Plasmonic Newton's cradle for low-loss subwavelength energy transport: Homogeneous or heterogeneous nanoparticle chains?

Wang Ningning,Wang Qiuyan,Huang Yuan 한국물리학회 2021 Current Applied Physics Vol.27 No.-

Five closely spaced Au or Ag NPs are linearly arranged in analogy with Newton’s cradle, forming various homogeneous and heterogeneous NP chains. Using small NPs, the Au–Ag–Ag–Ag–Au heterochain has the lowest propagation loss (17.6%) at short resonance wavelengths. When the NP diameter is increased to 80 nm, the dominant resonance is shifted to longer wavelengths. As low as 6% of the total energy dissipates in the intermediate NP component, and there seems to be little difference between the Au–Ag–Ag–Ag–Au heterochain and the Ag–Ag–Ag–Ag–Ag homochain. Besides the wavelength-dependent intrinsic loss (i.e., the imaginary part of the permittivity) in metals, the real part of the permittivity also plays a critical role in determining the propagation loss. Considering the high fabrication cost of the heterochain, the homochain composed of moderately large Ag NPs (<100 nm) may be an optimal choice for low-loss subwavelength energy transport in practice.

Green preparation of lipase@Ca3(PO4)2 hybrid nanoflowers using bone waste from food production for efficient synthesis of clindamycin palmitate

Anming Wang,Xinxin Chen,Jianyun Yu,Ningning Li,Huimin Li,Youcheng Yin,Tian Xie,Stephen Gang Wu 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.89 No.-

To prepare enzyme@Ca3(PO4)2 for environmentally friendly biocatalysis, Ca2+ and (PO4)3 were extractedfrom bone waste by acidification. In the nearly neutralizedfiltrate, the Ca2+ and (PO4)3 formed aCa3(PO4)2 sediment that crystallized on a template of Thermomyces lanuginosus lipase (TLL) at 4 ℃ for24 h, producing enzyme@Ca3(PO4)2-Bone hybrid nanoflowers (hNFs). Clindamycin palmitate wasefficiently synthesized by transfer of a palmityl moiety from vinyl palmitate to clindamycin free baseusing these hNFs as a biocatalyst. At 30 ℃ in petroleum ether (PE) as the solvent, the yield of the TLL hNFcatalyzedreaction was as high as 70.0%. Even at a high temperature (80 ℃), the yield in the hNF-catalyzedreaction was still 52.6%, but no product was detected when using free lipase as the catalyst. Moreover, thehNFs retained 90% of their initial activity after 10 cycles (120 h, 12 h per cycle). This green and sustainablemethod that utilizes bone waste from food production as the raw source of the inorganic component wasfacile and efficient, and the system may also be applicable for preparing other enzyme@Ca3(PO4)2 hNFsfor industrial applications.

Functional roles and mechanisms of ginsenosides from Panax ginseng in atherosclerosis

Qianqian Xue,Ningning He,Zhibin Wang,Xiuxiu Fu,Lynn Htet Htet Aung,Yan Liu,Min Li,Jae Youl Cho,Yanyan Yang,Tao Yu 고려인삼학회 2021 Journal of Ginseng Research Vol.45 No.1

Atherosclerosis (AS) is a leading cause of cardiovascular diseases (CVDs) and it results in a high rate of death worldwide, with an increased prevalence with age despite advances in lifestyle management and drug therapy. Atherosclerosis is a chronic progressive inflammatory process, and it mainly presents with lipid accumulation, foam cell proliferation, inflammatory response, atherosclerotic plaque formation and rupture, thrombosis, and vascular calcification. Therefore, there is a great need for reliable therapeutic drugs or remedies to cure or alleviate atherosclerosis and reduce the societal burden. Ginsenosides are natural steroid glycosides and triterpene saponins obtained mainly from the plant ginseng. Several recent studies have reported that ginsenosides have a variety of pharmacological activities against several diseases including inflammation, cancer and cardiovascular diseases. This review focuses on describing the different pharmacological functions and underlying mechanisms of various active ginsenosides (Rb1,-Rd, -F, -Rg1, -Rg2, and -Rg3, and compound K) for atherosclerosis, which could provide useful insights for developing novel and effective anti-cardiovascular drugs.

