Effect of extrusion temperature on microstructure and mechanical properties of a low-alloying and ultra-high strength Mg-Zn-Ca-Mn matrix composite containing trace TiC nanoparticles

Mechanical properties of microalloying Mg-2.2Zn-1.8Ca-0.5Mn(wt%)matrix composites reinforced by 0.5 wt%TiC nanoparticles before and after extrusion were investigated based on the detailed microstructural analysis.A uniform distribution of TiC nanoparticles was realized in the nanocomposite by the method of ultrasonic-assisted semisolid stirring.The morphology of eutectic Ca2Mg6Zn3 phases changed from plate-like in the free TiC nanoparticles region to lamellar in the dense TiC nanoparticles region for the as-cast nanocomposite.Both the grain structure and precipitates were obviously refined as the extrusion temperature decreased from 350 to 270℃.The nanocomposite exhibited excellent tensile yield strength(352-428 MPa)which was governed by the extrusion temperature.The grain refinement strengthening with the contribution ratio of^80%to this strength increment was much higher relative to thermal expansion effect,Orowan strengthening and dislocation strengthening.Ultrafine recrystallized grain structure with a substantial of ne precipitates appeared in the nanocomposite extruded at 270℃.The refined grain structure was not only due to dynamic recrystallization,but also the synergistic pinning effect of nano-TiCp,precipitated MgZn2 and α-Mn particles.The tensile toughness value of nanocomposite after extrusion improved with increasing the extrusion temperature.Massive micro-cracks formed along the remnant coarse Ca2Mg6Zn3 led to the structural failure during tension.

Synergistically Toughening Effect of SiC Whiskers and Nanoparticles in Al_2O_3-based Composite Ceramic Cutting Tool Material

In recent decades, many additives with different characteristics have been applied to strengthen and toughen Al2O3-based ceramic cutting tool materials. Among them, SiC whiskers and SiC nanoparticles showed excellent performance in improving the material properties. While no attempts have been made to add SiC whiskers and SiC nanoparticles together into the ceramic matrix and the synergistically toughening effects of them have not been studied. An Al2O3-SiCw-SiC np advanced ceramic cutting tool material is fabricated by adding both one-dimensional SiC whiskers and zero-dimensional SiC nanoparticles into the Al2O3 matrix with an effective dispersing and mixing process. The composites with 25 vol% SiC whiskers and 25 vol% SiC nanoparticles alone are also investegated for comparison purposes. Results show that the Al2O3-SiCw-SiCnp composite with both 20 vo1% SiC whiskers and 5 vol% SiC nanoparticles additives have much improved mechanical properties. The flexural strength of Al2O3-SiCw-SiCnp is 730＋ 95 MPa and fracture toughness is 5.6 ± 0.6 MPa.m1/2. The toughening and strengthening mechanisms of SiC whiskers and nanoparticles are studied when they are added either individually or in combination. It is indicated that when SiC whiskers and nanoparticles are added together, the grains are further refined and homogenized, so that the microstructure and fracture mode ratio is modified. The SiC nanoparticles are found helpful to enhance the toughening effects of the SiC whiskers. The proposed research helps to enrich the types of ceramic cutting tool and is benefit to expand the application range of ceramic cutting tool.

Cotton Breeding in Xinjiang and Its Intellectual Property Protection

In 2021,Xinjiang's cotton output was 5.129 million t,accounting for 89.50%of China's total.The autonomous region produces high-quality long-staple cotton,natural colored cotton,fine-staple cotton(upland cotton),organic cotton,etc.The southern Xinjiang cotton area is one of the three major long-staple cotton(island cotton)producing regions in the world.This paper introduced the history of cotton planting and breeding in Xinjiang from the aspects of cultural relics records,history of entering Xinjiang,historical achievements of breeding and breeding leaders.We studied the intellectual property protection of cotton breeding in the autonomous region from the aspects of biological genetic resources,invention patents,utility model patents and new plant varieties,analyzed the six main problems existing in cotton breeding and its intellectual property protection,and discussed the tactics for cotton breeding and its intellectual property protection in Xinjiang under the strategy of strengthening the country with intellectual property.Eight suggestions in response to the Xinjiang cotton incident were also put forward,including establishing a Xinjiang national cotton germplasm nursery,protecting biological genetic resources,and strengthening the protection of creative intellectual property rights in the field of breeding to escort technological innovation in the cotton seed industry.

