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The 5G sub-6 GHz radio frequency (RF) electromagnetic fields (EMF) are the most widely used in China's communications. The public has expressed concerns about possible brain health effects of the higher frequency bands in 5G compared to 2G, 3G, and 4G bands. It is imperative to empirically investigate the potential health hazards of these novel frequency bands in 5G communication technology. This study evaluates the assessment of brain tissue dose coupling from sub-6 GHz band EMF emitted by base stations in China. Based on the 3D virtual human body model, the simulation environment was established. Dose including specific absorption rate (SAR) and internal electric field (IEF) between 2G, 3G, and 4G bands and 5G sub-6 GHz was investigated using normalized exposure values and exposure limits. The results indicate that the sub-6 GHz high-frequency band of 5G has the lowest dose value. It can be concluded that high-frequency electromagnetic radiation in 5G sub-6 GHz reduces the dose and health threats to the brain. This provides strong support for the promotion of 5G commutation in China and other regions. [ABSTRACT FROM AUTHOR]

Radiofrequency thermocoagulation (RFTC) of the peripheral branches of the trigeminal nerve has been used for trigeminal neuralgia. However, the long-term outcomes of radiofrequency thermocoagulation have not been established. To evaluate the long-term efficacy of RFTC of peripheral branches in patients with refractory trigeminal neuralgia. A retrospective cohort study was conducted in a comprehensive medical center in China. Patients who underwent radiofrequency thermocoagulation of peripheral branches for refractory trigeminal neuralgia from May 2014 to March 2021 were included for analysis. A total of 84 patients with refractory trigeminal neuralgia underwent 105 procedures. BNI I–II which represents treatment success was achieved in 76/84 (90%) patients and 93/105 (89%) procedures. During follow-up, BNI I and II were maintained in 64/76 (84%), 40/73 (55%), 20/67 (30%), 17/65 (26%), 12/61 (20%), and 8/58 (14%) of patients at 1, 2, 3, 4, 5, and 6 years, after the first procedure, respectively. For all the 105 procedures, BNI I and II were maintained in 68/93 (73%), 41/89(46%), 22/82(27%), 15/79 (19%), 8/74 (11%), and 3/72 (4%) at 1, 2, 3, 4, 5, and 6 years, respectively. There is no significant difference between the first and repeat thermocoagulation in terms of immediate (90% vs. 81%, P=0.140) and long-term efficacies (24 months vs.18 months, P=0.266). Radiofrequency thermocoagulation resulted in better long-term outcomes in patients with typical purely paroxysmal pain (24 months vs. 11 months, P=0.033). Radiofrequency ablation of the peripheral branches of the trigeminal nerve might be a safe and effective method in the treatment of refractory trigeminal neuralgia. [ABSTRACT FROM AUTHOR]

Background: To evaluate the efficacy and safety of novel plasma radio frequency generator and its single-use polypectomy snares for endoscopic mucosal resection (EMR) of gastrointestinal (GI) polyps. Methods: A total of 217 patients with 413 GI polyps were recruited from four centers in China. Patients were assigned to experimental or control groups using a central randomization method. The experimental group used the novel plasma radio frequency generator and its matched single-use polypectomy snares (Neowing, Shanghai), while the control group used the high-frequency electrosurgical unit (Erbe, Germany) and disposable electrosurgical snares (Olympus, Japan). The primary endpoint was the en bloc resection rate, and the non-inferiority margin was set at 10%. Secondary endpoint included operation time, coagulation success rate, intraoperative and postoperative bleeding rate, and perforation rate. Results: The en bloc resection rate was 97.20% (104/107) in the experimental group and 95.45% (105/110) in the control group (P = 0.496). The operation time was 29.14 ± 20.21 min in the experimental group and 30.26 ± 18.74 min in the control group (P = 0.671). The average removal time of a single polyp in the experimental group was 7.52 ± 4.45 min, which was slightly shorter than that in the control group 8.90 ± 6.67 min, with no statistical difference (P = 0.076). The intraoperative bleeding rates of the experimental group and control group were 8.41% (9/107) and 10.00% (11/110), respectively (P = 0.686). No intraoperative perforation occurred in either group. The postoperative bleeding rates of the experimental group and the control group were 1.87% (2/107) and 4.55% (5/110), respectively (P = 0.465). No postoperative perforation occurred in the experimental group (0/107), while one case of delayed perforation occurred in the control group (1/110, 0.91%). There was no statistical difference between the two groups. Conclusions: Endoscopic mucosal resection of GI polyps with the novel plasma radio frequency generator is safe and effective, and non-inferior to the conventional high-frequency electrosurgical system. [ABSTRACT FROM AUTHOR]

With the rapid development of satellite internet, the shortage of bandwidth and spectrum resources has become increasingly prominent. Satellite laser communication has the characteristics of large bandwidth and no spectrum constraints, which makes it an effective means to alleviate the shortage of radio frequency resources and improve the communication bandwidth. Through the investigation of the development of satellite laser communication at home and abroad, this paper summarizes the future technical development trend in this field. The key technologies such as network reconstruction and efficient coding are studied via simulation, which provide theoretical and technical reference for the research of satellite laser communication in China. [ABSTRACT FROM AUTHOR]

Fine particulate matter (PM2.5) is a major pollutant in Guanzhong Urban Agglomeration (GUA) during the winter, and GUA is one of China's regions with the highest concentrations of PM2.5. Daily surface PM2.5 maps with a spatial resolution of 1 km × 1 km can aid in the control of PM2.5 pollution. Thus, the Random Forest and eXtreme Gradient Boosting (RF-XGBoost) model was proposed to fill the missing aerosol optical depth (AOD) at the station scale before accurately estimating ground-level PM2.5 using the recently released MODIS AOD product derived from Multi-Angle Implementation of Atmospheric Correction (MAIAC), high density meteorological and topographic conditions, land-use, population density, and air pollutions. The RF-XGBoost model was evaluated using an out-of-sample test, revealing excellent performance with a coefficient of determination (R2) of 0.93, root-mean-square error (RMSE) of 12.49 μg/m3, and mean absolution error (MAE) of 8.42 μg/m3. The result derived from the RF-XGBoost model indicates that the GUA had the most severe pollution in the winter of 2018 and 2019, owing to the burning of coal for heating and unfavorable meteorological circumstances. Over 90% of the GUA had an annual average PM2.5 concentrations decrease of 3 to 7 μg/m3 in 2019 compared to the previous year. Nevertheless, the air pollution situation remained grim in the winter of 2019, with more than 65% of the study area meeting the mean PM2.5 values higher than 35 μg/m3 and the maximum reaching 95.57 μg/m3. This research would be valuable for policymakers, environmentalists, and epidemiologists, especially in urban areas. [ABSTRACT FROM AUTHOR]

