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The electrical spark discharge method was used to prepare graphene copper nanocomposite (GNS-Cu) colloids under normal temperature and pressure. Cu and graphite were mixed in deionized water at a Cu : C mass ratio of 9 : 1 (99% purity), and the mixture was used to produce composite rods as the electrodes for spark machining. An electrical discharge machine with five settings of pulse cycle turn-on and turn-off times, namely 10-10, 30-30, 50-50, 70-70, and 90-90 μs, was used to prepare five different types of GNS-Cu colloids. The ultraviolet-visible spectroscopy results revealed that the highest absorbance (2.441) was observed when the turn-on and turn-off times were 30-30 μs, indicating that this configuration was most efficient for preparing GNS-Cu colloids. Transmission electron microscopy and X-ray diffraction analysis were also conducted to examine the surface characteristics and crystal structure of GNS-Cu colloids. The transmission electron microscopy results revealed that Cu particles in the GNS-Cu colloids were located within or on top of graphene sheets. The Cu particle size varied with the discharge efficiency, and the lattice spacing of the Cu particles was approximately 0.218 nm. The results of X-ray diffraction analysis revealed that no byproducts were formed from the preparation of GNS-Cu colloids, which had complete crystal structures.

This study used an electric discharge machine (EDM) to perform the electrical spark discharge method (ESDM) to prepare a graphene colloid and a graphene-Ag colloid. The characteristic wavelengths of graphene, and graphene-Ag are both 262 nm. They had the properties of high dispersion and are unlikely to aggregate. The XRD patterns of graphene and graphene-Ag are typical carbon diffraction peak angles and crystal orientations. Graphene-Ag in DW can increase the Raman signal intensity of graphene. Regarding the graphene colloid and graphene-Ag colloid, their average sheet resistance values are 0.0329 MΩ/sq and 0.00136 MΩ/sq, respectively. Moreover, when AgNPs composited with graphene layers, the average sheet resistance is only 1/24 that of graphene layers, indicating that graphene-Ag has superior conductivity.

In this study, graphene colloids were prepared using the electric spark discharge method (ESDM) with graphite rods (99.9% purity) in deionized water (DW) at a normal temperature and pressure. Five different types of graphene colloids were prepared using an electrical discharge machine (EDM) with five different pulse cycle switching times (Ton:Toff) = 10:10, 30:30, 50:50, 70:70, and 90:90 μs. According to the Ultraviolet-visible spectra (UV-Vis) and Zetasizer analysis, the results showed that the 10:10 μs parameter was the most suitable for the preparation of graphene colloids. UV-Vis was also used to detect the concentration of the graphene colloids; a comparison with a graphene oxide (GO) confirmed that this method could be used to calculate the discharge time needed to produce graphene colloids with different concentrations in the ESDM process.

PURPOSE This study evaluates the feasibility of our previously developed Respiratory Motion Compensation System (RMCS) combined with the Phase Lead Compensator (PLC) to eliminate system delays during the compensation of respiration-induced tumor motion. The study objective is to improve the compensation effect of RMCS and the efficay of radiation therapy to reduce its side effects to the patients. MATERIAL AND METHODS In this study, LabVIEW was used to develop the proposed software for calculating real-time adaptive control parameters, combined with PLC and RMCS for the compensation of total system delay time. Experiments of respiratory motion compensation were performed using 6 pre-recorded human respiration patterns and 7 sets of different sine waves. During the experiments, a respiratory simulation device, Respiratory Motion Simulation System (RMSS), was placed on the RMCS, and the detected target motion signals by the Ultrasound Image Tracking Algorithm (UITA) were transmitted to the RMCS, and the compensation of respiration induced motion was started. Finally, the tracking error of the system is obtained by comparing the encoder signals bwtween RMSS and RMCS. The compensation efficacy is verified by the root mean squared error (RMSE) and the system compensation rate (CR). RESULTS The experimental results show that the calcuated CR with the simulated respiration patterns is between 42.85% ∼3.53% and 33.76% ∼2.62% in the Right-Left (RL) and Superior-Inferior (SI), respectively, after the RMCS compensation of using the adaptive control parameters in PLC. For the compensation results of human respiration patterns, the CR is between 58.95% ∼8.56% and 62.87% ∼9.05% in RL and SI, respectively. CONCLUSIONS During the respiratory motion compensation, the influence of the delay time of the entire system (RMCS+RMSS+UITA) on the compensation effect was improved by adding an adaptive control PLC, which reduces compensation error and helps improve efficacy of radiation therapy.

In this study, the electric spark discharge method was used to prepare tungsten (W) and tungsten-trioxide (WO3) nanocomposite colloid. A high-energy arc was used to melt a W rod, and the W ions were then ionized with a medium arc to prepare W and WO3 nanocomposite colloid at a high temperature. This preparation method was simple, fast, and effective. The particle size and zeta potential of the samples were measured with a Zetasizer and the shape, size, distribution, and crystal lattice of the W (0.225 nm) and WO3 (0.355 nm) nanoparticles were observed and compared using a Transmission Electron Microscope. The optical properties of the nanocomposite colloids were measured with a UV–visible spectrophotometer (UV–Vis). X-ray diffraction and a Raman Spectrometer were used to detect the crystal properties of the W and WO3 nanoparticles. The results showed that the components of the nanocomposite colloid were W and WO3. The average size of the nanoparticles was 79.65 nm and the zeta potential was − 52.5 mV; thus, the W and WO3 nanoparticles had the suspension effect. There was a peak at 320 nm according to UV–Vis, which is the characteristic absorbance of W and WO3.

