ISSN: 0256-307X 中国物理快报 Chinese Physics Letters

A Series Journal of the Chinese Physical Society Distributed by IOP Publishing Online: http://www.iop.org/journals/cpl http://cpl.iphy.ac.cn

CHINESE PHYSICAL SOCIETY CHIN. PHYS. LETT. Vol. 27, No. 5 (2010) 056201 Frequency Response of the Sample Vibration Mode in Scanning Probe Acoustic Microscope *

ZHAO Ya-Jun(赵亚军), CHENG Qian(程茜), QIAN Meng-Lu(钱梦騄)** Institute of Acoustics, Tongji University, Shanghai 200092

(Received 22 December 2009) Based on the interaction mechanism between tip and sample in the contact mode of a scanning probe acoustic microscope (SPAM), an active mass of the sample is introduced in the mass-spring model. The tip motion and frequency response of the sample vibration mode in the SPAM are calculated by the Lagrange equation with dissipation function. For the silicon tip and glass assemblage in the SPAM the frequency response is simulated and it is in agreement with the experimental result. The living myoblast cells on the glass slide are imaged at resonance frequencies of the SPAM system, which are 20 kHz, 30 kHz and 120 kHz. It is shown that good contrast of SPAM images could be obtained when the system is operated at the resonance frequencies of the system in high and low-frequency regions.

PACS: 62. 30. +d, 68. 37. Ps, 07. 79. Lh DOI: 10.1088/0256-307X/27/5/056201

The quasi-static detection technology of scanning The sample contacting with the tip can be con- probe microscopy (SPM) has been rapidly develop- sidered as a dynamic load of the tip in the sample ing into a fully dynamic detection technology recently. vibration mode of SPAM. Effects of both the stiffness The sample vibration mode in scanning probe acoustic and the mass of the sample related to the motion of microscopy (SPAM) is known as an imaging and mea- the tip should be taken into account. Therefore an suring technology when the probe tip contacts with active mass of the sample should be introduced in the samples. The experimental setup was presented in mass-spring model of SPAM. Ref. [1]. The vibration applied to the sample is gener- The external force applied to the sample surface ated by a piezoelectric vibration table which is coupled by the cantilever is usually about several nN to µN, to its bottom. The signal is detected by the probe therefore the displacement at the sample surface is tip when it scans the top surface of the sample and very small. The SPAM system should be operated then sent to a lock-in amplifier. Thus an SPAM image at its resonance frequencies in order to obtain good in nano-scale is obtained and the contrast is related signal.[18] Thus it is crucial to develop a more com- to the surface topography, the variation of the tip- plete dynamical model for sample vibration mode in sample interaction forces and the mechanical proper- SPAM and analyze the relevant frequency characteris- ties at the surface and/or the subsurface of the sam- tic in order to improve the performance of the SPAM ple. SPAM imaging has been demonstrated to be a imaging and explore more detailed information of the powerful tool for the surface and subsurface imaging sample. of inorganic and organic materials, such as ferroelec- tric domains of ferroelectric material, properties of biological sample, nanostructure of nano-material as k well as the measurement of the local elastic stiffness R of sample surface.[1−11] The imaging mechanism and m z its spatial resolution of the sample vibration mode in  f SPAM have been studied by many researchers using linear mass-spring model, which consists of the mass k of the tip 푚1, cantilever spring constant 푘1, its damp- R ing coefficient 푅1, the tip-surface interaction stiffness [12−17] 푘 and damping coefficient 푅 . High driving m 2 2 z  frequency near the resonance frequency of cantilever  probe was considered to be helpful in improving image f quality.[1,2] However, some SPAM images with high Fig.1. The new mass-spring model of sample vibration spatial resolution were obtained at low driving fre- mode in SPAM. quency, recently.[4,5] This means that a more complete mass-spring model should be set up for the sample vi- A new mass-spring model of SPAM including an brating mode in SPAM. active mass of sample is shown in Fig. 1. The active

*Supported by the National Natural Science Foundation of China under Grant Nos 10774113 and 10834009, and the Doctoral Fund of Ministry of Education of China under Grant No 20070247042. **Email: [email protected] ○c 2010 Chinese Physical Society and IOP Publishing Ltd