The China Spallation Neutron Source project Phase-II aims to deliver 500 kW beam power to the spallation target. To meet the beam power requirement, an RF-driven negative hydrogen ion source with an external-antenna has been developed. In order to optimize the beam transmission through the radio frequency quadrupole and the downstream linac, the low energy beam transport line needs to be carefully studied and the transverse emittance is focused in this paper. With computational simulation and experimental verification, the emittance growth caused by nonlinear magnetic fields of the solenoid and the residual magnetic fields at the measuring position has been carefully analyzed. The measurement uncertainty of the double-slit scanner has also been quantitatively estimated. Using the same plasma-beam boundary setting, the beam extraction system is also optimized with particle tracking simulation in CST PARTICLE STUDIO. [ABSTRACT FROM AUTHOR]

When CubeSat projects are a useful means by which universities can engage their students in space-related activities. TURKSAT-3USAT is a three-unit amateur radio CubeSat jointly developed by the Space Systems Design and Test Laboratory and the Radio Frequency Electronics Laboratory of Istanbul Technical University (ITU), in collaboration with TURKSAT, A.S. company as well as the Turkish Amateur Technology Organization. It was launched on April 26, 2013 as a secondary payload on a CZ-2D rocket from China's Jiuquan Space Center to an altitude of approximately 680 km. The mission of the satellite has two primary goals: (1) to voice communication at Low Earth Orbit (LEO) and (2) to educate students by providing hands-on experience. TURKSAT-3USAT was designed to sustain a circular, near sun-synchronous LEO, and has dimensions of 10 x 10 x 34 cm3. Within the course of this paper, TURKSAT-3USAT's thermal control will be addressed. TURKSAT-3USAT's thermal control model was developed using ThermXL and ESATAN-TMS software. Using this model, temperature distributions of the CubeSat when subjected to various experimental conditions of interest were computed. Using a thermal vacuum chamber (TVAC), thermal cycling and bake-out testing were carried out on the flight model to verify the thermal design performance and check the mathematical model. Based on thermal analysis results, the temperature of equipment was within the allowable temperature range except for the batteries that were between 42.56 oC and -20.31 oC. Heaters were used for the batteries in order to maintain the batteries' temperature within the allowable temperature range. [ABSTRACT FROM AUTHOR]

A radiofrequency (RF) ion source with a megawatt power extraction, thunder I, has been developed for the neutral beam injector (NBI) on HL-2A tokamak. A full solid-state RF generator with output power of 80 kW and frequency of 2 MHz was built by an RF combiner using 8 modules of solid-state RF generator with power of PRF = 10 kW. The line electric efficiency of whole RF generator reaches 92% and its voltage standing wave ratio (VSWR) is 1.01, thus no water-cooling system is supplied. A quartz vessel with the inner diameter of 250 mm is directly adopted for resisting atmospheric pressure, which can dramatically simplify source structure. Nowadays, the extracted beam parameters of RF hydrogen ion source are 32 kV/20 A/0.1 s on a test bed, while the design parameters are 50 kV/20 A/3 s. The beam density profile measured by the infrared imaging technique at 1.3 m downstream from the grounded grid obeys a Gaussian distribution, and the corresponding half width of 1/e power decay at the matched condition is about 80 mm. Plasma homogeneity is over 90% at low RF power. The beam divergence angle meets the requirement of NBI system on HL-2A tokamak. The extractable current density increases almost linearly with the RF power. It reaches 2400 A m−2 at PRF = 32 kW. The ion density in front of plasma grid is about 1 × 1018 m−3, corresponding to an ionized fraction of about 1% at the gas pressure of 0.5 Pa. Single hydrogen ion fraction reaches 79% at the beam current of 12.4 A. Some improvements have been considered for optimizing ion source performance on next experimental campaign. One smaller auxiliary RF discharge chamber equipped with a gas feed path, driven by 13.56 MHz/3.5 kW generator, is connected to main discharge chamber driven by 2 MHz/40 kW generator. By this dual-driven configuration, the innovative RF plasma source with high-pressure density gradient solves the initial ignition problem of powerful RF ion source even if the gas pressure below 0.1 Pa. In addition, the RF negative hydrogen ion source of 200 kV/20 A/3600 s is also developed at SWIP for the China fusion engineering test reactor. [ABSTRACT FROM AUTHOR]

At present, most oilfields in China have entered the late stage of oil recovery, and the water content of crude oil has increased significantly, which has brought new challenges to the measurement of water content. For the problem of real-time measurement of water content of crude oil, this paper proposes a new method of water content measurement by radio frequency method under oil-water two-phase spiral flow. First, the oil-water two-phase flow is adjusted to a spiral flow state by a cyclone, then the radio frequency signal emitted by the antenna arranged concentrically in the tube under the spiral flow state is measured, and finally the water content ratio is achieved by establishing a relationship model between the water content and the RF signal measuring. This method can eliminate the influence of the oil-water two-phase flow pattern on the measurement results and widen the measurement range of the water content. The measurement model was statically calibrated, dynamically verified, and optimized through laboratory experiments. The experimental results show that when the inlet oil-water two-phase mixing flow rate is 0.60-1.20 m/s and the volumetric water content is higher than 43.81%, the error of the oil-water two-phase measurement using this method is within 6.29%. [ABSTRACT FROM AUTHOR]

