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Bao ZJ, Yang HY, Dong BX, Chang F, Li CD, Jiang Y, Chen LY, Shu SL, Jiang QC, Qiu F. Development Trend in Composition Optimization, Microstructure Manipulation, and Strengthening Methods of Die Steels under Lightweight and Integrated Die Casting. Materials (Basel) 2023; 16:6235. [PMID: 37763513 PMCID: PMC10532891 DOI: 10.3390/ma16186235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 09/07/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023]
Abstract
In the general environment of lightweight automobiles, the integrated die-casting technology proposed by Tesla has become the general mode to better achieve weight reduction in automobiles. The die-casting mold required by integrated die-casting technology has the characteristics of large scale and complexity. Hence, higher requirements are put forward for the comprehensive performance of the die steel. Despite the stagnation in the progress of conventional strengthening methods, enhancing the performance of die steel has become increasingly challenging. Indeed, it necessitates exploring novel die steel and optimizing heat treatment and reinforcement technologies. This article summarizes and analyzes the development status of die steel and corresponding heat treatment and microstructure manipulation as well as strengthening methods and elaborates on an excellent nano-strengthening technology. Furthermore, this review will aid researchers in establishing a comprehensive understanding of the development status of die steel and the processes utilized for its strengthening. It will also assist them in developing die steel with improved comprehensive performance to meet the high demand for mold steel in the integrated die-casting technology of the new era.
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Affiliation(s)
- Ze-Ju Bao
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China; (Z.-J.B.); (B.-X.D.); (F.C.); (C.-D.L.); (Y.J.); (Q.-C.J.)
| | - Hong-Yu Yang
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China; (Z.-J.B.); (B.-X.D.); (F.C.); (C.-D.L.); (Y.J.); (Q.-C.J.)
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street No. 5988, Changchun 130025, China
- School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China;
| | - Bai-Xin Dong
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China; (Z.-J.B.); (B.-X.D.); (F.C.); (C.-D.L.); (Y.J.); (Q.-C.J.)
| | - Fang Chang
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China; (Z.-J.B.); (B.-X.D.); (F.C.); (C.-D.L.); (Y.J.); (Q.-C.J.)
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street No. 5988, Changchun 130025, China
| | - Chuan-De Li
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China; (Z.-J.B.); (B.-X.D.); (F.C.); (C.-D.L.); (Y.J.); (Q.-C.J.)
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street No. 5988, Changchun 130025, China
| | - Ying Jiang
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China; (Z.-J.B.); (B.-X.D.); (F.C.); (C.-D.L.); (Y.J.); (Q.-C.J.)
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street No. 5988, Changchun 130025, China
| | - Liang-Yu Chen
- School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China;
| | - Shi-Li Shu
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China; (Z.-J.B.); (B.-X.D.); (F.C.); (C.-D.L.); (Y.J.); (Q.-C.J.)
- School of Mechanical and Aerospace Engineering, Jilin University, Renmin Street No. 5988, Changchun 130025, China
| | - Qi-Chuan Jiang
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China; (Z.-J.B.); (B.-X.D.); (F.C.); (C.-D.L.); (Y.J.); (Q.-C.J.)
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street No. 5988, Changchun 130025, China
| | - Feng Qiu
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China; (Z.-J.B.); (B.-X.D.); (F.C.); (C.-D.L.); (Y.J.); (Q.-C.J.)
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street No. 5988, Changchun 130025, China
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Sun JR, Dong BX, Yang HY, Shu SL, Qiu F, Jiang QC, Zhang LC. The Role of Lithium in the Aging Precipitation Process of Al-Zn-Mg-Cu Alloys and Its Effect on the Properties. Materials (Basel) 2023; 16:4750. [PMID: 37445064 DOI: 10.3390/ma16134750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/15/2023]
Abstract
It is well known that the development of lightweight alloys with improved comprehensive performance and application value are the future development directions for the ultra-high-strength 7xxx series Al-Zn-Mg-Cu alloys used in the aircraft field. As the lightest metal element in nature, lithium (Li) has outstanding advantages in reducing the density and increasing the elastic modulus in aluminum alloys, so Al-Zn-Mg-Cu alloys containing Li have gained widespread attention. Furthermore, since the Al-Zn-Mg-Cu alloy is usually strengthened by aging treatment, it is crucial to understand how Li addition affects its aging precipitation process. As such, in this article, the effects and mechanism of Li on the aging precipitation behavior and the impact of Li content on the aging precipitation phase of Al-Zn-Mg-Cu alloys are briefly reviewed, and the influence of Li on the service properties, including mechanical properties, wear resistance, and fatigue resistance, of Al-Zn-Mg-Cu alloys are explained. In addition, the corresponding development prospects and challenges of the Al-Zn-Mg-Cu-Li alloy are also proposed. This review is helpful to further understand the role of Li in Al-Zn-Mg-Cu alloys and provides a reference for the development of high-strength aluminum alloys containing Li with good comprehensive properties.