056201-1 CHIN. PHYS. LETT. Vol. 27, No. 5 (2010) 056201

[︁ 4 (︁ 2 2 2 휔1휔2 )︁ 2 2 2]︁ mass of the sample 푚2 will be numerically analyzed. 퐷 = 휔 − 휔1 + 휔2 + 휔12 + 휔 + 휔1휔2 푄1푄2 In the mass-spring model illustrated above, 푚1, 푅1 2 2 and 푘 represent the tip mass, damp coefficient and [︁(︁휔 휔2 휔 휔1 )︁ 1 + 푖휔 1 + 2 cantilever spring constant, and 푚2, 푅2 as well as 푘2 푄2 푄1 are the active mass of the sample, damping coefficient (︁ 휔1 휔2 푚2휔2 )︁ ]︁ − + + 휔2 . (6) and tip-surface interaction stiffness respectively. Here 푄1 푄2 푚1푄2 푓1 is the force applied to the sample surface by the cantilever, and 푓 the force applied on the active mass In Eq. (5) it is clearly shown that the displacement 2 of the tip is related not only to the driving force and 푚2 by piezoelectric table, 푧1 and 푧2 are the displace- ments of the tip and the sample surface respectively. properties of the sample, but also to the frequency Then the frequency characteristics of this system are characteristics of the system. investigated with Lagrange equations. The frequency response of the system is deter- mined by 퐹 (휔) = 1/|퐷|. The resonance frequencies of Choosing 푧1 and 푧2 as the generalized coordinates, the Lagrange equations with the dissipation function the system can be found from |퐷| = 0: can be expressed as [︁(︁ 휔 휔 푚 휔 )︁2 휔8 + 1 + 2 + 2 2 푑 휕퐿 휕퐿 휕퐹 푑 휕퐿 휕퐿 휕퐹 푄1 푄2 푚1푄2 − = − , − = − , (1) (︁ )︁]︁ 푑푡 휕푧˙1 휕푧1 휕푧˙1 푑푡 휕푧˙2 휕푧2 휕푧˙2 2 2 2 휔1휔2 6 − 2 휔1 + 휔2 + 휔12 + 휔 where 퐿 = 푇 − 푈, 푇 and 푈are the kinetic energy 푄1푄2 2 and potential energy of the dynamical system respec- [︁(︁ 2 2 2 휔1휔2 )︁ 2 2 + 휔1 + 휔2 + 휔12 + + 2휔1휔2 tively; 퐹 is the dissipation function, and they can be 푄1푄2 expressed as (︁휔2휔 휔2휔 )︁(︁ 휔 휔 푚 휔 )︁]︁ − 2 1 2 + 2 1 1 + 2 + 2 2 휔4 1 2 1 2 푄2 푄1 푄1 푄2 푚1푄2 푇 = 푚1푧˙1 + 푚2푧˙2 , 2 2 [︁ 2 2(︁ 2 2 2 휔1휔2 )︁ − 2휔1휔2 휔1 + 휔2 + 휔12 + 1 2 1 2 푄1푄2 푈 = 푘1푧 + 푘2(푧1 − 푧2) − 푓1푧1 − 푓2푧2, 1 2 2 2 2 2 (︁휔1휔2 휔2휔1 )︁ ]︁ 2 4 4 1 1 − + 휔 + 휔1휔2 = 0. (7) 퐹 = 푅 푧˙2 + 푅 (푧 ˙ − 푧˙ )2, 푄2 푄1 2 1 1 2 2 1 2 1 1 1 Obviously, it is more likely to obtain better signal 퐿 = 푚 푧˙2 + 푚 푧˙2 − 푘 푧2 2 1 1 2 2 2 2 1 1 when an SPAM system is operated at its resonance 1 frequencies. − 푘 (푧 − 푧 )2 + 푓 푧 + 푓 푧 . (2) 2 2 1 2 1 1 2 2 In order to simulate the frequency response of the SPAM system operated in sample vibration mode, all Substituting Eq. (2) into Eq. (1), we obtain of the system parameters in Eq. (7) must be deter- 푚1푧¨1 + (푅1 + 푅2)푧 ˙1 + (푘1 + 푘2)푧1 − 푅2푧˙2 − 푘2푧2 =푓1, mined. For subsystem of cantilever-tip, its spring