Results obtained from observations of ionospheric disturbances over the People's Republic of China during the course of the geospace storm of 14 May 2019, one of the largest storms in 2019, are presented. The Harbin Engineering University operates the multi-frequency multipath radio wave diagnostics employing software defined technology and continuously monitoring dynamic process acting in the ionosphere at oblique incidence since April 2018. The basic premise upon which this instrument operation is based is that the digital re-sampling remains coherent with radio frequency for each propagation path, which permits Doppler spectra and signal amplitudes to be calculated along each of the 14 propagation paths. UT dependences of the Doppler spectra, the main mode Doppler shifts of frequency, and signal amplitudes that were measured on the day of the ionospheric storm and on the reference days of 13 and 15 May 2019 have been analyzed. After the magnetic storm onset, the Doppler shift of frequency exhibits an abrupt –1-Hz decrease, indicating the ionospheric storm onset. In addition, quasi-periodic variations in the Doppler shift of frequency, with 5-, 15-, 20-, and 30-min periods and the amplitudes in the range from 0.05 Hz to 0.15 Hz, occur in the course of the storm. These variations are due to modulation by infrasound (5-min period oscillation) and atmospheric gravity waves (15-, 20-, and 30-min period oscillations). In the electron density, the corresponding waves have amplitudes equal to 0.7% and 4–8%, respectively. [ABSTRACT FROM AUTHOR]

The rapid development of sensing, computing, and wireless communication techniques has given rise to an increasing number and increasing availability of high-resolution data that record real-time traffic information. In this study, radio frequency identification (RFID) data collected in Nanjing (a major city in southern China) were used to estimate dynamic travel demands and develop an RFID data-based vehicle routing model that simultaneously considers individual benefits and social good. The proposed vehicle routing model also used information regarding driver origins that contribute to major congestion; therefore, the routing model can be applied to a group of targeted vehicles only, providing more adaptive, efficient, and feasible routing strategies to mitigate traffic congestion. [ABSTRACT FROM AUTHOR]

The photoelectric response characteristics of an infrared spectrometer based on an acousto-optic tunable filter (AOTF) are greatly affected by the temperature change of the radio frequency power amplifier and shortwave infrared detector. If calibration is not conducted, that will affect the quantitative level of the data. This paper puts forward a measurement and correction method for the temperature characteristics of an AOTF infrared spectrometer which is used in lunar surface detection and sets up a temperature characteristics correction model. This model was applied to an AOTF infrared spectrometer mounted on China's unmanned lunar rover. Laboratory tests show that the temperature causes an instrument variation of ∼20% when the temperature is between −20 ℃ and + 55 ℃, but this model reduces this variation to < 6%. Evaluating data from the lunar surface also verifies the effectiveness of this method. [ABSTRACT FROM AUTHOR]

Beam momentum spread is a key parameter of the linac injector at the Xi'an Proton Application Facility (XiPAF), China. A momentum spread measurement method using multiple beam position monitors (BPM) was successfully developed recently at Tsinghua University, China. This work is an extension of the method. The original method requires at least three BPMs to perform the measurement, and the BPMs should be installed far from the accelerator exit, causing long measurement space and low BPM signals. The new method only needs two BPMs, and a much shorter measurement space is proposed for the low-current linac in this paper. The new method was successfully tested at XiPAF. The measured rms momentum spread at the Radio Frequency Quadrupole exit is (5.05 ± 0.06) × 10−3, which agrees well with the spectrometer measured value (5.09 ± 0.05) × 10−3. [ABSTRACT FROM AUTHOR]

The China Spallation Neutron Source (CSNS) has been operational for five years. As the beam power increased from 10 kW to 140 kW, the radio frequency (RF) pulse width also increased, leading to an increased cavity frequency detuning along with the beam pulse width. Simulations were conducted to analyze the frequency shift of the drift tube linac (DTL) cavities under a pulse width of 650 μs and a repetition frequency of 25 Hz. These simulations investigated the contributions of the cavities' components to the frequency offset, and the results were consistent with the operating data. To evaluate the frequency detuning of the cavities in CSNS-Ⅱ with an extended pulse width, the sensitivity of frequency detuning to different pulse widths and inlet water temperature was assessed. The results indicate that the cavity detuning caused by an extended pulse width can be compensated by reducing the inlet water temperature or adjust the insertion depth of movable tuners in CSNS-Ⅱ. [ABSTRACT FROM AUTHOR]

In view of the problems such as the basic properties, usage, and location of prefabricated concrete building components, which are easy to be omitted, missed, and difficult to query in the field management, this study introduces building information modeling (BIM) and radio frequency identification (RFID) technologies to visualize the state information of prefabricated concrete components, such as component type, manufacturer, location, and temperature. In the design stage, a new RFID family can be built in the actual model in order to solve the lack of definition of RFID family through the Industry Foundation Class (IFC) standard, and the databases of BIM and RFID can be connected with C# language, realizing the effective integration of the two engineering technologies. In the application stage, through the secondary development of Revit, the information connection between PC terminal and RFID equipment is completed, and the component data collected by RFID tags are transmitted to the BIM model to realize the integration and visualization of prefabricated component state information. In this study, the traceability of prefabricated components of prefabricated concrete buildings can be improved, providing a basis for quality responsibility tracking in the later period, reducing unnecessary waste of human and material resources and helping to maximize economic benefits. [ABSTRACT FROM AUTHOR]

Engine re-manufacturing factory runs comparatively smaller but more changeable business than normal engine manufacturing factory. Therefore, it needs a simple, quick, effective, but less costly approach for process planning. This paper proposes a novel rapid simulation approach, named as Efficiency Validate Analysis, which can serve as process planning and process analysis tools. This approach is developed based on the flexible simulation framework and discrete event system specification formalism (DEVS). Internet-of-Things (IoT) data, in terms of the historical records of sensors and radio frequency identifications (RFIDs), is adopted to build the foundation of simulation. This new simulation approach is evaluated with a case in an engine re-manufacturing plant in China. By comparing with traditional methods, the results show that the new approach supports process planning tasks more effectively. This approach offers a simple but practical way to combine the virtual information world with the entity physical world and drive their bidirectional mapping in re-manufacturing process planning, analysis and optimisation. [ABSTRACT FROM AUTHOR]