This study employed the electrical spark discharge method to prepare platinum iodide nanocolloids at normal temperature and pressure. Wires composed of 99.5% platinum were applied as the electrodes, and 250 ppm liquid iodine was employed as the dielectric fluid. An electric discharge machine was applied to generate cyclic direct current pulse power between the electrodes. Five sets of turn-on and turn-off time (Ton–Toff) parameters, namely 10–10, 30–30, 50–50, 70–70, and 90–90 μs, were implemented to identify the optimal nanocolloid preparation conditions. An ultraviolet-visible spectroscope, a Zetasizer, and a transmission electron microscope were used to examine the nanocolloids' properties. The results revealed that the Ton–Toff parameter set of 10–10 μs was the most ideal setting for platinum iodide nanocolloid preparation. With this parameter set, the characteristic wavelengths of the nanocolloid were 285 and 350 nm, respectively; its absorbance values were 0.481 and 0.425, respectively; and its zeta potential and particle size were −30.3 mV and 61.88 nm, respectively. This parameter set yielded maximized absorbance, satisfactory suspension stability, and minimized nanoparticle sizes for the nanocolloid.

Background The reduction of the delaying effect in the respiratory motion compensation system (RMCS) is still impossible to completely correct the respiratory waveform of the human body due to each patient has a unique respiratory rate. In order to further improve the effectiveness of radiation therapy, this study evaluates our previously developed RMCS and uses the fast Fourier transform (FFT) algorithm combined with the phase lead compensator (PLC) to further improve the compensation rate (CR) of different respiratory frequencies and patterns of patients. Methods In this study, an algorithm of FFT automatic frequency detection was developed by using LabVIEW software, uisng FFT combined with PLC and RMCS to compensate the system delay time. Respiratory motion compensation experiments were performed using pre-recorded respiratory signals of 25 patients. During the experiment, the respiratory motion simulation system (RMSS) was placed on the RMCS, and the pre-recorded patient breathing signals were sent to the RMCS by using our previously developed ultrasound image tracking algorithm (UITA). The tracking error of the RMCS is obtained by comparing the encoder signals of the RMSS and RMCS. The compensation effect is verified by root mean squared error (RMSE) and system CR. Results The experimental results show that the patient's respiratory patterns compensated by the RMCS after using the proposed FFT combined with PLC control method, the RMSE is between 1.50-5.71 and 3.15-8.31 mm in the right-left (RL) and superior-inferior (SI) directions, respectively. CR is between 72.86-93.25% and 62.3-83.81% in RL and SI, respectively. Conclusions This study used FFT combined with PLC control method to apply to RMCS, and used UITA for respiratory motion compensation. Under the automatic frequency detection, the best dominant frequency of the human respiratory waveform can be determinated. In radiotherapy, it can be used to compensate the tumor movement caused by respiratory motion and reduce the radiation damage and side effects of normal tissues nearby the tumor.

BACKGROUND: An ultrasound image tracking algorithm (UITA) was combined with four-dimensional computed tomography (4DCT) to create a real-time tumor motion-conversion model. The real-time position of a lung tumor phantom based on the real-time diaphragm motion trajectories detected by ultrasound imaging in the superior-inferior (SI) and medial-lateral (ML) directions were obtained. METHODS: Three different tumor motion-conversion models were created using a respiratory motion simulation system (RMSS) combined with 4DCT. The tumor tracking error was verified using cone-beam computed tomography (CBCT). The tumor motion-conversion model was produced by using the UITA to monitor the motion trajectories of the diaphragm phantom in the SI direction, and using 4DCT to monitor the motion trajectories of the tumor phantom in the SI and ML directions over the same time period, to obtain parameters for the motion-conversion model such as the tumor center position and the amplitude and phase ratios. RESULTS: The tumor movement was monitored for 90 s using CBCT to determine the real motion trajectories of the tumor phantom and using ultrasound imaging to simultaneously record the diaphragm movement. The absolute error of the motion trajectories of the real and estimated tumor varied between 0.5 and 2.1 mm in the two directions. CONCLUSIONS: This study has demonstrated the feasibility of using ultrasound imaging to track diaphragmatic motion combined with a 4DCT tumor motion-conversion model to track tumor motion in the SI and ML directions. The proposed method makes tracking a lung tumor feasible in real time, including under different breathing conditions.

Electrical discharge machine was used to prepare platinum nanocolloid by electric spark discharge method (ESDM) at room temperature. Preparation of platinum nanocolloid needed only traditional electrical discharge machine, platinum wire (99.5%) and magnet mixer. Then verify whether platinum nanoparticles be could successfully prepared under different preparation and their suspension stability. The optical properties and zeta potential were measured by UV–vis and Zetasizer, and their characteristic peaks (surface plasmon resonant), while suspension stability was analysed. The results of transmission electron microscope showed size, shape and dispersibility of platinum nanoparticles with a size of mostly

This study used deionized water and ammonia (0.02%) as dielectric fluids and then employed electronic discharge machine to ionize them, with the arc-focused energy melting the surface of silver electrode rods. After the condensation of the dielectric fluid, silver nano-colloids were prepared under two conditions, named as Ag and Ag(NH3), respectively. The optical properties of the two samples were compared by a UV–Vis spectrum analyzer (UV–Vis), and the zeta potential was measured by Zetasizer. We then utilized a transmission electron microscope to observe the shape, size, and distribution of silver nanoparticles. The results showed that with the addition of NH3, the size of silver nanoparticles decreased, the concentration of nano-colloid increased, and the dispersive suspension of nano-colloid became better.

