DESIGN AND BRAKING STABILITY ANALYSIS OF A NOVEL INTERNAL PUMP-HYDRAULIC RETARDER AXLE FOR HEAVY ARTICULATED VEHICLE

Zhiwei Gao,Desheng Li,Zongqiang Liu,Lezhi Ye 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.5

The retarder is widely used to ensure braking safety in heavy vehicles due to its noncontact braking characteristics. Currently, retarders are generally mounted on tractors, but semi-trailers have greater inertia and are prone to accidents. Therefore, the semi-trailer’s brakes have to work frequently to maintain stability during downhill braking, which causes the brakes to generate high temperatures or even failure. Based on the above problems, a novel internal pump-hydraulic retarder axle (IP-HRA) is proposed, which integrates the pump and hydraulic retarder (HR) into the support axle. The prototype of the IP-HRA was made and a bench test was conducted. In the experiment, the single-side braking power of the IP-HRA reaches 300 kW and its torque can be controlled by adjusting the outlet pressure. A co-simulation model of articulated vehicles is established to predict the braking state by computer solutions. Based on the experimental data, the methods of IP-HRA braking semi-trailer and traditional HR braking tractor are compared. The results of co-simulation show that the IP-HRA is more conducive to the braking stability of the articulated vehicle than the traditional HR when only retarder is used. Finally, the braking time and braking deceleration of IP-HRA are verified by road experiments.

Modeling Method for Predicting the Shelf Life of Spare Parts under Automatic Modeling Process

Zhiwei Li,Qi Gao,Xinliang Jiang,Shenyang Liu,Tielu Gao 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.9

A modeling method which can predict the shelf life of various types of spare parts in a relatively short time is put forward in this article. At present, it is difficult to solve the problem of mass modeling because the shelf life prediction models for different kinds of spare parts are of great diversification. In this paper, the best fitting nonlinear variables are selected by Gram-Schmidt regression method, and the detailed steps of automatic modeling process are given, which have advantages of strong robustness and are easy in programming. Especially, it can eliminate the influence of multicollinearity among alternative models effectively. By using natural rubber heating elongation data, an example is taken to demonstrate the process of automatic modeling. The nonlinear regression models selected by automatic modeling process are consistent in Dakin equation, and the predict values of natural rubber shelf life are included in the storage period given by manufacturing plant.

Enjoy and Aspire

Gao Zhiwei 한국콘텐츠학회 2023 한국콘텐츠학회 ICCC 논문집 Vol.2023 No.12

Enjoy and Aspire

Gao Zhiwei 한국콘텐츠학회 2023 ICCC International Digital Design Invitation Exhib Vol.2023 No.12

A Scalable PKI Based on P2P Network

Zhiwei Gao,Jinsheng Fan,Yufeng Jia,Li Zhang 보안공학연구지원센터 2007 International Journal of Security and Its Applicat Vol.1 No.2

Public key infrastructure (PKI) is a powerful tool for protecting information. Currently a PKI system shows a trend toward an emerging global PKI which becomes more complicated. The global PKI has to handle an enormous number of queries for cryptographic certificates which attest the authenticity of public keys. So a decentralized organization of the PKI is advantageously. Therefore we developed a specialized Peer-to-Peer-PKI model realizing efficient search and transfer of certificates and trust-recommendations. Our model based on our own rigorous binary tree algorithm and has four advantages. First, there is no any bottleneck problem when establishing a certification path or authenticating. Second, the authentication path is short with two constant logic steps. Third, in our model the entities need to mutual authenticate don’t need to inquire or download the CRL. Fourth, it’s easy to extend and suitable for large-scale network.

Improved performance of polyamide nanofiltration membranes by incorporating reduced glutathione during interfacial polymerization

Zhiwei Jiao,Linjie Zhou,Mengyuan Wu,Kang Gao,Yanlei Su,Zhongyi Jiang 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.12

Inspired by the specific amino acid sequence Asn-Pro-Ala (NPA) of water channel aquaporins (AQPs), we fabricated polyamide (PA) nanofiltration (NF) membranes by introducing reduced glutathione (GSH) in interfacial polymerization (IP) method. Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectrometry (XPS), scanning electron microscope (SEM), atomic force microscopy (AFM), zeta potential and static water contact angle measurement were employed to characterize the chemical composition, morphology, electronegativity and hydrophilicity of the NF membranes. The water flux of GSH/PIP-TMC NF membrane reached 32.00 L m2 h1 at 0.2MPa, which was approximately twice than that of pristine PIP-TMC NF membrane when the ratio of GHS to piperazidine (PIP) was 40% during IP process. More water channels were built as GSH was embedded into PA layer. The fabricated NF membranes also took on potent rejection for dyes and Na2SO4. This study presents a simple and facile method to simulate water channels-based biological materials which may find potential application in water treatment.

