Search

Herein, we demonstrated for the first time the green fabrication of graphene by wet ball milling method which utilizes natural honey as exfoliation medium, further the 3D conductive networks (Graphene/Carbon nanotubes/PEDOT:PSS, G/CNT/PEDOT:PSS) were integrated into the biodegradable Starch/Chitosan/Poly vinyl alcohol (S/C/PVA) substrates. This electrode possesses an excellent optoelectronic performance (Rs = 43.2 Ω/sq., T = ca. 80% at 550 nm), and a very low Root Mean Square (RMS) roughness (approximately 1.38 nm). The sheet resistance of the films changed slightly after 1000 bending cycles and adhesion tests. The flexible green light OLED using G/CNT/PEDOT:PSS-S/C/PVA film as anode was successfully fabricated, the luminance of the device was 5701 cd/m2 at 15 V and the maximum current efficiency was 3.75 cd/A at 13 V. Moreover, this new type of OLED device degrades gradually within 10 min in 2 wt% lysozyme CH3COOH solution, which could be used to prepare the next generation of user-friendly, eco-friendly flexible wearable electronic devices.

Improved OLED systems have great potential for next-generation display applications. Carbon nanotubes (CNTs) and the conductive polymers poly (3,4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT: PSS) have attracted great interest for advanced applications, such as optoelectronic products. In this paper, the simultaneous enhancement of the conductivity, roughness, and adhesion properties of transparent conductive films with PEDOT: PSS/CNTs is reported. These films prepared by a simple spin-coating process were successfully used to produce high-performance organic light-emitting diodes (OLEDs) with an improved lifetime. Addition of PEDOT: PSS lowered the film sheet resistance and CNTs helped to enhance the stability and maintain the lifetime of the OLEDs. In addition, treatment with methanol and nitric acid changed the morphology of the polymer film, which led to greatly reduced sheet resistance, enhanced substrate adhesion, and reduced film roughness. The best performance of the film (PEDOT: PSS: CNT = 110: 1, W/W) was 100.34 Ω/sq.@ 90.1 T%. High transmittance, low sheet resistance, excellent adhesion, and low roughness (3.11 nm) were achieved synchronously. The fabricated OLED demonstrated a low minimum operating voltage (3 V) and could endure high voltage (20 V), at which its luminance reached 2973 cd/m2. Thus, the incorporation of CNTs within PEDOT: PSS electrodes has great potential for the improvement of the performance of OLED devices.

Carbon nanotubes (CNTs) and graphene (Gr) are promising materials for flexible transparent conductive films (TCFs) in optoelectronic application because of their exceptional electrical, optical, and mechanical properties. Here, high-quality graphene nanosheets were synthesized by the one-step green method which using natural polyphenols-gallic acid (GA) as the exfoliation medium through high-pressure homogenization; besides, GA molecules can also be used as a non-covalent modifier to obtain GA modified CNTs (GCNTs). Then, the Au decorated Gr/GCNT-PET (Au-Gr/GCNT-PET) TCFs were obtained by a simple spray-coating process. The TCFs exhibited an excellent optoelectronic performance (Rs = 45.6 Ω/sq., T = ca. 80% at 550 nm), relatively flat surface (roughness = 12.43 nm), good bending resistance (the ΔR Au-Gr/GCNT-PET TCF/R0 was 0.07 after 1000 times bending tests) and strong adhesion (the fT of all Au-Gr/GCNT PET films was higher than 0.8). Finally, the Au-Gr/GCNT-PET films were used as an anode to prepare flexible green-light OLED devices; the maximum luminance of the Au-Gr/GCNT-PET device was 6554.1 cd/m2 at 15V, and the maximum current efficiency was 4.03 cd/A. It confirmed that this type of TCFs has considerable potential application in photovoltaic devices.

In this paper, we used tannic acid (TA) functionalized carbon nanotubes (TCNTs), and silver nanowires (AgNWs) to construct a new type of transparent conductive film (TCF) with a double-layered conductive network structure. The hybrid film exhibits excellent light transmittance, high electrical conductivity, ultra-flexibility, and strong adhesion. These outstanding performances benefit from the filling and adhesion of hydrophilic TCNT layers to the AgNW networks. Besides, we introduced the post-treatment process of mechanical pressing and covering polymer conductive polymer PEDOT:PSS, which obtained three layers of TCNT/AgNW/PEDOT hybrid film and greatly improved the comprehensive properties. The hybrid film can reach a sheet resistance of 9.2 Ω sq−1 with a transmittance of 83.4% at 550 nm wavelength, and a low root mean square (RMS) roughness (approximately 3.8 nm). After 10 000 bends and tape testing, the conductivity and transmittance of the hybrid film remain stable. The resistance of the film has no significant degradation after 14 d of exposure to high temperature of 85 °C and humidity of 85%, indicating excellent stability. The organic light-emitting diodes (OLEDs) with TCNT/AgNW/PEDOT hybrid film as anode exhibit high current density and luminosity, confirming this process has considerable potential application in photovoltaic devices.

