Combined Study on Mold Taper and Corner Radius in Bloom Continuous Casting by FEM Simulation and Trial Experiment

Peng Lan,Liang Li,Zhanpeng Tie,Haiyan Tang,Jiaquan Zhang 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.6

A plane stress model was developed to study the coupled effect of mold taper and corner radius on the thermal–mechanicalbehavior of a 250 mm × 280 mm continuously cast bloom for a given special steel. Good agreement was obtained in both shellthickness and the off-corner cracking location from modeling and trial experiment. The results show that increasing moldtaper results in the obvious decrease of surface temperature near the corner, while enlarging mold corner radius makes theshell surface temperature at the corner region more even with the mold taper between 0 and 1.5% m−1. It is also found thatboth the mold corner radius and taper are the key factors influencing the shell crack sensitivity but with different mechanism. For the internal crack, the mold taper takes more dominant effect for its corner radius between 0–10 mm, as the hoop strainat the solidification front decreases with increasing mold taper. For the surface crack, more sensitivity is noticed to the moldcorner radius. Increasing mold corner radius leads to the increase of the surface hoop strain in the corner region, almostregardless of mold taper. The proper mold taper and corner radius for the present bloom casting should be 1.0–1.5% m−1and 15–25 mm respectively.

Heat Transfer and Solidification Microstructure Evolution of Continuously Cast Steel by Non-Steady Physical Simulation

Peng Lan,Diem Ai Nguyen,이수연,조정욱 대한금속·재료학회 2017 METALS AND MATERIALS International Vol.23 No.3

The heat transfer and solidification microstructure evolution during continuous casting were experimentally studiedin this work. A new approach to physically simulate the steel solidification behavior during continuous castingwas developed. Six steel grades with different solidification mode were introduced to elucidate the carbon equivalentdependent mold heat flux, prior austenite grain size and secondary dendrite arm spacing. It is found that thenon-steady mold heat fluxes in the experiment against time for all steel grades are comparative to that versus distancein practical continuous casting. Due to the occurrence of L→L+δ→δ+γ→γ transformation with the largestamount of volume contraction in hypo-peritectic steel, it shows the lowest mold heat flux among these six steelgrades. It is also demonstrated from the solidification microstructure results that the prior austenite grain size andsecondary dendrite arm spacing in the physical simulation are in good agreement with those in continuously caststrand. In addition, the steel with a higher temperature for the onset of δ→γ transformation reveals the larger prioraustenite grains resulted from the higher grains growth rate in the post solidification process.

Optimal Power Allocation and Relay Selection for Cognitive Relay Networks using Non-orthogonal Cooperative Protocol

( Peng Lan ),( Lizhen Chen ),( Guowei Zhang ),( Fenggang Sun ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.5

In this paper, we investigate joint power allocation and relay selection (PARS) schemes in non-orthogonal cooperative protocol (NOCP) based cognitive relay networks. Generally, NOCP outperforms the orthogonal cooperative protocol (OCP), since it can provide more transmit diversity. However, most existing PARS schemes in cognitive relay networks focus on OCP, which are not suitable for NOCP. In the context of NOCP, we first derive the joint constraints of transmit power limit for secondary user (SU) and interference constraint for primary user (PU). Then we formulate optimization problems under the aforementioned constraints to maximize the capacity of SU in amplify-and-forward (AF) and decode-and-forward (DF) modes, respectively. Correspondingly, we derive the closed form solutions with respect to different parameters. Numerical results are provided to verify the performance improvement of the proposed PARS schemes.

Realgar transforming solution suppresses angiogenesis and tumor growth by inhibiting VEGF receptor 2 signaling in vein endothelial cells

Peng Song,Yang Hai,Xin Wang,Longhe Zhao,Baoqiang Chen,Peng Cui,Qin-Jian Xie,Lan Yu,Yang Li,Zhengrong Wu,Hong Yu Li 대한약학회 2018 Archives of Pharmacal Research Vol.41 No.4