The study used arc discharge method (ADM) to produce silver nano-colloid in deionised water (DW), and compared the difference between pre-adding and post-adding of polyvinyl alcohol (PVA). First, they added 50 ppm of PVA into 200 mL silver nano-colloid, named Ag-PVA. Second, they added 50 ppm of PVA into 200 mL DW as the dielectrics and produced silver nano-colloid through it, named PVA-Ag. Then they compared the differences between two samples with several instruments. They examined wavelength and absorbance by using UV–visible spectrophotometer (UV–vis), used Zetasizer to measure particle size and zeta potential, adopted scanning electron microscope (SEM) and transmission electron microscope (TEM) to observe shape, size, and distribution of the silver nanoparticles in the colloid. The results indicated that colloid PVA-Ag had higher zeta potential and better suspension.

Platinum nanoparticles were prepared in ethanol by electric discharge method. The absorption of platinum nano-colloid was measured by UV–Visible Spectrophotometer (UV–Vis). Measurement of Zetasizer showed that the zeta potential is − 40.8 mV, representing the good suspension of platinum nano-colloid with a size of nanoscale. Platinum nano-colloid was identified by X-ray diffraction and Raman spectrometer. Transmission electron microscope (TEM) was used to observe the actual distribution of platinum nanoparticles. The results show that size of platinum nanoparticles are divided into three groups. Size distribution of 3 nm accounts for the majority, which is similar to the results of chemical preparations. The well distribution of platinum nanoparticles was observed clearly without precipitation by TEM.

This study applied an ultrasound image tracking algorithm (UITA) for tracking respiration and developed a 2D dose distribution simulation program (DDSP) for simulating a dose distribution map. We evaluated the feasibility of a 2D respiratory motion simulation system combined with the UITA during radiotherapy for tracking respiration. The recorded respiration signals were input to the DDSP to generate a simulated dose distribution map and verify the effectiveness of the Gafchromic Film EBT3 (EBT3 film) as a measured dose distribution map (MDDM), to validate the DDSP. A radiation dose was delivered to EBT3 film and the film response was quantified using the isodose area rate (IAR), average dose rate within the field (ADFR), conformity index rate (CIR), and gamma passing rate. The tracking performance was evaluated by calculating the root mean squared error (RMSE). The calculated RMSEs were 1.67–5.34 and 0.42–2.53 mm in superior–inferior and right–left directions, respectively. The ADFR was 0.93–1.21 and the IARs at 20, 50, 70, and 80% were 0.87–1.29, 0.84–1.16, 0.79–1.61, and 0.48–6.64, respectively. The CIRs at 50, 70, and 80% were 0.87–1.23, 0.84–1.29, and 0.81–4.40, respectively. The human respiration patterns exhibited a 3%/3 mm gamma passing rate of 76.56–96.94%. This study successfully used an ultrasound imaging system to capture human respiration signals and transmit them to the DDSP for simulating radiation dose distributions, thus demonstrating the feasibility of the system.

This study proposed respiratory motion compensation system (RMCS) combined with an ultrasound image tracking algorithm (UITA) to compensate for respiration-induced tumor motion during radiotherapy, and to address the problem of inaccurate radiation dose delivery caused by respiratory movement. This study used an ultrasound imaging system to monitor respiratory movements combined with the proposed UITA and RMCS for tracking and compensation of the respiratory motion. Respiratory motion compensation was performed using prerecorded human respiratory motion signals and also sinusoidal signals. A linear accelerator was used to deliver radiation doses to GAFchromic EBT3 dosimetry film, and the conformity index (CI), root-mean-square error, compensation rate (CR), and planning target volume (PTV) were used to evaluate the tracking and compensation performance of the proposed system. Human respiratory pattern signals were captured using the UITA and compensated by the RMCS, which yielded CR values of 34–78%. In addition, the maximum coronal area of the PTV ranged from 85.53 mm2 to 351.11 mm2 (uncompensated), which reduced to from 17.72 mm2 to 66.17 mm2 after compensation, with an area reduction ratio of up to 90%. In real-time monitoring of the respiration compensation state, the CI values for 85% and 90% isodose areas increased to 0.7 and 0.68, respectively. The proposed UITA and RMCS can reduce the movement of the tracked target relative to the LINAC in radiation therapy, thereby reducing the required size of the PTV margin and increasing the effect of the radiation dose received by the treatment target.

Electric Discharge Method (EDM) was used to prepare graphene in deionized water which CO2 had been dissolved in advance. According to law of mass conservation, the chemical equation of EDM was balanced to prove the component was graphene. Tyndall effect, ultraviolet–visible spectroscopy (UV–Vis), Zetasizer, Transmission Electron Microscope and Raman were used for the identification of graphene. Then the impact of CO2 concentration on graphene preparation was discussed. The results showed that carbon atoms assemble into forming graphene. And zeta potential of graphene was − 31.6 mV, which indicated good suspension of graphene.

This study used the submerged arc discharge method (SADM) to produce metal fluid containing nanoparticles and submicron particles, whereby the energy focused by an electric arc was used to disintegrate silver (Ag) metal in deionized water (DW). No additional chemical substances were required throughout the process, which enabled production to be fast and straightforward. This study proposed using colorimetry to define the interrelation between concentration and nano Ag as well as the Ag ions (Ag+) within a nano silver colloid (NSC) of a specific dilution factor, involving ultraviolet-visible (UV-Vis) spectroscopy and the measuring of electrical conductivity. The results showed that Ag+ activity increased under various dilution conditions, displaying an upward trend in activity with an increase in the dilution factor. The absorption values of Ag+ and nanoparticles increased over time, and the Ag+ activity increased by up to a factor of two after its dilution. Therefore, the Ag+ and nanoparticles demonstrated an interdependence between each other.

