Investigation of Quench Sensitivity and Microstructure Evolution During Isothermal Treatment in 2195 Al–Li Alloy

Zhiwu Zhang,Youping Yi,Wen You,Shiquan Huang,Yonglin Guo,Hailin He 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

To investigate the quenching sensitivity of the 2195 Al–Li alloy rolled sheet and guide the design of the quenching process,the time–temperature-property (TTP) curves of this material were researched through interrupted quenching experiments. The differential scanning calorimetry (DSC) and transmission electron microscope (TEM) were used to characterize theevolution of precipitates during isothermal treatment. The results of this essay demonstrated that the nose temperature of 2195Al–Li alloy is around 370 °C and the temperature range of quenching sensitivity is 340 °C to 400 °C. The microstructureobservation revealed that the T1particles precipitate and grow rapidly at the temperature from 340 to 400 °C, which is dueto the high nucleation rate of phase and fast solute diffusion kinetics, especially at the nose temperature. The needle-shapedθ′/θ″ and T1particles grow up quickly as the isothermal preservation time prolonged, leading to the decrease of the supersaturatedsolid solution of the matrix. This will reduce the number of the age-induced precipitate and weaken the subsequentage hardening effect. Therefore, the rate of cooling should be increased in the quenching sensitivity range (340–400 °C) toinhibit the precipitation of the second phase and obtain excellent mechanical properties. While in other temperature ranges,the cooling rate should be decreased appropriately to reduce residual stress. The appropriate average cooling rate is recommendedto be around 13 °C s−1 at the temperature from 340 to 400 °C.

Single-Phase Improved Auxiliary Resonant Snubber Inverter that Reduces the Auxiliary Current and THD

Zhang, Hailin,Kou, Baoquan,Zhang, He,Zhang, Lu The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.6

An LC filter is required to reduce the output current ripple in the auxiliary resonant snubber inverter (ARSI) for high-performance applications. However, if the traditional control method is used in the ARSI with LC filter, then unnecessary current flows in the auxiliary circuit. In addressing this problem, a novel load-adaptive control that fully uses the filter inductor current ripple to realize the soft-switching of the main switches is proposed. Compared with the traditional control implemented in the ARSI with LC filter, the proposed control can reduce the required auxiliary current, contributing to higher efficiency and DC-link voltage utilization. In this study, the detailed circuit operation in the light load mode (LLM) and the heavy load mode (HLM) considering the inductor current ripple is described. The characteristics of the improved ARSI are expressed mathematically. A prototype with 200 kHz switching frequency, 80 V DC voltage, and 8 A maximum output current was developed to verify the effectiveness of the improved ARSI. The proposed ARSI was found to successfully operate in the LLM and HLM, achieving zero-voltage switching (ZVS) of the main switches and zero-current switching (ZCS) of the auxiliary switches from zero load to full load. The DC-link voltage utilization of the proposed control is 0.758, which is 0.022 higher than that of the traditional control. The peak efficiency is 91.75% at 8 A output current for the proposed control, higher than 89.73% for the traditional control. Meanwhile, the carrier harmonics is reduced from -44 dB to -66 dB through the addition of the LC filter.

Single-Phase Improved Auxiliary Resonant Snubber Inverter that Reduces the Auxiliary Current and THD

Hailin Zhang,Baoquan Kou,He Zhang,Lu Zhang 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.6

An LC filter is required to reduce the output current ripple in the auxiliary resonant snubber inverter (ARSI) for high-performance applications. However, if the traditional control method is used in the ARSI with LC filter, then unnecessary current flows in the auxiliary circuit. In addressing this problem, a novel load-adaptive control that fully uses the filter inductor current ripple to realize the soft-switching of the main switches is proposed. Compared with the traditional control implemented in the ARSI with LC filter, the proposed control can reduce the required auxiliary current, contributing to higher efficiency and DC-link voltage utilization. In this study, the detailed circuit operation in the light load mode (LLM) and the heavy load mode (HLM) considering the inductor current ripple is described. The characteristics of the improved ARSI are expressed mathematically. A prototype with 200 ㎑ switching frequency, 80 V DC voltage, and 8 A maximum output current was developed to verify the effectiveness of the improved ARSI. The proposed ARSI was found to successfully operate in the LLM and HLM, achieving zero-voltage switching (ZVS) of the main switches and zero-current switching (ZCS) of the auxiliary switches from zero load to full load. The DC-link voltage utilization of the proposed control is 0.758, which is 0.022 higher than that of the traditional control. The peak efficiency is 91.75% at 8 A output current for the proposed control, higher than 89.73% for the traditional control. Meanwhile, the carrier harmonics is reduced from –44 ㏈ to –66 ㏈ through the addition of the LC filter.