Preparation and characterization of a novel graphene/biochar composite and its application as an adsorbent for Cd removal from aqueous solution

Yan Li,Ningning Song,Kairong Wang 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.5

A novel graphene/biochar composite (BG composite) was synthesized by mixing graphene (Gr) onto feedstock biomass followed by slow pyrolysis. The composite was then tested for its sorption capacity of Cd from aqueous solutions. Structure and morphology analysis showed that graphene was coated on the biochar surface, resulting in a larger surface area, more functional groups, greater thermal stability, and higher removal efficiency of Cd in comparison to unmodified biochar. The sorption capacity of the BG composite for Cd was 1.26-2.36 times that of biochar. A pseudo second-order model adequately simulated sorption kinetics. The sorption isotherms were simulated well by Langmuir models, and calculated maximum Cd adsorption capacities did not change significantly with increasing temperature. Thermodynamic parameters showed that the sorption process of Cd onto the BG composite was feasible and spontaneous. The results of the adsorption experiments, as well as the characteristics of biochar, demonstrate that the process of Cd adsorption on BG composites is mainly physical adsorption accompanied by other chemical adsorption phenomena, such as complexation and ion exchange. This study highlights the use of a BG composite as a multifunctional adsorbent for the efficient, economic, and environmentally friendly treatment of pollutants.

A study of P release from Fe-P and Ca-P via the organic acids secreted by Aspergillus niger

Tian Da,Wang Liyan,Hu Jun,Zhang Liangliang,Zhou Ningning,Xia Jingjing,Xu Meiyue,Yusef Kianpoor Kalkhajeh,Wang Shimei,Li Zhen,Gao Hongjian 한국미생물학회 2021 The journal of microbiology Vol.59 No.9

Phosphate solubilizing fungi (PSF) have been widely applied to dissolve insoluble phosphates (IPs). However, the PSF usually demonstrates a different phosphate solubilizing capacity for various IPs. This study explored the mechanisms of Aspergillus niger for the dissolution of ferric phosphate (FePO4, Fe-P), and tricalcium phosphate (Ca3[PO4]2, Ca-P) regarding the tricarboxylic acid (TCA) cycle. Aspergillus niger has higher phosphorus (P) content released from Ca-P, reached the maximum value of 861 mg/L after seven days of incubation, compared with the 169 mg/L from Fe-P. Oxalic acid promoted the release of P from Ca-P through the formation of calcium oxalate. The presence of Fe-P can stimulate A. niger to secrete large amounts of citric acid, confirmed by the enhancement of citrate synthase (CS) activity. However, citric acid only promotes 0.5% of P released from Fe-P. Meanwhile, although oxalic acid still dominates the release of P from Fe-P, its abundance was significantly declined. In contrast, oxalic acid also shows a higher P release ratio in Ca-P than citric acid, i.e., 36% vs. 22%. This study points to the future usage of A. niger to dissolve IPs in soil required to enhance oxalic acid secretion.

Adaptive Chaotic Gray Wolf Optimizer-Based Optimization of Decentralized AGC and Power Dispatching Controllers for Integrated Energy System with Heterogeneous Power Sources

Li Zhongwen,Bai Ningning,Cheng Zhiping,Wang Yi,Si Jikai 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.2

With the increasing use of renewable energy sources connected to inverters in modern power systems, traditional units’ rotary inertia and frequency regulation capacity are becoming inadequate. Therefore, exploring various types of frequency regulation resources is essential. However, these resources come with diferent system models, capacities, and response speeds, posing a signifcant challenge to automatic generation control (AGC). To address this issue and enhance the frequency regulation performance of these resources, a novel distributed coordination AGC method is proposed. The proposed method allows each frequency regulation unit to utilize a separate load frequency control (LFC) controller to participate in frequency regulation based on the area control error information calculated by the dispatching center. To ensure the coordination between the heterogeneous frequency regulation resources, an adaptive chaotic gray wolf algorithm is proposed to tune the parameters of the LFC controller. Furthermore, to release the fast frequency regulation ability of high-speed frequency regulation units and better prepare for the next round of frequency regulation service, an event-triggered power dispatching strategy is proposed. Simulation results of a single-area power system with fve diferent frequency regulation units demonstrate the superior performance of the proposed AGC method.