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Affiliation(s)
- Jing-Ran Sun
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China
| | - Bai-Xin Dong
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China
| | - Hong-Yu Yang
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China
- School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China
| | - Shi-Li Shu
- School of Mechanical and Aerospace Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China
- Chongqing Research Institute, Jilin University, Chongqing 401123, China
| | - Feng Qiu
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China
- Chongqing Research Institute, Jilin University, Chongqing 401123, China
| | - Qi-Chuan Jiang
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China
| | - Lai-Chang Zhang
- Centre for Advanced Materials and Manufacturing, School of Engineering, Edith Cowan University, 270 Joondalup Drive, Joondalup, Perth, WA 6027, Australia
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Dong BX, Qiu F, Li Q, Shu SL, Yang HY, Jiang QC. The Synthesis, Structure, Morphology Characterizations and Evolution Mechanisms of Nanosized Titanium Carbides and Their Further Applications. Nanomaterials (Basel) 2019; 9:nano9081152. [PMID: 31405228 PMCID: PMC6723659 DOI: 10.3390/nano9081152] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/08/2019] [Accepted: 08/08/2019] [Indexed: 12/20/2022]
Abstract
It is widely known that the special performances and extensive applications of the nanoscale materials are determined by their as-synthesized structures, especially their growth sizes and morphologies. Hereinto, titanium carbides, which show brilliant comprehensive properties, have attracted considerable attention from researchers. How to give full play to their potentials in the light-weight manufacture, microwave absorption, electromagnetic protection, energy conversion and catalyst areas has been widely studied. In this summarized article, the synthesis methods and mechanisms, corresponding growth morphologies of titanium carbides and their further applications were briefly reviewed and analyzed according to their different morphological dimensions, including one-dimensional nanostructures, two-dimensional nanosheets and three-dimensional nanoparticles. It is believed that through the investigation of the crystal structures, synthesis methods, growth mechanisms, and morphology characterizations of those titanium carbides, new lights could be shed on the regulation and control of the ceramic phase specific morphologies to meet with their excellent properties and applications. In addition, the corresponding development prospects and challenges of titanium carbides with various growth morphologies were also summarized.
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Affiliation(s)
- Bai-Xin Dong
- Key Laboratory of Automobile Materials, Ministry of Education and School of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China
| | - Feng Qiu
- Key Laboratory of Automobile Materials, Ministry of Education and School of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China.
- Qingdao Automotive Research Institute of Jilin University, Qingdao 266000, China.
| | - Qiang Li
- Key Laboratory of Automobile Materials, Ministry of Education and School of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China
| | - Shi-Li Shu
- School of Mechanical and Aerospace Engineering, Jilin University, Changchun 130025, China
| | - Hong-Yu Yang
- National Demonstration Center for Experimental Materials Science and Engineering Education, Jiangsu University of Science and Technology, Zhenjiang 212003, China
| | - Qi-Chuan Jiang
- Key Laboratory of Automobile Materials, Ministry of Education and School of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China.
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Lu HY, Tian SC, Tong CZ, Wang LJ, Rong JM, Liu CY, Wang H, Shu SL, Wang LJ. Extracting more light for vertical emission: high power continuous wave operation of 1.3-μm quantum-dot photonic-crystal surface-emitting laser based on a flat band. Light Sci Appl 2019; 8:108. [PMID: 31798847 PMCID: PMC6874546 DOI: 10.1038/s41377-019-0214-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 10/15/2019] [Accepted: 10/30/2019] [Indexed: 05/10/2023]
Abstract
For long distance optical interconnects, 1.3-μm surface-emitting lasers are key devices. However, the low output power of several milliwatts limits their application. In this study, by introducing a two-dimensional photonic-crystal and using InAs quantum dots as active materials, a continuous-wave, 13.3-mW output power, 1.3-μm wavelength, room-temperature surface-emitting laser is achieved. In addition, such a device can be operated at high temperatures of up to 90 °C. The enhanced output power results from the flat band structure of the photonic crystal and an extra feedback mechanism. Surface emission is realized by photonic crystal diffraction and thus the distributed Bragg reflector is eliminated. The proposed device provides a means to overcome the limitations of low-power 1.3-μm surface-emitting lasers and increase the number of applications thereof.
