Structure: Mainly composed of body, end cover, stop pin, union joint, manifold, quick-fit joint, etc.
effect:
3. When the floating hoop and floating shoes fail, the pressure can be restrained to prevent the cement slurry from falling.
single plug cement head and double plug cement head:
Casing cement head single plug cement head,double plug cement head,wellhead equipment Puyang Junhong Rubber Co., Ltd. , https://www.pyjhxs.com
Graphene and hexagonal boron nitride (h-BN) are similar in structure but have different electrical properties. Because graphene/hexagonal boron nitride planar heterojunctions have important potential in basic research and device exploration, they have attracted much attention from the academic community. The preparation of graphene/h-BN planar heterojunction is generally carried out by depositing graphene and h-BN in sequence, or in reverse order. Due to the difficulty in subsequent thin film nucleation control and the reaction gas in the growth process, the precursor film is easily destroyed. Therefore, the current literature reports that the quality of the graphene/h-BN planar heterojunction is not satisfactory. Lu Guangyuan and Wu Tianru from the State Key Laboratory of Information Functional Materials of Shanghai Institute of Microsystems, based on the research basis of high quality h-BN and graphene films grown on copper-nickel alloy substrates, grow graphene by depositing h-BN single crystals first. High quality graphene/h-BN planar heterojunctions were successfully prepared. Due to the extremely fast growth rate of graphene on copper-nickel alloy, the shorter graphene deposition time reduces the damage to h-BN film during the growth of graphene film. At the same time, due to the excellent catalytic ability of the copper-nickel alloy, the random nucleation of graphene is eliminated while the crystal quality of the boron nitride single crystal is improved, so that the graphene domain is only formed at the top corner of the triangular h-BN single crystal domain. The core grows along the h-BN side. The research team cooperated with the University of Rice University professor Jun Lou and other teams to develop a doctoral program. Based on high-quality graphene/h-BN planar heterojunction, graphene was used as the contact electrode and h-BN was used as the insulation. The WSe2/MoS2 two-dimensional photodetector was fabricated on the substrate to verify the quality and electrical properties of the graphene/h-BN planar heterojunction, and to conduct basic research and two-dimensional logic integrated circuit application based on the heterojunction material platform. Exploration provides the foundation.
The work was funded by the Ministry of Science and Technology's major project "Research on Wafer-Grade Graphene Electronic Materials and Devices" and related research projects of the Chinese Academy of Sciences and the Shanghai Municipal Science and Technology Commission. 
2. Withstand high pressure and adapt to various cementing processes.
Abstract: The research progress of graphene/hexagonal boron nitride plane heterojunction in Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences has made new progress. The research team led by researcher Xie Xiaoming successfully prepared high atomic graphite with monoatomic layer by chemical vapor deposition (CVD). Alkene/hexagonal nitriding...
New progress has been made in the study of graphene/hexagonal boron nitride planar heterojunctions at the Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences. The research team led by researcher Xie Xiaoming successfully prepared monoatomic high-quality graphene by chemical vapor deposition (CVD). / Hexagonal boron nitride planar heterojunction, and successfully applied to WSe2/MoS2 two-dimensional photodetector devices. The research paper Synthesis of High-Quality Graphene and Hexagonal Boron Nitride Monolayer In-Plane Heterostructure on Cu–Ni Alloy was published on May 19th in Advanced Science. Figure 1 CVD preparation of high quality graphene/h-BN planar heterojunction
Figure 2 Application of WSe2/MoS2 optoelectronic devices on Graphene/h-BN planar heterojunction