An Improved Active Damping Method with Capacitor Current Feedback

Yi-Wen Geng,Ya-Wen Qi,Hai-Wei Liu,Fei Guo,Peng-Fei Zheng,Yong-Gang Li,Wen-Ming Dong 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.2

Proportional capacitor current feedback active damping (CCFAD) has a limited valid damping region in the discrete time domain as (0, fs/6). However, the resonance frequency (fr) of an LCL-type filter is usually designed to be less than half the sampling frequency (fs) with the symmetry regular sampling method. Therefore, (fs/6, fs/2) becomes an invalid damping region. This paper proposes an improved CCFAD method to extend the valid damping region from (0, fs/6) to (0, fs/2), which covers all of the possible resonance frequencies in the design procedure. The full-valid damping region is obtained and the stability margin of the system is analyzed in the discrete time domain with the Nyquist criterion. Results show that the system can operate stably with the proposed CCFAD method when the resonance frequency is in the region (0, fs/2). The performances at the steady and dynamic state are enhanced by the selected feedback coefficient H and controller gain Kp. Finally, the feasibility and effectiveness of the proposed CCFAD method are verified by simulation and experimental results.

Non-Doped Organic Light-Emitting Diodes with Saturated Red Emission

Fei Xiao,Bing-xian Shao,Huan-rong Wu,Hui-ying Fu,Xiao-yuan Hou,Xin-dong Gao,Yi-qiang Zhan 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.2

Non-doped organic light-emitting diodes with saturated red emission were fabricated using 4-(2-(3,3-dicyanomethylene-5,5-dimethyl-1-cyclohexylidene)vinyl)phenyldi(1-naphthyl)amine (DNP-2CN) or 4-(2-(3,3-dicyanomethylene-5,5-dimethyl-1-cyclohexylidene)vinyl)phenyl(1-naphthyl)phe- nylamine (DPN-2CN) as the emitting layer. Different electron-transporting materials, tris(8-hydroxylquinoline) aluminum (Alq$_3$), 2,2',2''-(1,3,5-phenylene)tris[1-phenyl-1$H$-benzimidazole] (TPBI) and 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), were introduced into the devices for examining their energy level compatibility of DNP-2CN or DPN-2CN. The device with a structure of ITO/ NPB/ DNP-2CN/ BCP/ Alq$_3$/ LiF/ Al showed red emission with $\lambda_{max}$ at 670 nm (CIE coordinates: $x$ = 0.66, $y$ = 0.33) and a high luminance of 438 cd m$^{-2}$ at a driving voltage of 12 V. The device with a structure of ITO/ NPB/ DPN-2CN/ BCP/ Alq$_3$/ LiF/ Al showed a high brightness of 225 cd m$^{-2}$ at a driving voltage of 12 V with $\lambda_{max}$ at 674 nm (CIE coordinates: $x$ = 0.65, $y$ = 0.33).

Low temperature oxidation characteristics analysis of ultra-heavy oil by thermal methods

Yi-Bo Li,Ya-Fei Chen,Wan-Fen Pu,Hong Dong,Hao Gao,Fa-yang Jin,Bing Wei 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.48 No.-

To study the oxidation behavior of heavy oils, low temperature oxidation experiments under differentialtemperature and pressure conditions were carried out for both heavy oils (ordinary heavy and ultraheavyoils) with thermogravimetry (TG–DTG)/differential scanning calorimeter (DSC) analyses. And theresults indicated that the differences of physical properties and oxidation reactions for the heavy oilsascribe to the SARA compositions, H/C ratio and specific oxidation path. Owing to the asphaltenescontent, the ultra-heavy oil after the oxidation has more obvious coke deposition with lower activationenergy demand to make it possible for the in-situ combustion without combustion adjuvants.