This study developed an in vitro diaphragm motion reproduction system (IVDMRS) based on noninvasive and real-time ultrasound imaging to track the internal displacement of the human diaphragm and diaphragm phantoms with a respiration simulation system (RSS). An ultrasound image tracking algorithm (UITA) was used to retrieve the displacement data of the tracking target and reproduce the diaphragm motion in real time using a red laser to irradiate the diaphragm phantom in vitro. This study also recorded the respiration patterns in 10 volunteers. Both simulated and the respiration patterns in 10 human volunteers signals were input to the RSS for conducting experiments involving the reproduction of diaphragm motion in vitro using the IVDMRS. The reproduction accuracy of the IVDMRS was calculated and analyzed. The results indicate that the respiration frequency substantially affects the correlation between ultrasound and kV images, as well as the reproduction accuracy of the IVDMRS due to the system delay time (0.35s) of ultrasound imaging and signal transmission. The utilization of a phase lead compensator (PLC) reduced the error caused by this delay, thereby improving the reproduction accuracy of the IVDMRS by 14.09-46.98%. Applying the IVDMRS in clinical treatments will allow medical staff to monitor the target displacements in real time by observing the movement of the laser beam. If the target displacement moves outside the planning target volume (PTV), the treatment can be immediately stopped to ensure that healthy tissues do not receive high doses of radiation.

Purpose This study aimed to determine the feasibility of using an ultrasound image tracking algorithm (UITA) combined with a respiration compensating system (RCS) to track and compensate the respiration pattern of the diaphragm in real time. Methods Diaphragm motions and various respiration patterns were tracked and captured in volunteers using our previously developed UITA (Kuo et al., J Xray Sci Technol, 2016:875). A diaphragm phantom was placed on a respiration simulation system (RSS) that received signals with different respiration patterns to simulate actual human respiration signals. The RSS was mounted on the RCS, which is 180 cm long and driven by inputting a compensating signal to a linear actuator underneath with and without using a phase-lead compensator (PLC) (Chuang et al., J Xray Sci Technol, 2015:503). The target displacement was calculated automatically by the UITA and compensated by the RCS. The phantom displacements were observed using a fluoroscopic imaging system on the linear accelerator at the Department of Radiation Oncology, Taipei Medical University Hospital, and the results were also compared with the displacements measured by the UITA and the RSS for correlation verification. In addition, the compensating effect was analyzed after activating the RCS. Results The experimental results indicate a significant correlation between the UITA-calculated and actual displacements, with a correlation coefficient of up to 91% for the simulated respiration patterns. After activating the RCS, the obtained compensating effect was more than 65%, and even up to 85% if a PLC was used. Moreover, the compensation of 10 extreme respiration patterns of diaphragm was improved significantly through the use of a PLC, with a peak compensating rate of 88.92% being achieved. Finally, compensation effects ranging from 52% to 74% were obtained in 10 human volunteers. Conclusions This study combined ultrasound imaging tracking technology with the RCS to offset the respiration-induced diaphragm displacement and compensate the various respiration patterns, even including those with baseline-shift phenomenon in real time with the aid of a noninvasive ultrasound imaging system.

Purpose This study used an ultrasound image tracking algorithm (UITA) in combination with a proposed simulation program for the approximate irregular field dose distribution (SPAD) to assess the feasibility of performing dose distribution simulations for two-dimensional radiotherapy. Methods This study created five different types of multileaf collimator openings, and applied a SPAD to analyze the matrix position parameters for each regular field to generate a static program-simulation dose distribution map (PDDM), whose similarity was then compared with a static radiochromic film experimental-measurement dose distribution map (EDDM). A two-dimensional respiration motion simulation system (RMSS) was used to reproduce the respiration motion, and the UITA was used to capture the respiration signals. Respiration signals were input to the SPAD to generate two dynamic PDDMs, which were compared for similarity with the dynamic EDDM. Results In order to verify the dose distribution between different dose measurement techniques, the gamma passing rate with 2%/2 mm criterion was used for the EDDM and PDDM, the passing rates were between 94.31% and 99.71% in the static field analyses, and between 84.45% and 96.09% for simulations with the UITA signal input and between 89.35% and 97.78% for simulations with the original signal input in the dynamic field analyses. Conclusions Static and dynamic dose distribution maps can be simulated based on the proposed matrix position parameters of various fields and by using the UITA to track respiration signals during radiation therapy. The present findings indicate that it is possible to develop a reusable and time-saving dose distribution measurement tool.

Using the electrical spark discharge method, this study prepared a nano-Ag colloid using self-developed, microelectrical discharge machining equipment. Requiring no additional surfactant, the approach in question can be used at the ambient temperature and pressure. Moreover, this novel physical method of preparation produced no chemical pollution. This study conducted an in-depth investigation to establish the following electrical discharge conditions: gap electrical discharge, short circuits, and open circuits. Short circuits affect system lifespan and cause electrode consumption, resulting in large, non-nanoscale particles. Accordingly, in this study, research for and design of a new logic judgment circuit set was used to determine the short-circuit rate. The Ziegler&ndash, Nichols proportional&ndash, integral&ndash, derivative (PID) method was then adopted to find optimal PID values for reducing the ratio between short-circuit and discharge rates of the system. The particle size, zeta potential, and ultraviolet spectrum of the nano-Ag colloid prepared using the aforementioned method were also analyzed with nanoanalysis equipment. Lastly, the characteristics of nanosized particles were analyzed with a transmission electron microscope. This study found that the lowest ratio between short-circuit rates was obtained (1.77%) when PID parameters were such that Kp was 0.96, Ki was 5.760576, and Kd was 0.039996. For the nano-Ag colloid prepared using the aforementioned PID parameters, the particle size was 3.409 nm, zeta potential was approximately &minus, 46.8 mV, absorbance was approximately 0.26, and surface plasmon resonance was 390 nm. Therefore, this study demonstrated that reducing the short-circuit rate can substantially enhance the effectiveness of the preparation and produce an optimal nano-Ag colloid.

