Recent advances in transition metal layered double hydroxide based materials as efficient electrocatalysts

Yi Feng,Lei Chen,Zhong-Yong Yuan 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.120 No.-

The development of efficient electrocatalysts occupies a vital position in achieving efficient energy conversionand storage. Transition-metal-based layered double hydroxides (TM LDHs) featuring unique layeredstructure have received extensive attention in the field of designing highly cost-effectiveelectrocatalysts. Nevertheless, the practical application of TM LDH-based electrocatalysts still faces a seriesof challenges including insufficient active sites, inferior intrinsic conductivity and suboptimal robustness. Throughout this review, the most recent researches dedicated to TM LDH-based electrocatalysts arereviewed in terms of structural features, synthetic strategies, modification approaches and electrocatalyticapplications. This review focuses on the effective modification approaches and important electrochemicalapplications of TM LDHs. This review supplies the conducive tools to select the appropriatetechnics for adequately boosting the electrocatalytic performance of TM LDH-based electrocatalystsand concludes with a salient summary outlining orientations for further research.

“Entanglement of Echoes in Near / Miss” : Bernstein, Charles. Near / Miss Chicago: U of Chicago P, 2018.

( Yi Feng ) 한국영어영문학회 2018 영어 영문학 Vol.64 No.2

Multiscale singular value manifold for rotating machinery fault diagnosis

Yi Feng,Baochun Lu,Dengfeng Zhang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.1

Time-frequency distribution of vibration signal can be considered as an image that contains more information than signal in time domain. Manifold learning is a novel theory for image recognition that can be also applied to rotating machinery fault pattern recognition based on time-frequency distributions. However, the vibration signal of rotating machinery in fault condition contains cyclical transient impulses with different phrases which are detrimental to image recognition for time-frequency distribution. To eliminate the effects of phase differences and extract the inherent features of time-frequency distributions, a multiscale singular value manifold method is proposed. The obtained low-dimensional multiscale singular value manifold features can reveal the differences of different fault patterns and they are applicable to classification and diagnosis. Experimental verification proves that the performance of the proposed method is superior in rotating machinery fault diagnosis.

Global Power Transitions and Their Implications for the 21st Century

Yi Feng 인하대학교 국제관계연구소 2013 Pacific Focus Vol.28 No.2

This essay presents a theoretical approach toward war and peace, reviews basic conditions for world leadership, discusses four modes of global power transitions, illuminates the likely emergence of the future superpowers, and summarizes the differences and common interests between the United States,the incumbent world leader, and China, a potential contender for the global leadership in the 21st century. The theoretical background is powertransition theory, which predicts war when superpowers are close in power and peace when power preponderance exists. Power parity need be also considered in the context of common interests and preferences of superpowers. Conflict abates when the nations share fundamental rules of the game in world affairs. Four historical modes of transitions – co-dominion, deterrence,confrontation, and cooperation – were identified. Of the four historical transitions, each time, the challenger surpassed the hegemon in economic power, and deterrence and confrontation by the hegemon against the challenger did not prevent the challenger from assuming global leadership in the long term. Among the newly rising nations (BRICs), China is discussed as a potential contender for world leadership. The economic and financial interdependence between the United States and China is currently the driving force in their relations. It shapes their political arrangements, necessitating coordination and cooperation in policy issues. While economic collaboration and interdependence drive the relations between the two, they are not suffi-cient conditions for a peaceful transition, until their political and security relations are solidified and their preferences coalesce substantively.

Strength Prediction of a Single Tooth Bound to Composite Pre-tightened Tooth Connection (PTTC) Joints based on Different Failure Criteria

Yifeng Gao,Fei Li,Qilin Zhao,Jiangang Gao,Yubo Hu 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.8

A method capable to predict the strength of single tooth bound to composite pre-tightened tooth connection (PTTC) joints is presented. The proposed method uses four representative failure criteria: max-stress, Tsai-Hill, Tsai-Wu and Hashin. The characteristic length method is also used to obtain prediction strengths. Three types of experiments of single PTTC joints were conducted using the following variations: 1) tooth depth, 2) tooth length, and 3) pre-tightened force. The experimental results were compared with the two-dimensional failure envelope diagram calculated using the four representative failure criteria. The physical nature and the strength predictive ability of each criterion were investigated. The obtained results show that the shear failure mode of single PTTC joint was accurately predicted by all four failure criteria. However, the Tsai-Wu criterion when compared to Maximum Stress, Tsai-Hill and Hashin criteria, exhibits better accuracy regarding the prediction strength of single PTTC joints, this is due to the fact that the Tsai-Wu criterion reflects more accurately the increase in the interlaminar shear strength caused by the transverse compressive stress.

Diffusion-Weighted MR Imaging of Unicystic Odontogenic Tumors for Differentiation of Unicystic Ameloblastomas from Keratocystic Odontogenic Tumors

Yifeng Han,Xindong Fan,Lixin Su,Zhenfeng Wang 대한영상의학회 2018 Korean Journal of Radiology Vol.19 No.1

