Simulation Analysis of Potential Energy Recovery System of Hydraulic Hybrid Excavator

Peng-Yu Zhao,Ying-Long Chen,Hua Zhou 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.11

A new hydraulic hybrid excavator potential energy recovery system is proposed in this paper. The energy recovery system uses threechamber cylinders (TCCs) and accumulators to recover potential energy during work cycle. Within this structure, there is no throttle valve in the primary loop, and the recovered energy is stored in the form of hydraulic energy. Hence, energy loss of throttle valve and energy conversion process are avoided, and energy efficiency is improved. The mathematical model is established to analyze dynamic and energy recovery characteristics. From simulation analysis, the usage of accumulators and TCC influences the dynamic response and stability. The increase of accumulator volume weakens the control performance but heightens the stability. When the cross sectional area of the TCC increases, the control performance of the system are improved. In addition, the maximum power and energy consumption of pumps and engine with different accumulator volumes and different TCC diameters are obtained. Also, the maximum power and energy consumption of each pump and engine in different working conditions are obtained and compared with those without potential energy recovery system. According to the comparison, the potential energy recovery system can reduce the maximum power and energy of engine by 50%.

Mechanical properties and cushioning mechanism of shear thickening fluid

Peng Zhao,Qian Chen,Xue Gao,Zhaoyong Wu 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.11

Shear thickening fluid (STF) is one type of dispersed system with rapidly changing rheological properties under an impulse load. The apparent viscosity of such a suspension system changes dramatically under high-speed impact, and the system can even change from suspension to quasi-solid. Once the load is removed, the STF will quickly return to its original state. In this paper, a mechanical model based on a particle-jammed model and added mass was proposed by calculating the acceleration response of the impact bar, and the local hardening phenomenon of STF in the low-speed impact test was interpreted. Then with the low-speed impact test, the rheological properties of STF in the cushioning process were recorded by a high-speed camera. Meanwhile, a comparison was made with the cushioning efficiency of AV-200, a closed-cell foam material, by using the force-displacement curve. Finally, based on the constitutive relation of STF and by using the fluid-solid coupling method in the FEM, the lowspeed impact test of STF was analyzed to obtain more comprehensive dynamic characteristics. The acceleration response obtained in the test was consistent with the theoretical results, which further verified the rationality and effectiveness of the theoretical model. Compared with AV-200, STF has a cushioning efficiency of 50 %-60 %, and its cushioning performance was superior to AV-200. Starting with the rheological cloud map of STF and the acceleration response of the impact bar by the numerical model, a comparison was made with the results of low-speed impact test, and a good agreement is observed.

Aberrant Expression of HOXA5 and HOXA9 in AML

Zhao, Peng,Tan, Li,Ruan, Jian,Wei, Xiao-Ping,Zheng, Yi,Zheng, Li-Xia,Jiang, Wei-Qin,Fang, Wei-Jia Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.9

Background: Aberrant expression of HOX gene expression has been observed in cancer. The purpose of this study was to investigate the alteration of HOXA5 and HOXA9 expression and their clinical significance in acute meloid leukemia (AML). Materials and Methods: The expression of HOXA5 and HOXA9 genes of bone marrow samples from 75 newly diagnosed AML patients and 22 healthy controls for comparison were examined by Real-time quantitative PCR (RQ-PCR) assay. Statistical analysis was conducted to evaluate HOXA5 and HOXA9 expression as possible biomarkers for AML. Results: The results showed that the complete remission rate (52.6%) of the patients who highly expressed HOXA5 and HOXA9 was significantly lower than that (88.9%) in patients who lowly express the genes (P=0.015). Spearmann correlation coefficients indicated that the expression levels for HOXA5 and HOXA9 genes were highly interrelated (r=0.657, P<0.001). Meanwhile, we detected significant correlations between HOXA9 expression and age in this limited set of patients (P=0.009). Conclusions: The results suggest a prognostic impact of increased expression of HOXA5 and HOXA9 in AML patients.