High purified single-walled carbon nanotubes (SWCNTs) were dispersed in water and transparent conducting films (TCFs) were fabricated by a spray coating. The produced uniform SWCNT–TCFs treated by nitric acid have a relatively low sheet resistance and high transmittance. The current–voltage (I–V) behaviors of the TCFs were measured at room to higher temperature during the heating or cooling process. It was found that the I–V behavior of TCFs strongly dependent on the temperature and applied voltage. The sheet resistance showed semiconductor behavior at low temperature and low voltage, while it showed metallic behavior at high temperature and high voltage.

Objective. To investigate the effects of electroacupuncture (EA) at “Zusanli” (ST36) and “Shangjuxu”(ST37) on reducing inflammatory reaction and improving intestinal dysfunction in patients with sepsis-induced intestinal dysfunction with syndrome of obstruction of the bowels Qi. Methods. A total of 71 patients with sepsis-induced intestinal dysfunction with syndrome of obstruction of the bowels Qi were randomly assigned to control group (n=36) and treatment group (n=35). Patients in control group were given conventional therapies including fluid resuscitation, anti-infection, vasoactive agents, mechanical ventilation, supply of enteral nutrition, and glutamine as soon as possible. In addition to conventional therapies, patients in treatment group underwent 20 minutes of EA at ST36-ST37 twice a day for five days. At baseline, day 1, day 3, and day 7 after treatment, the plasma levels of procalcitonin (PCT), tumor necrosis factor-α (TNF-α), intestinal fatty acid-binding proteins (I-FABP), D-lactate, citrulline, and TCM quantitative score of intestinal dysfunction were measured and recorded, respectively. And days on mechanical ventilation (MV), length of stay in intensive care unit (ICU), and 28d mortality were recorded. Results. During treatment, the plasma levels of PCT, TNF-α, I-FABP, D-lactate, and TCM quantitative score of intestinal dysfunction were declining in both groups, while the treatment group showed a significant decline (P). Plasma levels of citrulline were increasing in both groups, while the treatment group showed a significant increase (P). However, there were no significant differences in the days on MV, length of stay in ICU, and 28d mortality between two groups (P>0.05). Conclusions. EA at ST36-ST37 can reduce inflammatory reaction and has protective effects on intestinal function in patients with sepsis-induced intestinal dysfunction with syndrome of obstruction of the bowels Qi. Trial Registration. This trial was registered at http://www.chictr.org.cn/(ChiCTR-IOR-17010910).

High-performance, flexible film heaters with carbon nanotube transparent conducting films are easily fabricated by both a rod-coating method and a spraying method. The main conclusion we have reached is that the film demonstrates a heating rate of 6.1°C s −1 at 35 V and sheet resistance as low as 94.7 Ω sq −1 with 72.04% optical transmittance at a wavelength of 550 nm by the spraying method after a series of post-treatment processes with acid and distilled water. Then, we adopt a mathematical method of nonlinear fitting to simulate the collected experimental data and the functions effectively. Furthermore, through analysis of the formula, the correlation between temperature and time is well explained. Therefore, carbon nanotube-based, flexible, transparent heaters exhibit high electrothermal performance and are expected to find different applications, e.g. various functional devices such as heating materials, heatable smart windows or dining tables.

We demonstrate a nanosecond all-fiber master oscillator power amplifier with linear-polarized output at 2040 nm, seeded by an in-band-pumped gain-switched thulium-doped fiber laser, which can directly output tens-of-microjoules pulses with designable pulse duration and Gaussian-like pulse profile. After only two stages of amplification, we achieve an average power of 70 W at a pulse width of 114 ns and a repetition rate of 10 kHz, corresponding to a pulse energy of 7 mJ and a peak power of 53.8 kW. Benefit from the on-site polarization control technique we proposed, a polarization extinction ratio (PER) of 25 dB at the highest output is also obtained. To the best of our knowledge, this is the highest power nanosecond all-fiber laser reported at 2-μm waveband and the PER is also a record among high-power fiber lasers.