Purpose Large supermarkets, chain stores and enterprises with large-scale warehousing put forward higher standards and requirements for the automation and informatization of warehouses. As one of the fast-growing commercial supermarkets in China, the traditional warehouse management mode has restricted the rapid development of Yonghui Superstores to a certain extent. The purpose of this paper is to find out how the existing warehouse mode can be changed and to solve the existing problems of warehouse management of Yonghui Superstores.Design/methodology/approach This research puts forward construction of warehouse center, which is based on radio frequency identification (RFID) and sensor technology, then designs the model for receiving, storage, operations management, distribution and outbound to solve the existing problems of warehouse management of Yonghui Superstores.Findings What technologies should be adopted to meet storage requirements? How to monitor the storage environment in real time and improve the operation and management level of the warehouse? This study found that building a warehouse center based on RFID and sensor technology was a good solution.Research limitations/implications The Yonghui Superstores warehouse center model lacks corresponding simulation experiments, and the investment and income are difficult to estimate quantitatively.Practical implications This paper has designed and discussed the warehouse center model based on RFID and sensor technology, which provides a few references for the actual investment and construction of a warehouse center. In addition, the warehouse center model has strong generalized applicability and could be widely used in various enterprises.Social implications The warehouse center could improve the warehouse management level of Yonghui Superstores and change the traditional warehouse management mode. To some extent, it improves the enterprise flexibility of the market, which will be of great significance to improve business efficiency and enhance brand image and competitiveness.Originality/value This study takes Yonghui Superstores as a case to analyze the problems of warehousing management in detail and then designs a warehouse center based on RFID and sensor technology. The study discusses the location and distribution, software and hardware selection, benefits evaluation, significances and return on investment, which makes the warehouse center model versatile, technically feasible and economically applicable. [ABSTRACT FROM AUTHOR]

• A transmitter with bandwidth of 40–100 MHz at 100-kilowatt level was cross-verified through three-dimensional (3D) simulations and experiments. • New phenomenons of high frequency oscillation between the short strip inductor and the shield cavity was found in the input simulation results. • The simulation can provide both the electric field energy and the surface current distribution of the structure of the entire amplifier at a particular power. • The amplifier installed with the new tetrode DB968 achieved the design objectives in the test experiment with 150 and 110 kW power outputs at 48 and 100 MHz, respectively. A 1.5 MW final power amplifier is to be developed for ion cyclotron resonance heating (ICRH) system for the China fusion engineering testing reactor (CFETR) project. First, the feasibility of driver power amplifier with input matching circuit and output resonator cavity and a newly developed tetrode was cross-verified through three-dimensional (3D) simulations and experiments. A single coaxial cavity in parallel with the tetrode covered the frequency range of 40 to 100 MHz at a 100-kilowatt level. In contrast to the previous method of deducing matching parameters using RF circuit and transmission line theory, the use of 3D transmitter simulations provided more accurate matching parameters of tuning components at different operating frequencies. A new phenomenon of high frequency oscillation between the short strip inductor and the shield cavity was found in the input simulation results, which was subsequently verified by experiments. Specific reasons for dividing the output into two parts of high and low frequency were found through output circuit simulations. One is that the length of short stub decreases with the increase of operating frequency, thus decreasing the frequency resolution if all frequencies were using low frequency port. The other is that the coupling capacitor increases sharply with the increase of frequency due to parasitic effect in the low output. Further, the simulation facilitated the study of parasitic effects on matching parameters caused by strip-inductance, inter electrode capacitances of tetrode, and RF cavity. Thus, facilitating the design of final power amplifier in the future. Finally, the amplifier installed with the new tetrode DB968 achieved the design objectives in the test experiment with 150 and 110 kW power outputs at 48 and 100 MHz, respectively. [ABSTRACT FROM AUTHOR]

Background: Atrial fibrillation (AF) adversely affects surgical outcomes of cardiac valve surgery. Surgical ablation is an effective way to treat valvular AF. The aim of this study was to evaluate the late outcome of surgical radiofrequency ablation and explore the risk factors of AF recurrence in Chinese patients undergoing cardiac valve surgery.Methods: Three hundred ninety six consecutive patients with persistent valvular AF were enrolled in this study. They underwent concomitant modified Maze IV and were completed follow-ups. Cox survival regression model was used to screen independent risk factors for predicting late recurrence of AF.Results: During the follow-up period of 28 (6 ~ 61) months, AF recurred in 151 patients (38.1%). In multivariate survival regression, factors predictive of AF late recurrence were AF duration, pre-operative serum B-type natriuretic peptide (BNP), pre-operative heart rate and left atrial diameter (LAD), post-operative atrial tachyarrhythmias and AF at discharge. According to receiver operating characteristic curve analysis, the best cutoff values for AF duration, BNP, heart rate and LAD were 66.5 months, 251 pg/ml, 82 beats/min and 67.9 mm, respectively.Conclusions: Longer AF duration, larger LAD, higher BNP level and lower heart rate indicated a poor late outcome of surgical radiofrequency ablation in persistent AF patients undergoing cardiac valve surgery. Therefore, indication to radiofrequency ablation should be carefully considered in these patients. [ABSTRACT FROM AUTHOR]

In the fourth-generation storage ring light sources (4GLSs), associated with the extremely strong nonlinearities inherent in the multi-bend achromat design, the dynamic acceptance is usually small and it is difficult to implement traditional off-axis local-bump injection. To release the requirement on dynamic acceptance, on-axis longitudinal injection schemes have been explored. In this paper, we present a multi-objective optimization of longitudinal injection with a multi-frequency RF system, based on the parameters of the Southern Advanced Photon Source, a 4GLS proposed in China. We show that by treating the optimal bunch lengthening condition as an optimizing objective rather than a condition that must be satisfied, a plethora of feasible candidate solutions can be found, showing different trade-offs among multi-objectives. From these candidate solutions, one can find an optimal RF parameter setting that is most adapted to a specific 4GLS physics design and the available technical level of injection kicker. Especially, it would be feasible to realize longitudinal injection within a static bucket enabled by a double-frequency RF system, suggesting an attractive longitudinal injection option for 4GLSs. [ABSTRACT FROM AUTHOR]