Hypoglycemic effect of Gynostemma pentaphyllum saponins by enhancing the Nrf2 signaling pathway in STZ-inducing diabetic rats

Dawei Gao,Min Zhao,Ximing Qi,Yanping Liu,Nan Li,Zhiwei Liu,Yanhong Bian 대한약학회 2016 Archives of Pharmacal Research Vol.39 No.2

Gynostemma pentaphyllum (GP) is a natural plant resources for diabetes therapy, however, there is little research on the mechanisms of GP. The present study was undertaken to characterize if G. pentaphyllum saponins (GPs) is the principal active compound of GP responsible for anti-diabetes, and to examine the relativity between blood glucose modulate and antioxidation. The GPs-treated streptozotocin diabetic rats had a more effective hypoglycemic status than those of diabetic control rats, which also ameliorate dyslipidemia. GPs has increased SOD and GSH-px activities, and the spleen and thymus indexes in diabetic rats. The insulin levels in the GPs-treated groups were significantly higher than diabetic control group. Our finding provides a new insight into the application of GPs for the treatment of oxidative stress related diseases.

Bioconversion of Pinoresinol Diglucoside from Glucose Using Resting and Freeze-Dried Phomopsis sp. XP-8 Cells

( Zhenhong Gao ),( Muhammad Shahid Riaz Rajoka ),( Jing Zhu ),( Zhiwei Zhang ),( Yan Zhang ),( Jinxin Che ),( Xiaoguang Xu ),( Junling Shi ) 한국미생물생명공학회(구 한국산업미생물학회) 2017 Journal of microbiology and biotechnology Vol.27 No.8

Phomopsis sp. XP-8 (an endophytic fungus) was previously found to produce pinoresinol diglucoside (PDG), a major antihypertensive compound of Tu-Chung (the bark of Eucommia ulmoides Oliv.), which is widely used in Chinese traditional medicines. In the present study, two bioconversion systems were developed for the production of PDG in Tris-HCl buffer containing glucose and Phomopsis sp. XP-8 cells (both resting and freeze-dried). When other factors remained unchanged, the bioconversion time, glucose concentration, cell ages, cell dosage, pH, temperature, and stirring speed influenced PDG production in a similar and decreasing manner after an initial increase with increasing levels for each factor. Considering the simultaneous change of various factors, the optimal conditions for PDG production were established as 70 g/l cells (8-day-old), 14 g/l glucose, 28°C, pH 7.5, and 180 rpm for systems employing resting cells, and 3.87 g/l cells, 14.67 g/l glucose, 28°C, pH 7.5, and 180 rpm for systems employing freeze-dried cells. The systems employing freeze-dried cells showed lower peak PDG production (110.28 μg/l), but at a much shorter time (12.65 h) compared with resting cells (23.62 mg/l, 91.5 h). The specific PDG production levels were 1.92 and 24 μg per gram cells per gram glucose for freeze-dried cells and resting cells, respectively. Both systems indicated a new and potentially efficient way to produce PDG independent of microbial cell growth.

Evolutionary Neural Network based on Quantum Elephant Herding Algorithm for Modulation Recognition in Impulse Noise

( Hongyuan Gao ),( Shihao Wang ),( Yumeng Su ),( Helin Sun ),( Zhiwei Zhang ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.7

In this paper, we proposed a novel modulation recognition method based on quantum elephant herding algorithm (QEHA) evolving neural network under impulse noise environment. We use the adaptive weight myriad filter to preprocess the received digital modulation signals which passing through the impulsive noise channel, and then the instantaneous characteristics and high order cumulant features of digital modulation signals are extracted as classification feature set, finally, the BP neural network (BPNN) model as a classifier for automatic digital modulation recognition. Besides, based on the elephant herding optimization (EHO) algorithm and quantum computing mechanism, we design a quantum elephant herding algorithm (QEHA) to optimize the initial thresholds and weights of the BPNN, which solves the problem that traditional BPNN is easy into local minimum values and poor robustness. The experimental results prove that the adaptive weight myriad filter we used can remove the impulsive noise effectively, and the proposed QEHA-BPNN classifier has better recognition performance than other conventional pattern recognition classifiers. Compared with other global optimization algorithms, the QEHA designed in this paper has a faster convergence speed and higher convergence accuracy. Furthermore, the effect of symbol shape has been considered, which can satisfy the need for engineering.

Review : Characterization of a Recombinant Thermostable Arylsulfatase from Deep-Sea Bacterium Flammeovirga pacifica

( Chao Gao ),( Min Jin ),( Zhiwei Yi ),( Runying Zeng ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.11

A novel sulfatase gene, ary423 (1,536 bp ORF), encoding a protein of 511 amino acids with a calculated molecular mass of 56 kDa, was identified from Flammeovirga pacifica, which was isolated from deep-sea sediments of west Pacific Ocean. Amino acid sequence analysis revealed that Ary423 possessed a conserved C-X-A-X-R motif, which was recognized as the sulfatase signature. Phylogenetic analysis suggested that Ary423 belonged to arylsulfatases. After heterologous expression in Escherichia coli cells, the recombinant Ary423 was purified with a N i+ affinity column, and was shown to be highly active at a broad range of temperatures from 30° to 70°C, with maximum activity at 40°C. Furthermore, recombinant Ary423 retained more than 70% and 40% of its maximum activity after 12 h of incubation at 50°C and 60°C, respectively, exhibiting good thermostability at high temperatures. The optimal pH for Ary423 was determined to be 8.0 and the activity of Ary423 could be slightly enhanced by Mg2+. The recombinant enzyme could hydrolyze sulfate ester bonds in pnitrophenyl sulfate (NPS) and Asparagus crude polysaccharides with a specific activity of 64.8 U/mg and 25.4 U/mg, respectively. These favorable properties could make Ary423 attractive for application in the desulfating process of agar production.