A Review of Computational Phantoms for Quality Assurance in Radiology and Radiotherapy in the Deep-Learning Era

Peng Zhao,Gao Ning,Wu Bingzhi,Chen Zhi,Xu X. George 대한방사선방어학회 2022 방사선방어학회지 Vol.47 No.3

The exciting advancement related to the “modeling of digital human” in terms of a computa- tional phantom for radiation dose calculations has to do with the latest hype related to deep learning. The advent of deep learning or artificial intelligence (AI) technology involving convo- lutional neural networks has brought an unprecedented level of innovation to the field of organ segmentation. In addition, graphics processing units (GPUs) are utilized as boosters for both real-time Monte Carlo simulations and AI-based image segmentation applications. These ad- vancements provide the feasibility of creating three-dimensional (3D) geometric details of the human anatomy from tomographic imaging and performing Monte Carlo radiation transport simulations using increasingly fast and inexpensive computers. This review first introduces the history of three types of computational human phantoms: stylized medical internal radiation dosimetry (MIRD) phantoms, voxelized tomographic phantoms, and boundary representation (BREP) deformable phantoms. Then, the development of a person-specific phantom is demon- strated by introducing AI-based organ autosegmentation technology. Next, a new development in GPU-based Monte Carlo radiation dose calculations is introduced. Examples of applying computational phantoms and a new Monte Carlo code named ARCHER (Accelerated Radia- tion-transport Computations in Heterogeneous EnviRonments) to problems in radiation pro- tection, imaging, and radiotherapy are presented from research projects performed by students at the Rensselaer Polytechnic Institute (RPI) and University of Science and Technology of China (USTC). Finally, this review discusses challenges and future research opportunities. We found that, owing to the latest computer hardware and AI technology, computational human body models are moving closer to real human anatomy structures for accurate radiation dose calcula- tions.

First-principles study of the switching characteristics of the 15,16-dinitrile DDP/CPD-based optical molecular switch with carbon nanotube electrodes

Peng Zhao,Chang-feng Fang,Yi-ming Wang,Ya-xi Zhai,De-sheng Liu 한국물리학회 2009 Current Applied Physics Vol.9 No.6

We have studied the switching characteristics of an optical molecular switch based on the 15,16-dinitrile dihydropyrene/cyclophanediene (DDP/CPD) molecule with two single-walled carbon nanotube (SWCNT) electrodes using first-principles transport calculations. It is shown that the DDP shows an overall higher conductance than the CPD at low bias which is independently of the SWCNT chirality. Meantime, the conductance of the molecular switch can be tuned by the chirality of the SWCNT. We have studied the switching characteristics of an optical molecular switch based on the 15,16-dinitrile dihydropyrene/cyclophanediene (DDP/CPD) molecule with two single-walled carbon nanotube (SWCNT) electrodes using first-principles transport calculations. It is shown that the DDP shows an overall higher conductance than the CPD at low bias which is independently of the SWCNT chirality. Meantime, the conductance of the molecular switch can be tuned by the chirality of the SWCNT.

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.

Anti-tumor effect of novel amino acid Schiff base nickel (II) complexes on oral squamous cell carcinoma cells (CAL-27) in vitro

Zhao Peng,Qiu Haiming,Wei Qiang,Li Yang,Gao Lei,Zhao Peiran 대한독성 유전단백체 학회 2023 Molecular & cellular toxicology Vol.19 No.2