− 푅2푧˙1 − 푘2푧1 + 푚2푧¨2 + 푅2푧˙2 + 푘2푧2 = 푓2. (3) constant 푘1 = 0.11 N/m, response frequency 푓1 = 푖휔푡 푖휔푡 푖휔푡 22.26 kHz and 푄1 = 54 are measured with thermal Then let 푓2 = 푓20푒 , 푧1 = 퐴푒 , 푧2 = 퐵푒 and tuning technique in the SPAM, respectively. Then substitute them into Eq. (3), the equations about 퐴 2 −12 the mass 푚1 = 푘1/휔1 = 5.76 × 10 kg and 푅1 = and 퐵 are obtained, 1.47 × 10−8 kg/s can be calculated by Eq. (4a). 2 [19−21] [−푚1휔 + 푖휔(푅1 + 푅2) + (푘1 + 푘2)]퐴 Based on the Hertz contact theory, the tip- surface interaction stiffness 푘 , the radius of contact − (푖휔푅2 + 푘2)퐵 = 0, 2 volume between the tip and the sample 푎, and the − (푖휔푅 + 푘 )퐴 + (−푚 휔2 + 푖휔푅 2 2 2 2 indentation depth on the sample surface 훿 can be es- + 푘2)퐵 = 푓20. (4) timated by

Using the expressions 1/3 2 * (︁3푅퐹푁 )︁ 푎 푘 푘 푘 푘2 = 2푎퐸 , 푎 = * , 훿 = , (8) 휔2 = 1 , 휔2 = 2 , 휔2 = 2 , 4퐸 푅 1 푚 2 푚 12 푚 1 2 1 where 푅 is the radius of curvature of the tip, 퐸* is the 푅 휔 푖 = 푖 , (푖 = 1, 2) (4a) reduced elastic modulus for sample-tip system, 푚푖 푄푖 2 2 the solutions to Eq. (4) can be expressed as 1 1 − 휈1 1 − 휈2 * = + , (9) 퐸 퐸1 퐸2 퐴 = 푓20(푘2 + 푖휔푅2)/∆, which is determined by Young’s modulus 퐸 and Pois- 푓20 2 퐵 = [(푘1 + 푘2 − 푚1휔 ) + 푖휔(푅1 + 푅2)], (5) son’s ratio 휈 of both the tip and the sample. 퐹 = ∆ 푁 퐺푆푘 is the applied static force, where 퐺 is the de- where 1 flection setpoint, 푆 deflection sensitivity and 푘1 is the ∆ = 푚1푚2퐷, spring constant of the cantilever. 056201-2 CHIN. PHYS. LETT. Vol. 27, No. 5 (2010) 056201

0 0 m) m) -10 FN -1 -11 -1 -2 -3 -2

Tip -4 -3 (a) -5 (b) -4 displacement (10 displacement (c)

z -6

0 1 2 3 4 5 (10 displacement 0 1 2 3 4 5 Slide r (-7) r r (-7) 1.0 m) m) 0 0.6 -10 -10 -1 0.2 -2 -0.2 -3

-4 -0.6 (d) displacement (10 displacement displacement (10 displacement (e) z -5 r -1.0 -2.0 -1.6 -1.2 -0.8 -0.4 0 -2.0 -1.6 -1.2 -0.8 -0.4 0 z (-7) z (-7) Fig.2. The range of deformation in the slide with the applied static force: (a) finite element model, (b) normal displacement in tangential direction, (c) tangential displacement in tangential direction, (d) normal displacement in normal direction, (e) tangential displacement in normal direction.