An Improved Active Damping Method with Capacitor Current Feedback

Geng, Yi-Wen,Qi, Ya-Wen,Liu, Hai-Wei,Guo, Fei,Zheng, Peng-Fei,Li, Yong-Gang,Dong, Wen-Ming The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.2

Proportional capacitor current feedback active damping (CCFAD) has a limited valid damping region in the discrete time domain as (0, $f_s/6$. However, the resonance frequency ($f_r$) of an LCL-type filter is usually designed to be less than half the sampling frequency ($f_s$) with the symmetry regular sampling method. Therefore, ($f_s/6$, $f_s/2$) becomes an invalid damping region. This paper proposes an improved CCFAD method to extend the valid damping region from (0, $f_s/6$ to (0, $f_s/2$), which covers all of the possible resonance frequencies in the design procedure. The full-valid damping region is obtained and the stability margin of the system is analyzed in the discrete time domain with the Nyquist criterion. Results show that the system can operate stably with the proposed CCFAD method when the resonance frequency is in the region (0, $f_s/2$). The performances at the steady and dynamic state are enhanced by the selected feedback coefficient H and controller gain $K_p$. Finally, the feasibility and effectiveness of the proposed CCFAD method are verified by simulation and experimental results.

Risk Factors, Patterns, and Outcomes of Late Recurrence after Liver Resection for Patients with Hepatocellular Carcinoma (Analysis of a Multicenter Cohort over 15 Years)

( Xin-fei Xu ),( Jiong-jie Yu ),( Ju-dong Li ),( Hao Xing ),( Jun Han ),( Zhen-li Li ),( Han Wu ),( Han Zhang ),( Jian-hong Zhong ),( Yi- Sheng Huang ),( Ya-hao Zhou ),( Ting-hao Chen ),( Hong Wang ) 대한간학회 2018 춘·추계 학술대회 (KASL) Vol.2018 No.1

Aims: Late recurrence (> 2 years) after liver resection of hepatocellular carcinoma (HCC) is usually considered as multi-centric tumors or de novo cancer formation. We aimed to investigate risk factors, patterns and outcomes of late recurrence after HCC resection. Methods: From a multicenter database from 2001 to 2015, 734 patients who were alive and recurrence-free at 2 years after curative resection of initial HCC were enrolled into this retrospective study. Univariate and multivariate Cox-regression analysis were used to identify independent risk factors of late recurrence. Patterns, treatments and outcomes of late recurrence were investigated and analyzed. Results: During a median follow-up of 78.0 months after surgery, 303 patients (41.3%) developed late recurrence. Multivariate analysis revealed that cirrhosis, macroscopic vascular invasion, satellites, and tumor size > 5cm were independent risk factors of late recurrence. Among them, 273 (90.1%) were sole intrahepatic recurrence, 30 (9.9%) were concurrent intrahepatic and extrahepatic recurrence, and none of them was sole extrahepatic recurrence; 165 (54.4%) patients received curative treatments for recurrent HCC, including re-resection, transplantation and local ablation. Multivariate analysis showed regular postoperative surveillance and receiving curative treatments were two independent protective factors of prolonging survival for those patients with late recurrence. Conclusions: Late recurrence is correlated with cirrhosis and certain tumor-related characteristics of initial HCC. The patterns of late recurrence suggest that postoperative surveillance after 2 years of surgery could be adjusted and more targeted. Regular postoperative surveillance improves the probability to receive curative treatments again, yielding to better outcomes for patients with late recurrence.

Preoperative Prealbumin Level as an Independent Predictor of Long-Term Prognosis after Curative Liver Resection of Hepatocellular Carcinoma (a Multicenter Study of 1,483 Patients)

( Ju-dong Li ),( Xin-fei Xu ),( Jiong-jie Yu ),( Jia-he Wang ),( Li- Yang Sun ),( Wen-tao Yan ),( Bing Quan ),( Jian-hong Zhong ),( Yi-sheng Huang ),( Ya-hao Zhou ),( Ting-hao Chen ),( Hong Wang ),( W 대한간학회 2018 춘·추계 학술대회 (KASL) Vol.2018 No.1

