Computational analysis of compressibility effects on cavity dynamics in high-speed water-entry

Chen Chen,Tiezhi Sun,Yingjie Wei,Cong Wang 대한조선학회 2019 International Journal of Naval Architecture and Oc Vol.11 No.1

The objective of this study is to analyze the compressibility effects of multiphase cavitating flow during the water-entry process. For this purpose, the water-entry of a projectile at transonic speed is investigated computationally. A temperature-adjusted Tait equation is used to describe the compressibility effects in water, and air and vapor are treated as ideal gases. First, the computational methodology is validated by comparing the simulation results with the experimental measurements of drag coefficient and the theoretical results of cavity shape. Second, based on the computational methodology, the hydrodynamic characteristics of flow are investigated. After analyzing the cavitating flow in compressible and incompressible fluids, the characteristics under compressible conditions are focused upon. The results show that the compressibility effects play a significant role in the development of cavitation and the pressure inside the cavity. More specifically, the drag coefficient and cavity size tend to be larger in the compressible case than those in the incompressible case. Furthermore, the influence of entry velocities on the hydrodynamic characteristics is investigated to provide an insight into the compressibility effects on cavitating flow. The results show that the drag coefficient and the impact pressure vary with the entry velocity, and the prediction formulas for drag coefficient and impact pressure are established respectively in the present study.

Experimental Investigation on the Effect of Curing Condition and Admixture on Meso-Structure of Recycled Aggregate Concrete Based on X-ray CT

Yuzhi Chen,Yingjie Ning,Xudong Chen,Weihong Xuan,Yuzhu Guo 한국콘크리트학회 2023 International Journal of Concrete Structures and M Vol.17 No.3

This study addresses the meso-structure of recycled aggregate concrete with different admixture and c;uring condition. The RCA (Recycled concrete aggregate) with admixture of slag power and fly ash and curing condition of steam was casted. X-ray CT (Computed tomography) was used to obtain meso-structure of RCA, and the pore structure, aggregate, and interface traction zone were analyzed. The results show that steam curing not only increases the pore volume but also makes the pore morphology more complex, the fractal dimension increases, the proportion of spherical pores decreases, and the pores develop from spherical to flat and slender with the increase of steam curing temperature. The porosity of micron pores in recycled aggregate concrete is about 2.3%, in which the pores with aperture less than 300 μm accounts for more than 85%. The thickness of the interface area between recycled aggregate and new mortar is about 200 μm, and the crack width in recycled aggregate is about 300– 400 μm.

『沙石集』における三学観の展開とその思想史的意義 ―多彩な「方便」の視点から―

陳穎傑 ( Chen Yingjie ) 동서대학교 일본연구센터 2021 次世代 人文社會硏究 Vol.17 No.-

本稿は、『沙石集』における三学観と多彩な方便との関連性を分析して、方便の組み合わせが導入される目的とその思想史的意義を考察しようとするものである。 『沙石集』では、三学が「方便」(手段)と「実所」(無相無念)に分けられているように、無住は常に三学の実所を見据え、それを実現できる方便に注目して、神明、和歌陀羅尼、衆生がもつ仏性を戒、定、恵の三学に配当している。かかるプロセスを経て、凡夫であっても悟りを開くことができると無住は信じていた。 鎌倉時代に成立した「禅教律」十宗観において、各宗派は自宗の論理に基づく三学の新解釈を打ち出したが、それらが三学の中の一学に絞り込んだ取捨選択であったため、自宗の論理を誇示すると同時に他の宗派を謗る風潮に拍車をかけた。この問題が、仏法の応用である三学を絶対的、排他的に捉えることによるものと無住は結論を導き出した。したがって、三学を戒定恵に拘らない形、かつ誰でも修行しやすい形で凡夫に説き聞かせることは『沙石集』の筆を起こし始めた最大の理由であり、その結果として、上述した方便の内容が盛り込まれてきたと考えられる。 By analysis of the correlation between Sangaku and Hoben within Shaseki-Shu, the paper describes the combination of Hoben and significant importance in history of thought. In Shaseki-Shu, the writer Muju focused on Hoben which is an efficient method in practice to achieve the goal (Mu). Meanwhile, Muju believed Buddha-nature could be aware of though Sangaku, which means Precept, Rule, and Wisdom. Through the process of Sangaku, Muju believed that people would be enlightened to arrive at a mental state of the no shape, no thought. During the Kamakura period the Zen and Ritsu Sects announced their theories focused on one side of Sangaku, and the expulsion among different denominations came to light. That is when Muju realized that the problem resulted from exclusive understanding about Sangaku. Therefore, Muju started Shaseki-Shu to awake people to Sangaku by concurrent practice instead of dwelling on formalities. Consequently, Shaseki-Shu is loaded with manifold stories of Hoben as awakening to Buddha-nature.