For silicon tip and glass sample assemblage, 퐸1 = in Fig.2. We consider the active sample mass to be 130 GPa, 휈1 = 0.27, 퐸2 = 73 GPa and 휈2 = 0.17. The the mass of a cylinder under the tip, whose height ℎ cantilever deflection setpoint 퐺 = 1 V, deflection sen- is about 1000 times the indentation depths 훿 and its sitivity 푆 = 88.2 nm/V and 푅 = 20 nm are used in our radius 푟 is 200 times the contact radius 푎. The dis- experiment, so the static force applied to the sample placements in normal and tangent direction outside is 퐹푁 = 푘1퐺푆 = 9.7 nN. Thus, 푎 = 1.44 nm, 푘2 = the cylinder, which are indicated in Figs.2(b)–2(d) by 140.74 N/m and 훿 = 0.10 nm are obtained by Eq. (8) dotted lines, are less than 0.1% of that at the cen- with 퐸* = 48.9 GPa. The damping coefficient of the tral point of tip-sample contact area. Thus the ef- [22] −17 glass 푅2 is about 0.0006–0.002 kg/s. Considering fective mass of the sample 푚2 = 6.22 × 10 kg can that the damping is relatively high in cell imaging, we be estimated by the cylinder height ℎ = 100 nm, and choose the damping coefficient 푅2 = 0.002 kg/s. its radius 푟 = 300 nm for the glass whose density is 2200 kg/m3. - 0.35 - 0.3 - 0.25

- 0.2 (y) V 0.15 log - 0.1 - 0.05 - 0 0 100 200 300 400 500 0 100 200 300 400 500 Frequency (kHz) Frequency (kHz) Fig.3. Frequency response curve of the system, resonance Fig.4. Frequency response obtained with the sweeping frequencies are at 19.7 kHz, 26.9 kHz, and 102.3 kHz. frequency function of our SPAM system at the sweeping frequencies from 0 to 500 kHz.

In the SPAM the contact radius between tip and Substituting all determined parameters into sample can be estimated from Eq. (8) and it is only Eq. (7), four resonance frequencies 19.7 kHz, 26.9 kHz, about several nanometers. Therefore the active mass 102.3 kHz and 5118 GHz are obtained. The frequency of the sample 푚2 can be considered as a very small response under the frequency range of 500 kHz is cal- part of the sample mass in which the active deforma- culated, as shown in Fig.3. It shows that the reso- tion is induced by the external force. With the finite nance frequencies exist not only in low frequency re- element software COMSOL the displacement field in gion, but also in high frequency region. Therefore the the sample is calculated when 퐹푁 = 9.7 nN, as shown good SPAM images can be obtained in both high and 056201-3 CHIN. PHYS. LETT. Vol. 27, No. 5 (2010) 056201 low frequency range. The system resonance response in a wide frequency For the silicon tip and glass sample assemblage range is calculated and measured, in good agreement. the frequency response is measured with the sweep- The images of a living myoblast cell on glass slide ob- ing frequency function in our SPAM system, as shown tained at system resonance frequencies present high in Fig.4. The resonance peaks exist at 19.6 kHz, spatial resolution. It is proved to be effective to in- 30.4 kHz and 120 kHz. Therefore this experimental troduce the active mass of sample in the mass-spring result is in good agreement with the calculated result model for contact mode in the SPAM, and the research as shown in Fig. 3. of the frequency characteristics of SPAM is important The SPAM imaging for living myoblast cell on for understanding the SPAM imaging mechanism and glass slide is obtained at the resonance frequencies thus is the guidance for analysis, design and experi- 20 kHz, 30 kHz and 120 kHz. The results are shown ment. However, the interaction between the tip and in Fig. 5. The nucleus, karyotheca and cytoskeleton the sample is of considerable complexity, a more rig- can be observed in these images clearly. orous definition about active mass of sample should be studied further. 1.1 mm 700.0 mV

