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Finite element analysis for die casting parameters in high-pressure die casting process

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China Foundry 2019年第4期16卷 272-276页

作者： Xin-yu Qin Yong Su Jian Chen lan-jun liu School of Materials Science and Engineering Hefei University of Technology

The gating system and the overflow system were designed according to the casting structure during high pressure die casting(HPDC) process. The simulation was carried out by ProCAST software to visualize the injection chamber pre-crystallization and the flow of molten metal. The main work is to research four die casting process parameters, i.e. injection temperature, low-pressure velocity, high-and low-pressure velocity’s switching position, and high-pressure velocity. Experimental results show that the higher injection temperature and lowpressure velocity can mitigate the pre-crystallization of the injection chamber. However, when the low-pressure velocity exceeds 0.2 m·s-1, the air entrapment in the chamber occurs. Besides, when the high-pressure velocity is greater than 2.5 m·s-1, the overflow channel at the final filling position is covered by the liquid metal too early. Finally, the injection temperature of 650 °C, the low-pressure velocity of 0.2 m·s-1, the high-and low-pressure velocity’s switching position of 320 mm and the high-pressure velocity of 2 m·s-1 are obtained as the optimal parameters by the software simulation, which has been verified by actual production.

关键词： aluminum alloy die casting process simulation optimization

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An underwater acoustic direct sequence spread spectrum communication system using dual spread spectrum code

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Frontiers of Information Technology & Electronic Engineering 2018年第8期19卷 972-983页

作者： lan-jun liu Jian-fen LI Lin ZHOU Peng ZHAI Hao ZHAO Jiu-cai JIN Zhi-chao LV College of Engineering Ocean University of China The First Institute of Oceanography State Oceanic Administration College of Underwater Acoustic Engineering Harbin Engineering University

With the goal of achieving high stability and reliability to support underwater point-to-point communications and code division multiple access(CDMA) based underwater networks, a direct sequence spread spectrum based underwater acoustic communication system using dual spread spectrum code is proposed. To solve the contradictions between the information data rate and the accuracy of Doppler estimation, channel estimation, and frame synchronization, a data frame structure based on dual spread spectrum code is designed. A long spread spectrum code is used as the training sequence, which can be used for data frame detection and synchronization, Doppler estimation, and channel estimation. A short spread spectrum code is used to modulate the effective information data. A delay cross-correlation algorithm is used for Doppler estimation, and a correlation algorithm is used for channel estimation. For underwater networking, each user is assigned a different pair of spread spectrum codes. Simulation results show that the system has a good anti-multipath, anti-interference, and anti-Doppler performance, the bit error rate can be smaller than 10^(-6) when the signal-to-noise ratio is larger than-10 dB, the data rate can be as high as 355 bits/s, and the system can be used in the downlink of CDMA based networks.

关键词： Underwater acoustic communication Direct sequence spread spectrum Doppler estimation and compensation Channel estimation and equalization Gold code Single carrier Code division multiple access

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Synthesis Chiral Dihydropyridine Derivatives from Geniposide and Primary Amine

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有机化学 2003年第Z1期23卷 296-296页

作者： liu Zhu-lan LEI jun liu Jian-Li Department of Chinese Material Medica Northwest University Xi''an 710069 Department of Chinese Material Medica Northwest University Xi''an 710069 Department of Chinese Material Medica Northwest University Xi''an 710069

　　Since Ohno and co-workers[1] reported the first example of asymmetric reduction using a model of coenzyme NADH in 1975, numerous efforts have been made to construct model compounds mimicking the activity of NADH and many publications have appeared. [2] Here we reported the design and synthesis of novel chiral dihydropyridine derivatives which can be used as NADH model from geniposide and primary amine.……

关键词： design and synthesis asymmetric reduction construct model

Approach from the laboratory to the field: New strategies in the control of mosquito-borne infectious diseases

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Science China Life Sciences 2025年第1期68卷 303-305页

作者： Ziqian Xu Lianpan Dai jun liu National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases (NITFID) National Institute for Viral Disease Control and PreventionChinese Center for Disease Control and Prevention CAS Key Laboratory of Pathogen Microbiology and Immunology Institute of MicrobiologyChinese Academy of Sciences

Vector-borne viruses, transmitted among humans and animal hosts through bites of vectors such as mosquitoes and ticks,pose a great and ongoing threat to public health and biosafety(Yang et al., 2022).Among them, dengue virus-induced epidemics, have dramatically increased worldwide in recent decades. The report released by the World Health Organization(WHO) at the end of 2023 showed that dengue epidemic globally surged in2023, with the number of reported cases nearing a historical peak.