This paper uses Electrical Discharge Machining (EDM), Submerged Arc Discharge Method (SADM), and arc concentrated energy to ionize the medium of DI water. During submerged arc discharge, the silver metal surface melts and is condensed into a metal fluid containing Nano and Sub-micron particles by DI water after high temperature vaporization. There is no chemical byproduct produced in the process, and it is characterized by a simple and rapid process and green preparation. The procedure of this study runs as follows: (1) 200ml DI water is prepared as dielectric fluid; during submerged arc discharge, the electrode silver bar is molten in this dielectric fluid to prepare the Nano-Ag colloid; (2) 150ml DI water containing 5ml Nh3 is used as a dielectric fluid; the electrode silver bar is molten by a submerged arc discharge in this dielectric fluid to prepare the Nano-Ag colloid (Nh3-Ag) to be different from the former one. The two kinds of Nano-Ag colloid are analyzed by a UV-Vis spectrum analyzer and Zetasizer so as to work out the relationship between the surface plasmon resonance generated wavelength and absorbance. The Nano-Ag colloid derived from Nh3-Ag is compared with the Nano-Ag colloid derived from Ag. The Nh3-Ag particles have good stability, and the concentration and Zeta potential are increased.

The purpose of this study is to assess the feasibility of using the analytical technique of ultrasound images in combination with an auto tumor localization system. During respiration, the activity of breathing in and out causes organs displacement at the lower lobe of the lung, and the maximum displacement range happens in the Superior-Inferior (SI) direction. Therefore, in this study all the tumor positioning is in SI direction under respiratory compensation, in which the compensations are carried out to the organs at the lower lobe and adjacent to the lower lobe of lung.In this research, due to the processes of ultrasound imaging generation, image analysis and signal transmission, when the captured respiratory signals are sent to auto tumor localization system, there was a signal time delay. The total delay time of the entire signal transmission process was 0.254 ± 0.023 seconds (with the lowest standard deviation) after implementing a series of analyses. To compensate for this signal delay time (0.254 ± 0.023 sec), a phase lead compensator (PLC) was designed and built into the auto tumor localization system. By analyzing the impact of the delay time and the respiratory waveforms under different frequencies on the phase lead compensator, an overall system delay time can be configured. Results showed as the respiratory frequency increased, variable value ``a'' and the subsequent gain ``k'' in the controller becomes larger. Moreover, value ``a'' and ``k'' increased as the system delay time increased when the respiratory frequency was fixed. The relationship of value ``a'' and ``k'' to the respiratory frequency can be obtained by using the curve fitting method to compensate for the respiratory motion for tumor localization. Through the comparison of the uncompensated signal and the compensated signal performed by the auto tumor localization system on the simulated respiratory signal, the feasibility of using ultrasound image analysis technology combined with the developed auto tumor localization system can be evaluated. The results show that the simulated respiratory signals under different frequencies of 0.5, 0.333, 0.25, 0.2 and 0.167 Hz with phase lead compensators were improved and stabilized. The compensation rate increased to the range of 7.04$∼ $18.82%, and the final compensation rate is about 97%. Therefore the auto tumor localization system combined with the ultrasound image analysis techniques is feasible.In this study, the developed ultrasound image analysis techniques combined into the auto tumor localization system has the following four advantages: (1) It is a non-invasive way (ultrasonic images) to monitor the entire compensating process of the active respiration instead of using a C-arm (invasive) to observe the organs motion. (2) During radiation therapy, the whole treatment process can be continuous, which can save the overall treatment time. (3) It is an independent system, which can be mounted onto any treatment couch. (4) Users can operate this system easily without the need of prior complicated training process.

This study developed a system monitoring the electric discharge machine's (EDM) discharge energy and success rate to replace conventional oscilloscope observation. By using logic circuit, the signals are transmitted to the PC monitoring platform in order to display the discharge success times, discharge success rate, and electrode's consumption energy. The advantage of the proposed system is the capability to observe real-time discharges and record the experimental conditions, as well as optimize the discharge parameter settings. The experimental results suggest that, in the preparation of nanosilver colloid, the cost-performance of Ton–Toff at 10–100 µs is the optimal setting. The monitoring system also can take advantage of the discharge success rate to control the energy consumption of the electrode to obtain the standardization of products. The results suggest that, while discharge success rate, electrode's weight loss and wavelength of the absorption peak are considerably accurate, but concentration ...

Purpose: The purpose of this study was to determine if it is feasible to use ultrasound imaging as an aid for moving the treatment couch during diagnosis and treatment procedures associated with radiation therapy, in order to offset organ displacement caused by respiratory motion. A noninvasive ultrasound system was used to replace the C-arm device during diagnosis and treatment with the aims of reducing the x-ray radiation dose on the human body while simultaneously being able to monitor organ displacements. Methods: This study used a proposed respiratory compensating system combined with an ultrasound imaging system to monitor the compensation effect of respiratory motion. The accuracy of the compensation effect was verified by fluoroscopy, which means that fluoroscopy could be replaced so as to reduce unnecessary radiation dose on patients. A respiratory simulation system was used to simulate the respiratory motion of the human abdomen and a strain gauge (respiratory signal acquisition device) was used to capture the simulated respiratory signals. The target displacements could be detected by an ultrasound probe and used as a reference for adjusting the gain value of the respiratory signal used by the respiratory compensating system. This ensured that the amplitude of the respiratory compensation signalmore » was a faithful representation of the target displacement. Results: The results show that performing respiratory compensation with the assistance of the ultrasound images reduced the compensation error of the respiratory compensating system to 0.81–2.92 mm, both for sine-wave input signals with amplitudes of 5, 10, and 15 mm, and human respiratory signals; this represented compensation of the respiratory motion by up to 92.48%. In addition, the respiratory signals of 10 patients were captured in clinical trials, while their diaphragm displacements were observed simultaneously using ultrasound. Using the respiratory compensating system to offset, the diaphragm displacement resulted in compensation rates of 60%–84.4%. Conclusions: This study has shown that a respiratory compensating system combined with noninvasive ultrasound can provide real-time compensation of the respiratory motion of patients.« less