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Affiliation(s)
- Huan-Yu Lu
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 130033 Changchun, China
- The University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Si-Cong Tian
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 130033 Changchun, China
- Bimberg Chinese-German Center for Green Photonics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 130033 Changchun, China
| | - Cun-Zhu Tong
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 130033 Changchun, China
| | - Li-Jie Wang
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 130033 Changchun, China
| | - Jia-Min Rong
- National Key Laboratory for Electronic Measurement Technology, School of Instrument and Electronics, North University of China, 030051 Taiyuan, China
| | - Chong-Yang Liu
- Temasek Laboratories, Nanyang Technological University, 50 Nanyang Drive, 637553 Singapore, Singapore
| | - Hong Wang
- Nanyang Technological University, 50 Nanyang Drive, 637553 Singapore, Singapore
| | - Shi-Li Shu
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 130033 Changchun, China
| | - Li-Jun Wang
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 130033 Changchun, China
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Tian SC, Wan RG, Wang LJ, Shu SL, Lu HY, Zhang X, Tong CZ, Feng JL, Xiao M, Wang LJ. Asymmetric light diffraction of two-dimensional electromagnetically induced grating with PT symmetry in asymmetric double quantum wells. Opt Express 2018; 26:32918-32930. [PMID: 30645452 DOI: 10.1364/oe.26.032918] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 11/09/2018] [Indexed: 06/09/2023]
Abstract
An asymmetric double semiconductor quantum well is proposed to realize two-dimensional parity-time (PT) symmetry and an electromagnetically induced grating. In such a nontrivial grating with PT symmetry, the incident probe photons can be diffracted to selected angles depending on the spatial relationship of the real and imaginary parts of the refractive index. Such results are due to the interference mechanism between the amplitude and phase of the grating and can be manipulated by the probe detuning, modulation amplitudes of the standing wave fields, and interaction length of the medium. Such a system may lead to new approaches of observing PT-symmetry-related phenomena and has potential applications in photoelectric devices requiring asymmetric light transport using semiconductor quantum wells.
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Qiu F, Tong HT, Gao YY, Zou Q, Dong BX, Li Q, Chu JG, Chang F, Shu SL, Jiang QC. Microstructures and Compressive Properties of Al Matrix Composites Reinforced with Bimodal Hybrid In-Situ Nano-/Micro-Sized TiC Particles. Materials (Basel) 2018; 11:ma11081284. [PMID: 30044419 PMCID: PMC6117683 DOI: 10.3390/ma11081284] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 07/18/2018] [Accepted: 07/20/2018] [Indexed: 11/16/2022]
Abstract
Bimodal hybrid in-situ nano-/micro-size TiC/Al composites were prepared with combustion synthesis of Al-Ti-C system and hot press consolidation. Attempt was made to obtain in-situ bimodal-size TiC particle reinforced dense Al matrix composites by using different carbon sources in the reaction process of hot pressing forming. Microstructure showed that the obtained composites exhibited reasonable bimodal-sized TiC distribution in the matrix and low porosity. With the increasing of the carbon nano tube (CNT) content from 0 to 100 wt. %, the average size of the TiC particles decreases and the compressive strength of the composite increase; while the fracture strain increases first and then decreases. The compressive properties of the bimodal-sized TiC/Al composites, especially the bimodal-sized composite synthesized by Al-Ti-C with 50 wt. % CNTs as carbon source, were improved compared with the composites reinforced with single sized TiC. The strengthening mechanism of the in-situ bimodal-sized particle reinforced aluminum matrix composites was revealed.
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Affiliation(s)
- Feng Qiu
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China.
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China.
- Qingdao Automotive Research Institute of Jilin University, Qingdao 266000, China.
| | - Hao-Tian Tong
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China.
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China.
| | - Yu-Yang Gao
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China.
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China.
| | - Qian Zou
- Department of Mechanical Engineering, Oakland University, Rochester, MI 48309, USA.
| | - Bai-Xin Dong
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China.
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China.
| | - Qiang Li
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China.
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China.
| | - Jian-Ge Chu
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China.
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China.
| | - Fang Chang
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China.
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China.
| | - Shi-Li Shu
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130012, China.
| | - Qi-Chuan Jiang
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China.
- Key Laboratory of Automobile Materials, Ministry of Education and Department of Materials Science and Engineering, Jilin University, Renmin Street NO. 5988, Changchun 130025, China.
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Tian SC, Wan RG, Wang CL, Shu SL, Wang LJ, Tong CZ. Creation and Transfer of Coherence via Technique of Stimulated Raman Adiabatic Passage in Triple Quantum Dots. Nanoscale Res Lett 2016; 11:219. [PMID: 27107772 PMCID: PMC4842202 DOI: 10.1186/s11671-016-1433-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 04/13/2016] [Indexed: 06/05/2023]
Abstract
We propose a scheme for creation and transfer of coherence among ground state and indirect exciton states of triple quantum dots via the technique of stimulated Raman adiabatic passage. Compared with the traditional stimulated Raman adiabatic passage, the Stokes laser pulse is replaced by the tunneling pulse, which can be controlled by the externally applied voltages. By varying the amplitudes and sequences of the pump and tunneling pulses, a complete coherence transfer or an equal coherence distribution among multiple states can be obtained. The investigations can provide further insight for the experimental development of controllable coherence transfer in semiconductor structure and may have potential applications in quantum information processing.