Aims: Serum prealbumin is more sensitive to profile nutritional status and liver function than albumin, which could hardly be affected by infusion supplement. This study aims: to identify the relationship between preoperative prealbumin level and the long-term prognosis after curative resection of hepatocellular carcinoma (HCC). Methods: Patients undergone HCC curative resection between 2001 and 2014 at six institutions in China were enrolled. By using 170 mg/dl as cut-off value of serum prealbumin level, these patients were divided into the low and normal preoperative prealbumin groups. The overall survival (OS) and recurrence-free survival (RFS) were analyzed and compared. Univariable and multivariable Cox-regression analyses were performed to identify predictive factors of OS and RFS. Results: Among 1,483 patients, 437 (29.5%) had a low prealbumin level within a week before surgery. The 1-, 3-, and 5-year OS and RFS rates of patients in the low prealbumin group were 83.8, 57.0, and 31.1%, and 67.0, 39.8, and19.9%, respectively, which was significantly poorer than those in the normal group (93.0, 75.5, and 42.6%, and 77.0, 56.4, and 28.4%, both P<0.001). Multivariable analyses revealed that preoperative prealbumin level, but not albumin level, was an independent predictor of OS (HR, 1.789; 95% CI: 1.544 -2.072, P<0.001) and RFS (HR, 1.420; 95% CI: 232-1.636, P<0.001). Conclusions: Preoperative prealbumin level is useful for predicting long-term prognosis in patients undergoing liver resection for HCC. Prealbumin may be suitable to displace albumin, yielding to an updated Child-Pugh grade for accessing liver function.

Effect of metallic copper on the electrothermal properties of carbon nanofibers

He‑Dong Huang,Hao Pu,Jun‑Wei Fan,Bing Su,Hong‑Yang Liu,Xin‑Yi Ha,Yong‑Fei Ren,Ze‑yu Guo 한국탄소학회 2024 Carbon Letters Vol.34 No.4

Effects of zinc sources and levels of zinc amino acid complex on growth performance, hematological and biochemical parameters in weanling pigs

Zhang, Yi,Ward, Terry Lynn,Ji, Fei,Peng, Chucai,Zhu, Lin,Gong, Limin,Dong, Bing Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.8

Objective: The objective of the study was to investigate the effects of zinc amino acid complex (ZnAA) on growth performance, hematological and biochemical parameters in weanling pigs. Methods: In Exp. 1, a total of 216 Duroc${\times}$Landrace${\times}$Large White weanling pigs were assigned randomly to 6 dietary treatments. Each treatment had 6 replicates (pens) with 6 pigs each. The diets were corn-soybean meal based with supplementation of 0, 20, 40, 80, 120 mg Zn/kg from ZnAA or 40 mg Zn/kg from feed-grade zinc sulfate. The experiment lasted 42 days. In Exp. 2, a total of 180 weanling pigs were assigned randomly to 3 dietary treatments supplemented with 0, 80, or 800 mg Zn/kg from ZnAA. Results: In Exp. 1, pigs fed 40 to 80 mg Zn/kg from ZnAA had higher (p<0.05) average daily gain (ADG) than the unsupplemented group during d 0 to 14. During d 0 to 42, the pigs fed 20 to 120 mg Zn/kg from ZnAA had increased (p<0.05) ADG. Pigs fed 20 to 120 mg/kg Zn from ZnAA had lower feed:gain (p<0.05), increased the activity of serum Cu-Zn superoxide dismutase on d 14, and increased serum Zn levels on d 42 (p<0.05). In Exp. 2, pigs fed diets with 800 mg Zn/kg had increased average daily feed intake during d 15 to 28 (p<0.05) compared to the unsupplemented group. During d 0 to 28, the pigs fed supplemental Zn had increased ADG (p<0.05). On d 14 and d 28, pigs fed supplemental Zn had higher the serum alkaline phosphatase activities (p<0.05). No significant differences were observed in the hematological parameters and organ indices. Conclusion: Supplementation with 20 to 80 mg/kg Zn from ZnAA improved the growth performance in weaned pigs. The piglets can tolerate up to 800 mg/kg Zn from ZnAA with limited potential health effects.