A gas-fired coal preheating (GFCP) technology, offering a flexible method to reduce NOx, could be used with other de-NOx combustion technology such as air staging to seek maximum NOx reduction. The preheating chamber key apparatus of GFCP was investigated with the help of infrared camera. The results show that devolatilization and partial oxidation (combustion) of coal occurred in the preheating chamber, and this may prove the main heat source of preheating chamber is combustion of coal volatiles and gas is only used to prevent flameout. A self-sustaining combustion drop furnace was used to investigate the NOx reduction potential of GFCP with air staging. Gas species concentrations along furnace are plotted for several runs, offering details to further study and analyze the GFCP. With GFCP, much HCN, CiHj, and soot were produced in the preheating chamber, so under the similar air staging condition, the NO destructed by HCN and soot was stronger than that without. NOx reduction could archive up to 72% with...

Selective Catalytic Reduction (SCR) technology is currently the most widely used DeNO x technology in coal boilers. However, the nonuniform distribution of flue gas decreases the utilization efficiency of catalysts, which leads to great economic losses, so improving the airflow uniformity in the DeNO x reaction tower has great significance. In this research, the velocity distribution of airflow in gas flue was measured in a lab-scale SCR system, and the uniformity was shown in isovelocity graphs. The results show: the airflow distribution of the wedge reaction tower was better than of the flat-top reaction tower and the transition-type reaction tower; in the range of the equivalent length Le from 0 to 0.4, the velocity distribution was more and more uniform as the increase of Le.

Low-light stereo vision is a challenging problem because images captured in dark environment usually suffer from strong random noises. Some widely adopted algorithms, such as semiglobal matching, mainly depend on pixel-level information. The accuracy of local feature matching and disparity propagation decreases when pixels become noisy. Focusing on this problem, we proposed a matching algorithm that utilizes regional information to enhance the robustness to local noisy pixels. This algorithm is based on the framework of ADCensus feature and semiglobal matching. It extends the original algorithm in two ways. First, image segmentation information is added to solve the problem of incomplete path and improve the accuracy of cost calculation. Second, the matching cost volume is calculated with AD-SoftCensus measure that minimizes the impact of noise by changing the pattern of the census descriptor from binary to trinary. The robustness of the proposed algorithm is validated on Middlebury datasets, synthetic data, and real world data captured by a low-light camera in darkness. The results show that the proposed algorithm has better performance and higher matching rate among top-ranked algorithms on low signal-to-noise ratio data and high accuracy on the Middlebury benchmark datasets.

With the rapid development of computer network and the network application, network has plays an increasingly important role in the social progress and economic development. Rapid development of information technology makes the network traffic behavior has become increasingly complex, and the reliability of the network becomes crucial. Cluster algorithm using for network traffic flow is an entry to analysis network status. Support Vector Machine (SVM) is a machine learning method to solve binary classification problem. An improved cluster analysis algorithm of combining SVM with supervised subset density clustering is proposed in this paper, and minimize the training set of SVM by means of clustering is researched. A supervised self-adaptive method for the improved density clustering is designed to make out multiple centers choosing and referring the samples to SVM. The experimental results show that the algorithm reduces the iteration time of the whole training process without compromising the accuracy and generalization capacity of the algorithm obviously.

An array of random-oriented zinc oxide nanowires (ZnO NWs) was fabricated on silicon substrate by thermal evaporation. After a thermal evaporation process, the silicon substrate was covered with a large number of uniformly distributed ZnO islands, from which non-aligned NWs with a diameter of several ten nanometres were grown. During this process, the temperature around the substrate was intentionally kept below 500 degrees C for practical consideration. From these ZnO NWs field emission was achieved. The turn-on field, under which a 10μA/cm2 current density was extracted, was measured to be 3.0V/μm. Also, the emission site distribution was investigated using the transparent anode technique. The field emission was observed to have occurred from the whole sample surface. These results suggest that ZnO NWs have great potential application in flat panel displays.

In this paper, we proposed an algorithm to discovery physical layer topology structure of Ethernet networks with incomplete address forwarding table information by collecting data via SNMP. The new algorithm is also able to handles VLANs and layer-3 switches. We have implemented our algorithm in networks of Beijing University of Posts and Telecommunications which demonstrated that our algorithms works well in many heterogeneous networks.

