Investigation on High Temperature Mechanical Behaviors of TiC-γ′ Reinforced Ni Composite

Wenqiang Hu,Zhenying Huang,Qun Yu,Yuanbo Wang,Yidan Jiao,Yang Zhou,Hongxiang Zhai 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.8

A duplex TiC and γ′-Ni3(Al,Ti) reinforced nickel composite was fabricated through hot-press sintering a 30 vol% Ti2AlC–Nimixtures followed by thermal treatment method. Detailed microstructural detection was performed by adopting the routeof high-resolution transmission electron microscopy. In situ generated submicron TiC particulate and nanosized L12-γ′were homogeneously distributed in a fcc γ-Ni matrix. The high temperature tensile and compression behaviors of the TiC-γ′/Ni composites were evaluated in the temperature range of 25–800 °C. The results indicated that ultimate tensile andcompression properties exhibited the dependence of temperatures. The tensile properties of the composite determined at600 °C was 945 MPa, decreasing by 28.1% and 23.0% for elongation, compared to those of measured at room temperature(UTS = 1305 MPa, elongation = 5.35%). However, the yield strength exhibited the temperature independent until to 600 °C. The yield strength of the TiC-γ′/Ni composite are comparable with conventional superalloy under 600 °C, proving that TiCand γ′ particles constitute efficient reinforcements for Ni matrix according to thermal expansion dislocations strengthening,load-transfer and coherent strengthening mechanisms. The monotonic temperature dependence of yield strength at600–800 °C indicates that plastic deformation of TiC-γ′/Ni composite follows the thermally activated mechanism. TheTiC-γ′/Ni composite exhibited superior mechanical properties both at room and high temperatures, which can be ascribedto the synergistic strengthening effect in term of dislocation density, Orowan, coherent and atomic ordering strengtheningmechanisms. The present work reveals the deformation behaviors of in situ TiC-γ′/Ni composite from room to high temperatures,which is critical to predict the failure and thereby optimize the microstructure to further enhance the high temperatureproperties of TiC-γ′/Ni composite.

Deep Learning Assisted Differential Cryptanalysis for the Lightweight Cipher SIMON

( Wenqiang Tian ),( Bin Hu ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.2

SIMON and SPECK are two families of lightweight block ciphers that have excellent performance on hardware and software platforms. At CRYPTO 2019, Gohr first introduces the differential cryptanalysis based deep learning on round-reduced SPECK32/64, and finally reduces the remaining security of 11-round SPECK32/64 to roughly 38 bits. In this paper, we are committed to evaluating the safety of SIMON cipher under the neural differential cryptanalysis. We firstly prove theoretically that SIMON is a non-Markov cipher, which means that the results based on conventional differential cryptanalysis may be inaccurate. Then we train a residual neural network to get the 7-, 8-, 9-round neural distinguishers for SIMON32/64. To prove the effectiveness for our distinguishers, we perform the distinguishing attack and key-recovery attack against 15-round SIMON32/64. The results show that the real ciphertexts can be distinguished from random ciphertexts with a probability close to 1 only by 28.7 chosen-plaintext pairs. For the key-recovery attack, the correct key was recovered with a success rate of 23%, and the data complexity and computation complexity are as low as 28 and 220.1 respectively. All the results are better than the existing literature. Furthermore, we briefly discussed the effect of different residual network structures on the training results of neural distinguishers. It is hoped that our findings will provide some reference for future research.

Microstructural and Mechanical Properties of TiCX–Ni3(Al,Ti)/Ni Functionally Graded Composites Fabricated from Ti3AlC2 and Ni Powders

Guangming Zheng,Zhenying Huang,Qun Yu,Wenqiang Hu,Xingyang Qiu,A. Lixia,Yuanbo Wang,Yidan Jiao,Yang Zhou,Hongxiang Zhai 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.6

In this paper, a novel type of functionally graded material (FGM) was successfully fabricated from pure Ni and Ti3AlC2powder mixtures by hot-press sintering route at 1200 °C and 17 MPa. In each layer, Ti3AlC2particles transformed into TiCxphase, while the additional Al–Ti atoms decomposed from Ti3AlC2diffused into the Ni matrix, giving rise to the formationof γ′-Ni3(Al,Ti). Part of the submicron TiCxand Ni3(Al,Ti) particles were uniformly distributed in the Ni matrix, whilesome of the TiCxmaintained the original Ti3AlC2plate-like morphology. Both TiCxand Ni3(Al,Ti) content decreased from60Ti3AlC2/Ni layer to 10Ti3AlC2/Ni layer in a stepwise manner was fabricated. The microstructural analysis indicatesthat no cracks, delamination and step-type abrupt changes occured in the graded layer of the manufactured FGM. Flexuralstrength and Vickers hardness enhanced with the increasing Ti3AlC2content except for fracture strain and toughness. Theoverall fracture toughness and the flexural strength of FGM can reach 21.76 MPa m1/2 and 1329 ± 34 MPa, respectively. Theprepared FGM, herein, with a hard ceramic surface on one side to resist local plastic deformation, and a ductile metallicsurface on the other side to provide toughness.

