factor-1α is an independent risk factor for lymph node metastasis in early gastric cancer

SONG, IK-CHAN,LIANG, ZHE-LONG,LEE, JUNG-CHAN,HUANG, SONG-MEI,KIM, HA-YON,OH, YOON-SUK,YUN, HWAN-JUNG,SUL, JI-YOUNG,JO, DEOG-YEON,KIM, SAMYONG,KIM, JIN-MAN,LEE, HYO-JIN Spandidos Publications 2011 Oncology letters Vol.2 No.6

<P>Lymph node metastasis is considered to be a significant prognostic factor for early gastric cancer (EGC). However, no real consensus exists on which patient and/or tumor characteristics are associated with lymph node metastasis. We investigated whether stromal cell-derived factor (SDF)-1α expression correlates with lymph node metastasis in patients with EGC by immunohistochemically examining the expression of SDF-1α in 138 archival tissue specimens of EGC. Of these specimens, 59 (42.8%) and 79 (57.2%) were grouped into SDF-1α-positive and SDF-1α-negative groups, respectively. No significant differences existed with respect to age, gender, tumor location, proportion of tumors >20 mm in size, macroscopic type, depth of invasion or histology between the SDF-1α-positive and -negative groups. However, the SDF-1α-positive group was significantly correlated with lymphovascular invasion and lymph node metastasis. Results of the univariate analyses indicated that lymphovascular invasion, undifferentiated histology and SDF-1α positivity were statistically significant risk factors affecting lymph node metastasis in patients with EGC. Multivariate analyses showed that lymphovascular invasion [hazard ratio (HR), 8.595; 95% confidence interval (CI), 1.694-43.595; P=0.009], undifferentiated histology (HR, 2.965; 95% CI, 1.037-8.471; P=0.043) and SDF-1α positivity (HR, 2.108; 95% CI, 1.316-10.135; P=0.013) were independent risk factors predicting lymph node metastasis in EGC. In conclusion, these results suggest that SDF-1α expression in tumor cells is a predictive marker of lymph node metastasis in EGC.</P>

L1 cell adhesion molecule as a novel independent poor prognostic factor in gallbladder carcinoma

Choi, Song-Yi,Jo, Young Suk,Huang, Song-Mei,Liang, Zhe Long,Min, Jeong-Ki,Hong, Hyo Jeong,Kim, Jin-Man Elsevier 2011 Human pathology Vol.42 No.10

<P><B>Summary</B></P><P>Gallbladder carcinoma is a lethal malignancy and is hard to cure by current treatment. Thus, identification of molecular prognostic markers to predict gallbladder carcinoma as therapeutic targets is urgently needed. Recent studies have demonstrated that L1 cell adhesion molecule is associated with the prognosis of variable malignancy. Here, we investigated L1 cell adhesion molecule expression in gallbladder carcinoma and its prognostic significance. In this study, we examined L1 cell adhesion molecule expression in tumor specimens from 69 patients with gallbladder carcinoma by immunohistochemistry and analyzed the correlation between L1 cell adhesion molecule expression and clinicopathologic factors or survival. L1 cell adhesion molecule was not expressed in the normal epithelium of the gallbladder but in 63.8% of gallbladder carcinomas, remarkably at the invasive front of the tumors. In addition, L1 cell adhesion molecule expression was significantly associated with high histologic grade, advanced pathologic T stage and clinical stage, and positive venous/lymphatic invasion. Multivariate analyses showed that L1 cell adhesion molecule expression (hazard ratio, 3.503; <I>P</I> = .028) and clinical stage (hazard ratio, 3.091; <I>P</I> = .042) were independent risk factor for disease-free survival. L1 cell adhesion molecule expression in gallbladder carcinoma was significantly correlated with tumor progression and unfavorable clinicopathologic features. L1 cell adhesion molecule expression was an independent poor prognostic factor for disease-free survival in patients with gallbladder carcinoma. Taken together, our findings suggest that L1 cell adhesion molecule expression could be used as a novel prognostic factor for patient survival and might be a potential therapeutic target in gallbladder carcinomas.</P>

Inhibition of MicroRNA-92a Improved Erectile Dysfunction in Streptozotocin-Induced Diabetic Rats via Suppressing Oxidative Stress and Endothelial Dysfunction

