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| 1 | Ultrasound-Assisted Transient Liquid Phase Bonding of Magnesium Alloy Using Brass Interlayer in Air显示文摘The microstructure evolution and oxide film behavior in ultrasound-assisted transient liquid phase(U-TLP) bonding of Mg alloy were investigated by applying different ultrasonic time at 460?C with brass interlayer in air. The results indicated that with increasing ultrasonic time, brass interlayer disappeared gradually and the Mg-Cu-Zn eutectic compounds were formed. The eutectic compounds in the joint decreased as the ultrasonic time increased further. The oxide removal process was divided into four steps. Continuous oxide film at the interface was partially fractured by ultrasonic vibration,and then suspended into liquid by undermining eutectic reaction. After that, the suspended oxide film was broken into small oxide fragments by ultrasonic cavitation effect, which was finally squeezed out of the joint by ultrasonic squeeze action. In addition, the mechanical properties of the joints were investigated. The maximum shear strength of the joint reached 105 MPa, which was 100% of base metal. | Zhiwei Lai Ruishan Xie Chuan Pan Xiaoguang Chen Lei Liu Wenxian Wang Guisheng Zou | 2017 | Journal of Materials Science & Technology2017，33，6： | 7 |
| 2 | Interfacial Structure and Formation Mechanism of Ultrasonic-assisted Brazed Joint of SiC Ceramics with Al—12Si Filler Metals in Air显示文摘Ultrasonic-assisted brazing of SiC ceramics was performed by filling with an Al—12Si alloy at a low temperature of 620 °C in air. The interfacial characteristics and formation mechanism were investigated. The joint shear strength reached 84–94 MPa using the ultrasonic time of 2–16 s. The fracture morphology showed that the fracture path initiated and propagated in the joint alloy. The thin film of amorphous SiO 2 that formed on the SiC surface was non-uniformly decomposed and diffused into the liquid Al—12Si alloy under the cavitation erosion effect of ultrasound. Abnormal isolated blocks of Al_2 SiO_5 compounds formed at the interface between Al—12Si and a thicker SiO_2 layer formed during the thermal oxidation treatment of the Si C ceramic. The SiO_2 layer on the Si C ceramic did not hinder or impair the wetting and bonding process, and a stronger bond could form between Al—12Si and SiO_2 or Si C in ultrasonicassisted brazing. | Xiaoguang Chen Ruishan Xie Zhiwei Lai Lei Liu Jiuchun Yan Guisheng Zou | 2017 | Journal of Materials Science & Technology2017，33，5： | 6 |
| 3 | Biocatalytic access to diverse prenylflavonoids by combining a regiospecific C-prenyltransferase and a stereospecific chalcone isomerase显示文摘Prenylflavonoids are valuable natural products that have diverse biological properties, and are usually generated biologically by multiple metabolic enzymes in nature. In this study, structurally diverse prenylflavonoids were conveniently synthesized by enzymatic catalysis by combining GuILDT, a regiospecific chalcone prenyltransferase, and Gu CHI, a stereospecific chalcone isomerase that has promiscuous activity for both chalcones and prenylchalcones as substrates. Our findings provided a new approach for the synthesis of natural/unnatural bioactive prenylflavonoids, including prenylchalcones and optical prenylflavanones with chalcone origins. | Jianhua Li Ridao Chen Ruishan Wang Xiao Liu Kebo Xie Dawei Chen Jungui Dai | 2018 | Acta Pharmaceutica Sinica B2018，8，4： | 4 |
| 4 | Improved distortion prediction in additive manufacturing using an experimental-based stress relaxation model显示文摘In additive manufacturing(AM),numerous thermal cycles make stress relaxation a significant factor in affecting the material mechanical response.However,the traditional material constitutive model cannot describe repeated annealing behavior.Here,we propose an improved constitutive model based on a serial of stress relaxation experiments,which can descript the temperature and time-dependent stress relaxation behavior during AM.By using the proposed relaxation model,the prediction accuracy is significantly improved due to the recovery of inelastic strain during multilayer deposition.The results are validated by both in-situ and final distortion measurements.The influence mechanism of the relaxation behavior on material mechanical response is explained by the three-bar model in thermo-elastic-plastic theory.The relaxation behavior during the whole AM process is clarified.The stress behavior is found to have a limited effect when merely depositing several layers;nevertheless,it becomes a prominent impact when depositing multiple layers.The proposed model can enhance modeling accuracy both in AM and in multilayer welding. | Ruishan Xie Qingyu Shi Gaoqiang Chen | 2020 | Journal of Materials Science & Technology2020，59，24： | 1 |
| 5 | Unclear but present danger:An asymptomatic SARS-CoV-2 carrier显示文摘Superspreaders are critical infectious resources in multiple infectious diseases.They can be asymptomatic or present mild symptoms but can transmit pathogens to susceptible populations,leading to severe symptoms,and even death.Early identification of this population is extremely important to inhibit the spread of infectious diseases.Right now,the whole global world is suffering from a devastating infectious disease caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).In this article,a superspreader cluster event in coronavirus disease 2019(COVID-19)was identified by tracking contacting histories of infected patients.This cluster was found to be originated from an asymptomatic SARS-CoV-2 carrier,which resulted in 13 secondary cases getting infected.All the secondary patients presented with non-typical symptoms of COVID-19,such as fever,dry cough,and myalgia,one of which died of respiratory failure at the end.From this cluster,we learn that people with older ages,low immunity,multiple underlying diseases,especially pulmonary diseases,can contribute to a poor prognosis.Thus,asymptomatic superspreaders of COVID-19 can be extremely dangerous and must be handled time-efficiently. | Xuejing Yu Dongchuan Ran Jinhui Wang Yuan Qin Ruishan Liu Xueli Shi Yiping Wang Chang Xie Jia Jiang Jianzhong Zhou | 2020 | Genes & Diseases2020，7，4： | 0 |
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