This study proposes a respiratory compensating system which is mounted on the top of the treatment couch for reverse motion, opposite from the direction of the targets (diaphragm and hemostatic clip), in order to offset organ displacement generated by respiratory motion. Traditionally, in the treatment of cancer patients, doctors must increase the field size for radiation therapy of tumors because organs move with respiratory motion, which causes radiation‐induced inflammation on the normal tissues (organ at risk (OAR)) while killing cancer cells, and thereby reducing the patient's quality of life. This study uses a strain gauge as a respiratory signal capture device to obtain abdomen respiratory signals, a proposed respiratory simulation system (RSS) and respiratory compensating system to experiment how to offset the organ displacement caused by respiratory movement and compensation effect. This study verifies the effect of the respiratory compensating system in offsetting the target displacement using two methods. The first method uses linac (medical linear accelerator) to irradiate a 300 cGy dose on the EBT film (GAFCHROMIC EBT film). The second method uses a strain gauge to capture the patients' respiratory signals, while using fluoroscopy to observe in vivo targets, such as a diaphragm, to enable the respiratory compensating system to offset the displacements of targets in superior‐inferior (SI) direction. Testing results show that the RSS position error is approximately 0.45 ~ 1.42 mm, while the respiratory compensating system position error is approximately 0.48 ~ 1.42 mm. From the EBT film profiles based on different input to the RSS, the results suggest that when the input respiratory signals of RSS are sine wave signals, the average dose (%) in the target area is improved by 1.4% ~ 24.4%, and improved in the 95% isodose area by 15.3% ~ 76.9% after compensation. If the respiratory signals input into the RSS respiratory signals are actual human respiratory signals, the average dose (%) in the target area is improved by 31.8% ~ 67.7%, and improved in the 95% isodose area by 15.3% ~ 86.4% (the above rates of improvements will increase with increasing respiratory motion displacement) after compensation. The experimental results from the second method suggested that about 67.3% ~ 82.5% displacement can be offset. In addition, gamma passing rate after compensation can be improved to 100% only when the displacement of the respiratory motion is within 10 ~ 30 mm. This study proves that the proposed system can contribute to the compensation of organ displacement caused by respiratory motion, enabling physicians to use lower doses and smaller field sizes in the treatment of tumors of cancer patients. PACS number: 87.19. Wx; 87.55. Km

The colloidal silver solution was successfully prepared in dielectric fluid by using electrical spark discharge (ESD) without any surfactants. It does not require the toxic chemical agents in the process, which may affect the effectiveness of nanosilver colloid as an antibacterial agent. Nanocolloidal silver produced by ESD is characterized as low cost, zero environmental pollution, continuous, and rapid mass production process. In order to test the effect of antibioactivity, nanosilver dough was tested; the silver nanofluid was prepared by ESD machine, made into dough at different concentrations, and fermented for three hours in order to observe changes in the diameter of the dough. The results showed that the effect of effectiveness of nanosilver at the concentration of 100 ppm was weak, whereas the effect of 60 ppm silver ion (100 ppm AgNO3) was significant, as the dissociation rate of silver ion concentration correlates to the antibioactivity.

This study used the submerged arc discharge method (SADM) to produce metal fluid containing nanoparticles and submicron particles, whereby the energy focused by an electric arc was used to dissolve silver metal in deionised water. No additional chemical substances were required throughout the process, which enabled production to be fast and straightforward. Conventional concentration measurement of silver ions (Ag+) uses 200 ml of sample solution for every test wherein the Ag+ revert to atoms, resulting in the incapacity of the solution to be reused. This study devised a new quantification method that requires only a trace amount (6 ml) of Ag+ solution and used equations and data from electrical conductivity, concentration and ultraviolet-visible (UV-Vis) absorption values to determine their respective relationships with Ag+ concentration, after which the solution can still be reused.

The adhesion behavior of di-n-butyl phthalate (DBP) onto different substrates (quartz, glass, and silicon) used as wafer surfaces was studied by using an in situ UV spectrophotometric technique. The results from the closed cell experiments revealed that greatest extent of DBP adhesion occurred on the quartz chip (0.154 μg cm−2), followed in the order by the glass (0.054 μg cm−2) and silicon (0.039 μg cm−2). By means of the in situ spectrophotometric observation, application of an electrical field at 290 V cm−1 in the cell proved to be effective in inducing charging of DBP aerosols, which were consequently attracted towards the electrodes. This method can be applied to wafer storage and transport equipments to prevent wafer contamination from material outgassing representative by DBP.

In this study, submerged arc discharge method (SADM) was used to prepare graphene-nanosilver composites (graphene impregnated with nanosilver) and verified whether it can be prepared under different methods. The optical properties, zeta potentials, and particle sizes of the composites were analyzed through ultraviolet–visible spectroscopy and Zetasizer. The suspensibility of composites were much better than that of noncomposites. Then, we compared the components of composites and noncomposites through transmission electron microscopy. The results confirmed that even when fabricated from similar materials, the composites and noncomposites yielded by SADM featured significantly different properties.

