16 results on '"Songhao Liu"'
Search Results
2. Novel wavelength division multiplex-radio over fiber-passive optical network architecture for multiple access points based on multitone generation and triple sextupling frequency.
- Author
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Guangming Cheng, Banghong Guo, Songhao Liu, and Xuguang Huang
- Subjects
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WAVELENGTH division multiplexing , *OPTICAL communications , *BRAGG gratings , *OPTICAL fiber communication , *SIMULATION methods & models - Abstract
An innovative wavelength division multiplex-radio over fiber-passive optical network architecture for multiple access points (AP) based on multitone generation and triple sextupling frequency is proposed and demonstrated. A dual-drive Mach-Zehnder modulator (DD-MZM) is utilized to realize the multitone generation. Even sidebands are suppressed to make the adjacent frequency separation twice the frequency of the local oscillator by adjusting the modulation voltage of the DD-MZM. Due to adopting three fiber Bragg gratings to reflect the unmodulated sidebands for uplink communications source free at optical network unit (ONU), is achieved. The system can support at least three APs at one ONU simultaneously with a 30 km single-mode fiber (SMF) transmission and 5 Gb/s data rate both for uplink and downlink communications. The theoretical analysis and simulation results show the architecture has an excellent performance and will be a promising candidate in future hybrid access networks. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
3. Extraction of physical parameters from photoacoustic spectroscopy using wavelet transform.
- Author
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Jianghua Li, Changshui Chen, Chujun Zheng, Songhao Liu, and Zhilie Tang
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PHOTOACOUSTIC spectroscopy , *WAVELETS (Mathematics) , *SIGNAL processing , *LASER spectroscopy , *WAVE functions - Abstract
Photoacoustic (PA) signals carry much information related to the physical parameters of a sample, such as its optical, thermal, acoustic, and elastic properties. These physical parameters synchronously make their own contributions to PA signals. It is difficult to distinguish the contributions of different physical parameters to the mixed PA signals. To separate these parameters and to extract the featured information, we report herein a means of dissecting the transient PA signal using time-frequency analysis in a forward detection model. The simulated and experimental results indicate that the features of different physical parameters related to the sample can be qualitatively extracted from the mixed PA signals. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
4. Redox-responsive biodegradable PEGylated nanographene oxide for efficiently chemo-photothermal therapy: A comparative study with non-biodegradable PEGylated nanographene oxide.
- Author
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Honglian Xiong, Zhouyi Guo, Wen Zhang, Huiqing Zhong, Songhao Liu, and Yanhong Ji
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OXIDATION-reduction reaction , *PHOTOTHERMAL effect , *GRAPHENE oxide , *BIODEGRADABLE nanoparticles , *POLYETHYLENE glycol , *COMPARATIVE studies , *NANOCARRIERS - Abstract
Nanographene oxide (NGO) with a non-sheddable poly(ethylene glycol) (PEG) coating has been used for chemo-photothermal therapy. However, the drug release of PEGylated NGO (NGO-PEG) with an amine bond is adversely affected by the diffusion barrier effect of PEG shells. Here, we developed a simple new method for the preparation of biodegradable PEGylated NGO conjugates (NGO-SS-PEG) with cleavable disulfide bonds for rapid drug release and more efficiently chemo-photothermal therapy. The glutathione (GSH)-induced and photothermal-mediated intracellular release of doxorubicin (DOX) from NGO-SS-PEG was studied in A549 cells using confocal laser scanning microscopy and flow cytometry analysis. In vivo cytotoxicity experiments were performed on chemo-photothermal therapy. Furthermore, we presented a comparative study of intracellular drug release and biological efficacy between NGO-SS-PEG/DOX and NGO-PEG/DOX. The results demonstrated that the rapid drug release from the NGO-SS-PEG conjugates with sheddable PEG was triggered upon the stimulus of high GSH levels inside A549 cells. Interesting, the DOX release mediated by the photothermal effect from the NGO-SS-PEG conjugates was found to be more obvious than that for NGO-PEG. Additionally, NGO-SS-PEG showed a higher efficacy than NGO-PEG for anti-tumor therapy compared with NGO-PEG. Thus, NGO-SS-PEG can improve therapeutic efficacy and is an attractive drug nanocarrier. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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- View/download PDF