Fault Diagnosis of High Voltage Circuit Breaker Based on Multi‑classifcation Relevance Vector Machine

Yingjie Zhang,Yuan Jiang,Yan Chen,Ying Zhang 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.1

The high voltage circuit breaker’s fault as an important form of electrical contact fault in the power system, which is extremely difcult to diagnose under the condition of small fault dataset. This paper proposes a fault diagnosis method based on multiclassifcation relevance vector machine for high voltage circuit breakers. To make up with the scarcity of the sample fault data in classifying the features of the high voltage circuit breakers, a multi-classifcation relevance vector machine algorithm is designed on the basis of “One-Against-One” multi-classifcation model, and tested by public data-sets to verify the good generating performance of this algorithm on small sample data-sets. Then, the time and the currents features are extracted from the closing coil current information of the high voltage circuit breaker to form fault eigenvector. Consequently, numerous two-classifcation relevance vector machine models were trained and then tested for the optimality of the acquired parameters. The results show that the proposed algorithm can efectively identify many faults of circuit breaker and has better classifcation accuracy than BP neural network and Support Vector Machine under conditions of small sample data.

Metabolism of ginsenosides Rk3 and Rh4 from steamed notoginseng in zebrafish by ultraperformance liquid chromatography/quadrupole-time-of-flight mass spectrometry

Bin Chen,Yingjie Wei,Dandan Wang,Xiaobin Jia 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.8

In this work, the metabolite profiles of ginsenosides Rk3 and Rh4 from steamed notoginseng in zebrafish were qualitatively investigated, and their possible metabolic pathways were subsequently proposed. Metabolites of ginsenosides Rk3 and Rh4 after exposing to zebrafish for 24 h were identified by Ultraperformance Liquid Chromatography/Quadrupole -Time-of-Flight Mass Spectrometry (UPLC-TOF/MS). The separation was performed with a UPLC BEH C18 column using a binary gradient elution of 0.1 % formic acetonitrile -0.1 % formic acid water. The quasi-molecular ions of compounds were detected in negative mode. According to the quasi-molecular ions and MS2 spectra, after comparison with reference standards, molecular mass information and the potential structures about metabolites of ginsenosides Rk3 and Rh4 were obtained. In all, 5 and 6 metabolites of ginsenoside Rk3 and Rh4 including M1(M6), M2(M7), M3–M5 and N1, N2(N7), N3–N6 were identified in zebrafish respectively, which were to our knowledge reported for the first time. The results indicated that ginsenosides Rk3 and Rh4 were metabolized via desugarization, glucuronidation, sulfation, dehydroxylation, and loss of C-17 and C-23 residue pathways in zebrafish. Loss of glucose at position C-6 and glucuronidation at position C-3 or C-6 in zebrafish were considered as the main physiologic processes of ginsenosides Rk3 and Rh4.

Investigation of the Deformation and Failure Characteristics of High-Strength Concrete in Dynamic Splitting Tests

Xudong Chen,Jin Wu,Kai Shang,Yingjie Ning,Lihui Bai 한국콘크리트학회 2022 International Journal of Concrete Structures and M Vol.16 No.6

The dynamic response properties of concrete have been of interest during the use of buildings due to seismic, impact, and explosion events. The splitting Hopkinson lever is a classical device for testing the dynamic mechanical properties of materials. In this paper, dynamic splitting tests on concrete were conducted using it, and a time series predictive computational model for the incident, reflected and transmitted pulses of high-strength concrete specimens at high strain rates was developed, and the extension mechanism of splitting tensile cracks in high-strength concrete was detected and analyzed based on the DIC technique. The results show that: the peak strength of C60 specimens and C80 specimens increased by about 60% and 90%, respectively, from 0.05 MPa to 0.09 MPa in impact strength; the triangular damaged area at the end of the contact surface of the specimen and the rod subjected to high impact pressure increased significantly, the dynamic energy dissipation increased, and the damage degree of the specimens increased; under the action of high strain rate, the brittleness of the concrete specimens with higher strength increased, the damage rate The higher strength concrete specimens have increased brittleness, faster damage rate and higher crack extension under high strain rate. The results of the paper can provide important references for the design of buildings under impact loading.

