Analysis, Modeling and Control of a Non-grid-connected Source-Load Collaboration Wind-Hydrogen System

Jing Kai,Liu Chang,Cao Xin,Sun Hexu,Dong Yan 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.5

Non-grid-connected wind power water-electrolytic hydrogen production system is an eff ective solution to wind power curtailment. However, the stability of the Source power supply is aff ected by the intermittent and volatility of the wind energy, which will lead to low effi ciency of hydrogen production on the Load. In this paper, a novel non-grid-connected Source-Load collaboration wind-hydrogen system is proposed to adapt to the variation of wind energy, which directly connects the Source wind turbines and the Load hydrogen production devices through a DC bus with a super capacitor group and auxiliary AC grid power supply. For the system, quasi-Z-source rectifi ers with a wide DC voltage adjustment range are developed for the Source and a modular proton exchange membrane (PEM) water electrolytic hydrogen production array is designed for adjusting the Load capacity. The basic architecture and the modelling method of the Source, the Load and DC bus are analyzed. A control strategy for the system is put forward to regulate the size of the PEM array with three diff erent operating modes and DC voltage collaboratively, by which the power fl ow management between the Source and the Load can be realized according to the wind power variation. Finally, two cases are carried out in the presence of diffi dent randomly varying wind power. The results show that the proposed non-grid-connected Source-Load collaboration of the wind-hydrogen system can maximize wind energy utilization of the Source and increase the effi ciency of hydrogen production of the Load in the case of wind power fl uctuations.

Isolation and Characterization of Lactic Acid Bacteria from Fresh Chinese Traditional Rice Wines Using Denaturing Gradient Gel Electrophoresis

Jingkai Jiao,Lanwei Zhang,Huaxi Yi 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.1

Lactic acid bacteria (LAB) are a prevalent bacterial group in rice wine maturation that contributes to flavor, texture, and nutritive value. To better understand LAB diversity in rice wines, 6 rice wine varieties from different regions in China were investigated using denaturing gradient gel electrophoresis (DGGE). Lactobacillus plantarum, L. namurensis, and Pediococcus acidilactici were identified using DGGE. Forty nine isolates were screened using a culture-dependent method. Prominent taxa were identified as Enterococcus sp., Lactobacillus delbrueckii, L. rhamnosus, L. plantarum, and Pediococcus acidilactici. Isolates were grouped and used for fermentation of rice wines. Greater numbers of species involved in fermentation lead to better sensory attributes of wine. DGGE analysis combined with a culture-dependent method can be a tool for investigation of the bacterial compositions of fermented rice wines.

Small Molecule-Based Strategy Promotes Nucleus Pulposus Specific Differentiation of Adipose-Derived Mesenchymal Stem Cells

Jianming Hua,Ning Shen,Jingkai Wang,Yiqing Tao,Fangcai Li,Qixin Chen,Xiaopeng Zhou 한국분자세포생물학회 2019 Molecules and cells Vol.42 No.9

Adipose tissue-derived mesenchymal stem cells (ADSCs) are promising for regenerating degenerated intervertebral discs (IVDs), but the low efficiency of nucleus pulposus (NP)-specific differentiation limits their clinical applications. The Sonic hedgehog (Shh) signaling pathway is important in NP-specific differentiation of ADSCs, and Smoothened Agonist (SAG) is a highly specific and effective agonist of Shh signaling. In this study, we proposed a new differentiation strategy with the use of the small molecule SAG. The NP-specific differentiation and extracellular matrix (ECM) synthesis of ADSCs were measured in vitro, and the regenerative effects of SAG pretreated ADSCs in degenerated IVDs were verified in vivo. The results showed that the combination of SAG and transforming growth factor-β3 (TGF-β3) is able to increase the ECM synthesis of ADSCs. In addition, the gene and protein expression levels of NP-specific markers were increased by treatment with SAG and TGF-β3. Furthermore, SAG pretreated ADSCs can also improve the disc height, water content, ECM content, and structure of degenerated IVDs in vivo. Our new differentiation scheme has high efficiency in inducing NP-specific differentiation of ADSCs and is promising for stem cell-based treatment of degenerated IVDs.