THE IMPACT OF CORPORATE SOCIAL RESPONSIBILITY ON NEW PRODUCT DEVELOPMENT PERFORMANCE: MEDIATING EFFECT OF INTERNAL CAPABILITY AND AS WELL AS EXTERNAL NETWORK QUALITY

Hailin Zhang,Xina Yuan,Seongsoo Jang,Xin Wang 글로벌지식마케팅경영학회 2020 Global Marketing Conference Vol.2020 No.11

Optimal Elman Neural Network based on Improved Gorilla Troops Optimizer for Short-Term Electricity Price Prediction

Zhang Hailin,Razmjooy Navid 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1

In the competitive electric energy market, the price signal for electricity plays a crucial role in all planning and operational operations. Additionally, the price of energy is unpredictable and is infuenced by a variety of factors both immediately and over time. To successfully manage risk in the market, the factors involved in the electricity industry must anticipate the power price signal with high efciency. The pricing in the electricity market has been impacted by this new element because of the growing use of green and sustainable energy, particularly wind energy. This is because the fuctuating nature of wind generation makes real-time balancing of power system demand versus generation more difcult. Because of the importance of short-term electric power price prediction in the electricity market, today, many researchers have addressed this issue in their studies. An Elman neural network learning power is then enhanced by combining with an improved version of Gorilla Troops Optimizer. The method's ability to optimize wavelet decomposition and neural network architecture, for which there is no ideal paradigm, is another advantage. In a day-ahead framework, numerical testing was conducted on historical data relevant to spot marketplaces in eve

CHOICE OF CAUSE IN CRM AFTER BRAND SCANDAL: BASED ON REGULATORY FOCUS THEORY

Hailin Zhang,Leping Li,Xina Yuan 글로벌지식마케팅경영학회 2019 Global Fashion Management Conference Vol.2019 No.07

Terahertz Characteristics of Hydroxygraphene Based on Microfluidic Technology

Boyan Zhang,Siyu Qian,Bo Peng,Bo Su,Zhuang Peng,Hailin Cui,Shengbo Zhang,Cunlin Zhang 한국광학회 2023 Current Optics and Photonics Vol.7 No.4

Hydroxygraphene as a kind of functionalized graphene has important applications in composite, photoelectric and biological materials. In the present study, THz and microfluidic technologies were implemented to study the THz transmission characteristics of hydroxygraphene with different concentrations and residence times in magnetic and electric fields. The results show that the THz transmission intensity decreases with the increase in sample concentration and duration of an applied electric field, while it increases by staying longer in the magnetic field. The phenomenon is analyzed and explained in terms of hydrogen bond, conductivity and scattering characteristics. The results establish a foundation for future research on the THz absorption characteristics of liquid graphene based on microfluidic technology in different external environments. It also provides technical support for the application and development of graphene in THz devices.

Competitive Resource Sharing Based on Game Theory in Cooperative Relay Networks

Guopeng Zhang,Li Cong,Liqiang Zhao,Hailin Zhang,Kun Yang 한국전자통신연구원 2009 ETRI Journal Vol.31 No.1

This letter considers the problem of resource sharing among a relay and multiple user nodes in cooperative transmission networks. We formulate this problem as a sellers’ market competition and use a noncooperative game to jointly consider the benefits of the relay and the users. We also develop a distributed algorithm to search the Nash equilibrium, the solution of the game. The convergence of the proposed algorithm is analyzed. Simulation results demonstrate that the proposed game can stimulate cooperative diversity among the selfish user nodes and coordinate resource allocation among the user nodes effectively.

An Investigation of the Terahertz Absorption Characteristics of a Graphene Oxide Aqueous Solution Using Microfluidic Technology

Ningyi Cai,Boyan Zhang,Qinghao Meng,Siyu Qian,Bo Su,Hailin Cui,Shengbo Zhang,Cunlin Zhang 한국광학회 2023 Current Optics and Photonics Vol.7 No.2

The vibratory and rotational levels of many biological macromolecules lie in the terahertz (THz) band, which means that THz techniques can be used to identify and detect them. Moreover, since the biological activity of most biomolecules only becomes apparent in aqueous solution, we use microfluidic technology to study the biological properties of these biomolecules. THz time-domain spectroscopy was used to study the THz absorption characteristics of graphene oxide (GO) aqueous solution at different concentrations and different exposure times in fixed electric or magnetic fields. The results show that the spectral characteristics of the GO solution varied with the concentration: as the concentration increased, the THz absorption decreased. The results also show that after placing the solution in an external electric field, the absorption of THz first increased and then decreased. When the solution was placed in a magnetic field, the THz absorption increased with the increase in standing time. In this paper, these results are explained based on considerations of what is occurring at the molecular scale. The results of this study provide technical support for the further study of GO and will assist with its improved application in various fields.

In silico Analysis and Experimental Improvement of Taxadiene Heterologous Biosynthesis in Escherichia coli

Hailin Meng,Yong Wang,Qiang Hua,Siliang Zhang,Xiaoning Wang 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.2

The biosynthesis of terpenoids in heterologous hosts has become increasingly popular. Isopentenyl diphosphate (IPP) is the central precursor of all isoprenoids, and the synthesis can proceed via two separate pathways in different organisms: The 1-deoxylulose 5-phosphate (DXP)pathway and the mevalonate (MVA) pathway. In this study,an in silico comparison was made between the maximum theoretical IPP yields and the thermodynamic properties of the DXP and MVA pathways using different hosts and carbon sources. We found that Escherichia coli and its DXP pathway have the most potential for IPP production. Consequently, codon usage redesign, and combinations of chromosomal engineering and various strains were considered for optimizing taxadiene biosynthesis through the endogenic DXP pathway. A high production strain yielding 876 ± 60 mg/L taxadiene, with an overall volumetric productivity of 8.9 mg/(L × h), was successfully obtained by combining the chromosomal engineered upstream DXP pathway and the downstream taxadiene biosynthesis pathway. This is the highest yield thus far reported for taxadiene production in a heterologous host. These results indicate that genetic manipulation of the DXP pathway has great potential to be used for production of terpenoids, and that chromosomal engineering is a powerful tool for heterologous biosynthesis of natural products.