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Affiliation(s)
- Si-Cong Tian
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, China.
| | - Ren-Gang Wan
- School of Physics and Information Technology, Shaanxi Normal University, Xi'an, 710062, China
| | - Chun-Liang Wang
- Centre for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun, 130024, China
| | - Shi-Li Shu
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, China
| | - Li-Jie Wang
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, China
| | - Chun-Zhu Tong
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, China.
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Qiu F, Zuo R, Shu SL, Wang YW, Jiang QC. Effect of Al addition on the microstructures and compression properties of (TiCxNy–TiB2)/Ni composites fabricated by combustion synthesis and hot press. POWDER TECHNOL 2015. [DOI: 10.1016/j.powtec.2015.09.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Chuang MF, Ni HF, Yang HR, Shu SL, Lai SY, Jiang YL. First Report of Stem Canker Disease of Pitaya (Hylocereus undatus and H. polyrhizus) Caused by Neoscytalidium dimidiatum in Taiwan. Plant Dis 2012; 96:906. [PMID: 30727398 DOI: 10.1094/pdis-08-11-0689-pdn] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Pitaya (Hylocereus undatus and H. polyrhizus Britt. & Rose), a perennial succulent plant grown in the tropics, is becoming an emerging and important fruit plant in Taiwan. In September of 2009 and 2010, a number of pitaya plants were found to have a distinctive canker on stems. The disease expanded quickly to most commercial planting areas in Taiwan (e.g., Pintung, Chiayi, and Chunghua). Symptoms on the stem were small, circular, sunken, orange spots that developed into cankers. Pycnidia were erumpent from the surface of the cankers and the stems subsequently rotted. After surface disinfestation with 0.1% sodium hypochloride, tissues adjacent to cankers were placed on acidified potato dextrose agar (PDA) and incubated at room temperature for 1 week, after which colonies with dark gray-to-black aerial mycelium grew. Hyphae were branched, septate, and brown and disarticulated into 0- to 1-septate arthrospores. Sporulation was induced by culturing on sterile horsetail tree (Casuarina equisetifolia) leaves. Conidia (12.79 ± 0.72 × 5.14 ± 0.30 μm) from pycnidia were one-celled, hyaline, and ovate. The internal transcribed spacer (ITS) region of ribosomal DNA was PCR amplified with primers ITS1 and ITS4 (2) and sequenced. The sequence (GenBank Accession No. HQ439174) showed 99% identity to Neoscytalidium dimidiatum (Penz.) Crous & Slippers (GenBank Accession No. GQ330903). On the basis of morphology and nucleotide-sequence identity, the isolates were identified as N. dimidiatum (1). Pathogenicity tests were conducted in two replicates by inoculating six surface-sterilized detached stems of pitaya with either mycelium or conidia. Mycelial plugs from 2-day-old cultures (incubated at 25°C under near UV) were inoculated to the detached stems after wounding with a sterile needle. Conidial suspensions (103 conidia/ml in 200 μl) were inoculated to nonwounded stems. Noninoculated controls were treated with sterile medium or water. Stems were then incubated in a plastic box at 100% relative humidity and darkness at 30°C for 2 days. The symptoms described above were observed on inoculated stems at 6 to 14 days postinoculation, whereas control stems did not develop any symptoms. N. dimidiatum was reisolated from symptomatic tissues. To our knowledge, this is the first report of N. dimidiatum causing stem canker of pitaya. References: (1) P. W. Crous et al. Stud. Mycol. 55:235, 2006. (2) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, New York, 1990.
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Affiliation(s)
- M F Chuang
- Department of Plant Protection, Chiayi Agricultural Experiment Branch, Agricultural Research Institute, Chiayi, Taiwan
| | - H F Ni
- Department of Plant Protection, Chiayi Agricultural Experiment Branch, Agricultural Research Institute, Chiayi, Taiwan
| | - H R Yang
- Department of Plant Protection, Chiayi Agricultural Experiment Branch, Agricultural Research Institute, Chiayi, Taiwan
| | - S L Shu
- Department of Plant Protection, Chiayi Agricultural Experiment Branch, Agricultural Research Institute, Chiayi, Taiwan
| | - S Y Lai
- Department of Plant Protection, Chiayi Agricultural Experiment Branch, Agricultural Research Institute, Chiayi, Taiwan
| | - Y L Jiang
- Department of Horticulture, National Taiwan University, Taipei, Taiwan, R.O.C
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