Correction: Adaptive Chaotic Gray Wolf Optimizer-Based Optimization of Decentralized AGC and Power Dispatching Controllers for Integrated Energy System with Heterogeneous Power Sources

Li Zhongwen,Bai Ningning,Cheng Zhiping,Wang Yi,Si Jikai 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

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On DC-Side Impedance Frequency Characteristics Analysis and DC Voltage Ripple Prediction under Unbalanced Conditions for MMC-HVDC System Based on Maximum Modulation Index

Yiqi Liu,Qichao Chen,Ningning Li,Bing Xie,Jianze Wang,Yanchao Ji 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.1

In this study, we first briefly introduce the effect of circulating current control on the modulation signal of a modular multilevel converter (MMC). The maximum modulation index is also theoretically derived. According to the optimal modulation index analysis and the model in the continuous domain, different DC-side output impedance equivalent models of MMC with/without compensating component are derived. The DC-side impedance of MMC inverter station can be regarded as a series xR + yL + zC branch in both cases. The compensating component of the maximum modulation index is also related to the DC equivalent impedance with circulating current control. The frequency characteristic of impedance for MMC, which is observed from its DC side, is analyzed. Finally, this study investigates the prediction of the DC voltage ripple transfer between two-terminal MMC high-voltage direct current systems under unbalanced conditions. The rationality and accuracy of the impedance model are verified through MATLAB/Simulink simulations and experimental results.

Curcumin Ameliorates Reserpine-Induced Gastrointestinal Mucosal Lesions Through Inhibiting IκB-α/NF-κB Pathway and Regulating Expression of Vasoactive Intestinal Peptide and Gastrin in Rats

Lingli Long,Jingnan Wang,Ningning Chen,Shuhui Zheng,Lanying Shi,Yuxia Xu,Canqiao Luo,Yubin Deng 한국식품영양과학회 2016 Journal of medicinal food Vol.19 No.6

The objective of our study was to investigate whether curcumin protects against reserpine-induced gastrointestinal mucosal lesions (GMLs) in rats and to explore the mechanism of curcumin’s action. Sprague-Dawley rats were randomly divided into four groups: control group, reserpine-treated group, reserpine treatment group with curcumin at high dose (200 mg/kg), and reserpine treatment group with curcumin at low dose (100 mg/kg). Rats in reserpine-treated group were induced by intraperitoneally administered reserpine (0.5 mg/kg) for 28 days. TUNEL staining and hematoxylin and eosin staining were used to evaluate the apoptotic cells and morphologic changes. In addition, to explore the mechanism of curcumin in protecting GMLs, we used serum of experimental rats to assess the level of vasoactive intestinal peptide (VIP), gastrin, interleukin-6, interleukin-10, tumor necrosis factor-α and interferon-γ by ELISA and radioimmunoassay. The protein levels of NF-κB, p-IκB-α, IκB-α, Bcl-2, Bax, and cleaved-caspase-3 were examined by western blot analysis. Data were analyzed with SPSS 19.0 software package. Curcumin treatment prevented tissue damage and cell death in the reserpinetreated rats and effectively decreased inflammatory response and balanced the expression of VIP and gastrin in the reserpinetreated rats. NF-κB, p-IκB-α, Bax, and cleaved-caspase-3 were increased in the reserpine group, but the curcumin high-dose group inhibited them. Curcumin can target the IκB-α/NF-κB pathway to inhibit inflammatory response and regulate the level of VIP and gastrin in reserpine-induced GML rats.

Axial Hole Air-Entraining Cooling Technique of Radial-Flow Turbines

Ma Chao,Zhang Jianjian,Wang Ningning,Zhu Zhifu 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.5

In response to the continually increasing thermal load caused by the rising gas temperature in the inlet of radial-flow turbines, this paper proposes the use of axial hole air-entraining cooling to cool the turbine shaft and turbo wheel back-disc. The cooling effect of this technique, as well as its influence on the aerodynamic performance of turbines, were investigated through numerical simulations. The results demonstrate that the axial hole air-entraining cooling technique can significantly improve the local cooling efficiency of the turbine back-disc. Under a blowing ratio of 0.25 %, the local cooling efficiency increased by 154 %, and the temperature decreased by up to 233 K. The maximum temperature on the surface of the turbine shaft at the floating bearing location decreased significantly, thus reducing the coking risk of the lubricating oil. When the blowing ratio was within 0.5 %, the impact of this cooling technique on the overall turbine performance was negligible.