The role of exosomal miR-181b in the crosstalk between NSCLC cells and tumor-associated macrophages

Ma Junliang,Chen Shaolin,Liu Yingjie,Han Hao,Gong Ming,Song Yongxiang 한국유전학회 2022 Genes & Genomics Vol.44 No.10

Background: It has been reported that tumor-associated macrophages (TAMs) participate in modulating the progression of cancer in the tumor microenvironment. However, the crosstalk between TAMs and non-small cell lung cancer (NSCLC) is still unclear. Objective: We investigated whether NSCLC-derived exosomes could affect TAMs, which feedback modulated progression of NSCLC. Methods: MiR-181b expression was measured by RT-PCR. Human THP-1 monocyte was differentiated into macrophages with phorbol myristate acetate, which were further identified by transmission electron microscopy and western blot. Macrophage M1 and M2 polarizations were detected by flow cytometry, RT-PCR and western blot. Proliferation, migration, and invasion of NSCLC cells treated with conditioned mediums were detected by EdU and Transwell assays. Results: We demonstrated that miR-181b was up-regulated in exosomes derived from NSCLC patients' serum and NSCLC cells. MiR-181b could be transferred to macrophages via exosomes in the co-culture system of macrophages and NSCLC cells, which promoted macrophage M2 polarization. Further examinations revealed that exosomes derived from NSCLC cells could enhanced macrophage M2 polarizations by regulating miR-181b/JAK2/STAT3 axis, and silencing miR-181b in NSCLC cells and JAK2 inhibitor used in macrophages could reverse the effects. Importantly, the conditioned medium of macrophages treated with NSCLC cell-derived exosomes could promote NSCLC cell proliferation, migration, and invasion. Silencing miR-181b in NSCLC cells and JAK2 inhibitor used in macrophages could block the effects. Conclusions: All of these results indicated that exosomal miR-181b participated in the crosstalk between NSCLC cells and TAMs, providing potential therapeutic targets for NSCLC.

Establishment and analysis of thermo-fluid-solid coupling model of ink roller-ink under dynamic pressing contact

Hongyan Chu,Yingjie Hong,Caixia Zhang,Qi Chen,Ruilong Ding,Congbin Yang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7

In order to improve the printing quality, this study focused on the thermo-fluidsolid coupling process of ink roller-ink. One of the highlights of this study is to consider the influence of temperature on the rubber hyperelastic parameters, viscoelastic parameters, and ink viscosity. The other highlight is to improve the elastohydrodynamic lubrication theory and Hertz contact theory through the rubber elastic modulus, which is determined by the relaxation curve considering the temperature and working conditions. Furthermore, based on the improved theory, the thermo-fluid-solid coupling model of ink roller-ink was established. Finally, the effect of temperature on the coupling process was analyzed. The results show that under the working conditions, with increasing temperature from 20 °C to 40 °C, the contact half-width increases from 4.2335 mm to 4.4701 mm, and the minimum ink film thickness decreases from 0.5097 mm to 0.1410 mm, and the maximum ink pressure decreases from 0.6802 MPa to 0.6618 MPa.

Trajectory optimization of an electrohydraulic robot

Xueju Peng,Guangzhu Chen,Yingjie Tang,Changwei Miao,Yang Li 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.10

The electro-hydraulic robot has great driving torque and plays an irreplaceable role in manufacturing. In this paper, a trajectory planning method for a 6-DOF electro-hydraulic robot based on time-energy-jerk is proposed and realized. A multi-objective function of the electro-hydraulic robot about working efficiency, impact, stability and energy consumption factors was built, at the same time, the kinematic and dynamic constraint functions were also built. The multi-objective trajectory function of the robot was optimized by using the nondominated neighborhood immune genetic algorithm, and the optimal position, velocity, acceleration and jerk planning curves of each joint were obtained. In the experiment, the flow output curves of the hydraulic system of joint 6 based on fuzzy-PID control strategy under noload, 1.5 kg load, 4 kg load were obtained, and show that the velocity and position trajectory of the joint can be well controlled using the presented fuzzy PID control strategy.

Towards efficient sharing of encrypted data in cloud-based mobile social network

( Xin Sun ),( Yiyang Yao ),( Yingjie Xia ),( Xuejiao Liu ),( Jian Chen ),( Zhiqiang Wang ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.4

Mobile social network is becoming more and more popular with respect to the development and popularity of mobile devices and interpersonal sociality. As the amount of social data increases in a great deal and cloud computing techniques become developed, the architecture of mobile social network is evolved into cloud-based that mobile clients send data to the cloud and make data accessible from clients. The data in the cloud should be stored in a secure fashion to protect user privacy and restrict data sharing defined by users. Ciphertext-policy attribute-based encryption (CP-ABE) is currently considered to be a promising security solution for cloud-based mobile social network to encrypt the sensitive data. However, its ciphertext size and decryption time grow linearly with the attribute numbers in the access structure. In order to reduce the computing overhead held by the mobile devices, in this paper we propose a new Outsourcing decryption and Match-then-decrypt CP-ABE algorithm (OM-CP-ABE) which firstly outsources the computation-intensive bilinear pairing operations to a proxy, and secondly performs the decryption test on the attributes set matching access policy in ciphertexts. The experimental performance assessments show the security strength and efficiency of the proposed solution in terms of computation, communication, and storage. Also, our construction is proven to be replayable choosen-ciphertext attacks (RCCA) secure based on the decisional bilinear Diffie-Hellman (DBDH) assumption in the standard model.