检索结果-南通市图书馆

Microwave propagation in air drilling

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2010年第3期7卷 390-396页

作者： Meng Xiaofeng Chen Yijian Zhou Jing Meng Yingfeng physics department Beijing Normal University Beijing 100875 China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum University Chengdu Sichuan 610500 China

This paper examines the feasibility in air drilling of transmitting down-hole signals by using microwaves. Firstly the basic theory of microwave propagation in the drill-pipe or casing was studied, including power loss, cutoff wavelength, and dust scattering. Theoretical analysis indicates that the microwave propagation distance in a cb2.4mm casing can easily reach 5,000 m. When the effect of dust particles is taken into account, the propagation distance decreases to 2.000 m. We conducted both laboratory experiments and field tests in casings commonly used in oil fields. The field tests show that the effective propagation distance of microwave in the casing is about 1,300 m. The experimental results do not match well with theoretical prediction, but are acceptable. In future commercial applications, by applying multiple relay amplifiers, the microwave propagation distance could be long enough for most drilling wells.

关键词： Microwave waveguide drill-pipe casing air drilling

Recent progress in terahertz science and technology

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2002年第10期 11-18页

作者： XU Jingzhou, ZHANG Cunlin and ZHANG Xicheng(1. department of physics, Applied physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12.80-3590, USA 2. department of physics, Capital normal University, Beijing 100037, china) department of physics Applied Physics and AstronomyRensselaer Polytechnic Institute Troy NY 12180-3590 USA department of physics Capital Normal University Beijing 100037 China

The relatively new technique of coherent electromagnetic radiation, in the region of 10 Hz, has potential to detect the nature of low energy processes in physics, chemistry and biomedicine. In this review article, an overview of recent progress of terahertz (THz) science and technology is presented. The development of the THz generation and detection system, the THz radiation applications which include THz time-domain spectroscopy and T-ray imaging, and the future potential of THz wave research are discussed.

关键词： terahertz coherent electromagnetic radiation THz time-domain spectroscopy T-ray imaging.

(2.1)维Broer-Kaup方程的局域相干结构

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

物理学报 2002年第4期51卷 705-711页

作者：张解放韩平浙江师范大学非线性物理研究室金华321004 浙江海洋学院物理系舟山316004

利用推广的齐次平衡方法 ,研究了 (2.+1)维Broer Kaup方程的局域相干结构 .首先根据领头项分析 ,给出了这个模型的一个变换 ,并把它变换成一个线性化的方程 ,然后由具有两个任意函数的种子解构造出它的一个精确解 ,发现 (2.+1)维Broer K... 详细信息

利用推广的齐次平衡方法 ,研究了 (2.+1)维Broer Kaup方程的局域相干结构 .首先根据领头项分析 ,给出了这个模型的一个变换 ,并把它变换成一个线性化的方程 ,然后由具有两个任意函数的种子解构造出它的一个精确解 ,发现 (2.+1)维Broer Kaup方程存在相当丰富的局域相干结构 .合适的选择这些任意函数 ,一些特殊型的多dromion解 ,多lump解 ,振荡型dromion解 ,圆锥曲线孤子解 ,运动和静止呼吸子解和似瞬子解被得到 .孤子解不仅可以存在于直线孤子的交叉点上 ,也可以存在于曲线孤子的交叉点或最临近点上 .呼吸子在幅度和形状上都进行了呼吸 .本方法直接而简单 ,可推广应用一大类 (2.+1)维非线性物理模型 .

关键词：扩展齐次平衡法 (2.1)维Broer-Kaup方程非线性物理孤子解 dromion解局域相干结构

在线全文

学校读者我要写书评

暂无评论

再循环T细胞昼夜节律现象的数学模型

生物化学与生物物理进展 2001年第5期28卷 670-676页

作者：李方廷漆安慎北京大学物理系北京100871 北京师范大学物理系北京100875

根据人体和小鼠免疫细胞昼夜节律实验结果 ,提出皮质类激素对淋巴结和脾脏中T细胞再循环产生不同作用的假设 ,建立了皮质类激素作用下的T细胞在不同外周淋巴器官 (淋巴结、脾脏 )与血液之间再循环过程的数学模型 ,讨论了皮质类激素作用... 详细信息