(a) (b) Cytoskeleton References

Nucleus [1] Kolosov O V, Castell M R, Marsh C D and Briggs G A D 1998 Phys. Rev. Lett. 81 1046 [2] Striegler A, K¨ohlerB and Bendjus B 2007 Proc. SPIE 6528 65281B Karyotheca [3] Passeri D, Rossi M, Alippi A, Bettucci A, Manno D, Serra A, Filippo E, Lucci M and Davoli I 2008 Superlattices Mi- crostruct. 44 641 0 20 40 60 80 0 20 40 60 80 [4] Yin Q R, Yu H F, Zeng H R, Li G R and Xu Z K 2005 Height (mm) Amplitude (mm) Mater. Sci. Eng. B 120 100 800.0 mV 400.0 mV [5] Zhao K Y, Zeng H R, Song H Z, Hui S X, Li G R, Yin Q (c) (d) R, Shimamura K, Kannan C V, Villora E A G, Takekawa S and Kitamura K 2008 Chin. Phys. Lett. 25 3429 [6] Diebold A C 2005 Science. 310 61 [7] Shekhawat G S and Dravid V P 2005 Science. 310 89 [8] Tittmann B R, Du J, Ebert A and Piccione B 2005 Proc. SPIE 5768 11 [9] Ebert A, Tittmann B R, Du J and Scheuchenzuber W 2006 Ultrasound Med. Biol. 32 1687 [10] Banerjee S, Gayathri N, Shannigrahi S R, Dash S, Tyagi A K and Raj B 2007 J. Phys. D: Appl. Phys. 40 2539 [11] Li Y and Qian J Q 2009 Chin. Phys. Lett. 26 100703 0 20 40 60 80 0 20 40 60 80 Amplitude (mm) Amplitude (mm) [12] Banerjee S, Gayathri N, Dash S, Tyagi A K and Raj B 2005 Appl. Phys. Lett. 86 211913 Fig.5. Topography (a) and SPAM images of the my- [13] Rabe U Kopycinska M, Hirsekorn S and Arnold W 2002 oblast cell at driving frequency 20 kHz (b), 30 kHz (c), Ultrasonics 40 49 and 120 kHz (d). [14] Burnham N A, Kulik A J, Gremaud G, Gallo P J and In conclusion, we have established an improved Oulevey F 1996 J. Vac. Sci. Technol. B 14 794 [15] Cantrell J H and Cantrell S A 2008 Phys. Rev. B 77 165409 mass-spring model including an active sample mass [16] Zhao Y J, Cheng Q and Qian M L 2008 Tech. Acoust. 27 in a contact mode of an SPAM. The frequency re- 180 (in Chinese) sponse of this dynamic system is calculated using the [17] Turner J A, Hirsekorn S, Rabe U and Arnold W 1997 Lagrange equation with dissipation function. It shows J. Appl. Phys. 82 966 [18] Cantrell S A, Cantrell J H and Lillehei P T 2007 that SPAM imaging could be obtained at either higher J. Appl. Phys. 101 114324 or lower response frequencies of the SPAM system. [19] Johnson K L 1985 Contact Mechanics (London: Cambridge For the silicon tip and glass assemblage, the active University) mass of sample in a cylinder, whose height is about [20] Fischer-Cripps A C 1999 J. Mater. Sci. 34 129 [21] Kogut L and Etsion I 2002 J. Appl. Mech. 69 657 1000 times indentation depth and the radius is about [22] Beards C F 1983 Structual Vibration Analysis (Chichester: 200 times contact radius, is estimated numerically. Ellis Horwood)