According to the upgrade plan of CSNS-II (China Spallation Neutron Source Phase II), the beam power on target of CSNS needs to be increased to 400 kW in the future. In order to achieve this goal, a superconducting acceleration section will be added behind the LINAC (Linear Accelerator) section of CSNS-I. The superconducting acceleration section includes two superconducting cavity types operating at 324 MHz and 648 MHz. At present, the 324 MHz superconducting cavity couplers have been produced. In order to perform the RF conditioning and test the power transmission capability of the coupler, we designed and built a corresponding automatic RF conditioning control platform in the gallery of CSNS LINAC. The control system hardware is based on Micro TCA (Micro Telecommunications Computing Architecture, MTCA) LLRF (low-level radio frequency) control system, and the software development is based on EPICS (Experimental Physics and Industrial Control System). PLC (Programmable Logic Controller) based data acquisition and monitoring slow protection system, in-house developed interlocking fast protection system and some general equipment constitute the main hardware facilities, while EPICS IOC (input and output controller) and CSS (Control System Studio) OPI (Operator Interface) constitute a main pillar of control software. The control logic of the RF conditioning program mainly uses the vacuum pressure readings collected from the coupler as the judgment standard, and controls the power autonomously according to the real-time vacuum data, which can largely avoid human misoperation and greatly reduce the operator's workload. At present, the system has started to run, and the actual work results show that its hardware and software performance are excellent, which ensures the safe and smooth progress of the RF condition process. In this article, we will first introduce the hardware architecture of the entire system, secondly introduce the software architecture and control logic of RF conditioning, and finally give the actual working results of the control system. [ABSTRACT FROM AUTHOR]

Background: Idiopathic ventricular arrhythmias (VAs) originating from the pulmonary sinus cusp (PSC) have not been sufficiently clarified.Objectives: The goal of this study was to investigate the prevalence, electrocardiographic characteristics, mapping, and ablation of idiopathic VAs arising from the PSC.Methods: Data were analyzed from 218 patients undergoing successful endocardial ablation of idiopathic VAs with a left bundle branch block morphology and inferior axis deviation.Results: Twenty-four patients had VAs originating from the PSC. In the first 7 patients, initial ablation performed in the right ventricular outflow tract failed to abolish the clinical VAs but produced a small change in the QRS morphology in 3 patients. In all 24 patients, the earliest activation was eventually identified in the PSC, at which a sharp potential was observed preceding the QRS complex onset by 28.2 ± 2.9 ms. The successful ablation site was in the right cusp (RC) in 10 patients (42%), the left cusp (LC) in 8 (33%), and the anterior cusp (AC) in 6 (25%). Electrocardiographic analysis showed that RC-VAs had significantly larger R-wave amplitude in lead I and a smaller aVL/aVR ratio of Q-wave amplitude compared with AC-VAs and LC-VAs, respectively. The R-wave amplitude in inferior leads was smaller in VAs localized in the RC than in the LC but did not differ between VAs from the AC and LC.Conclusions: VAs arising from the PSC are not uncommon, and RC-VAs have unique electrocardiographic characteristics. These VAs can be successfully ablated within the PSC. [ABSTRACT FROM AUTHOR]

The amplitudes of the Earth's free oscillations have a close relationship to earthquake focal mechanisms. Focal mechanisms of large earthquakes can be well analyzed and constrained with observations of long period free oscillations. Although the 2013 Lushan earthquake was only moderately sized, observable spherical normal modes were excited and clearly observed by a superconductive gravimeter and a broadband seismometer. We compare observed free oscillations with synthetic normal modes corresponding to four different focal mechanisms for the Lushan earthquake. The results show that source parameters can be analyzed and constrained by spherical normal modes in a 2.3-5 mHz frequency band. The scalar seismic moment M has a major influence on the amplitudes of free oscillations; additionally, the strike, dip, rake and depth of the hypocenter have minor influences. We found that the synthetic modes corresponding to the focal mechanism determined by the Global Centroid Moment Tensor show agreement to the observed modes, suggesting that earthquake magnitudes predicted in this way can readily reflect the total energy released by the earthquake. The scalar seismic moment obtained by far-field body wave inversion is significantly underestimated. Focal mechanism solutions can be improved by joint inversion of far- and near-field data. [ABSTRACT FROM AUTHOR]

A Chinese head phantom (CHP) is constructed for evaluating the specific absorption rate (SAR) by the wireless transceivers. The dimensions of the head phantom are within 4 % difference compared with the 95th percentile data from the China's standard. The shell's thickness and the configuration of the pinna are the same as those of the specific anthropomorphic mannequin (SAM). Three computable models for the mobile phones are generated and used in the SAR simulations with the SAM and the CHP. The results show that the simulated SAR from the SAM head is similar. Its morphological reason has been analysed. The authors discuss the conservativeness of the two head phantoms as well. The CHP can be used in the inter-laboratory evaluation for the SAR uncertainty. It can also provide the information for the SAR variability due to physical difference, which will benefit the maintenance and the harmonisation of the standards. [ABSTRACT FROM PUBLISHER]

Since the 1980s big changes have been taking place in the character of China's radio programmes. Radio's role has changed, from a propaganda tool of the government to a medium seeking to meet the multifarious needs of its listeners. Under the 'socialist market economy' which was introduced in 1992, radio in China has become unashamedly market oriented. Its funding has moved from a complete dependency on the public purse to the independent pursuit of profit. With the aid of digital technology, the traditional forms of programming, which were dominated by a culture of writing and reading, have also been transformed into ones which involve audience interaction. This article is a case study of Helping Each Other in Beijing, a programme for the elderly which is broadcast on the public service frequency of Radio Beijing. It analyses the concept of the programme, its content, its interaction with the audience and the style of its presentation. In this fiercely competitive age of new media and globalization, it illustrates how Chinese broadcasters are developing a new programming philosophy, how they are developing a new relationship with the audience and how they are fashioning a new media image. [ABSTRACT FROM AUTHOR]

Since 2016, numerous American and Canadian diplomats and secret (intelligence) agents in Cuba, China, and other places in the world have experienced an abrupt onset of unusual clinical symptoms including, tinnitus, visual problems, vertigo, and cognitive difficulties, after they encountered strange sounds; this has been called "Havana syndrome" (HS). MEDLINE, Scopus, and Ovid databases from 2016 until 24 September 2021 were systematically searched for the related published manuscripts. The following search strategy was implemented: "Havana syndrome" OR "Neurological Symptoms and US Diplomats". The primary search yielded 120 publications. Only five original studies and 18 non-original articles were considered to be relevant. While these studies provided a constellation of signs and symptoms for HS, none provided a good level of evidence. In conclusion, Havana syndrome is a nonspecific neurological illness with an unidentified causative factor(s), an acute phase of auditory-vestibular symptoms and a chronic phase of nonspecific neurobehavioral symptoms. This syndrome should be considered and investigated as a health concern, and not as a political issue., (© 2022 Walter de Gruyter GmbH, Berlin/Boston.)