Thermal Shock Behavior of a Novel TiCx–Ni3(Al,Ti)/Ni Functionally Graded Composite

Qun Yu,Zhenying Huang,Guangming Zheng,Wenqiang Hu,Cong Lei,Yuanbo Wang,Yidan Jiao,Hongxiang Zhai 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.12

This paper focuses on the study of thermal shock behaviors of a novel TiCx–Ni3(Al,Ti)/Ni functionally graded material (FGM)fabricated from Ti3AlC2and Ni powders. Thermal shock resistance of resulted FGM was conducted by water quenching atdifferent temperatures, mechanical properties and microstructures after thermal shocks were correspondingly determined andcharacterized. The microstructure of the FGM after thermal shocks shows no cracks of instability failure between the transitionzones, and the reinforcement phases were closely combined with the matrix. Meanwhile, compared with the strengthof 1329 MPa without thermal shock, when the temperature of the thermal shock reached 800 °C and 1000 °C respectively,with 10 repeated heat-water quench cycles, the residual flexural strength of FGM decreased slightly, but it could still reach1100 MPa. Notably, the strength can still maintain at 843 MPa after 10 cycles of thermal shock at 1200 °C. Such excellentthermal shock performance may be the result of the good interfacial bonding and the special gradient structure, the oxidationlayer also plays a protective role.

Identification of QTLs associated with the anaerobic germination potential using a set of Oryza nivara introgression lines

Licheng Liu,Xiaoxiang Li,Sanxiong Liu,Jun Min,Wenqiang Liu,Xiaowu Pan,Baohua Fang,Min Hu,Zhongqi Liu,Yongchao Li,Haiqing Zhang 한국유전학회 2021 Genes & Genomics Vol.43 No.4

Background Rice (Oryza sativa L.) is an important crop and a staple food for half of the population around the world. The recent water and labor shortages are encouraging farmers to shift from traditional transplanting to direct-seeding. However, poor germination and slow elongation of the coleoptile constrains large-scale application of direct-seeding. Objective Thisstudy was aimed to investigate the genetic basis of the anaerobic germination(AG) potential using a set of Oryza nivara (O. nivara) introgressionlines (ILs). Methods Inthis study, a total of 131 ILs were developed by introducing O. nivara chromosomesegments into the elite indica rice variety 93-11 through advanced backcrossingand repeated selfng. A high-density genetic map has been previouslyconstructed with 1,070 bin-markers. The seeds of ILs were germinated and usedto measure coleoptile length under normal and anaerobic conditions. QTLsassociated with AG potential were determined in rice. Results Basedon the high-density genetic map of the IL population, two QTLs, qAGP1 and qAGP3 associated with AG tolerance were characterized and locatedon chromosomes 1 and 3, respectively. Each QTL explained 15% of the phenotypic variance.Specifcally, the O. nivara-derived chromosomesegments of the two QTLs were positively tolerance to anaerobic condition byincreasing coleoptile length. In a further analysis of public transcriptomedata, a total of 26 and 36 genes within qAGP1 and qAGP3 were transcriptionallyinduced by anaerobic stress, respectively. Conclusions Utilizationof O. nivara-derived alleles at qAGP1 and qAGP3 can potentially enhance tolerance to anaerobic stress at thegermination stage in rice, thereby accelerating breeding of rice varieties tobe more adaptative for direct-seeding.

A national survey on how to improve traditional Chinese medicine learning internationally: Perceptions from both teachers and students

Zhu Yu-Hang,Yan Wu,Hao Zhang,Yanfei Zhao,Yule Ren,Wei Hu,Pan Li,Huiyi Wang,Ying Wang,Boda Zhang,Yujie Wang,Hongwen Yuan,Jiping Zhang,Wenqiang Li,Yufang Zhao,Jie Zhao,Yedong Shi,Yanye Shu,Xiao Zhang,Ya 한국한의학연구원 2022 Integrative Medicine Research Vol.11 No.4

Background With the increasing popularity of traditional Chinese medicine (TCM) by the global community, how to teach basic knowledge of TCM to international students and improve the teaching quality are important issues for teachers of TCM. The present study was to analyze the perceptions from both students and teachers on how to improve TCM learning internationally. Methods A cross-sectional national survey was conducted at 23 universities/colleges across China. A structured, self-reported on-line questionnaire was administered to 34 Chinese teachers who taught TCM course in English and to 1016 international undergraduates who were enrolled in the TCM course in China between 2017 and 2021. Results Thirty-three (97.1%) teachers and 900 (88.6%) undergraduates agreed Chinese culture should be fully integrated into TCM courses. All teachers and 944 (92.9%) undergraduates thought that TCM had important significance in the clinical practice. All teachers and 995 (97.9%) undergraduates agreed that modern research of TCM is valuable. Thirty-three (97.1%) teachers and 959 (94.4%) undergraduates thought comparing traditional medicine in different countries with TCM can help the students better understand TCM. Thirty-two (94.1%) teachers and 962 (94.7%) undergraduates agreed on the use of practical teaching method with case reports. From the perceptions of the undergraduates, the top three beneficial learning styles were practice (34.3%), teacher's lectures (32.5%), case studies (10.4%). The first choice of learning mode was attending to face-to-face teaching (82.3%). The top three interesting contents were acupuncture (75.5%), Chinese herbal medicine (63.8%), and massage (55.0%). Conclusion To improve TCM learning among international undergraduates majoring in conventional medicine, integration of Chinese culture into TCM course, comparison of traditional medicine in different countries with TCM, application of the teaching method with case reports, and emphasization of clinical practice as well as modern research on TCM should be fully considered.