Tang Zhe,Song Jingyu,Yu Zhe,Cui Kai,Ruan Yajun,Liu Yang,Wang Tao,Wang Shaogang,Liu Jihong,Yang Jun 대한남성과학회 2023 The World Journal of Men's Health Vol.41 No.1

Purpose: To determine whether microRNA could be a therapy target of erectile dysfunction (ED) and the underlying mecha-nisms. Materials and Methods: Eight-week-old fasting male SD rats were intraperitoneally injected with streptozotocin to construct diabetic rat models. Diabetic ED rats were treated with miRNA-92a inhibitor. The cavernous nerves were electrically stimu-lated to measure the intracavernous pressure and mean arterial pressure of rats in each group. After the detection, the penile cavernous tissues are properly stored for subsequent experiments. Rat aortic endothelial cells were used in in vitro studies. Results: The expression of miR-92a was significantly increased in the corpus cavernosum of Streptozocin (STZ)-induced di- abetic rats and injection of miR-92a antagomir into the corpus cavernosum of diabetic rats significantly increased eNOS/NO/ cGMP signaling pathway activities, cavernous endothelial cell proliferation, endothelial cell-cell junction protein expression and decreased the levels of oxidative stress. These changes restored erectile function in STZ-induced diabetic rats. Moreover, in vitro study demonstrated that the miR-92a expression increased significantly in endothelial cells treated with high glucose, inhibiting AMPK/eNOS and AMPK/Nrf2/HO-1 signaling pathways in rat aortic endothelial cells via targeting Prkaa2, causing endothelial dysfunction and overactive oxidative stress, miR-92a inhibitor can improve the above parameters. Conclusions: miRNA-92a inhibitor could exert an inhibition role on oxidative stress and endothelial dysfunction to improve diabetic ED effectively.

Microstructure design for blended feedstock and its thermal durability in lanthanum zirconate based thermal barrier coatings

Song, Dowon,Paik, Ungyu,Guo, Xingye,Zhang, Jing,Woo, Ta-Kwan,Lu, Zhe,Jung, Sung-Hoon,Lee, Je-Hyun,Jung, Yeon-Gil Elsevier 2016 Surface & coatings technology Vol.308 No.-

<P><B>Abstract</B></P> <P>The effects of microstructure design on the lifetime performance of lanthanum zirconate (La<SUB>2</SUB>Zr<SUB>2</SUB>O<SUB>7</SUB>; LZO)-based thermal barrier coatings (TBCs) were investigated through various thermal exposure tests, such as furnace cyclic thermal fatigue, thermal shock, and jet engine thermal shock. To improve the thermal durability of LZO-based TBCs, composite top coats using two feedstock powders of LZO and 8wt.% yttria-doped stabilized zirconia (8YSZ) were prepared by mixing in different volume ratios (50:50 and 25:75, respectively). In addition, buffer layers were introduced in layered LZO-based TBCs deposited using an air-plasma spray method. The TBC with the double buffer layer showed the best thermal cycle performance among all samples in all tests. For applications with relatively slow cooling rates, the thermal durability in single-layer TBCs is more effectively enhanced by controlling a composition ratio in the blended powder, better than introducing a single buffer layer. For applications with relatively fast cooling rates, the thermal durability can be effectively improved by introducing a buffer layer than controlling a composition in the top coat, since the buffer layer provides fast localized stress relief due to its high strain compliance. These research findings allow us to control the TBC structure, and the buffer layer is efficient in improving thermal durability in cyclic thermal environments.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Thermal durability in La<SUB>2</SUB>Zr<SUB>2</SUB>O<SUB>7</SUB> based TBCs has been investigated. </LI> <LI> Cyclic thermal exposure tests were employed in determining thermal durability. </LI> <LI> Buffer layer can improve the thermal durability of TBC in fast cooling rates. </LI> <LI> Blended composition can enhance the thermal durability of TBC in slow cooling rates. </LI> <LI> TBC with a double buffer layer showed the most outstanding thermal durability in all tests. </LI> </UL> </P>

A Revocable Fingerprint Template for Security and Privacy Preserving

( Zhe Jin ),( Andrew Beng Jin Teoh ),( Thian Song Ong ),( Connie Tee ) 한국인터넷정보학회 2010 KSII Transactions on Internet and Information Syst Vol.4 No.6