Microbial contamination is a persistent problem for grain industry. Many studies have shown that radio frequency (RF) heating can effectively reduce pathogens populations in low moisture foods, but there is a lack on the efficacy to decontaminate natural microbiome. The main objectives of this study were to investigate the effects of different RF heating conditions on natural microbial populations and physicochemical properties of buckwheat. In this study, 30 buckwheat samples collected from 10 different Provinces in China were analyzed for their microbial loads, and the samples with the highest microbial populations were used for further study to select the suitable RF heating conditions. The results showed that microbial loads in tested buckwheat kernels were in the range of 3.4–6.2 log CFU/g. Samples from Shanxi (SX-3) had significantly higher microbial counts than other samples. The selected four temperature-time combinations: 75 °C-20 min, 80 °C-10 min, 85 °C-5 min, and 90 °C-0 min of RF heating could reduce microbial counts to <3.0 log CFU/g in buckwheat kernels at 16.5% w.b. moisture content. Furthermore, the reduction populations of the inoculated pathogens (Salmonella Typhimurium , Escherichia coli , Cronobacter sakazakii, and Bacillus cereus) reached 4.0 log CFU/g under the above conditions, and almost 5.0 log CFU/g especially at high temperature-short holding time combinations (85 °C-5 min and 90 °C-0 min). Besides, physicochemical properties evaluation also showed the insignificant color changes and nutrients loss after RF treatment at 90 °C-0 min. Therefore, the RF heating at 90 °C-0 min holds greater potential than the other lower temperature-longer holding time combinations for applications in buckwheat pasteurization. • Effects of RF heating on microbial populations and physicochemical properties of buckwheat were determined. • Samples from Shanxi had significantly higher microbial counts than others. • Selected four temperature-time combinations resulted in required microbial reductions. • Insignificant color changes and nutrient losses in RF treated buckwheat were observed. [ABSTRACT FROM AUTHOR]

With the rapidly increasing popularity of 5G mobile technology, the effect of radiofrequency radiation on human health has caused public concern. This study explores the effects of a simulated 3.5 GHz radiofrequency electromagnetic radiation (RF-EMF) environment on the development and microbiome of flies under intensities of 0.1 W/m2, 1 W/m2 and 10 W/m2. We found that the pupation percentages in the first 3 days and eclosion rate in the first 2 days were increased under exposure to RF-EMF, and the mean development time was shortened. In a study on third-instar larvae, the expression levels of the heat shock protein genes hsp22 , hsp26 and hsp70 and humoral immune system genes AttC , TotC and TotA were all significantly increased. In the oxidative stress system, DuoX gene expression was decreased, sod2 and cat gene expression levels were increased, and SOD and CAT enzyme activity also showed a significant increase. According to the 16S rDNA results, the diversity and species abundance of the microbial community decreased significantly, and according to the functional prediction analysis, the genera Acetobacter and Lactobacillus were significantly increased. In conclusion, 3.5 GHz RF-EMF may enhance thermal stress, oxidative stress and humoral immunity, cause changes in the microbial community, and regulate the insulin/TOR and ecdysteroid signalling pathways to promote fly development. [Display omitted] • Simulating the most representative 3.5 GHz RF-EMF band of 5G in China. • We study the long-term effects of 3.5 GHz RF-EMF on flies' development. • The microbial community may participate in the development under long-term RF-EMF. • It provides a reference for the hidden health effects of RF-EMF. [ABSTRACT FROM AUTHOR]

An ultra-wideband(UWB) frequency adaptive detect and avoid design method based on direct sequence spread spectrum-carrier modulation is proposed for 4. 2~4. 8 GHz frequency band interference suppression in China. Furthermore, the composite Gaussian n-th derivative pulse is considered as UWB original pulse. Simulation results show that the proposed DAA method can meet with the China UWB spectral mask, provide the stable UWB normal transmit power and have high transmission efficiency. [ABSTRACT FROM AUTHOR]

Abstract: The spatial distribution of soil types is controlled by a set of environmental factors such as climate, organisms, parent material and topography as well as time and space. A change of these factors will lead to a change in the spatial distribution of soil types. In this study, we use a digital soil mapping approach to improve our knowledge about major soil type distributing factors in the steppe regions of Inner Mongolia (China) which currently undergo tremendous environmental change, e.g. climate and land use change. We use Random Forests in an effort to map Reference Soil Groups according to the World Reference Base for Soil Resources (WRB) in the Xilin River catchment. We benefit from the superior prediction capabilities of RF and additional interpretive results in order to identify the major environmental factors that control spatial patterns of soil types. The nine WRB soil groups that were identified and spatially predicted for the study area are Arenosol, Calcisol, Cambisol, Chernozem, Cryosol, Gleysol, Kastanozem, Phaeozem and Regosol. Model and prediction performances of the RF model are high with an Out-of-Bag error of 51.6% for the model and a misclassification error for the predicted map of 28.9%. The main controlling factors of soil type distribution are land use, a set of topographic variables, geology and climate. However, land use and climate are of major importance and topography and geology are of minor importance. The visualizations of the predictions, the variable importance measures as result of RF and the comparisons of these with the spatial distribution of the environmental factors delivered additional, quantitative information of these controlling factors and revealed that intensively grazed areas are subjected to soil degradation. However, most of the area is still governed by natural soil forming processes which are driven by climate, topography and geology. Most importantly though, our study revealed that a shift towards warmer temperatures and lower precipitation regimes will lead to a change of the spatial distribution of RSGs towards steppe soils that store less carbon, i.e. a decrease of spatial extent of Phaeozems and an increase of spatial extent of Chernozems and Kastanozems. [Copyright &y& Elsevier]

We report the spatiotemporal statistical characteristics of amplitude scintillation over Nanjing. A FFT method for computing scintillation intensity power spectra is briefly described. Using this method, the data with ISATM in Nanjing is analyzed. Spectra characteristic is presented and the irregularities property is discussed preliminarily. The results reveal that the power spectra obtained for Nanjing is consistent with theoretical modeling. At frequencies below the Fresnel frequency, the power density plotted on log-log scale is almost constant whereas above it asymptotes to a straight line. The spectral index ranges from 1.71 to 1.92, which has positive correlation with the S index. Finally, the average drift velocity of irregularities is computed assumably and compared with that obtained for Xinxiang and Haikou. [ABSTRACT FROM AUTHOR]