A Study on Intellectual Property Right Protection of Geographical Indications and Regional Public Brand Building in Xinjiang

This paper studies the geographical indication resources of Xinjiang and their distribution in administrative regions,national grain production functional zones,protected zones for production of major agricultural products,advantageous areas of Chinese characteristic agricultural products,and national advantageous characteristic industrial clusters.It analyzes the main problems existing in the protection of intellectual property rights of geographical indications.Besides,it discusses the strategies for the protection of intellectual property rights of geographical indications in the autonomous region and the building of regional public brands in the contest of the strategy of strengthening the country with intellectual property and rural revitalization strategy.Finally,it comes up with recommendations,including collecting and sorting out the human factors and natural factors of geographical indications of famous,excellent and special products,strengthening the protection of geographical indications of Xinjiang cotton and its products,enhancing the protection of geographical indications of grain and oil crops and sugar beet,implementing the protection of geographical indications for products with special needs for ethnic minorities,building national geographical indication product protection demonstration areas,formulating national and international standards for geographical indication products,and take full advantage of the EU-China Agreement on Cooperation on and Protection of Geographical Indications to actively participate in the EU protection of geographical indications.

Inheritance,Innovation and Development of Wuling Mountain Area in Hubei Province Based on Intellectual Property Rights

Using the methods of field survey and literature collection,this paper firstly introduces the intellectual property resources of the Wuling Mountain Area in Hubei Province from folk literature and arts,traditional knowledge,biological genetic resources,new plant varieties,patents,geographical indications,and trademarks.Then,it analyzes the main problems in the protection and inheritance,innovation and development of intellectual property rights(IPRs).In addition,it discusses the strategy of inheritance,innovation and high-quality development of this ethnic area in the context of the strategy of strengthening the country with intellectual property rights and the strategy of rural revitalization.Finally,it comes up with recommendations including carrying forward and inheriting folk literature and art,protecting traditional knowledge of traditional craftsmanship,inheriting and innovating to develop traditional Chinese medicine and ethnic medicine,improving the protection and use of geographical indications,and strengthening the IPR protection.

Intellectual Property Protection and High-quality Development of Cotton Industry in Xinjiang

This paper firstly introduces the general situation of cotton planting areas in China and cotton industry in Xinjiang,and the current situation of intellectual property protection of Xinjiang's cotton industry.Then,it analyzes the main problems in its intellectual property protection and high-quality development.On this basis,it comes up with the recommendations for high-quality development of cotton industry in Xinjiang under the strategy of strengthening the country with intellectual property.The recommendations include improving the level of creation of creative intellectual property rights,building an intellectual property rule system in the entire cotton industry chain in Xinjiang,building protected zones for production of major high quality agricultural product cotton,establishing a demonstration zone to undertake the transfer of the domestic cotton textile and garment industry,undertaking education on the sense of community for the Chinese nation in response to the Xinjiang cotton incident,and developing the"Belt and Road"blue market for Xinjiang cotton and its products.

China Strengthens the Protection of Intellectual Property

The intellectual property protection system was formed when civilization and the commodity economy were developing to a certain extent, and was a significant landmark for mankind in respecting talents and knowledge. Now it is playing an important role in promoting scientific and technical progress, cultural prosperity and economic development. Such an important system ensures the smooth performance of the socialist economy, making up one of the basic premises for

First-principles Calculations of Strengthening Compounds in Magnesium Alloy： A General Review

First-principles computation methods play an important role in developing and designing new magnesium alloys.In this article,we present an overview of the first-principles modeling techniques used in recent years to simulate ideal models of the structure of strengthening compounds in Mg alloys.For typical Mg compounds,structural stability,mechanical properties,electronic structure and thermodynamic properties have been discussed.Specifically,the elastic anisotropies of these compounds are examined,which is highly correlated with the possibility of inducing micro-cracks.Furthermore,some heterogeneous nucleation interfaces investigated by first-principles method are reviewed.Some of the theoretical results are compared with available experimental observations.We hope to illustrate that the first-principles computation can help to accelerate the design of new Mg-based materials and the development of materials genome initiative.Remaining problems and future directions in this research field are considered.