Realgar (As4S4), as an arsenic sulfide mineraldrug, has a good therapeutic reputation for anticancer inTraditional Chinese Medicine, and has recently beenreported to inhibit angiogenesis in tumor growth. However,considering the poor solubility and low bioavailability ofrealgar, large dose of realgar and long period of treatmentare necessary for achieving the effective blood medicineconcentration. In present study, we resolved the crucialproblem of poor solubility of realgar by using intrinsicbiotransformation in microorganism, and investigatedunderlying mechanisms of realgar transforming solution(RTS) for antiangiogenesis. Our results demonstrated thatRTS had a strong activity to inhibit HUVECs proliferation,migration, invasion, and tube formation. Moreover, RTSinhibited VEGF/bFGF-induced phosphorylation ofVEGFR2 and the downstream protein kinases includingERK, FAK, and Src. In vivo zebrafish and chickenchorioallantoic membrane model experiments showed thatRTS remarkably blocked angiogenesis. Finally, comparedwith the control, administration of 2.50 mg/kg RTSreached more than 50% inhibition against H22 tumorallografts in KM mice, but caused few toxic effects in thehost. The antiangiogenic effect was indicated by CD31immunohistochemical staining and alginate-encapsulatedtumor cell assay. In summary, our findings suggest thatRTS inhibits angiogenesis and may be a potential drugcandidate in anticancer therapy.

The simple and easy way to manufacture counter electrode for dye-sensitized solar cells

Jo-Lin Lan,Yung-Yun Wang,Chi-Chao Wan,Tzu-Chien Wei,Hsien-Ping Feng,Chao Peng,Hai-Peng Cheng,Ya-Huei Chang,Wen-Chi Hsu 한국물리학회 2010 Current Applied Physics Vol.10 No.2

We previously developed poly-N-vinyl-2-pyrrolidone (PVP)-capped Pt nanoclusters on ITO glass via a simple ‘‘2-step dip coating process” as counter electrode for DSSC. This new counter electrode was examined by transmission electron microscopy (TEM), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and current–voltage curve (I–V curve). The TEM results revealed that PVP-capped Pt nanoclusters’ size is about 3 nm, and the amount of Pt deposited on ITO glass is about 5 ㎍/㎠. Comparing with sputtered Pt and Solaronix thermal cluster Pt-catalyst T/SP, the PVP-capped Pt counter electrode has lower amount of Pt deposited on TCO glass,more positive potential of tri-iodide reduction, and better performance for the charge-transfer resistance (RCT) and the cell efficiency (g).

cAMP induction by ouabain promotes endothelin-1 secretion via MAPK/ERK signaling in beating rabbit atria

Peng, Li-qun,Li, Ping,Zhang, Qiu-li,Hong, Lan,Liu, Li-ping,Cui, Xun,Cui, Bai-ri The Korean Society of Pharmacology 2016 The Korean Journal of Physiology & Pharmacology Vol.20 No.1

Adenosine 3',5'-cyclic monophosphate (cAMP) participates in the regulation of numerous cellular functions, including the $Na^+-K^+$-ATPase (sodium pump). Ouabain, used in the treatment of several heart diseases, is known to increase cAMP levels but its effects on the atrium are not understood. The aim of the present study was to examine the effect of ouabain on the regulation of atrial cAMP production and its roles in atrial endothelin-1 (ET-1) secretion in isolated perfused beating rabbit atria. Our results showed that ouabain ($3.0{\mu}mol/L$) significantly increased atrial dynamics and cAMP levels during recovery period. The ouabain-increased atrial dynamics was blocked by KB-R7943 ($3.0{\mu}mol/L$), an inhibitor for reverse mode of $Na^+-Ca^{2+}$ exchangers (NCX), but did not by L-type $Ca^{2+}$ channel blocker nifedipine ($1.0{\mu}mol/L$) or protein kinase A (PKA) selective inhibitor H-89 ($3.0{\mu}mol/L$). Ouabain also enhanced atrial intracellular cAMP production in response to forskolin and theophyline ($100.0{\mu}mol/L$), an inhibitor of phosphodiesterase, potentiated the ouabain-induced increase in cAMP. Ouabain and 8-Bromo-cAMP ($0.5{\mu}mol/L$) markedly increased atrial ET-1 secretion, which was blocked by H-89 and by PD98059 ($30{\mu}mol/L$), an inhibitor of extracellular-signal-regulated kinase (ERK) without changing ouabain-induced atrial dynamics. Our results demonstrated that ouabain increases atrial cAMP levels and promotes atrial ET-1 secretion via the mitogen-activated protein kinase (MAPK)/ERK signaling pathway. These findings may explain the development of cardiac hypertrophy in response to digitalis-like compounds.