056201-4 Chinese Physics Letters Volume 27 Number 5 2010

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(Continued on inside back cover) 052501 Emission of Neutral Pions with High Transverse Momenta in A-A and p-p Collisions at En- ergies Available at the BNL Relativistic Heavy Ion Collider FAN San-Hong, MENG Cai-Rong, -Hu 052502 Influence of the Nucleon Hard Partons Distribution on J/Ψ Suppression in a GMC Framework WANG Hong-Min, HOU Zhao-Yu, SUN Xian-Jing 052503 Rapidity Losses in Heavy-Ion cCollisions from AGS to RHIC Energies ZHOU Feng-Chu, YIN Zhong-Bao, ZHOU Dai-Cui 052901 Gallium Nitride Room Temperature α Particle Detectors LU Min, ZHANG Guo-Guang, FU Kai, YU Guo-Hao 052902 Optimization of Experimental Discharge Parameters to Increase the Arc Efficiency of the Bucket Ion Source YU Li-Ming, LEI Guang-Jiu, CAO Jian-Yong, ZHONG Guang-Wu, JIANG Shao-Feng, ZOU Gui-Qing, JIANG Tao, LU Da-Lun, ZHANG Xian-Ming, LIU He 052903 Varying Track Etch Rates along the Fission Fragments’ Trajectories in CR-39 Detectors N. Ali, E. U. Khan, A. Waheed, S. Karim, F. Khan, A. Majeed ATOMIC AND MOLECULAR PHYSICS 053201 Chip-Based Square Wave Dynamic Micro Atom Trap DAN Lin, YAN Hui, WANG Jin, ZHAN Ming-Sheng 053202 A Novel Observation of “a Sharp Absorption Line” Using Much More Broad Laser Lights: Quantum Interference in the Autoionization Spectra of Sc ZHONG Zhi-Ping, GAO Xiang, ZHANG Xiao-Le, LI Jia-Ming 053401 Collision of Low Energy Proton with Ethylene WANG Zhi-Ping, WANG Jing, ZHANG Feng-Shou 053701 Ionization Detection of Ultracold Ground State Cesium Molecules JI Zhong-Hua, WU Ji-Zhou, MA Jie, FENG Zhi-Gang, ZHANG Lin-Jie, ZHAO Yan-Ting, WANG Li-Rong, XIAO Lian-Tuan, JIA Suo-Tang FUNDAMENTAL AREAS OF PHENOMENOLOGY(INCLUDING APPLICATIONS) 054101 Rayleigh Scattering for An Electromagnetic Anisotropic Medium Sphere LI Ying-Le, WANG Ming-Jun, DONG Qun-Feng, TANG Gao-Feng 054201 Characteristics and New Measurement Method of NCSFs of Individual Color Mechanisms of Human Vision GE Jing-Jing, WANG Zhao-Qi, WANG Yan, ZHAO Kan-Xing 054202 A Phase-Controlled Optical Parametric Amplifier Pumped by Two Phase-Distorted Laser Beams REN Hong-Yan, QIAN Lie-Jia, YUAN Peng, ZHU He-Yuan, FAN Dian-Yuan 054203 Broadband Convergence of 40 GHz-ROF and 10-Gb/s WDM-PON Systems in the Duplex Access Network ZHANG Li-Jia, XIN Xiang-Jun, LIU Bo, ZHANG Qi, WANG Yong-Jun, YU Chong-Xiu 054204 Fabrication and Characterization of High Power InGaN Blue-Violet Lasers with an Array Structure JI Lian, ZHANG Shu-Ming, JIANG De-Sheng, LIU Zong-Shun, ZHANG Li-Qun, ZHU Jian-Jun, ZHAO De-Gang, DUAN Li-Hong, YANG Hui 054205 A Hybrid Method of Solving the Electromagnetic Inverse Scattering Problem in Lossy Medium , , GOU Ming-Jiang, SHI Qing-Fan, SUN Gang 054206 Wavelength Modulation Absorption Spectroscopy Using a Frequency-Quadruped Current- Modulated System SHAO Jie, SUN Hui-Juan, WANG Hui, ZHOU Wei-Dong, WU Gen-Zhu 054207 Intensity Spatial Profile Analysis of a Gaussian Laser Beam at Its Waist Using an Optical Fiber System ZHANG Liangmin 054208 Silicon-Based Asymmetric Add-Drop Microring Resonators with Ultra-Large Through-Port Extinctions XIAO Xi, LI Yun-Tao, YU Yu-De, -Zhong 054209 Measurement of Ultrashort Laser Pulse Width in a Wide Spectrum Range Using Dimethyl Sulfoxide by Optical Kerr Effect Technique KONG De-Gui, CHANG Qing, YE Hong-An, GAO Ya-Chen, ZHANG Li-Xin, WANG Yu-Xiao, -Ru, YANG Kun, SONG Ying-Lin 054210 Synthesis of Fiber Bragg Gratings with Right-Angled Triangular Spectrum LI Li-Sha, FENG Xuan-Qi 054211 Generation of Sub-2 Cycle Optical Pulses with a Differentially Pumped Hollow Fiber ZHANG Wei, TENG Hao, YUN Chen-Xia, ZHONG Xin, HOU Xun, WEI Zhi-Yi 054212 Residual Doppler Effect on Electromagnetically Induced Transparency in a Zeeman Sublevel System -Yan, LI Lu-Ming, CHEN Pei-Rong, SUN Xin 054213 Suppercontinuum Generation in InP Nano Inner Cladding Fibers DUAN Yu-Wen, ZHANG Ru, WANG Jin, CHEN Xi, ZHONG Kun 054301 A Combined Reconstruction Algorithm for Limited-View Multi-Element Photoacoustic Imag- ing YANG Di-Wu, XING Da, ZHAO Xue-Hui, PAN Chang-Ning, FANG Jian-Shu 054701 Capillary Rise in a Single Tortuous Capillary CAI Jian-Chao, YU Bo-Ming, MEI Mao-Fei, LUO Liang 054702 Intermittency and Thermalization in Turbulence ZHU Jian-Zhou, Mark Taylor 054703 Generation Mechanism of Liquid Column during the Burst of a Rising Bubble near a Free Surface WANG Han, ZHANG Zhen-Yu, YANG Yong-Ming, ZHANG Hui-Sheng PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES 055201 Electron Emission Suppression from Cathode Surfaces of a Rod-Pinch Diode GAO Yi, YIN Jia-Hui, -Feng, ZHANG Zhong, ZHANG Peng-Fei, SU Zhao-Feng 055202 First Charge Exchange Recombination Spectroscopy Diagnostic in HL-2A Tokamak HAN Xiao-Yu, DUAN Xu-Ru, YANG Li-Mei, YU De-Liang, ZHONG Wu-Lv, FU Bing-Zhong, LIU Yong, LIU Yi, YAN Long-Wen, YANG Qing-Wei 055203 Characteristics of a Novel Water Plasma Torch NI Guo-Hua, MENG Yue-Dong, CHENG Cheng, LAN Yan 055204 Propagation Characteristics of Whistler-Mode Chorus during Geomagnetic Activities ZHOU Qing-Hua, HE Yi-Hua, HE Zhao-Guo, YANG Chang CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES 056101 Quantitative Characterization of Partial Dislocations in Nanocrystalline Metals NI Hai-Tao, ZHANG Xi-Yan, ZHU Yu-Tao 056201 Frequency Response of Sample Vibration Mode in Scanning Probe Acoustic Microscope ZHAO Ya-Jun, CHENG Qian, QIAN Meng-Lu