With the wide deployment of biometric authentication systems, several issues pertaining security and privacy of the biometric template have gained great attention from the research community. To resolve these issues, a number of biometric template protection methods have been proposed. However, the design of a template protection method to satisfy four criteria, namely diversity, revocability and non-invertibility is still a challenging task, especially performance degradation when template protection method is employed. In this paper, we propose a novel method to generate a revocable minutiae-based fingerprint template. The proposed method consists of feature extraction from fingerprint minutiae pairs, quantization, histogram binning, binarization and eventually binary bit-string generation. The contributions of our method are two fold: alignment-free and good performance. Various experiments on FVC2004 DB1 demonstrated the effectiveness of the proposed methods.

Realization of Fractional Order Controllers by Using Multiple Tuning-Rules

Zhe Yan,Jing He,Yingyan Li,Kai Li,Changqi Song 보안공학연구지원센터(IJSIP) 2013 International Journal of Signal Processing, Image Vol.6 No.6

여성에서 왜 우울증이 많은가?

송지영,이광철 경희대학교 2002 慶熙醫學 Vol.18 No.3-4

Managing Knowledge Transfer in MNCs

Yu Zhe Miao,Soon Kyoo Choe,Jae Yong Song 한국경영학회 2009 한국경영학회 통합학술발표논문집 Vol.2009 No.08

중국 초등학생이 지각한 부모의 양육방식과 동생에 대한 수용성의 관계에서 자존감과 자기애의 매개효과

Li, Zhe,오인수(Oh, Insoo),송지연(Song, Jiyeon) 연세대학교 교육연구소 2020 미래교육학연구 Vol.33 No.1

본 연구는 중국 초등학생이 지각한 부모의 양육방식이 동생에 대한 수용성에 영향을 미치는 관계에서 자존감과 자기애(외현적 자기애와 내현적 자기애)의 매개효과를 검증하였다. 이를 검증하기 위해 중국 산서성(山西省) 진중시(晋中市)에 소재한 7개 초등학교에서 5, 6학년 학생을 대상으로 설문조사를 하여 동생이 있는 666명 학생의 응답을 토대로 경로 분석을 하였다. 연구결과, 첫째, 자존감은 부모의 민주적 양육방식과 동생에 대한 수용성의 관계에서 부분 매개하고, 허용적 양육방식과 동생에 대한 수용성의 관계에서 매개하지 않으며 권위주의적 양육방식과 동생에 대한 수용성 관계에서 완전매개하는 것으로 확인되었다. 둘째, 외현적 자기애와 내현적 자기애 모두 부모의 민주적 양육방식과 동생에 대한 수용성의 관계에서 부분매개 하고 허용적 양육방식 및 권위주의적 양육방식과 동생에 대한 수용성의 관계에서는 완전매개하는 것으로 확인되었다. 따라서 중국 초등학생이 부모의 양육방식을 민주적으로 지각할수록 자존감과 외현적 자기애를 높이고 내현적 자기애를 낮춰 동생에 대한 수용성을 높이는 것을 확인하였다. 이러한 결과를 바탕으로 초등학생의 자존감과 외현적 자기애를 높이고 내현적 자기애를 낮추는 측면에서 동생에 대한 수용성을 높이는 중요성을 제시하고 논의하였다. This study examined the mediating effects of self-esteem and narcissism (external narcissism and internal narcissism) in the relationship between parental parenting style and sibling acceptance among elementary school students in China. To verify this, a questionnaire survey was conducted in 7 elementary schools in Jinzhong city, Shanxi province, China, and a path analysis was conducted based on the responses of 666 students with younger siblings. The results of this study are as follows: first, self-esteem had a partial mediating effect on the relationship between democratic parenting style and sibling acceptance, and did not have a mediating effect between the permissive parenting style and sibling acceptance. while it had a completely mediating effect on the relationship between authoritarian parenting style and siblings acceptance. Second, both external narcissism and internal narcissism had a partial mediating effect on the relationship between democratic parenting style and sibling acceptance, and had a completely mediating effect on the relationship between permissive parenting/authoritarian parenting style and sibling acceptance. Based on these results, the importance of enhancing the acceptance of siblings in terms of enhancing self-esteem, external narcissism and lowering internal narcissism was suggested and discussed.