5. Noninvasive prostate cancer screening based on serum surface-enhanced Raman spectroscopy and support vector machine.
- Author
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Shaoxin Li, Yanjiao Zhang, Junfa Xu, Linfang Li, Qiuyao Zeng, Lin Lin, Zhouyi Guo, Zhiming Liu, Honglian Xiong, and Songhao Liu
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PROSTATE cancer , *MEDICAL screening , *RAMAN scattering , *SURFACE enhanced Raman effect , *NANOPARTICLES , *PHYSICS research - Abstract
This study aims to present a noninvasive prostate cancer screening methods using serum surface-enhanced Raman scattering (SERS) and support vector machine (SVM) techniques through peripheral blood sample. SERS measurements are performed using serum samples from 93 prostate cancer patients and 68 healthy volunteers by silver nanoparticles. Three types of kernel functions including linear, polynomial, and Gaussian radial basis function (RBF) are employed to build SVM diagnostic models for classifying measured SERS spectra. For comparably evaluating the performance of SVM classification models, the standard multivariate statistic analysis method of principal component analysis (PCA) is also applied to classify the same datasets. The study results show that for the RBF kernel SVM diagnostic model, the diagnostic accuracy of 98.1% is acquired, which is superior to the results of 91.3% obtained from PCA methods. The receiver operating characteristic curve of diagnostic models further confirm above research results. This study demonstrates that label-free serum SERS analysis technique combined with SVM diagnostic algorithm has great potential for noninvasive prostate cancer screening. [ABSTRACT FROM AUTHOR]
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- 2014
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- View/download PDF
6. Analysis of sunlight loss for femtosecond laser microstructed silicon and its solar cell efficiency.
- Author
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Fang, Wang, Changshui, Chen, Huili, He, and Songhao, Liu
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SUNSHINE , *FEMTOSECOND lasers , *MICROSTRUCTURE , *SILICON , *SOLAR cells , *IONIZATION (Atomic physics) , *LASER beams - Abstract
Black silicon, which is obtained by irradiating the surface of a Si wafer with femtosecond laser pulses in the presence of a sulfur-bearing gas, holds great promise in the preparation of high-performance intermediate band silicon solar cells. Using a three-level model, the enhanced usefulness of sunlight of the microstructured silicon was firstly analyzed. A detailed study on the relationship between the light loss, the ionization energy of doped impurities in silicon and the impurity band width were given. Then the effect of the position of intermediate band within the forbidden gap of silicon on the theoretical conversion efficiency for the corresponding solar cell is discussed using the Detailed Balance Theory. Finally problems need to be resolved in making intermediate band solar cells based on femtosecond laser microstructured silicon are pointed out with great emphasis. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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7. Synergistic Effect of Ultrasound and Thiazone–PEG 400 on Human Skin Optical Clearing In Vivo.
- Author
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Huiqing Zhong, Zhouyi Guo, Wei, Huajiang, Long Guo, Chuanxing Wang, Yonghong He, Honglian Xiong, and Songhao Liu
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ULTRASOUND contrast media , *DRUG synergism , *POLYETHYLENE glycol , *POLYOLS , *TISSUES - Abstract
In this paper, we propose a new physical method in combination with mixed solution of thiazone and polyethylene glycol 400 (thiazone PEG 400 solution) penetration into tissue to assess the skin optical clearing . Four treatments were performed: (1) control group (C); (2) polyethylene glycol 400 (PEG400); (3) 0.25% thiazone (0.25%T); (4) 0.25% thiazone and 5-min ultrasound (0.25%T/SP). The diffuse reflectance spectra and imaging depth of human skin in vivo at different times were measured by spectroscopy and optical coherence tomography (OCT). The optical clearing efficacy of skin was qualitatively and quantitatively analyzed. The results showed that the diffuse reflectance at 540 nm of samples at 10 min after being treated by 0.25%T/SP decreased by approximately 15.51%, whereas, 0.46%, 4.73% and 5.75% were received in C, PEG400 and 0.25%T, respectively. And at 60 min, the decrease in diffuse reflectance of samples in 0.25%T/SP is about 2.22-fold, 1.20-fold compared with that of the samples in PEG 400 and 0.25%T, at 540 nm, respectively. Simultaneously, 0.25%T/SP results in 41.33% increase in OCT 1/e light penetration depth after 60 min. There was a significant difference in the optical clearing effect on skin between ultrasound-mixed solution of thiazone in combination with PEG 400 and the mixed solution ( P < 0.05). [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