The study of nanoparticles has become a target of major interest in science. Metallic silver nanoparticles (Ag0) and ionic silver (Ag+) are the future of the post-antibiotic era, with the latter playing perhaps the central role in this fight. Traditional chemical synthesis methods for colloidal silver (CS) may lead to the presence of toxic chemical species or chemical residues, which may inhibit the effective authentication of CS as an antibacterial agent. To counter these problems a good alternative method—electric spark discharge system (ESDS) was used to fabricate a silver nanoparticles suspension in deionized water with no added chemical additives. Most related research in this field is confined to exploring the composition of nanoparticle, ignoring ions. However, we aim to identify and quantify the proportion of ionic silver in ESDS-CS. The results reveal that ESDS-CS contains both metallic silver nanoparticles and ionic silver. Furthermore, the antimicrobial affect of ESDS-CS on Staphylococcus aureus was also studied. The experimental data suggest that CS solutions with an ionic silver concentration of 30 ppm or higher are strong enough to eliminate S. aureus. In addition, it was found that a solution's antimicrobial potency is directly related to its level of silver ion concentration.

A new method using the arc discharge method (ADM) to synthesize gold nanoparticles in an anhydrous ethanol was studied. Fabricated gold nanoparticles were characterized by different techniques. Unlike conventional methods for metal nanoparticles synthesis, the ADM method does not require application of chemical surfactants and stabilizers. The microstructure of ADM-produced gold nanoparticles was examined by transmission electron microscope (TEM) and scanning electron microscope (SEM). The particle size was found in the range of 2–40 nm. The chemical composition of gold nanoparticles has been confirmed by the energy dispersive X-ray analysis (EDX). The crystal structure of the nanoscale gold particles was studied using the X-ray diffraction (XRD) method. Images of the gold nanoparticles, Zeta potential, size distribution, and ultraviolet–visible (UV–vis) absorbance were investigated. This innovative approach for gold nanoparticles preparation has been successfully established. The experimental results showed that the ADM technique is easy, cheap and clean method which can be used to manufacture gold nanoparticles suspended in ethanol solution without any surfactant.

As a result of mankind’s over-reliance on antibiotics, germs are becoming more drug-resistant every year. The gradual but inexorable decline in the efficacy of traditional antibiotics is forcing scientists and doctors to search for new weapons in the fight against germs. Metallic silver nanoparticle (Ag 0 ) and ionic silver (Ag + ) are the future of the post-antibiotic era, with the latter playing perhaps the central role in this fight. Using the arc discharge method (ADM), our research has allowed us to fabricate silver nanoparticle suspension (SNPS) in deionized water with no added surfactants. Most related research in this field is confined to explore the composition of nanoparticle, ignoring ions. However, we aim to identify and measure the proportion of ionic silver in ADM-SNPS, using conductivity meters, centrifuges, titrator, and atomic absorption spectrophotometer (AA). The results of our experiments show that SNPS fabricated by means of ADM with no added surfactants contains metallic silver nanoparticle and ionic silver. The fabrication consumes silver rods at a rate of 100 mg/min, yielding metallic silver nanoparticle and ionic silver with concentrations of approximately 11 ppm and 19 ppm, respectively. © 2007 Elsevier B.V. All rights reserved.

In this paper a method of spark discharge method (SDM) for producing gold nanoparticles in organic or inorganic medium (pure ethanol/deionized water) is proposed. The microstructure of SDM-produced gold nanoparticles was examined by Transmission Electron Microscopy. The crystal structure and surface plasmon resonance of the nanoscale gold particles were studied using X-ray diffraction and UV–Visible spectroscopy. Zeta potential analysis showed that negative charges on the particle surface may be contributing to the stability of the suspension. The experiment's results revealed that SDM is an alternative process to synthesize gold nanoparticle suspension with different particle sizes and shapes in different media without any surfactant.

Gold nanoparticles have been attracting attention due to their extensive application in chemistry, physics, material science, electronics, catalysis and bionanotechnology. Synthesis of gold nanoparticles often involves toxic and expensive physical-chemistry methods. Preparation of gold nanoparticles by arc discharge in water is proposed for the first time. Fabrication of gold nanostructures in deionized water has been successfully established. The evidence of gold particles’ light absorbance reveals a unique surface plasmon resonance for Au nanoparticles suspended in deionized water. Gold nanostructures uniformly dispersed in water, their UV–Vis absorption and crystalline size are shown. Our experimental results demonstrate that fabrication of gold nanoparticles by arc discharge in water is an alternative, cheap, effective and environmentally friendly method.

The advantage of applying the EDM (electric discharge machine) in the preparation of nano-fluids is that it does not require chemicals, unlike other nano-manufacturing methods that use chemicals to increase particle stability. Moreover, the operation of EDM is simple and without complex processes. This study proposes a discharge success rate measurement system to determine discharge effectiveness and seek the optimal discharge control parameter settings. Its advantage is the ability to observe the success rate curve every 0.1 seconds to learn the discharge quality. Studies of nano silver have suggested that the same duty cycle, shorter discharge, and repose can result in a higher success rate. When Ton uses 10μs as the fixed value, and only the ratio of Toff increases, the success rate of 10–100μs is the highest. Without the pursuit of processing speed, the setting of 10–100μs of a high discharge success rate is the optimal parameter setting.

This study proposed the principle of spark discharge using an EDM system programmable controller as the control core, and further explored the process optimization of nano metal particles. The proposed system was used to change the discharge pulse cycle time and verify the results by spectrophotometer. Its purpose was to increase the concentration, as well as the degree of dispersion and mean particle size of nano metal fluids, in order to improve the potency of future applications. According to the above EDM process parameter optimization, nano silver has the optimal control parameters in the discharge cycle 30–30us; while nano copper has the optimal control parameters in the discharge cycle 10–10us. This study realized the advantages of no addition of other chemicals, simple low-cost process, and potential for continuous mass production for the pursuit of long time (over one year) stable suspension of pure nano metal fluids in deionized water.