Background Oral squamous cell carcinoma (OSCC) is a common skin/oral malignant tumor. In recent years, advancements in the fi eld of medical technology resulted in signifi cant improvement in the treatment and management of OSCC. However, adverse reactions associated with the application of radiotherapy and chemotherapeutic drugs resulted in a low overall survival rate. Therefore, it is important to develop and explore alternative chemotherapy drugs, which can eff ectively treat OSCC, and clarify their mechanism of action. Objective The present study aimed to investigate the eff ect of three hexa-coordinated octahedral nickel (II) complexes, namely [Ni(sal- L -phe)(phen)(CH 3 OH)] CH 3 OH ( 1 ), [Ni(naph- L -phe)(phen)(CH 3 OH)] ( 2 ), and [Ni( o -van- L -phe)(phen) (CH 3 OH)] 5CH 3 OH ( 3 ), on proliferation, migration, and apoptosis of CAL-27 cells. Results The results of the study showed that complex 3 exhibited sensitive/signifi cant cytotoxicity toward CAL-27 cells, with an IC 50 value of 15.90 mΜ. Further, an assessment of the underlying mechanism showed that complex 3 could signifi cantly increase autophagy and reactive oxygen species (ROS) levels in CAL-27 cells. At the same time, it reduced mitochondrial membrane potential (MMP) in a dose-dependent manner. Additionally, complex 3 might act via inhibition of proliferation and migration of CAL 27 cells and induction of apoptosis, which was mediated via regulation of the expression of Bcl-2 family proteins in vitro. Conclusion The results of the study showed that nickel complexes could potently inhibit the growth of CAL-27 cells, which was mediated via mitochondrial dysfunction, intracellular ROS accumulation, and ROS-mediated DNA damage. Altogether, the fi ndings of the study would provide new leads for the designing and synthesis of novel metal drugs for OSCC.

Research on Peak-detection Algorithm for High-precision Demodulation System of Fiber Bragg Grating

Peng Wang,Xu Han,Simin Guan,Hong Zhao,Minglei Shao 보안공학연구지원센터 2014 International Journal of Hybrid Information Techno Vol.7 No.6

In order to improve the detection accuracy of wavelength, the filtering and curve fitting technologies were applied in the FBG wavelength demodulation system based on tunable F-P filter. These methods could realize the accurate peak-location of output signals of the photo detector. According to the characteristics of noise, the FIR low-pass filter was designed to filter the obtained light power signals so as to provide the input signals with high SNR for the peak-detection algorithms. By analyzing and comparing several typical peak-searching algorithms, the algorithm of Gauss formula nonlinear curve fitting (L-M) was chosen to fit the digitized light power signals. The experimental results show that L-M fitting algorithm reduces the mean square error by 7.5% compared with the Gauss fitting algorithm. For the Gauss signal in the wavelength demodulation system designed in the paper, the L-M algorithm has lower mean square error than other peak-searching algorithms. This algorithm is suitable for FBG wavelength demodulation system based on tunable F-P filter. It can efficiently raise the accuracy of wavelength demodulation system.

The evolution of the Pyongnam basin: Its relationship with the adjacent basins and tectonic implications

Peng Peng,Mingguo Zhai,Jong-Hyok Yang,Chang-Whan Oh,Hyon-Uk Pak,Yanbin Zhang,Lei Zhao,Zhiyue Zhang,Fengbo Sun 대한지질학회 2019 대한지질학회 학술대회 Vol.2019 No.10

Opportunistic Routing for Bandwidth-Sensitive Traffic in Wireless Networks with Lossy Links

Peng Zhao,Xinyu Yang 한국통신학회 2016 Journal of communications and networks Vol.18 No.5

Opportunistic routing (OR) has been proposed as a vi-able approach to improve the performance of wireless multihopnetworks with lossy links. However, the exponential growth ofthe bandwidth-sensitivemobile traffic (e.g.,mobile video streamingand online gaming) poses a great challenge to the performance ofOR in term of bandwidth guarantee. To solve this problem, a novelmechanism is proposed to opportunistically forwarding data pack-ets and provide bandwidth guarantee for the bandwidth-sensitivetraffic. The proposal exploits the broadcast characteristic of wire-less transmission and reduces the negative effect of wireless lossylinks. First, the expected available bandwidth (EAB) and the ex-pected transmission cost (ETC) under OR are estimated basedon the local available bandwidth, link delivery probability, for-warding candidates, and prioritization policy. Then, the policiesfor determining and prioritizing the forwarding candidates is de-vised by considering the bandwidth and transmission cost. Finally,bandwidth-aware routing algorithm is proposed to opportunisti-cally delivery data packets; meanwhile, admission control is ap-plied to admit or reject traffic flows for bandwidth guarantee. Ex-tensive simulation results show that our proposal consistently out-performs other existing opportunistic routing schemes in providingperformance guarantee.