8. Study of Optimal Cavity Parameter in Optically Pumped DO Gas Terahertz Laser.
- Author
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Zhihong He, Yuping Zhang, Huiyun Zhang, Qingmao Zhang, Jianhong Liao, Yongheng Zhou, Songhao Liu, and Xizhang Luo
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DEUTERIUM oxide , *ABSORPTION , *WAVELENGTHS , *MOLECULES , *TERAHERTZ technology , *ELECTROMAGNETISM - Abstract
Heavy water gas (DO gas) which owns special structure property, can generate terahertz radiation by optically pumping technology, and its 385 μm wavelength radiation can be widely used. In this research, on the base of semi-classical density matrix theory, we set up a three-level energy system as its theoretical model, a TEA-CO laser 9R (22) output line (λ = 9.26 μm) acted as pumping source, DO gas molecules were operating medium, the expressions of pumping absorption coefficient G and Terahertz signal gain coefficient G were deduced. It was shown that the gain of Terahertz signal was related with the energy-level parameters of operating molecules and some operating parameters of the Terahertz laser cavity, mainly including cavity length. By means of iteration method, the output power density of Terahertz pulse signal was calculated numerically. Changing the parameter of cavity length and keeping others steady, the relationship curve between the output power intensity (Is) of Terahertz pulse laser and the operating cavity length (L) was obtained. The curve showed that the power intensity (Is) increased with cavity length (L) in a certain range, but decreased when the length (L) exceeded some value because of the absorption effect, and there was an optimal cavity length for the highest output power. We used a grating tuned TEA-CO laser as pumping power and a sample tube of variable length in 70-160 cm as terahertz laser operating cavity to experiment. The results of theoretical calculation and experiment matched with each other, and it is helpful for miniaturizing terahertz laser volume to make it practical. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
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9. Low-Intensity Pulsed Laser Irradiation Affects RANKL and OPG mRNA Expression in Rat Calvarial Cells.
- Author
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Min Xu, Tietao Deng, Feizhi Mo, Bin Deng, Wingho Lam, Pingxiang Deng, Xiaohui Zhang, and Songhao Liu
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MEDICAL lasers , *OSTEOCLASTS , *MESSENGER RNA , *BONE diseases , *GENE expression , *LABORATORY rats , *SPECTROPHOTOMETRY - Abstract
AbstractObjective:This study aimed to investigate the effect of low-intensity pulsed laser (LIPL; 650 nm, 2 mW) irradiation on mRNA expression of receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) in rat calvarial cells. Materials and Methods:Cultured cells were treated with LIPL irradiation of 1.14 J/cm2(group A) or 2.28 J/cm2(group B), and non-irradiated cells (group C) were used as controls. The changes in cell numbers, alkaline phosphatase (ALP) activity, RANKL, and OPG mRNA expression in the three study groups was determined using MTT, UV/VIS spectrophotometry, and RT-PCR analyses. Results:The cell numbers in groups A and B increased significantly (7.52 and 8.80, respectively), as did ALP activity (71.95 and 88.20, respectively), compared with group C (p< 0.001). Meanwhile, RANKL and OPG mRNA expression in group A were 51.06 lower and 3.35 times higher, respectively, than those seen in the controls (p< 0.05), and the RANKL:OPG mRNA ratio in group A was 81.82 lower than that in group C (p< 0.005). Conclusion:LIPL irradiation may directly promote osteoblast proliferation and differentiation, and indirectly inhibit osteoclast differentiation, by downregulating the RANKL:OPG mRNA ratio in osteoblasts. Thus LIPL irradiation may play an important role in bone remodeling, and should be valuable for the treatment of bone diseases such as osteoporosis. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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10. Potential ability of hematoporphyrin to enhance an optical coherence tomographic image of gastric cancer in vivo in mice.