The purpose of this study was to determine if it is feasible to use ultrasound imaging as an aid for moving the treatment couch during diagnosis and treatment procedures associated with radiation therapy, in order to offset organ displacement caused by respiratory motion. A noninvasive ultrasound system was used to replace the C-arm device during diagnosis and treatment with the aims of reducing the x-ray radiation dose on the human body while simultaneously being able to monitor organ displacements.This study used a proposed respiratory compensating system combined with an ultrasound imaging system to monitor the compensation effect of respiratory motion. The accuracy of the compensation effect was verified by fluoroscopy, which means that fluoroscopy could be replaced so as to reduce unnecessary radiation dose on patients. A respiratory simulation system was used to simulate the respiratory motion of the human abdomen and a strain gauge (respiratory signal acquisition device) was used to capture the simulated respiratory signals. The target displacements could be detected by an ultrasound probe and used as a reference for adjusting the gain value of the respiratory signal used by the respiratory compensating system. This ensured that the amplitude of the respiratory compensation signal was a faithful representation of the target displacement.The results show that performing respiratory compensation with the assistance of the ultrasound images reduced the compensation error of the respiratory compensating system to 0.81-2.92 mm, both for sine-wave input signals with amplitudes of 5, 10, and 15 mm, and human respiratory signals; this represented compensation of the respiratory motion by up to 92.48%. In addition, the respiratory signals of 10 patients were captured in clinical trials, while their diaphragm displacements were observed simultaneously using ultrasound. Using the respiratory compensating system to offset, the diaphragm displacement resulted in compensation rates of 60%-84.4%.This study has shown that a respiratory compensating system combined with noninvasive ultrasound can provide real-time compensation of the respiratory motion of patients.

A green method, using pulsed spark discharge (PSD) to synthesize colloidal gold, is studied in this thesis. PSD uses spark discharge to synthesize gold nanoparticles (AuNPs) in deionized water (DIW) and/or ethanol (EtOH). While gold nanoparticles have widespread applications in many fields, especially for the human body, in use them must overcome the influence of NaCl and pH value; therefore, this study adds NaCl into PSD-AuNPs to simulate the human body to study its stability. Furthermore, a variety of protectants are added in an attempt to determine the best protectant for AuNPs and improve biologically compatible potency. From the results of this study, adding the long-chain-polymer Carboxymethyl cellulose (CMC) or Polyvinyl pyrrolidone (PVP-k30) can prevent nanogold from aggregation and precipitation in NaCl or different pH value and maintain the characteristic of nanogold dispersion by raising the repulsive force between the particles. The results of this study can be a reference of nanogold applying in biomedical science.

This study aims to investigate the temperature effect on particle size of copper oxide nanofluid produced under optimal parameters of the Arc Spray Nanoparticle Synthesis System (ASNSS) developed in this research. The purpose is to understand the aggregation feature of copper oxide nanofluid in a higher-than-room-temperature environment and to analyze its size change and the motion behavior of suspended nanoparticles. This study employs an ambient temperature controller to maintain the environment temperature within the scope of normal fluid work temperature to obtain data on the change in suspended particles of copper oxide nanofluid under varying temperatures and through change of time. Experimental result shows that the particle size distribution of copper oxide nanofluid changes when the temperature rises due to the slight absorption and aggregation phenomena between particles, and that the change in environmental temperature can accelerate the aggregation of copper oxide nanofluid, which can affect its stability in application. However, the change in particle size distribution will gradually stabilize for a longer duration of constant temperature.

Many methods of producing colloidal silver (CS) include the introduction of surfactants to improve the suspensivity of the silver particles. The electric spark discharge method (ESDM) which involves pulses of direct current being passed through a silver electrode submerged in deionized water has been shown to successfully produce colloidal silver in a stable suspension without the use of chemical additives. A by-product of the electric spark discharge method, a silver ion compound (AgX), is shown to be the cause of the high suspensivity of the silver nanoparticles (AgNPs). The silver ion compound has been identified as Ag 2 CO 3 using X-ray diffraction, and it has been determined that the Ag 2 CO 3 is formed during the electric spark discharge process through a reaction with atmospheric CO 2 . It has been shown that an Ag 2 CO 3 concentration of 10 ppm or more is sufficient to generate a stable suspension of silver particles. Because of the occurrence of Ag 2 CO 3 , the electric spark discharge method can produce stable colloidal silver.

Extremely high financial support has been provided to different scientific institutes due to a world priority to find new kinds of energy sources. This has a clear strategic importance for the energy industry. Hydrogen is the most energetic material known and safe for our environment. However, it creates a lot of problems to achieve safe, effective and reversible storage. Some of the theoretical simulations show that carbon nanotubes (CNTs) and/or CNTs hybrid systems could be quite promising material for hydrogen storage. To study a new carbon material for gas adsorption–desorption properties the ultra-high vacuum (UHV) system is proposed here.

This study evaluated the tumor targeting and therapeutic efficacy of a novel theranostic agent (131)I-labeled immuno-gold-nanoparticle ((131)I-C225-AuNPs-PEG) for high epidermal growth factor receptor (EGFR)-expressed A549 human lung cancer. Confocal microscopy demonstrated the specific uptake of C225-AuNPs-PEG in A549 cells. (131)I-C225-AuNPs-PEG induced a significant reduction in cell viability, which was not observed when incubated with AuNPs-PEG and C225-AuNPs-PEG. MicroSPECT/CT imaging of tumor-bearing mice after intravenous injection of (123)I-C225-AuNPs-PEG revealed significant radioactivity retention in tumor suggested that (131)I-labeled C225-conjugated radioimmuno-gold-nanoparticles may provide a new approach of targeted imaging and therapy towards high EGFR-expressed cancers.