The hole reaming and side cutting characteristics of offset one-cone bit and conventional one- cone bit were investigated on simulated drilling experimental equipment. The borehole diameter was a little larger than th...The hole reaming and side cutting characteristics of offset one-cone bit and conventional one- cone bit were investigated on simulated drilling experimental equipment. The borehole diameter was a little larger than the bit diameter due to side force. However, the reaming effect was not very apparent, whether drilling with an offset or conventional one-cone bit. The side cutting displacement increased gradually with increasing depth of drilling and side force. The side cutting displacement of offset onecone bits was larger than that of conventional ones under the same conditions of weight-on-bit （WOB）, rotary speed, side force and borehole depth.展开更多
In order to improve the matrix performance of impregnated diamond drill bit to better meet the drilling needs,the effects of the addition of nano-WC and nano-NbC particles on the matrix material together with the mech...In order to improve the matrix performance of impregnated diamond drill bit to better meet the drilling needs,the effects of the addition of nano-WC and nano-NbC particles on the matrix material together with the mechanical properties and microstructure of the diamond-matrix composite material of the Fe-based diamond drill bit were studied by using the method of uniform formula design,regression analysis and solution finding.An indoor drilling test was also carried out using the fabricated impregnated diamond drill bit.The results showed that after the addition of nano-NbC and nano-WC,the hardness and flexural strength of the matrix material got improved,as the flexural strength of the diamond composite material increased to 4.29%,the wear-resistance ratio increased to 8.75%,and the tighter the chemical bonding between the diamond and the matrix.This,indicates that the addition of nanoparticles has a positive significance in improving the performance of the diamond composite.The results of the drilling test showed that the mechanical drilling speed of the impregnated diamond drill bit after nanoparticle strengthening is 25.85%higher than that of the conventional drill bit,and the matrix wear was increased by 17.5%.It proves that nanoparticles can improve the drilling performance and efficiency of drill bit.展开更多
逐次逼近寄存器模数转换器(SAR ADC)在逐次逼近的过程中,电容的切换会使参考电压上出现参考纹波噪声,该噪声会影响比较器的判定,进而输出错误的比较结果。针对该问题,基于CMOS 0.5μm工艺,设计了一种具有纹波消除技术的10 bit SAR ADC...逐次逼近寄存器模数转换器(SAR ADC)在逐次逼近的过程中,电容的切换会使参考电压上出现参考纹波噪声,该噪声会影响比较器的判定,进而输出错误的比较结果。针对该问题,基于CMOS 0.5μm工艺,设计了一种具有纹波消除技术的10 bit SAR ADC。通过增加纹波至比较器输入端的额外路径,将参考纹波满摆幅输入至比较器中;同时设计了消除数模转换器(DAC)模块,对参考纹波进行采样和输入,通过反转纹波噪声的极性,消除参考纹波对ADC输出的影响。该设计将信噪比(SNR)提高到56.75 dB,将有效位数(ENOB)提升到9.14 bit,将积分非线性(INL)从-1~5 LSB降低到-0.2~0.3 LSB,将微分非线性(DNL)从-3~4 LSB降低到-0.5~0.5 LSB。展开更多
出版物的结构化处理是语义出版发展的基础。图书交换标签集(Book Interchange Tag Suite,BITS)是一套面向科技类图书的结构化表示模型。本文通过分析BITS模型的元素和结构,比较BITS与期刊标签集JATS以及电子书标准Docbook和DITA的异同,...出版物的结构化处理是语义出版发展的基础。图书交换标签集(Book Interchange Tag Suite,BITS)是一套面向科技类图书的结构化表示模型。本文通过分析BITS模型的元素和结构,比较BITS与期刊标签集JATS以及电子书标准Docbook和DITA的异同,并结合中文科技类图书的特点,以探讨BITS对中文图书的适用性和改进方向。展开更多
本文提出一种多协议,可变位宽发射机系统,最高数据位宽40 bits,最高数据速率10.312 5 Gbps.整个系统由归一化数据位宽(Normalization of Data Width,NMDW)变换电路,40:1合路器(MUX),时钟分布电路及3抽头前馈均衡器(Feed-Forward-Equaliz...本文提出一种多协议,可变位宽发射机系统,最高数据位宽40 bits,最高数据速率10.312 5 Gbps.整个系统由归一化数据位宽(Normalization of Data Width,NMDW)变换电路,40:1合路器(MUX),时钟分布电路及3抽头前馈均衡器(Feed-Forward-Equalizer,FFE)组成,文章中提出了改进的40:1 MUX电路结构.本文采用SMIC 40 nm CMOS工艺,电源电压1.1 V.发射机(Transmitter,TX)整体功耗34mW@10.3125 Gbps,信道前差分输出眼图最大幅度大于800 mV.同时,本发射机支持4种不同协议,7种不同数据速率,9种工作状态,工作温度范围-45℃~125℃.展开更多