Analysis of contact characteristics of ball screws under the combined loads considering non-uniform load distribution

YongJiang Chen,Jianghai Zhao,Chuangfan Yuan,Jingkai Sun 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

An analysis model of the contact characteristics of the double-nut preloaded ball screw which can consider the combined action of the axial load and the overturning moment is established, the model can consider non-uniform load distribution, and the validity of the model is verified by experiments. Based on this model, the influence of the combined action of axial load and overturning moment on the average value and distribution fluctuation value of the contact angle of the ball screw, the number of unloaded balls, the distribution fluctuation value of the contact load, and the static contact stiffness and other contact parameters are systematically analyzed, and get the following conclusions: The contact parameters of the ball screw are mainly affected by the axial load and the contact state between the ball and the raceway. The gradually increasing axial load basically reduces the influence of the overturning moment on the contact parameters of the ball screw. There is a critical value of the load in the axial direction within the range of the action value of the preload load. Only when the critical value is above the critical value, the contact parameters will change regularly with the changes in the axial stiffness and overturning moment. However, different critical values for the regular variation of contact parameters with axial load and overturning moment vary.

Small Molecule-Based Strategy Promotes Nucleus Pulposus Specific Differentiation of Adipose-Derived Mesenchymal Stem Cells

Hua, Jianming,Shen, Ning,Wang, Jingkai,Tao, Yiqing,Li, Fangcai,Chen, Qixin,Zhou, Xiaopeng Korean Society for Molecular and Cellular Biology 2019 Molecules and cells Vol.42 No.9

Adipose tissue-derived mesenchymal stem cells (ADSCs) are promising for regenerating degenerated intervertebral discs (IVDs), but the low efficiency of nucleus pulposus (NP)-specific differentiation limits their clinical applications. The Sonic hedgehog (Shh) signaling pathway is important in NP-specific differentiation of ADSCs, and Smoothened Agonist (SAG) is a highly specific and effective agonist of Shh signaling. In this study, we proposed a new differentiation strategy with the use of the small molecule SAG. The NP-specific differentiation and extracellular matrix (ECM) synthesis of ADSCs were measured in vitro, and the regenerative effects of SAG pretreated ADSCs in degenerated IVDs were verified in vivo. The results showed that the combination of SAG and transforming growth factor-${\beta}3$ ($TGF-{\beta}3$) is able to increase the ECM synthesis of ADSCs. In addition, the gene and protein expression levels of NP-specific markers were increased by treatment with SAG and $TGF-{\beta}3$. Furthermore, SAG pretreated ADSCs can also improve the disc height, water content, ECM content, and structure of degenerated IVDs in vivo. Our new differentiation scheme has high efficiency in inducing NP-specific differentiation of ADSCs and is promising for stem cell-based treatment of degenerated IVDs.

Recent advances in the food application of electrospun nanofibers

Wei-Hua Han,Xiao Li,Gui-Feng Yu,Bin-Chang Wang,Lin-Peng Huang,Jingkai Wang,Yun-Ze Long 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.110 No.-

Electrospinning (e-spinning) has excellent advantages in producing functional and versatile nanofibersand electrospun (e-spun) nanofibers have a variety of potential applications, including in food industry. This paper reviews the recent progress of e-spinning and food-related e-spun nanofibers, covering ediblenanofibers (natural materials and food ingredients), active food packaging (antibacterial packaging,antioxidant packaging, high temperature and humidity resistant packaging), food filtration membranes,and food sensors. Additionally, we discussed the new trend of combining nanomaterials with food andthe challenges of applying e-spinning in food science. The results indicated that e-spinning is a promisingand efficient alternative for the production of daily and functional food.