Numerical analysis of unsteady hydrodynamic performance of pump-jet propulsor in oblique flow

Qiu, Chengcheng,Pan, Guang,Huang, Qiaogao,Shi, Yao The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.1

In this study, the SST k - ω turbulence model and the sliding mesh technology based on RANS method have been adopted to simulate the exciting force and hydrodynamic of a pump-jet propulsor in different oblique inflow angle (0°, 10°, 20°, 30°) and different advance ratio (J = 0.95, J = 1.18, J = 1.58).The fully structured grid and full channel model have been adopted to improved computational accuracy. The classical skewed marine propeller E779A with different advance ratio was carried out to verify the accuracy of the numerical simulation method. The grid independence was verified. The time-domain data of pump-jet propulsor exciting force including bearing force and fluctuating pressure in different working conditions was monitored, and then which was converted to frequency domain data by fast Fourier transform (FFT). The variation laws of bearing force and fluctuating pressure in different advance ratio and different oblique flow angle has been presented. The influence of the peak of pulsation pressure in different oblique flow angle and different advance ratio has been presented. The results show that the exciting force increases with the increase of the advance ratio, the closer which is to the rotor domain and the closer to the blades tip, the greater the variation of the pulsating pressure. At the same time, the exciting force decrease with the oblique flow angle increases. And the vertical and transverse forces will change more obviously, which is the main cause of the exciting force. In addition, the pressure distribution and the velocity distribution of rotor blades tip in different oblique flow angles has been investigated.

Numerical analysis of unsteady hydrodynamic performance of pump-jet propulsor in oblique flow

Qiu, Chengcheng,Pan, Guang,Huang, Qiaogao,Shi, Yao The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.-

In this study, the SST k - ω turbulence model and the sliding mesh technology based on RANS method have been adopted to simulate the exciting force and hydrodynamic of a pump-jet propulsor in different oblique inflow angle (0°, 10°, 20°, 30°) and different advance ratio (J = 0.95, J = 1.18, J = 1.58).The fully structured grid and full channel model have been adopted to improved computational accuracy. The classical skewed marine propeller E779A with different advance ratio was carried out to verify the accuracy of the numerical simulation method. The grid independence was verified. The time-domain data of pump-jet propulsor exciting force including bearing force and fluctuating pressure in different working conditions was monitored, and then which was converted to frequency domain data by fast Fourier transform (FFT). The variation laws of bearing force and fluctuating pressure in different advance ratio and different oblique flow angle has been presented. The influence of the peak of pulsation pressure in different oblique flow angle and different advance ratio has been presented. The results show that the exciting force increases with the increase of the advance ratio, the closer which is to the rotor domain and the closer to the blades tip, the greater the variation of the pulsating pressure. At the same time, the exciting force decrease with the oblique flow angle increases. And the vertical and transverse forces will change more obviously, which is the main cause of the exciting force. In addition, the pressure distribution and the velocity distribution of rotor blades tip in different oblique flow angles has been investigated.

Sandwich Structure Electrode as Advanced Performance Anode for Lithium-Ion Batteries

Wei Chengcheng,Sun Xiaogang,Liang Guodong,Huang Yapan,Hu Hao,Xu Yuhao 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.10

In this work, a sandwich structure electrode was prepared by a simple vacuum filtration and rolling process. The SEM showed that the active materials were uniformly embedded in the pores of the three-dimensional conductive network of the carbon nanotube (CNTs) conductive paper. The contact interface area of active material and the conductive network significantly increased and the interface resistance was greatly reduced. The porous anode can accommodate the volume expansion of the silicon and effectively alleviated pressed during cycle. The electrode also exhibited good stability in cycles. Electrochemical tests showed that the first discharge specific capacity of the sandwich electrode reached 2330 mAh/g with a coulombic efficiency of 86%. After 500 cycles, the specific capacity was still maintained at 1512 mAh/g. At a large current density of 2 A/g, the specific capacity hold was 840 mAh/g compared with the copper foil electrode of 100 mAh/g.

Computational investigation of three-faced blade errors on contact behaviors for face-hobbed hypoid gears

Chaosheng Song,Chengcheng Liang,Caichao Zhu,Kunming Liu,Siyuan Liu,Qianhong Huang 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.7

An accurate mathematical model of face-hobbed hypoid gear tooth surface based on the three-faced blade is established. The correctness of the mathematical model was verified by comparing the contact pattern results from KIMOS software and finite element tooth contact analysis. Then, the effects of tool errors on mesh characteristics of face-hobbed hypoid gear were investigated by loaded tooth contact analysis. Results show that the influences of pressure angle error and regrind angle error on contact pattern are obvious. The location of contact pattern moves from the root on the heel side to the top on the toe side of the tooth surface when the error value increases. The peak-to-peak value of transmission error gradually increases with those two types of errors. The influences of spheric radius error, rake angle error and cutting side relief angle error on contact behaviors are similar and not obvious for facehobbed hypoid gears.