根据人体和小鼠免疫细胞昼夜节律实验结果 ,提出皮质类激素对淋巴结和脾脏中T细胞再循环产生不同作用的假设 ,建立了皮质类激素作用下的T细胞在不同外周淋巴器官 (淋巴结、脾脏 )与血液之间再循环过程的数学模型 ,讨论了皮质类激素作用的强度、有关参量的取值范围和模型对参数的依赖性 .模型能够解释参与再循环的T细胞在淋巴结、脾脏与血液中的稳定振荡行为。

关键词：免疫细胞昼夜节律 T细胞再循环皮质类激素数学模型

An accurate three-dimensional potential energy surface for the He-Na_2.complex

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2008年第6期51卷 539-544页

作者： WANG Yue,HUANG WuYing,FENG ErYin& CUI ZhiFeng department of physics,Anhui {2. University,Wuhu 2.1000,china 1. department of physics Anhui Normal University Wuhu 241000 China

An accurate three-dimensional potential energy surface(PES) for the He-Na2.van der Waals comple was calculated at the coupled cluster singles-and-doubles with noniterative inclusion of connecte triple(CCSD(T)) level of theory.A mixed basis set,aug-cc-pVQZ for the He atom and cc-pCVQZ for th sodium atom,and an additional(3s3p2.1f) set of midbond functions were *** computed inte action energies in 819 configurations were fitted to a 96-parameter analytic potential model by leas squares *** PES has two shallow wells corresponding to the T-shaped structure and the linea configuration,which are located at 12.5a0 and 14 a0 with depths of 1.769 and 1.684 cm-1,respectivel The whole potential energy surface exhibits weak *** on the fitted PES,state-to-stat differential cross sections were calculated.

关键词： van der Waals complex potential energy surface ab initio calculation

NONGRAVITATIONAL EFFECT ON ORBITAL MOTIONS OF COMETS

在线全文

学校读者我要写书评

暂无评论

中国科学院上海天文台年刊 2000年 174-181页

作者： Wang Yu Zhou Hongnan (1. department of Astronomy, Nanjing University, Nanjing 2.0093) (2. department of physics, Nanjing {2. University, Nanjing 2.0097)

Since the concept of Nongravitational Force (hereafter NF) was first proposed a century and a half ago, different models of it have been suggested and being modified. Its effect on the orbital motions of comets has been studied. Especially, some researchers have attempted to draw some inclues of the physical nature of the cometary nucleus from the NF parameters. In this paper, we try to give a concise review about the different models of NF and their effects on orbit computation. And then, we will try to detect whether there is nongravitational effect on Comet Hale-Bopp’s orbital motion using Style II NF model.

关键词： Comet - Orbital Motion - Nongravitational Force

Multi-carbazole derivatives for two-photon absorption data storage:Synthesis,optical properties and theoretical calculation

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2010年第4期53卷 884-890页

作者： LI Lin1, YANG JiaXiang1,2. WANG CaiXia1, HU ZhangJun1, TIAN YuPeng1,2. LI Jing3, WANG ChuanKui3, LI Ming4, CHENG GuangHua4, TANG HuoHong5, HUANG WenHao5, TAO XuTang2.& JIANG MinHua2.1department of Chemistry, Anhui University, Hefei 2.0039, china 2.tate Key Laboratory of Crystal Materials, Institute of Crystal Materials of Shandong University, Jinan 2.0100, china 3department of physics, Shandong normal University, Jinan 2.0014, china 4State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an 710119, china 5department of Precision Machinery and Precision Instrumentation, University of Science and Technology of china, Hefei 2.002., china 1. department of Chemistry Anhui University Hefei 230039 China2. State Key Laboratory of Crystal Materials Institute of Crystal Materials of Shandong University Jinan 250100 China3. Department of Physics Shandong Normal University Jinan 250014 China4. State Key Laboratory of Transient Optics and Photonics Xi’an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Xi’an 710119 China5. Department of Precision Machinery and Precision Instrumentation University of Science and Technology of China Hefei 230026 China