Single-walled carbon nanotube (SWCNT) transparent conducting films (TCFs) were fabricated for the electrodes of organic light-emitting diodes (OLEDs); three types of film were studied. The as-prepared SWCNT TCFs displayed a relatively low sheet resistance of 82.6 Ω/sq at 80.7 T% with a relatively large surface roughness of 30 nm. The TCFs were top-coated with poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) to obtain PEDOT:PSS-coated TCFs. The PEDOT:PSS cover improved the conductivity and decreased the surface roughness to 12 nm at the cost of film transmittance. The SWCNT TCFs mixed with PEDOT:PSS (PM-TCFs) exhibited a high conductivity (70.6 Ω/sq at 81 T%) and a low surface roughness (3 nm) and were thus selected as the best TCFs for OLEDs. Blue flexible OLEDs with 4,4'-bis(2,2'-diphenylvinyl)-1,1'-biphenyl (Dpvbi) as the emitting layer were fabricated on TCFs with the same structures to evaluate the performances of the different types of SWCNT films for use in OLEDs. Of these three types of OLEDs, the PM-TCF devices exhibited the optimal performance with a maximum luminance of 2587 cd m(-2) and a current efficiency of 5.44 cd A(-1). This result was explored using field-emission scanning electron microscopy and atomic force microscopy to further study the mechanisms that are involved in applying SWCNT TCFs to OLEDs.

By introducing an adjustment waveguide besides the incident waveguide, zero-dispersion slow light with wide bandwidth can be realized due to anticrossing of the incident waveguide mode and the adjustment waveguide mode. The width of the adjustment waveguide (W2) and the hole radii of the coupling region (r') will change the dispersion of incident waveguide mode. Theoretical investigation reveals that zero dispersion at various low group velocity νg in incident waveguide can be achieved. In particular, proper W2 and r' can lead to the lowest νg of 0.0085c at 1550 nm with wide bandwidth of 202 GHz for zero dispersion.

Profile information about a three-dimensional target can be obtained directly by analyzing two-dimensional data of the pulse laser range profile (LRP). The profile, shape, and posture of the target can be detected using LRPs. An analytical LRP model from rough convex quadric bodies of revolution is presented. This model can be used to analyze the effects of geometric parameters, surface material, and orientation on LRPs. The numerical results of the effects on LRPs of four typical targets are given. Based on the results of the simulated model and theoretical analysis, the rough convex quadric bodies of revolution can be identified. The analytical expressions of this model are significant in the application of LiDAR imaging.

Arrays of single crystalline gold nanowires were synthesized electrochemically in porous polycarbonate membranes. The polycarbonate membrane was then removed to obtain free-standing nanowires for field emission measurements. The turn-on electric field strength for field emission is found to be lower than 2V/µm. The actual electric field that extracted electrons out of the gold nanowires is estimated to be about 103 times higher than the field directly expected in the model of a parallel plate condenser. The availability of the field emission is therefore attributed to the strong electric field at the tips resulting from small curvature radius of the gold nanowires.

To investigate the appropriate time for combination therapy in HBeAg positive chronic hepatitis B (CHB) patients with decompensated cirrhosis.Thirty HBeAg positive CHB patients with decompensated cirrhosis were enrolled in the study. All of the patients were given 48 wk combination therapy with lamivudine (LAM) and adefovir dipivoxil (ADV). Briefly, 10 patients were given the de novo combination therapy with LAM and ADV, whereas the other 20 patients received ADV in addition to LAM after hepatitis B virus (HBV) genetic mutation.Serum alanine aminotransferase and total bilirubin were both improved in the two groups at 4, 12, 24 and 48 wk after treatment. Serum albumin was also improved at 24 and 48 wk after combination therapy in both groups. The serum HBV DNA level was still detectable in every patient in the two groups at 4 and 12 wk after combination treatment. However, in the de novo combination group, serum HBV DNA levels in 4 (40%) and 9 (90%) patients was decreased to below 1×10(3) copies/mL at 24 and 48 wk after the combination treatment, respectively. In parallel, serum HBV DNA levels in 2 (20%) and 8 (40%) patients in the add-on combination group became undetectable at 24 and 48 wk after combination treatment, respectively. Furthermore, 6 (60%) patients in the de novo combination group achieved HBeAg seroconversion after 48 wk treatment, whereas only 4 (20%) patients in the add-on combination group achieved seroconversion. Child-Pugh score of patients in the de novo combination group was better than that of patients in the add-on combination group after 48 wk treatment. Moreover, patients in the de novo combination group had a significantly decreased serum creatinine level and elevated red blood cell counts.De novo combination therapy with LAM and ADV was better than add-on combination therapy in terms of Child-Pugh score, virus inhibition and renal function.

