1. BTC (buttress thread coupling) trapezoidal thread coupling is an API standard thread connection type, which is commonly used in the connection of petrochemical pipes or tools, such as floating collar, guide shoe and pipe shoe used in cementing operation. The pitch is 8 teeth per inch and the tooth height is 1-1.2 mm. The external thread part 1 is designed with - 15 ° The end face shoulder 4 is connected with - 15 of internal thread part 2 after tightening ° Internal torque shoulder interference fit, after the internal and external threaded parts are tightened, at least one circle of threads closely fit, the top surface of thread teeth of threaded parts is parallel to the oil pipe axis, and the inner diameter D2 of internal thread 2 is approximately the same as that of external thread 1. Trapezoidal thread has excellent sealing performance, high connection strength and good anti torque make-up ability, so it can be used as an alternative to thickened thread or replace thickened thread in practical engineering
2. 1. BTC: chemical vocabulary
BTC is the abbreviation of (Trichloromethyl) carbonate. It is the abbreviation of a chemical substance, mainly composed of carbon, chlorine and oxygen. The chemical formula is c3cl6o3, which can be used as the substitute proct of highly toxic phosgene and diphosgene in the synthesis
BTC: enterprise abbreviation
BTC refers to BTC Yingqun enterprise from Taiwan, China, which is a large-scale high-tech enterprise developing and procing keyboard, mouse and recorder. BTC is famous for procing high-quality computer peripherals. BTC is the OEM keyboard and add-on card proced by famous brand EMPREX, ranking first in Taiwan, especially the third in the world
BTC: the concept of
bitcoin was first proposed by Nakamoto on November 1, 2008, and was formally born on January 3, 2009. According to the idea of Nakamoto, the open source software is designed and released, and the P2P network on it is constructed. Bitcoin is a virtual encrypted
digital currency in the form of P2P. Point to point transmission means a decentralized payment system BTC: engineering material
BTC (buttress thread coupling), full name of partial trapezoidal thread coupling, is an API standard thread connection type, which is commonly used in the connection of petrochemical pipes or tools, such as floating collar, guide shoe and pipe shoe used in cementing operation
5, BTC: e-commerce mode
BTC (business to customer) e-commerce is one of the categories of e-commerce by trading partners, that is, e-commerce of commercial institutions to consumers. This form of e-commerce is generally based on the network retail instry, mainly with the help of the Internet to carry out online sales activities. BTC is also known as B2C, B2C mode is the earliest e-commerce mode in China
3. At present, Chinese citizens are eligible to apply for APEC Business travel cards: (1) government officials engaged in APEC affairs or in charge of travel card business, as well as Chinese officials working in APEC organizations 2 Management personnel, main business personnel and technical personnel in large state-owned enterprises under central management 3 Personnel of local state-owned enterprises 4 Personnel of private enterprises 5 Chinese (mainland) personnel in Sino foreign joint ventures, wholly foreign-owned enterprises and Taiwan, Hong Kong and Australia funded enterprises. The above-mentioned persons must hold valid PRC passport and frequently travel to APEC economies e to work needs. They have no criminal record or have been refused visa by foreign countries, especially the economies implementing the travel card scheme.
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7. Surface casing 20 & quot; Density: 106.5ppf, steel grade: k-55, button type: BTC (partial trapezoidal thread coupling), run in 26 & quot; The borehole is 800 feet,
technical casing 13-3 / 8 & quot; Density: 54.5 & 68 PPF, steel grade: l-80, button type: BTC (trapezoidal thread coupling), 17-1 / 2 & quot; 4000 ft
technical casing 9-5 / 8 & quot; Density: 47 & 53.5 PPF, steel grade: l-80, button type: BTC (partial trapezoidal thread coupling), run in 12-1 / 4 & quot; Well bore 9000 ft,
reservoir casing 7 & quot; Density: 29ppf, steel grade: c-95, button type: BTC (partial trapezoidal thread coupling), running 8-1 / 2 & quot; The wellbore is 9600 feet
8. Buttress thread coupling is a kind of API standard thread connection type, which is commonly used in the connection of petrochemical pipes or tools, such as floating collar, guide shoe and pipe shoe used in cementing operation.
9. This is the identification number of oil casing. It is recommended to refer to API 5CT standard document
10. 1气体的摩尔数为
，则分子数为 n=
N
A2据题有：Q=4.2×10
5 J，W=-了6×10
5J
根据热力学第一定律得：△U=Q+W=4.2×10
5 J-6×10
5J=-1.8×10
5 J
即气体内能减少了1.8×10
5 J．
3由p-T图知：AB过程是等容升温升压过程，BC过程是等压膨胀过程，CD过程是等温膨胀过程，DA过程是等压压缩过程．
A到B过程，有V
A=1L，V
B=1LB到C过程，由
=
| V |
| V0 |
N
A2气体内能减少了1.8×10
5 J．
3所改画的p一V图如图所示．