Abstract: The Peking University Neutron Imaging Facility (PKUNIFTY) is being constructed, which is a compact acceleratordriven neutron source. The accelerator is a radio frequency quadrupole (RFQ) accelerator, which can deliver a 2 MeV deuteron beam. The neutrons are generated by deuterons bombarding beryllium target. The accelerator facility mainly consists of ECR (electron cyclotron resonance) ion source, LEBT (low energy beam transportation), RFQ cavity, HEBT (high energy beam transportation), RF transmitter and control system. This paper will introduce the requirements and design of that accelerator facility. [Copyright &y& Elsevier]

Abstract: The design and construction status of the Radio Frequency Quadrupole (RFQ) accelerator for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University is presented. The RFQ will accelerate protons from 50 keV to 3 MeV, with the RF frequency of 325MHz. The total length of the RFQ cavity is about 3 m with the transmission rate of 97.2% predicted by PARMTEQM. Fine machining of the RFQ cavity was completed in July, 2011. The brazing of the vanes, the flanges and the cooling pipes has been finished in September, 2011. [Copyright &y& Elsevier]

Abstract: The Compact Pulsed Hadron Source (CPHS) system has been proposed and designed by the Department of Engineering Physics of Tsinghua University in Beijing, China. It consists of an accelerator front-end—a highintensity ion source, a 3 MeV radiofrequency quadrupole linac (RFQ), and a 13 MeV drift-tube linac (DTL), a neutron target station, and some experimental stations. In design of our RF power supply, both RFQ and DTL share a single klystron which is capable of 2.5 MW peak RF power and a 3.33% duty factor. The 325MHz klystron contains a modulating anode and has a 100kW average output power. Portions of the RF power system, such as pulsed high voltage power supply, modulator, crowbar protection and RF power transmission are all presented in details in this paper. [Copyright &y& Elsevier]

In the field of wireless communications the idea of cognitive radio is of utmost interest. Due to its advantageous propagation properties, the TV white space can be considered to become the first commercial application of cognitive radio. It allows the usage of secondary communication systems at non-occupied frequency bands. Within this paper, spectrum sensing algorithms are introduced for the three predominant Chinese TV standards DTMB, CMMB, and PAL-D/K. A prototype platform is presented and its underlying architecture based on a combination of DSP and FPGA is illustrated including the setup of the cognitive radio application. Furthermore, the performance of the sensing algorithms implemented on the prototype platform is shown in comparison to simulation results. [ABSTRACT FROM AUTHOR]

The total solar eclipse of 22 July 2009, was visible from some regions of China and the intense sporadic-E (Es) that broke out during the solar eclipse period over the eastern China provided a unique chance to study solar eclipse effects on the Es-layer. The ground based high-frequency (HF) vertical-incidence and oblique-incidence backscatter radio systems in Wuhan and an HF oblique receivers located in Suzhou were operated to detect the Es-layer. The vertical, oblique and backscatter ionograms of 22 and 23 July were recorded, processed and analyzed. The analyzing results show that the critical frequency of Es, the hop number and power of the rays transmitted from Wuhan to Suzhou as well as the Doppler frequency shift of the one-hop oblique-incidence waves reflected by the Es-layer all increased during the solar eclipse period. These variations are displayed in the paper and explained to be induced by the wind-field, which is produced by the powerful meridional air flows from the sunshine region to the moon's shadow. [ABSTRACT FROM AUTHOR]

Abstract: Separated Function Radio Frequency Quadrupoles (SFRFQ) structure is a new post accelerator of RFQ, the higher accelerating efficiency and transmission make it become a proper choice for the post acceleration after the integral split ring RFQ (ISR RFQ)-1000 accelerator at Peking University . A novel design strategy is proposed in this paper to avoid the sparking problem and decrease the energy spread at the exit of SFRFQ. Correspondingly, a code SFRFQCODEV1.0 was developed specially for beam dynamic simulations and error studies. A prototype cavity with 14 accelerating gaps has been constructed and tested at low and high RF power successfully. The operating energy region of SFRFQ structure and the results of error study are presented. [Copyright &y& Elsevier]

In order to accommodate the luminosity improvement strategy, two superconducting 499.8 MHz radio frequency (rf) cavities have been adopted for the Upgrade project of Beijing Electron Positron Collider (BEPCII), a double-ring electron–positron collider as well as a synchrotron radiation (SR) light source. The in-house development of the 499.8 MHz superconducting cavity system was initiated at IHEP since 2008. One prototype niobium cavity with all the parts except for the flanges and the pickup port formed by spinning was fabricated and then vertical-tested successfully in July 2011. Four prototype input couplers were manufactured and high-power tested with one reaching a maximum rf power of continuous wave (cw) 420 kW. One prototype HOM damper with a satisfactory absorbing efficiency at the desired frequency band was also constructed and high power tested up to cw 4.4 kW. In the meanwhile, a frequency tuner consisting of a stepping motor and a piezoelectric oscillator was developed. Finally, the bare cavity was dressed with one input coupler, two HOM dampers and one frequency tuner, mounted in a domestic-developed cryostat and then high-power tested successfully in Oct. 2011. The achieved accelerating voltage is 2.2 MV with corresponding Q 0 measured to be 5.8 × 10 8 , beyond the designed goal. This is the first in-house developed 499.8 MHz HOM-damped superconducting cavity system in China. The design, fabrication, post processing and tests of the niobium bare cavity and its auxiliaries, as well as the horizontal high-power test of the cavity system are presented. [ABSTRACT FROM AUTHOR]

The Radio Frequency Identification (RFID) is a new technology to identify packages for China railway. The purpose of this paper is to simulate the RFID system to track packages during the whole trip, and then examine the applicableness of it. The trial results show that RFID is the suitable approach to automatically identify railway packages, as it can satisfy the requirements of package express operations. Some process advices that may result in more efficient identification in RFID system are also proposed. [ABSTRACT FROM AUTHOR]