Objective: Differentiating unicystic ameloblastomas from keratocystic odontogenic tumors (KCOT) is necessary for the planning of different treatment strategies; however, it is difficult based on conventional CT and MR sequences alone. The purpose of this study was to investigate the utility of diffusion-weighted imaging (DWI) and apparent diffusion coefficients (ADCs) in the differentiation of the two tumors. Materials and Methods: We prospectively studied 40 patients with odontogenic cysts and tumors of the maxillomandibular region using conventional MR imaging and DWI. ADCs were measured using 2 b factors (500 and 1000). Results: Unicystic ameloblastomas (n = 11) showed free diffusion on DWI and a mean ADC value of 2.309 ± 0.17 x 10-3 mm2/s. KCOT (n = 15) showed restricted diffusion on DWI with a mean ADC value of 0.923 ± 0.20 x 10-3 mm2/s. The ADC values of unicystic ameloblastomas were significantly higher than those of KCOT (p < 0.001, Mann-Whitney U-test). An ADC cut-off value of 2.0 x 10-3 mm2/s to differentiate KCOT and unicystic ameloblastomas resulted in a 100% sensitivity and 100% specificity. Dentigerous cysts (n = 3) showed restricted diffusion on DWI and similar ADC values (1.257 ± 0.05 x 10-3 mm2/s) to those of KCOT. Conclusion: Diffusion-weighted imaging and ADC determination can be used as an adjuvant tool to differentiate between unicystic ameloblastomas and KCOT, although the ADC values of dentigerous cysts overlap with those of KCOT.

Ameliorative effects of Lycium chinensis on male sexual dysfunction and testicular oxidative damage in streptozotocin-induced diabetic rats

Yifeng Zhou,Opeyemi Joshua Olatunji,Hongxia Chen 한국식품과학회 2019 Food Science and Biotechnology Vol.28 No.4

The root bark of Lycium chinense (LC) has beenreported to have potent antioxidant and antidiabetic properties. In the present study, we investigated the attenuativeeffect of LC against diabetes induced sexual dysfunctionand testicular damages in animal models. Diabetic animalswere treated with LC (100 and 400 mg/kg) once daily for6 weeks. At the end of the treatment, mating behavior testswere performed and the animals were sacrificed for thedetermination of hormonal profile, oxidative stress indicesand sperm analysis. LC administration significantlydecreased blood glucose level, enhancement of theantioxidant enzyme activities, restored altered spermcharacteristics and markedly improved levels of luteinizinghormone, follicle-stimulating hormone and testosterone ascompared to the untreated diabetic animals. Furthermore,LC also improved sperm count, viability, motility,increased the reproductive organs weight. The resultsobtained indicated that L. chinense has beneficial effects indiabetes sexual dysfunction.

Monitoring of bridge overlay using shrinkage-modified high performance concrete based on strain and moisture evolution

Yifeng Ling,Gilson Lomboy,Zhi Ge,Kejin Wang Techno-Press 2023 Structural monitoring and maintenance Vol.10 No.2

High performance concrete (HPC) has been extensively used in thin overlay for repair purpose due to its excellent strength and durability. This paper presents an experiment, where the sensor-instrumented HPC overlays have been followed by dynamic strain and moisture content monitoring for 1 year, under normal traffic. The vibrating wire and soil moisture sensors were embedded in overlay before construction. Four given HPC mixes (2 original mixes and their shrinkage-modified mixes) were used for overlays to contrast the strain and moisture results. A calibration method to accurately measure the moisture content for a given concrete mixture using soil moisture sensor was established. The monitoring results indicated that the modified mixes performed much better than the original mixes in shrinkage cracking control. Weather condition and concrete maturity at early age greatly affected the strain in concrete. The strain in HPC overlay was primarily in longitudinal direction, leading to transverse cracks. Additionally, the most moisture loss in concrete occurred at early age. Its rate was very dependent on weather. After one year, cracking survey was carried out by vision to verify the strain direction and no cracks observed in shrinkage modified mixes.

PRESSURE DROP CHARACTERISTICS OF R410A-OIL MIXTURE FLOW BOILING IN SMALL SMOOTH TUBES

YIFENG GAO,BIN DENG,GUOLIANG DING,HAITAO HU,XIANGCHAO HUANG 대한설비공학회 2010 International Journal of Air-Conditioning and Refr Vol.18 No.2

This study presents experimental frictional pressure drop for R410A/oil mixture flow boiling in small horizontal smooth tubes with inside diameters of 4.18 mm and 2.0 mm. Experimental conditions cover nominal oil concentrations from 0 to 5%. The test results show that the presence of oil enhances two-phase frictional pressure drop about 0–120% and 0–90% at present test conditions for 4.18 mm I.D. smooth tube and 2.0 mm I.D. smooth tube, respectively, and the enhanced effect is more evident at higher vapor qualities where the local oil concentrations are higher. A new correlation to predict the local frictional pressure drop of R410A/oil mixture flow boiling inside conventional size and small smooth tubes is developed based on local properties of refrigerant–oil mixture, and the experimental data of 4.18 mm I.D. and 2.0 mm I.D. smooth tubes and that of 6.34 mm I.D. smooth tube (Hu et al., 2008) are well-correlated with the new correlation.

Discovery of Isoquinolinoquinazolinones as a Novel Class of Potent PPARγ Antagonists with Anti-adipogenic Effects

( Yifeng Jin ),( Younho Han ),( Daulat Bikram Khadka ),( Chao Zhao ),( Kwang Youl Lee ),( Won-jea Cho ) 전남대학교 약품개발연구소 2016 약품개발연구지 Vol.25 No.-

Conformational change in helix 12 can alter ligand-in duced PPARγ activity; based on this reason, isoquinolinoquinazolinones, structural homologs of berberine, were designed and synthesized as PPARγ antagonists. Computational docking and mutational study indicated that isoquinolinoquinazolinones form hydrogen bonds with the Cys285 and Arg288 residues of PPARγ. Furthermore, SPR results demonstrated strong binding affinity of isoquinolinoquinazolinones towards PPARγ. Additionally, biological assays showed that this new series of PPARγ antagonists more strongly inhibit adipocyte differentiation and PPARγ2-induced transcriptional activity than GW9662.