An image fusion method of 9/7 wavelet transform based on lifting scheme is proposed. After the registration of multi-source sensor images, the obtained images are decomposed into several coefficients of low frequency and high frequency by using 9/7 wavelet transform based on lifting scheme. Aiming at the characteristic of the coefficients of low frequency and high frequency after decomposition, fusion rules based on local region are chosen to fuse the coefficients, and the fusion image is obtained by inverse wavelet transform based on lifting scheme. By means of designing simulation experiments using visible image and infrared image, the image fusion method of 9/7 wavelet transform based on lifting scheme is compared qualitatively and quantitatively with other three kinds of image fusion methods including weighted average, selecting maximum pixel gray value and Laplacian pyramid transform. Lots of experiments and comparisons with other fusion methods show that the effectiveness and superiority of image fusion method of 9/7 wavelet transform based on lifting scheme.

This paper shows us the coverage performance and Doppler shift of the IGSO constellation with 2, 3 or 4 satellites, and then contrasted with the GEO satellite. The IGSO constellation is better than GEO satellite in average elevation angle and multi-satellite coverage. It is concluded after simulation and analysis that the IGSO constellation with 3 or 4 IGSO satellites can provide higher coverage performance for the Chinese areas and nearby, especially communication elevation in high latitude area, just with a small Doppler shift increase. The IGSO satellite constellation can be used more properly as the regional mobile satellite communication constellation.

An analytical expression for the fourth order moment of the plane wave scattering from two-dimensional randomly rough surface with small roughness is presented based on the Kirchhoff and physical optics approximation. The fourth order moment has been simplified to get the two-position and two-frequency mutual correlation function. With the incidence wavelength 1.06 mum and different root-mean-square (rms) heights, the distributions of FOM changing with the coherence bandwidth frequency difference and scattering angles have been given. It is shown that the rms height of rough surface greatly influences on results and the scattered FOM mainly comes from the specular direction and zero frequency difference with small rms height. If the frequency difference is greater than zero, FOM will quickly decreases to zero in other directions; while at zero frequency, with the increase of rms height, there is also the biggest value which is smaller than that with smaller rms height, and the value in specular direction decreases but others increase, which we call "speckle effect". In addition, the increase of rms height results in the correlation bandwidth narrowing.

Summary of thematerial parameters forSWCNTs: (a) diameters,(b) burning temperature andpurity, (c) The ratio of theintensity of D-band to G-bandand G -band to G-band of theSWCNTs at excitationenergies of 514 and 633nm where n and p are the n -type (electrons) and p -type (holes) carrier concentrations,respectively, and μ n and μ p are the respective electron and hole mobility. Themobility is dominated by a succession of random scattering from collisions withlattice atoms, impurity atoms, and other scattering centers. The intrinsic carrierconcentration decreases exponentially with band gap, n i = n o exp( − E g / 2 k B T) ,where k B and T are the Boltzmann constant and temperature of the system, respec-tively. The p -type and n -type nanotube carrier concentrationsare, p = n i exp [ (E i − E f )/k B T ], and n = n i exp [ (E f − E i )/k B T ], where the intrinsic Fermi level E i is frequently used as a reference level when the extrinsic semiconductors are dis-cussed with a Fermi level of

We report in this paper that low-voltage indium-zinc oxide (IZO) junctionless thin-film transistors (TFT) can be fabricated at room temperature, and the device stability performance influenced by oxygen pressure is studied. IZO junctionless TFT has a high mobility and novel structure, but the oxide channel layers are vulnerable due to the influence of oxygen and water molecules, which will lead to the degradation of the device stability. In this study, we fabricate transparent and conductive IZO thin-films at room temperature as channel layers, and source/drain electrodes by controlling the oxygen flow, and also analyze the effect of oxygen on the stability of oxide junctionless TFT. In order to operate at low-voltage (2 nanoparticle films as gate dielectric, which have electron double layers (EDL) effect and large gate capacitance, and the TFTs show excellent electrical performance with small operating voltage of 1 V, large on/off ratio(>106), small subthreshold swing(20 cm2/V·s). The study indicates that the resistivity of IZO thin-film fabricated in increasing oxygen content, leads the threshold voltage to drift in a positive direction, and makes operating mode of TFT change from depletion mode to enhanced mode.