Radio frequency usage fees were first charged in Taiwan in 1997. Since then, spectrum-efficient radio technologies have been making rapid progress, and many new innovative wireless services are demanding allocation of spectrum bandwidth. Therefore, frequency usage fees need to be revised in order to better meet society's needs, and to improve the efficiency and effectiveness of radio spectrum utilization. This research studied the characteristics of frequency usage fee structures of some selected countries, including the UK, Canada, Australia, Korea, Singapore, France, and Israel. A survey of local frequency users concerning their complaints and expectations was also conducted. With future frequency needs in mind, a revision of Taiwan's frequency usage fee system was recommended. The Taiwan Directory General of Telecommunications has fully adopted this revision and made it effective starting 2001. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To assess the clinical efficacy of radiofrequency (RF) ablation in treating liver cancers. The indications, contraindications and side-effects of the technique were also evaluated. METHODS: One hundred and fifty-four patients with liver cancers were treated between May 1999 and July 2000. One hundred and thirty-two cases were hepatocellular carcinomas (HCC) and 22 cases were metastatic liver cancers. The diameter of the cancers ranged from 1.5 to 19.0 cm, with a mean diameter of 7.07 cm. All patients were treated with RF2000TM RF under ultrasonographic guidance and the results and side effects were evaluated. RESULTS: One hundred and fifty-four patients were treated 182 times, with the average number of treatments for each patient being 1.18 and the average number of therapeutic points was 5.74. Symptoms improved after therapy and the levels of α-fetoprotein (AFP) dropped from 1553.68 to 883.70 ng/mL. The AFP level declined in 60.8% of patients, remained unchanged in 32.7% of patients and was elevated in 6.5% of patients. After RF ablation, the size of the tumor was reduced in 87 cases (56.6%), stabilized in 52 cases (33.7%) and enlarged in 15 cases (9.7%). The common side-effects of RF were local pain, fever and leukocytosis; no life-threatening complications were observed. CONCLUSIONS: Percutanous RF ablation of liver cancers is a simple, safe, effective method. It can be curative for small liver cancers but for large liver cancers multiple treatments combined with arterial chemoembolization therapy may be needed to enhance its effectiveness. [ABSTRACT FROM AUTHOR]

China Spallation Neutron Source (CSNS) has been in operation for about 2 years, and an upgrade is proposed to compensate the space charge effect. A superconducting radio frequency (SRF) linac with double spoke cavities and medium-beta elliptical cavities has been designed to increase the injection energy from 80MeV to 300MeV, and institute of high energy physics (IHEP) has developed a prototype double spoke cavity at β 0 0.5. The cavity shape was optimized to minimize Ep/Eacc while keeping Bp/Eacc reasonably low. Meanwhile, mechanical design was applied to check stress, Lorentz force detuning and microphonic effects, and to minimize pressure sensitivity. A new input power coupling scheme was proposed to avoid electrons hitting directly on ceramic window. After fabrication and post processing of cavity, the cavity was vertical tested for several times, and mechanical polishing was applied to improve the performance. The cavity finally reached Bp of 140mT at Eacc = 16.1MV/m and Q 0 = 1. 42 × 1 0 10 under vertical test at 2K. [ABSTRACT FROM AUTHOR]

During the last decades, photocathode rf gun has been proven to be successful in generating the high brightness electron beam (~1nC,~1pmmmrad,~1 ps) which is required by the ILC, XFEL, Thomson scattering x-ray source, etc. A photocathode rf gun system is built to develop electron source for the Thomson scattering x-ray source at Accelerator Laboratory of Tsinghua University. The system consists of a BNL/ATF-type 1.6 cell S-band rf cavity, a solenoid for emittance compensation, a laser system and some simple equipments for beam diagnosis. The first beam measurements of the photocathode rf gun, including the dark current, transverse beam profile, charge and quantum efficiency, are reported. [ABSTRACT FROM AUTHOR]

Microorganism control and product quality (texture, sensory, lipid oxidation and carotenoids content) improvement of stewed pork with carrots pasteurized using ZnO nanoparticles combined with radio frequency (ZNCRF) were studied in comparison to conventional high pressure steam (HPS) sterilization. The experimental results showed that ZNCRF pasteurization was better than traditional HPS sterilization. ZNCRF pasteurization reduced the product quality loss (texture, sensory, lipid oxidation and carotenoids content) of stewed pork with carrots and the sensory score remained at 85 out of 100. Measurement of the secondary structure confirmed that ZNCRF was less destructive. From the above, ZNCRF pasteurization may be beneficial for the food industry to manufacture high quality pasteurized stewed pork with carrots and similar products. • Nano-ZnO combined with radio frequency (ZNCRF) is a new pasteurization method. • ZNCRF led to less change in protein secondary structure. • ZNCRF pasteurization met the requirement of China's National Standard. • ZNCRF led to less texture degradation than high pressure steam sterilization. [ABSTRACT FROM AUTHOR]

Recent Experimental Advanced Superconducting Tokamak (EAST) experiments have successfully demonstrated a long-pulse steady-state scenario with improved plasma performance through integrated operation since the last IAEA FEC in 2016. A discharge with a duration over 100 s using pure radio frequency (RF) power heating and current drive has been obtained with the required characteristics for future long-pulse tokamak reactors such as good energy confinement quality (H98y2 ~ 1.1) with electron internal transport barrier inside ρ  <  0.4, small ELMs (frequency ~100–200 Hz), and good control of impurity and heat exhaust with the tungsten divertor. The optimization of X-point, plasma shape, the outer gap and local gas puffing near the low hybrid wave (LHW) antenna were integrated with global parameters of BT and line-averaged electron density for higher current drive efficiency of LHW and on-axis deposition of electron cyclotron heating in the long-pulse operation. More recently, a high βP RF-only discharge (βP ~ 1.9 and βN ~ 1.5, /nGW ~ 0.80, f bs ~ 45% at q95 ~ 6.8) was successfully maintained over 24 s with improved hardware capabilities, demonstrating performance levels needed for the China Fusion Engineering Test Reactor steady-state operation. A higher energy confinement is observed at higher βP and with favorable toroidal field direction. Towards the next goal (⩾400 s long-pulse H-mode operations with ~50% bootstrap current fraction) on EAST, an integrated control of the current density profile, pressure profile and radiated divertor will be addressed in the near future. [ABSTRACT FROM AUTHOR]