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Laser image refractive index sensor based on the combination of a coreless optical fiber and a digital camera

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Optoelectronics Letters 2025年第2期21卷 65-68页

作者： GUO Jingzhong lan Feng CHEN Xiang liu Haifeng Xi'an Institute of Space Radio Technology Key Laboratory of Optoelectronic Sensor and Sensing Network Technology College of Electronic Information and Optical Engineering Nankai University

As a laser passes through a scattering medium,the light interacts with the irregular reflections within the medium,resulting in light scattering and the formation of *** this paper,an image sensor based on the combination of a coreless optical fiber and a digital camera is proposed for liquid refractive index sensing *** coreless fiber is used as a sensing unit,and the change in the speckle pattern is measured using the digital correlation method to detect the magnitude of the liquid's refractive *** experimental results indicate that the laser image sensing technique is capable of effectively distinguishing liquid samples with refractive indices ranging from 1.332 8 to1.390 8,with a sensing sensitivity of-1.306 ***,the laser image sensing technique,with its advantages of high experimental reproducibility,simple system design,remote over-control,holds great research significance and potential application in laser communication and sensor integration.

关键词： Digital cameras

Transumbilical single-port laparoscopic cholecystectomy： a case report

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Chinese Medical Journal 2008年第23期121卷 2463-2464页

作者： GUO Wei ZHANG Zhong-tao HAN Wei LI Jian-she JIN lan liu jun ZHAO Xiao-mu WANG Yu Department of General Surgery Beijing Friendship Hospital Capital Medical University Beijing 100050 China

Recently, scarless surgery has become a widely used surgical technique, which has made considerable progress owing to extensive animal model studies and clinical trials. Here, we report the first case of transumbilica... 详细信息

关键词： laparoscopic cholecystectomy clinical trials mainland China animal model

Synthesis Chiral Dihydropyridine Derivatives from Geniposide and Primary Amine

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Synthesis Chiral Dihydropyridine Derivatives from Geniposide...

Anomalous quality factor evolution of induced transparency in a virtualized coupled-oscillator system

第三届全国有机化学学术会议

作者： liu, Zhu-lan LEI, jun liu, Jian-Li (Department of Chinese Material Medica , Northwest University, Xi''an 710069)

＜正＞ Since Ohno and co-workers reported the first example of asymmetric reduction using a model of coenzyme NADH in 1975, numerous efforts have been made to construct model compounds mimicking the activity of NADH and many publications have appeared. Here we reported the design and synthesis of novel chiral dihydropyridine derivatives which can be used as NADH model from geniposide and primary amine.

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 148-155页

作者： Yunhan Yang Han Jia Tuo liu Yuzhen Yang jun Yang Key Laboratory of Noise and Vibration Research Institute of Acoustics Chinese Academy of Sciences University of Chinese Academy of Sciences State Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences

The phenomenon of induced transparency, characterized by a high quality(Q) factor, holds significant importance in the fields of high-precision sensing, energy storage and wave manipulation. Conventional transparency systems are often constrained by the limited experimentally accessible parameter space and the lack of independent control over intrinsic parameters, thereby hindering advanced research on high-Q effects. Here we propose a virtualized coupled-oscillator system that enables reconfigurable induced transparency in the reflection spectrum. By virtually incorporating a pair of coupled oscillators into an individual acoustic meta-atom, we achieve the manipulation of induced transparency in a decoupled, wide-ranging, and elaborate manner. Exploiting the diverse evolutions across the intrinsic parameter space, we show experimentally a counter-intuitive increase in the Q-factor of the transparency window, which is attributed to the enhanced dissipation of the bright ***, a constant group delay at the center frequency is observed accompanying this evolution. Our work demonstrates an intriguing platform as well as a novel strategy to engineer high-Q induced transparency phenomenon, and paves the way towards applications in programmable acoustic sensors, filters and slow-wave devices.

关键词： induced transparency acoustic meta-atom high quality-factor scattering programmable intrinsic parameter

Observation of topological charge transformations in acoustic vortex using passive periodic systems

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 140-147页

作者： Di-Chao Chen Xie liu Changqing Xu Da-Jian Wu Ying Cheng Xiao-jun liu School of Physics and Technology Nanjing Normal University Key Laboratory of Modern Acoustics School of Physics Nanjing University

Vortex transmutation utilizes a periodic system, which not only enables the alteration of the topological charge(TC) of unstable input vortices but also facilitates their transformation into stable structures. This approach is crucial for investigating the characteristics of vortices in various wave systems. Here, we achieve acoustic vortex TC transmutation by employing a welldesigned dual-structured plate external system(DPES). The interactions between the acoustic vortex and the finite-order discrete rotational symmetry lead to the transformation of its topological charge when complete rotational symmetry is broken to Nthorder discrete symmetry. Our results experimentally demonstrate the acoustic vortex TC transmutation based on passive artificial structures, enabling numerous applications in particle manipulation and information multiplexing as well as advancing our understanding and control over free-space acoustic vortices.

关键词： acoustic vortex topological charge transformation artificial structure