- Author
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Honglian Xiong, Changchun Zeng, Zhouyi Guo, Huiqing Zhong, Ruikang Wang, Songhao Liu, and Yonghong He
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HEMATOPORPHYRIN , *OPTICAL coherence tomography , *STOMACH cancer , *LABORATORY mice , *CONTRAST media , *WAVELENGTHS , *TISSUES - Abstract
An ideal diagnostic system for the tumor tissues should be able to detect and define the location of tumor tissues and the early development of malignant diseases. There is great need for enhancement of imaging ability to tumor tissues. Optical coherence tomography (OCT) is used in detection and location of varied tumor tissues. In order to improve the sensitivity and specificity of an OCT image, hematoporphyrin as a new type of contrast agent was used in this study. The orthotopic graft model of gastric cancer in nude mice was used. The image formations of the tumor tissues without and with injection of hematoporphyrin in vivo were obtained by an OCT system at a 1310 nm central wavelength. The experimental results showed that the tumor tissues accumulated with hematoporphyrin have an ability of light absorption which results in the increase of signal attenuation in the gastric cancer tissues, and that the boundary between the tumor tissues and surrounding normal tissues was perfectly defined owing to the accumulation of hematoporphyrin. From the experimental results, it is found that hematoporphyrin, a photosensitizing agent, could be used as a contrast agent for OCT imaging of tumor tissues, which offer an effective OCT image method for clinical detection and localization of tumor tissues in vivo. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
11. An integral gated mode single photon detector at telecom wavelengths.
- Author
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Zhengjun Wei, Peng Zhou, Jindong Wang, Changjun Liao, Jianping Guo, Ruisheng Liang, and Songhao Liu
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PHOTON detectors , *NUCLEAR counters , *WAVELENGTHS , *TELECOMMUNICATION - Abstract
We demonstrate an integral gated mode single photon detector at telecom wavelengths. The charge number of an avalanche pulse rather than the peak current is monitored for single photon detection. The transient spikes in conventional gated mode operation are cancelled completely by integrating, which enables one to effectively improve the performance of single photon detector with the same avalanche photodiode. This method achieved a detection efficiency of 29.9% at the dark count probability per gate equal to 5.57 × 10[?]6/gate (1.11 × 10[?]6 ns[?]1) at 1550 nm. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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12. Discrimination of dimethyl sulphoxide diffusion coefficient in the process of optical clearing by confocal micro-Raman spectroscopy.
- Author
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Ping Liu, Yanyue Huang, Zhouyi Guo, Jianping Wang, Zhengfei Zhuang, and Songhao Liu
- Subjects
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DIMETHYL sulfoxide , *DIFFUSION processes , *DIFFUSION coefficients , *CONFOCAL microscopy , *RAMAN spectroscopy - Abstract
Confocal micro-Raman spectroscopy is employed to study the diffusion process of dimethyl sulfoxide (DMSO) in porcine skin optical clearing. The variation of DMSO concentration with time at different depths of the skin was obtained and then the DMSO diffusion coefficient with the passive diffusion model was calculated. Results show that it has a significant difference at different depths of the skin. Also, the DMSO concentration with the depth at different times was obtained and the same method was used to find the change law of the DMSO diffusion coefficient. Results indicate that it also changes with the treatment time. The experimental results are consistent with the theoretical model in a previous study. The current results demonstrate that Raman spectroscopy has the ability to quantitatively monitor the process of optical clearing. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
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13. Achievement of alternative amorphous AlAs/crystalline AlGaAs multilayers.
- Author
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Hao Wang, Changjun Liao, Shuwen Zheng, and Songhao Liu
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AMORPHOUS semiconductors , *ORGANOMETALLIC compounds , *CHEMICAL vapor deposition , *TRANSMISSION electron microscopy , *SEMICONDUCTORS , *ATOMIC structure - Abstract
A hybrid multilayer, composed of ten period amorphous AlAs/crystalline GaAlAs stacks, is realized by metalorganic chemical vapor deposition method on a GaAs substrate. Cross-sectional transmission electron microscopy shows the presence of sharp amorphous/crystalline interfaces. The electron diffraction patterns reveal the coexistence of both amorphous and crystalline phases and the perfect coherence of atom arrows between substrate and crystalline AlGaAs layers was also demonstrated. Perfect crystalline AlGaAs quality was further confirmed by x-ray rocking curves. The potential application of such hybrid multilayers is discussed and its behavior as a Bragg reflector is explored with a stop band gap of 75% reflectance. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
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14. In vitrostudy of ultrasound and different-concentration glycerol–induced changes in human skin optical attenuation assessed with optical coherence tomography.