Bottom-gate junctionless thin-film transistors (TFTs) based on indium-tin-oxide (ITO) are fabricated at room temperature. Source/drain electrodes and channel layer are the same ITO thin films without source/drain junction formation, hence the fabrication process is greatly simplified and the fabrication cost is reduced. We employ electric-double-layer (EDL) SiO2 with large capacitance as the gate dielectric, and find that the drain current can be effectively modulated by the gate bias when the thickness of ITO film decreases to about 20 nm. These junctionless TFTs show excellent electrical performances with a small subthreshold swing of 0.13 V/dec, a high mobility of 21.56 cm2/V·s and a large on/off ratio of 1.3× 106. The performances of these junctionless TFTs do not show significant degradation even after 4 months in air ambient, the subthreshold swing is still 0.13 V/dec, the mobility slightly decreases to 18.99 cm2/V·s and the on/off ratio is still larger than 106. Such TFTs are very promising for the applications in low-cost low-power portable electronic products and novel sensors.

We report on the realization of optical true-time delay (TTD) by a two-dimensional photonic crystal waveguide (PCWG). Design and fabrication of the PCWG are investigated. The spectral dependence of the group delay is measured by detecting the phase shifts of a 10 GHz modulating signal, and a maximum delay of 25 ± 2.5 ps is obtained.

Pulse laser one-dimensional range profile theory and simulation are investigated. Laser one-dimensional range profile simulation is studied based on pulse wave scattering theory and the radar equation, and the calculated formula of laser one-dimensional range profile is obtained. As examples, the range profile simulations are calculated for the sloped-plane, sphere, and cone. It is also analyzed that the influences of target shape, radial length and pulsewidth on the simulation results. This paper offers theory bases and simulation method for abstraction and identification target feature on the laser.

Based on the Kirchhoff approximation and Gaussian moment theorem, we present a general expression of the intensity correlation scattered from a weakly one-dimensional rough surface, which is applicable to the cases by either two different wavelengths or two different angles of incidence. By using a Gaussian surface model, we give the numerical results for the intensity correlation function with two different wavelengths specially. The results show that with the increasing surface roughness and the decreasing surface correlation length, the correlation function decreases in specular direction and increases in other directions, which indicates that the study of the correlation of the intensities is helpful when investigating the statistical parameters of rough objects. Also the results show that the increase of rms roughness can result in the narrower correlation bandwidth.

Two kinds of vertically aligned, well-ordered zinc oxide nanoneedle arrays were synthesized on silicon substrates without any catalyst by a simple thermal evaporation method. The nanoneedle arrays have uniform distribution and unique orientation and height. The field emission study shows that both of them have not only low turn-on field and threshold field, but also the ability of stable and long time emission. The low turn-on field and threshold field result from the high aspect ratio and thin apex of the nanoneedles. The stable and long time emission are due to the uniform distribution and good contact between the nanoneedles and the substrate. The results show that regular nanoneedle arrays are ideal candidates for flat panel field emission applications.

A semiconductor laser that generates a chaotic signal with optical feedback can be treated as a chaotic transmitter. Based on single mode rate equations of semiconductor laser with optical feedback and external injection, the numerical simulation shows that the bandwidth of the transmitter is expanded by external optical injection. When the injection index kinj is 0.39, the bandwidth is increased from the value of 2.7 GHz without optical injection to 14.5GHz. The results also reveal that, under the same injection strength, the enhancement of bandwidth depends evidently on the frequency detuning between the external injection laser diode and the chaotic carrier transmitter. The maximum bandwidth of the chaotic transmitter can be obtained when the frequency detuning is in the range from 2 to 4GHz. The bandwidth of the chaotic transmitter can also be enhanced by increasing the bias current.

The optical absorption properties of Ag-BaO composite thin film with excess barium were measured while a vertical electric field was applied on the film surface.Total two absorption peaks were observed in the visible and near-infrared region,and only the peak that lies in the near-infrared region was dependent on the applied electric filed,i.e.,the absorption intensity was decreased with the increasing electric field.The dominant peak in the visible region is attributed to the surface plasmons resonance of Ag ultrafine particles embedded into the BaO semiconductor matrix.However,the weaker one in the near-infraed region is considered to arise from the transition of bound electrons at impurity energy level of the BaO semiconductor matrix,and such an impurity energy level is related to the negative ion vacancies caused by the excess braium in the BaO crystal.When the external surface electric field was applied,some of the impurities in the BaO Semiconductor matrix were ionized,and which further resulted in a decrease of the density of bound electrons at the impurity energy level.So that,part of the optical absorption owing to the impurity energy level was decreased with the enhanced electric field.