Dose-Dense Rituximab-CHOP versus Standard Rituximab-CHOP in Newly Diagnosed Chinese Patients with Diffuse Large B-Cell Lymphoma: A Randomized, Multicenter, Open-Label Phase 3 Trial

Xueying Li,He Huang,Bing Xu,Hongqiang Guo,Yingcheng Lin,Sheng Ye,Jiqun Yi,Wenyu Li,Xiangyuan Wu,Wei Wang,Hongyu Zhang,Derong Xie,Jiewen Peng,Yabing Cao,Xingxiang Pu,Chengcheng Guo,Huangming Hong,Zhao 대한암학회 2019 Cancer Research and Treatment Vol.51 No.3

Purpose Rituximab with cyclophosphamide, doxorubicin, vincristine, and prednisone administered every 3 weeks (R-CHOP-21) is the standard care for diffuse large B-cell lymphoma (DLBCL). It is unknown whether the dose-dense R-CHOP (R-CHOP-14) could improve the outcome of the disease in Asian population. Materials and Methods Newly diagnosed DLBCL patients were centrally, randomly assigned (1:1) to receive R-CHOP- 14 or R-CHOP-21. R-CHOP-14 was administered every 2 weeks, and R-CHOP-21 was administered every 3 weeks. Primary end point was disease-free survival (DFS). Secondary end points included overall survival (OS), progression-free survival (PFS), response rate and toxicities. Results Seven hundred and two patients were randomly assigned to receive R-CHOP-14 (n=349) or R-CHOP-21 (n=353). With a median follow-up of 45.6 months, the two groups did not differ significantly in 3-year DFS (79.6% for R-CHOP-14 vs. 83.2% for R-CHOP-21, p=0.311), 3-year OS (77.5% for R-CHOP-14 vs. 77.6% for R-CHOP-21, p=0.903), or 3-year PFS (63.2% for R-CHOP-14 vs. 66.1% for R-CHOP-21, p=0.447). Patients with an International Prognostic Index (IPI) score ! 2 had a poorer prognosis compared to those with an IPI score < 2. Grade 3/4 hematologic and non-hematologic toxicities were manageable and similar between R-CHOP-14 and R-CHOP-21. Conclusion R-CHOP-14 did not improve the outcome of DLBCL compared to R-CHOP-21 in Asian population. With manageable and similar toxicities, both of the two regimens were suitable for Asian DLBCL patients. For high-risk patients with IPI ! 2, new combination regimens based on R-CHOP deserve further investigation to improve efficacy.

Electrochemical Properties of Supercapacitors Using Boron Nitrogen Double-Doped Carbon Nanotubes as Conductive Additive

Hao Hu,Xiaogang Sun,Wei Chen,Jie Wang,Xu Li,Yapan Huang,Chengcheng Wei,Guodong Liang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.7

Carbon nanotubes (CNTs) were doped by ammonium borate as the sources of nitrogen and boron. Under the protection of Ar gas, boron-nitrogen doped CNTs were prepared through nitriding and boronization at high temperature. It is a conductive additive. Then, the obtained CNTs were mixed with activated carbon (AC), SP, sodium dodecyl sulfate (SDS), and cellulose fiber to prepare electrodes. With all the materials, a symmetric electric double-layer supercapacitor (EDLC) was assembled. Next, the materials and electrodes were also characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The factors, chemical connections, and specific surface area of the CNTs were analyzed by X-ray energy spectrum analysis (EDS), X-ray photoelectron spectroscopy (XPS), as well as a specific surface area and porosimetry analyzer (BET). In addition, the electrochemical performances of electric double-layer capacitors were tested with the help of cyclic voltammetry, constant-current charging and discharging, and so on. From the results, we can make a conclusion, that is, both B and N atoms were added into the CNTs and formed bonds successfully with carbon atoms mutually. Besides, the specific surface area is about 1.5 times than that of the CNT. When the charge/discharge current density reaches 50 mA/g, we can find that the mass specific capacitance of the capacitor can run up to 32.19 F/g. Also, we observe that the maximum power density is close to 220 W/kg (700 mA/g), and the energy density can arrive 9.31 Wh/kg (50 mA/g). Based on the impedance test, the electrodes are characterized with low impedance. After 2000 cycles, the boron-nitrogen doped double-layer capacitors maintain a capacitance retention ratio of above 95%. Its power density can still achieve 220 W/kg when the energy density keeps at 3.46 Wh/kg. In other words, the electrochemical performance functions of the electric double-layer capacitors are enhanced while the CNTs serve as the electrodes.