Radial drilling technology, of which the jet bit is the key device, is a research focus in the field of oil drilling and production. This paper establishes mechanical equations for jet bits and analyzes the hydroseal ...Radial drilling technology, of which the jet bit is the key device, is a research focus in the field of oil drilling and production. This paper establishes mechanical equations for jet bits and analyzes the hydroseal of backward jets in bottom holes. Meanwhile this paper establishes a mechanical equation for a high pressure hose and analyzes the axial force distribution. Laboratory experiments indicate that the flow rate, the angle between the backward nozzle axis and the jet bit axis, and the hole diameter are the major influencing factors; the generation of the pulling force is mainly due to the inlet pressure of the jet bit; the backward jets can significantly increase not only the pulling force but also the stability of jet bits. The pulling force would reach 8,376 N under experimental conditions, which can steadily pull the high-pressure hose forward.展开更多
文摘The hole reaming and side cutting characteristics of offset one-cone bit and conventional one- cone bit were investigated on simulated drilling experimental equipment. The borehole diameter was a little larger than the bit diameter due to side force. However, the reaming effect was not very apparent, whether drilling with an offset or conventional one-cone bit. The side cutting displacement increased gradually with increasing depth of drilling and side force. The side cutting displacement of offset onecone bits was larger than that of conventional ones under the same conditions of weight-on-bit （WOB）, rotary speed, side force and borehole depth.
基金National Center for International Research on Deep Earth Drilling and Resource Development,Faculty of Engineering,China University of Geosciences(Wuhan)(No.DEDRD-2022-08).
文摘In order to improve the matrix performance of impregnated diamond drill bit to better meet the drilling needs,the effects of the addition of nano-WC and nano-NbC particles on the matrix material together with the mechanical properties and microstructure of the diamond-matrix composite material of the Fe-based diamond drill bit were studied by using the method of uniform formula design,regression analysis and solution finding.An indoor drilling test was also carried out using the fabricated impregnated diamond drill bit.The results showed that after the addition of nano-NbC and nano-WC,the hardness and flexural strength of the matrix material got improved,as the flexural strength of the diamond composite material increased to 4.29%,the wear-resistance ratio increased to 8.75%,and the tighter the chemical bonding between the diamond and the matrix.This,indicates that the addition of nanoparticles has a positive significance in improving the performance of the diamond composite.The results of the drilling test showed that the mechanical drilling speed of the impregnated diamond drill bit after nanoparticle strengthening is 25.85%higher than that of the conventional drill bit,and the matrix wear was increased by 17.5%.It proves that nanoparticles can improve the drilling performance and efficiency of drill bit.
文摘出版物的结构化处理是语义出版发展的基础。图书交换标签集(Book Interchange Tag Suite,BITS)是一套面向科技类图书的结构化表示模型。本文通过分析BITS模型的元素和结构,比较BITS与期刊标签集JATS以及电子书标准Docbook和DITA的异同,并结合中文科技类图书的特点,以探讨BITS对中文图书的适用性和改进方向。
基金supported by High-tech Research and Development Program of China (No. 2007AA09Z315)Doctoral Foundation of Ministry of Education of China (No. 20070425006)
文摘Radial drilling technology, of which the jet bit is the key device, is a research focus in the field of oil drilling and production. This paper establishes mechanical equations for jet bits and analyzes the hydroseal of backward jets in bottom holes. Meanwhile this paper establishes a mechanical equation for a high pressure hose and analyzes the axial force distribution. Laboratory experiments indicate that the flow rate, the angle between the backward nozzle axis and the jet bit axis, and the hole diameter are the major influencing factors; the generation of the pulling force is mainly due to the inlet pressure of the jet bit; the backward jets can significantly increase not only the pulling force but also the stability of jet bits. The pulling force would reach 8,376 N under experimental conditions, which can steadily pull the high-pressure hose forward.