056801 Temperature-Dependent Raman Spectrum of Hexagonal YMnO3 Films Synthesized by Chem- ical Solution Method LIU Yue-Feng, WANG Bei, ZHENG Hai-Wu, LIU Xiang-Yang, GU Yu-Zong, ZHANG Wei-Feng 056802 Influence of Au-Doping on Morphology and Visible-Light Reflectivity of TiN Thin Films De- posited by Direct-Current Reactive Magnetron Sputtering NA Yuan-Yuan, WANG Cong, 056803 Research of Equilibrium Composition Map in Conic Quantum Dots ZHAO Wei, YU Zhong-Yuan, LIU Yu-Min, FENG Hao, XU Zi-Huan 056804 Large-Area Self-Assembly of Rubrene on Au(111) Surface LIU Xiao-Qing, KONG Hui-Hui, CHEN Xiu, DU Xin-Li, CHEN Feng, LIU Nian-Hua, WANG Li CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES 057101 Quantum Mechanical Study on Tunnelling and Ballistic Transport of Nanometer Si MOSFETs DENG Hui-Xiong, JIANG Xiang-Wei, TANG Li-Ming

057102 Spectral Response and Photoelectrochemical Properties of Cd1−xZnxSe Films N. J. Suthan Kissinger, G. Gnana Kumar, K. Perumal, J. Suthagar

057103 Mechanism of Visible Photoactivity of F-Doped TiO2 GUO Mei-Li, ZHANG Xiao-Dong, LIANG Chun-Tian, JIA Guo-Zhi 057104 Variation of Optical Quenching of Photoconductivity with Resistivity in Unintentional Doped GaN HOU Qi-Feng, WANG Xiao-Liang, XIAO Hong-Ling, WANG Cui-Mei, YANG Cui-Bai, LI Jin-Min 057201 Thermoelectric Performances of Free-Standing Polythiophene and Poly(3-Methylthiophene) Nanofilms LU Bao-Yang, LIU Cong-Cong, LU Shan, -Kun, JIANG Feng-Xing, LI Yu-Zhen, ZHANG Zhuo 057202 Spin Current Through Triple Quantum Dot in the Presence of Rashba Spin-Orbit Interaction LI Jin-Liang, LI Yu-Xian 057301 Anomalous Effect of Interface Traps on Generation Current in Lightly Doped Drain nMOS- FET’s MA Xiao-Hua, GAO Hai-Xia, CAO Yan-Rong, CHEN Hai-Feng, HAO Yue