Dirac semimetal-enabled multi-bit coding metasurface for dynamic manipulation of terahertz beams

Zhang Yonggang,Yin Kehao,Liang Lanju,Yao Haiyun,Yan Xin,Hu Xiaofei,Huang Chengcheng,Qiu Fu,Zhang Rui,Li Yuanping,Wang Yaru,Li Zhenhua,Wang Ziqun 한국물리학회 2024 Current Applied Physics Vol.58 No.-

In this study, a switchable multi-bit coding metasurface that is applied under a terahertz (THz) frequency by adjusting the Fermi level (EF) of Dirac semimetals (DSMs) is proposed. At a EF of 0.2 eV, a 1-bit coding metasurface can be applied in the 2.58–2.62 THz. At 0.3 eV, a 3-bit coding metasurface is realized at 1.88 THz, and at 0.05 eV, the phase of the coding units coincides in the 1.5–3 THz. So, different functions of the metasurface can be realized. The proposed coding metasurfaces has promising applications in terahertz communication.

Research on the Comprehensive Benefit Evaluation of Electric Vehicle Technology Promotion and Application Under the Strategic Background of “Carbon Peaking and Carbon Neutrality”

Jia Dexiang,Li Xinda,Guo Shaodong,Liu Fang,Fu Chengcheng,Huang Xingde,Dong Zhen,Liu Jing 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

On the one hand, as a substitute for traditional fuel vehicles, electric vehicles (EV) is an important measure to achieve “carbon peak and carbon neutralization” in transportation. On the other hand, as an energy storage unit in the new power system, it can make up for the disadvantages brought by renewable energy power generation. Therefore, scientifc and efective evaluation of EV benefts is the premise to promote the development of EV. In view of the characteristics of EV involving many interest groups and huge market potential, this paper introduces the comprehensive evaluation theory in operations research: analytic hierarchy process (AHP) and entropy weight method, and combines the respective advantages of the two methods to avoid the distortion of evaluation results caused by a single evaluation method. First of all, under the background of building a new power system and realizing a powerful automobile country, the EV promotion beneft evaluation index system is constructed from fve frst-class indexes and 18 s-class indexes of consumers, distribution network, charging network, social beneft and environmental beneft. Then, aiming at the shortcomings of single evaluation method, the subjective and objective combination method of AHP entropy weight method is established to solve each weight index, so as to realize the scientifc quantifcation of the index. Finally, a certain area of a coastal city is selected for example analysis. The results show that the evaluation method established in this paper has a positive efect on EV promotion, and can provide suggestions for EV promotion.

The natural product salicin alleviates osteoarthritis progression by binding to IRE1α and inhibiting endoplasmic reticulum stress through the IRE1α-IκBα-p65 signaling pathway

Zhu Zhenglin,Gao Shengqiang,Chen Cheng,Xu Wei,Xiao Pengcheng,Chen Zhiyu,Du Chengcheng,Chen Bowen,Gao Yan,Wang Chunli,Wang Chunli,Huang Wei 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Despite the high prevalence of osteoarthritis (OA) in older populations, disease-modifying OA drugs (DMOADs) are still lacking. This study was performed to investigate the effects and mechanisms of the small molecular drug salicin (SA) on OA progression. Primary rat chondrocytes were stimulated with TNF-α and treated with or without SA. Inflammatory factors, cartilage matrix degeneration markers, and cell proliferation and apoptosis markers were detected at the mRNA and protein levels. Cell proliferation and apoptosis were evaluated by EdU assays or flow cytometric analysis. RNA sequencing, molecular docking and drug affinity-responsive target stability analyses were used to clarify the mechanisms. The rat OA model was used to evaluate the effect of intra-articular injection of SA on OA progression. We found that SA rescued TNF-α-induced degeneration of the cartilage matrix, inhibition of chondrocyte proliferation, and promotion of chondrocyte apoptosis. Mechanistically, SA directly binds to IRE1α and occupies the IRE1α phosphorylation site, preventing IRE1α phosphorylation and regulating IRE1α-mediated endoplasmic reticulum (ER) stress by IRE1α-IκBα-p65 signaling. Finally, intra-articular injection of SA-loaded lactic-co-glycolic acid (PLGA) ameliorated OA progression by inhibiting IRE1α-mediated ER stress in the OA model. In conclusion, SA alleviates OA by directly binding to the ER stress regulator IRE1α and inhibits IRE1α-mediated ER stress via IRE1α-IκBα-p65 signaling. Topical use of the small molecular drug SA shows potential to modify OA progression.