5‑Methoxytryptophan pretreatment alleviates lipopolysaccharide‑induced cardiac injury and dysfunction

Fu Yang,Dong Yi-Fei 한국응용생명화학회 2022 Applied Biological Chemistry (Appl Biol Chem) Vol.65 No.3

Reducing inflammation is a promising therapeutic approach for sepsis-induced cardiomyopathy (SIC). The 5-Methoxytryptophan (5-MTP) is a tryptophan metabolite that demonstrates anti-inflammatory, anti-fibrosis, anti-tumorigenesis, and anti-senescence features. Current investigations aimed to assess the 5-MTP pretreatment impacts on lipopolysaccharide (LPS)-induced cardiac injury and dysfunction. For in vivo studies, the mice were categorized randomly into four groups: control, LPS, LPS+5-MTP (25 mg/kg) and LPS+5-MTP (50 mg/kg). The mice in the LPS+5-MTP groups were given 5-MTP intraperitoneally once a day for 7 days. LPS (10 mg/kg) was then administered intraperitoneally for 24 h. Echocardiography, cardiac injury biomarkers, and H & E staining evaluated heart anatomy and function. The findings indicate that 5-MTP pretreatment significantly reduced LPS-induced heart dysfunction and morphological alterations. Western blot assay was used for investigating molecular mechanisms. After LPS stimulation, the pro-inflammatory cytokines (IL-1β, IL-6, TNF-α and NLRP3) protein levels increased while anti-inflammatory cytokine (IL-10) decreased; however, 5-MTP pretreatment mitigated this response by suppressing the stimulation of the NF-κB signaling pathway. Furthermore, 5-MTP administration reduced LPS-induced cardiac apoptosis, as demonstrated by increased protein levels of cleaved-Casepase-1, cleaved-Casepase-3 and Bax, and decreased protein level of Bcl-2 after LPS stimulation, whereas LPS-induced cardiac apoptosis was reversed by 5-MTP pretreatment. In vitro, 5-MTP pretreatment had a similar cardioprotective effect on cultured cardiac fibroblasts challenged with LPS. In conclusion, 5-MTP pretreatment can reduce LPS-induced cardiac inflammation and apoptosis, implying that 5-MTP is a possible therapeutic option for SIC.

Experimental Study on the Static Strain Aging of Q345 Steel Using Complementary In-Situ Non-destructive Testing Techniques

Zhou Wei,Li Dong-qi,Su Yi-fan,Zhang Yi-fei 한국강구조학회 2024 International Journal of Steel Structures Vol.24 No.3

The detection of the static strain aging extent of steel structures holds paramount signifi cance in the safety assessment system. Tensile tests were performed on Q345 steel specimens subjected to static strain aging treatment, while simultaneously employing complementary in-situ detection techniques: acoustic emission, infrared thermography, and digital image correlation for real-time monitoring. The physical eff ect mechanism is initially confi rmed through an analysis of the mechanical response of strain aging Q345 steel. The acoustic emission signals from the cluster 3 exhibiting high frequency and low amplitude are linked to the microplastic yield phenomenon. These signals, detected through acoustic emission technology, are considered representative of the dislocation activity in Q345 steel after strain aging. Illustrating via specimen S16-150, it is evident that as strain aging advances, there is a notable decrease of 63.02% in information entropy, 22.4% in partial power, and 55.04% in the wavelet coeffi cient of typical acoustic emission signals. Subsequently, digital image correlation was utilized to examine the local strain variation associated with microplastic deformation, and it was observed that Lüders bands did not form in specimens S12-150 and S16-150 due to strain aging. Finally, infrared technology was employed to monitor the instantaneous temperature of strain aging Q345 steel, facilitating the examination of its thermal energy conversion effi ciency. Specimen S16-200 exhibited a fracture instantaneous temperature that was 21% higher compared to specimen S0-25. These fi ndings establish a solid foundation for the integrity assessment of steel structures.