Two novel quadrupolar organic compounds, 3-(4-((E)-2.(9-butyl-9H-carbazol-6-yl) vinyl)styryl)-9-propyl-9H-carbazole (BCSPC) and 3-(3-(3-((1E)-2.(4-((E)-2.(3-(3,5-bis(9-butyl-9H-carbazol-6-yl)phenyl)-9-butyl-9H-carbazol-6-yl)vinyl)phenyl) vinyl)-9-butyl-9H-carbazol-6-yl)-5-(9-butyl-9H-carbazol-6-yl)phenyl)-9-butyl-9H-carbazole (BCPBC), with different conjugated arms, have been designed and synthesized. Their one-and two-photon absorption (TPA) and excited fluorescence properties have been experimentally investigated. The two-photon absorption cross-sections of two compounds were estimated by two-photon excited fluorescence technique using 2.0 fs, 76 MHz, Ti:sapphire laser, which are 2. and 154 GM for BCSPC and BCPBC, respectively. The optimal excitation wavelengths are 780 nm for both BCSPC and BCPBC. A data recording experiment proved the potential application of the materials.

关键词： initiator optical data storage fluorescence two-photon absorption theoretical calculation

Energy Spectra of the Tunable Laser Crystal Gd3GasO12.Cr3+ and Their Pressure-Induced Shifts

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical physics 2004年第1期 141-150页

作者： MA Dong-Ping~(1,2. 1 department of Applied physics,Sichuan University,Chengdu 610065,{2. 2.International Centre for Materials physics,Academia Sinica,Shenyang 110015,{2.

By means of both the theory for pressure-induced shifts（PS）of energy spectra and the theory for shiftsof energy spectra due to electron-phonon interaction（EPI）,at 300K,the‘pure electronic’contributions and the contri-butions from EPI to R1line,R2.ine,and U band of GGG:Cr3+as well as their PS have been calculated,*** total calculated results are in good agreement with all the experimental *** physical origins have *** is found that the mixing-degree of|t（2.2.(3T1)e4T2.and|t2.2.〉base-wavefunctions in the wavefunctions ofR1level of GGG:Cr3+is considerable under normal pressure,and the mixing-degree rapidly decreases with *** change of the mixing-degree with pressure plays a key role for PS of R1line or *** 300K,boththe temperature-independent contribution to R1line（or R2.ine or U band）from EPI and the temperature-dependentone are *** remarkable difference between pressure-dependent behaviors of PS of R1lines of GGG:Cr3+andGSGG:Cr3+results from the differences of their microscopic *** features of emission spectra of GGG:Cr3+at various pressures have satisfactorily been explained.

关键词： high-pressure effect line shift spin-orbit interaction electron-phonon interaction d-orbital coupling between t2.(3T1)e4T2.and t2. 2. tunable laser crystal

Quantum Inequality Bounds for Free Rarita-Schwinger Field in Flat Spacetime

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical physics 2006年第7期 87-90页

作者： SHU Wei-Xing,~1 YU Hong-Wei,~2.LI Fei,~1 WU Pu-Xun,~2.and REN Zhong-Zhou~1 ~1department of physics, NanJing University, Nanjing 2.0093,{2. ~2.0} of physics, Hunan normal University, Changsha 410081,{2.

Although quantum field theory allows the local energy density negative, it also places severe restrictions on the negative energy. One of the restrictions is the quantum energy inequality (QEI), in which the energy density is averaged over time, or space, or over space and time. By now temporal QEIs have been established for various quantum fields, but less work has been done for the spacetime quantum energy inequality. In this paper we deal with the free Rarita-Schwinger field and present a quantum inequality bound on the energy density averaged over space and time. Comparison with the QEI for the Rarita-Schwinger field shows that the lower bound is the same with the QEI. At the same time, we find the quantum inequality for the Rarita-Schwinger field is weaker than those for the scalar and Dirac fields. This fact gives further support to the conjecture that the more freedom the field has, the more easily the field displays negative energy density and the weaker the quantum inequality becomes.

关键词： negative energy density quantum inequality