Forest Fire Detection Solution Based on UAV Aerial Data

Lan Zhang,Bing Wang,Weilong Peng,Chao Li,Zeping Lu,Yan Guo 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.8

Treatment of fever with traditional Chinese medicine according to Zheng on cancer patients (based on case reports)

Peng Cao,Lan-Ying Liu,Xue-Ting Cai,Xiao-Ning Wang,Jie-Ge Huo,Zhong-Ying Zhou 셀메드 세포교정의약학회 2012 셀메드 (CellMed) Vol.2 No.2

Fever in cancer patients is often due to the following causes: evil qi and toxity stagnancy, disorders of qi and blood, deficiencies of zang and fu organs, and the disorder of yin and yang. The treatments given to cancer patients with a fever are according to five: (a) Excessive inner heat and toxicants: remove heat and the toxicant, induce purgation. We use Cheng-Qi-Tang plus Qing-Wen-Bai-Du-Yin. (b) Tangle of damp and heat, and qi stagnancy: remove damp and heat, smooth the qi channel. We use Gan-Lu-Xiao-Du-Dan or San-Ren-Tang. (c) Obvious blood and heat stagnancy: remove heat and blood stasis. We use Xue-Fu-Zhu-Yu-Tang. (d) Deficiency of spleen qi, inner heat caused by a yin deficiency: nourish spleen qi and yin to remove the inner heat. We use Bu-Zhong-Yi-Qi-Tang or Xiao-Jian-Zhong-Tang. (e) Prominent yin deficiency and hectic fever: replenish yin and remove inner heat. We use Qing-Hao-Bie-Jia-Tang or Chai-Qian-Mei-Lian-San. The pathogenesis of fever in cancer patients is complicated. We can see both deficiency and excess in one differentiation. Therefore, we must make sure of it, then we can get the most effective treatment.

The triply periodic minimal surface-based 3D printed engineering scaffold for meniscus function reconstruction

Lan Li,Peng Wang,Jing Jin,Chunmei Xie,Bin Xue,Jiancheng Lai,Liya Zhu,Qing Jiang 한국생체재료학회 2022 생체재료학회지 Vol.26 No.4

Background: The meniscus injury is a common disease in the area of sports medicine. The main treatment for this disease is the pain relief, rather than the meniscal function recovery. It may lead to a poor prognosis and accelerate the progression of osteoarthritis. In this study, we designed a meniscal scaffold to achieve the purposes of meniscal function recovery and cartilage protection. Methods: The meniscal scaffold was designed using the triply periodic minimal surface (TPMS) method. The scaffold was simulated as a three-dimensional (3D) intact knee model using a finite element analysis software to obtain the results of different mechanical tests. The mechanical properties were gained through the universal machine. Finally, an in vivo model was established to evaluate the effects of the TPMS-based meniscal scaffold on the cartilage protection. The radiography and histological examinations were performed to assess the cartilage and bony structures. Different regions of the regenerated meniscus were tested using the universal machine to assess the biomechanical functions. Results: The TPMS-based meniscal scaffold with a larger volume fraction and a longer functional periodicity demonstrated a better mechanical performance, and the load transmission and stress distribution were closer to the native biomechanical environment. The radiographic images and histological results of the TPMS group exhibited a better performance in terms of cartilage protection than the grid group. The regenerated meniscus in the TPMS group also had similar mechanical properties to the native meniscus. Conclusion: The TPMS method can affect the mechanical properties by adjusting the volume fraction and functional periodicity. The TPMS-based meniscal scaffold showed appropriate features for meniscal regeneration and cartilage protection.

Influences of Wire Diameters on Output Power in Electromagnetic Energy Harvester

Yan Peng,Lan Zhang,Zhongjie Li,Songyi Zhong,Yong Liu,Shaorong Xie,Jun Luo 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.1

In this paper, we systematically investigate how the wire diameter affects the output performance of electromagnetic energy harvesters. The harvesters with the same structure but different coils mainly comprised of a magnet array, two coil arrays, a pair of springs and a housing. Different discrete wire diameters of coils are selected to compare the output performance and explore the optimal value. We first set up the theoretical model of the configuration to predict optimal wire diameter and conduct simulations to observe open-circuit voltage and output power, and find the hypothetically optimal diameter leading to the best performance. Subsequently, we fabricate a series of prototypes and conduct four groups of experiments from the following aspects for comparison purposes: constant frequency excitation, frequency sweep, impedance matching and charging capacitors, and validate the theoretically estimated value. When we operate the prototypes under the excitation of 20 Hz, 1.0 g, the maximum average power of 37.45 mW is generated with the best wire diameter, at least 1.62 times as high as that in other cases. The results of capacitor charging experiments, i.e., charging rate, further validate the output power trend. This study can be of great significance for power density improvement in electromagnetic energy harvesters.