057302 Shape-Controlled Synthesis and Related Growth Mechanism of Pb(OH)2 Nanorods by Solution- Phase Reaction CHENG Jin, ZOU Xiao-Ping, SONG Wei-Li, CAO Mao-Sheng, SU Yi, YANG Gang-Qiang, LU¨ Xue-Ming, ZHANG Fu-Xue 057303 Infrared Absorption Spectra of Undoped and Doped Few-Layer Graphenes XU Yue-Hua, JIA Yong-Lei, ZHOU Jian, DONG Jin-Ming 057304 Observation of Coulomb Oscillations with Single Dot Characteristics in Heavy Doped Ultra Thin SOI Nanowires FANG Zhong-Hui, ZHANG Xian-Gao, CHEN Kun-Ji, QIAN Xin-Ye, XU Jun, HUANG Xin-Fan, HE Fei 057305 Blue Luminescent Properties of Silicon Nanowires Grown by Solid-Liquid-Solid Method PENG Ying-Cai, FAN Zhi-Dong, BAI Zhen-Hua, ZHAO Xin-Wei, LOU Jian-Zhong, CHENG Xu 057306 White Emitting ZnS Nanocrystals: Synthesis and Spectrum Characterization HUANG Qing-Song, DONG Dong-Qing, XU Jian-Ping, ZHANG Xiao-Song, ZHANG Hong-Min, LI Lan 057501 Microwave Magnetic Properties and Natural Resonance of ε-Co Nanoparticles YANG Yong, XU Cai-Ling, QIAO Liang, Li Xing-Hua, LI Fa-Shen

057502 Effective Anisotropy in Magnetically Nd2Fe14B/α-Fe Nanocomposite -Jun, CHEN Lei, ZHAO Xu, FAN Su-Li, CHEN Wei CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY 058101 Improvement of AlN Film Quality by Controlling the Coalescence of Nucleation Islands in Plasma-Assisted Molecular Beam Epitaxy ZHANG Chen, HAO Zhi-Biao, REN Fan, HU Jian-Nan, LUO Yi 058102 Preparation of Functional Gradient Material n-PbTe with Continuous Carrier Concentration ZHU Pin-Wen, HONG You-Liang, WANG Xin, CHEN Li-Xue, IMAI Yoshio 058103 Deposition Behavior and Mechanism of Ni Nanoparticles on Surface of SiC Particles in Solution Systems XU Hui, KANG Yu-Qing, , JIN Hai-Bo, WEN Bo, WEN Bao-Li, YUAN Jie, CAO Mao-Sheng 058501 A Single Photon Counting Detector Based on One-Dimensional Vernier Anode YANG Hao, ZHAO Bao-Sheng, SHENG Li-Zhi, LI Mei, YAN Qiu-Rong, LIU Yong-An 058502 Extrinsic Base Surface Passivation in High Speed “Type-II” GaAsSb/InP DHBTs Using an InGaAsP Ledge Structure -Gang, JIN Zhi, SU Yong-Bo, WANG Xian-Tai, CHANG Hu-Dong, ZHOU Lei, LIU Xin-Yu, WU De-Xin 058901 Detecting Overlapping Communities Based on Community Cores in Complex Networks SHANG Ming-Sheng, CHEN Duan-Bing, ZHOU Tao 058902 Increase of Traffic Flux in Two-Route Systems by Disobeying the Provided Information SUN Xiao-Yan, JIANG Rui, WANG Bing-Hong GEOPHYSICS, ASTRONOMY, AND ASTROPHYSICS 059101 Prediction and Elimination of Multiples Based on Energy Flux Conservation Theorem and Prediction Operator Equation He Li, LIU Hong, DING Ren-Wei, LI Bo