- Author
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Huiqing Zhong, Zhouyi Guo, Huajiang Wei, Changchun Zeng, Honglian Xiong, Yonghong He, and Songhao Liu
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OPTICAL coherence tomography , *SKIN , *MEDICAL imaging systems , *GLYCERIN , *MEDICAL ultrasonics - Abstract
Previous studies have demonstrated the ultrasound-induced skin optical clearing enhancement with topical application of 60 glycerol (G) on in vitroporcine skin and in vivohuman skin. Our purpose was to find the relation between the effect of optical skin clearing and different concentrations of glycerol and to find more effective ultrasound-glycerol combinations on optical skin clearing. The enhancement effect of ultrasound Sonophoresis (SP) delivery in combination with 40 G, 60 G, and 80 G on in vitrohuman skin optical clearing was investigated. Light imaging depths of skin were measured using optical coherence tomography. Different concentrations of glycerol and ultrasound with a frequency of 1 MHzand an intensity of 0.5 Wcm2was simultaneously applied for 15 min. The results show that with the increase of concentration of glycerol, the optical clearing of skin is much improved. Optical clearing capability of glycerol was more enhanced with simultaneous application of ultrasound compared with glycerol alone. The attenuation coefficients of skin tissues after application of 40 G/SP, 60 G/SP, and 80 G/SP decreased approximately 11.8, 18.5, and 20.0 at 15 mincompared with 40 G, 60 G, and 80 G alone, respectively. The greatest decrease in attenuation coefficients at 60 minwas approximately 52.3 and 63.4 for 80 G (without ultrasound) and 80 G/SP (with ultrasound), respectively, which are 2.1-fold and 2.6-fold to that in the 40 G. [ABSTRACT FROM AUTHOR]
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- 2010
- Full Text
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15. Application of hyperosmotic agent to determine gastric cancer with optical coherence tomography ex vivoin mice.
- Author
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Honglian Xiong, Zhouyi Guo, Changchun Zeng, Like Wang, Yonghong He, and Songhao Liu
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TISSUES , *TUMORS , *MEDICAL radiography , *CANCER treatment - Abstract
Noninvasive tumor imaging could lead to the early detection and timely treatment of cancer. Optical coherence tomography (OCT) has been reported as an ideal diagnostic tool for distinguishing tumor tissues from normal tissues based on structural imaging. In this study, the capability of OCT for functional imaging of normal and tumor tissues based on time- and depth-resolved quantification of the permeability of biomolecules through these tissues is investigated. The orthotopic graft model of gastric cancer in nude mice is used, normal and tumor tissues from the gastric wall are imaged, and a diffusion of 20 aqueous solution of glucose in normal stomach tissues and gastric tumor tissues is monitored and quantified as a function of time and tissue depth by an OCT system. Our results show that the permeability coefficient is (0.94±0.04)×10−5 cmsin stomach tissues and (5.32±0.17)×10−5 cmsin tumor tissues, respectively, and that tumor tissues have a higher permeability coefficient compared to normal tissues in optical coherence tomographic images. From the results, it is found that the accurate and sensitive assessment of the permeability coefficients of normal and tumor tissues offers an effective OCT image method for detection of tumor tissues and clinical diagnosis. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
16. Quantitative analysis on tongue inspection in traditional Chinese medicine using optical coherence tomography.
- Author
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Haixin Dong, Zhouyi Guo, Changchun Zeng, Huiqing Zhong, Yonghong He, Ruikang K. Wang, and Songhao Liu
- Subjects
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QUANTITATIVE chemical analysis , *CHINESE medicine , *OPTICAL coherence tomography , *RATS - Abstract
Tongue inspection (TI) is an important and unique diagnostic method in traditional Chinese medicine (TCM), because significant connections between various viscerae diseases and abnormalities in the tongue have been verified. In TCM, TI is simple and non invasive, but in clinical applications, TI is subjectively based on the experience and technique of physicians. To avoid this problem, optical coherence tomography (OCT) imaging is introduced here for TI. We study OCT imaging in rats in vivo from chronic gastritis group (model) and normal group (control) and quantitatively analyze the relative parameters, such as the thickness and the moisture degree of TI. Our results show that OCT images properly demonstrate the thickness of the tongue coating and the moisture degree of the tongue in both groups, and the thickness is increased in the model group from that in the normal group, while the moisture degree decreases. As a result, OCT technology has the potential to provide physicians with an objective diagnostic standard for visual TI in TCM clinical practice and research. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
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