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We performed a systematic review and meta-analysis to determine an optimal rehabilitation protocol following surgical repair for flexor tendon injury in zone II of the hand.Records from PubMed, Embase, and Cochrane were retrieved from their establishment to January 12, 2020. Seven studies were included in the final analysis. A total of 569 digits with a flexor tendon injury in zone II of the hand were included in this meta-analysis: 135 in a place and hold group; 161 in an active flexion and extension group; and 273 in an early passive motion group.There was no significant difference between the place and hold and early passive motion regimes in the incidence of rupture. There was a significant difference between the active flexion and extension and early passive motion regimes in the incidence of rupture. In the early active motion group, the possibility of 1 or more grades of improvement on the Strickland grading system was increased.The early active motion group obtained greater total active motion than the early passive motion group. A higher risk of rupture was noted in the active flexion and extension subgroup repaired by 2-strand core suture. The 2-strand technique was not sufficient for active flexion and extension protocols. Further study in multistrand tendon repair technique with early active exercise in zone II should be undertaken to determine its efficacy.Therapeutic IV.

Arising in coherent diffraction imaging (CDI), the phase retrieval problem is to reconstruct a complex object by measuring only diffraction intensity patterns. Existing approaches, such as iterative Fourier algorithm (IFA), transport intensity equation (TIE) methods and matrix optimisation, result in near-optimal solutions rather than exact solutions. This paper proposes an analytic method to get the exact phase retrieval solution without relying on direct reference waves. Based on structured template windows, the object far-field phase is solved analytically from the recorded Fourier intensities, from which the exact object reconstruction can be achieved. Sufficient conditions for obtaining exact phase retrieval solution are analysed rigorously and verified by numerical simulations, which also show the robustness of the method through simulations under noises, dynamic range, nonlinear response and bad alignment. A simple experimental result is provided to demonstrate the practical feasibility of the method. It achieves analytic phase retrieval for arbitrary complex-valued objects and may be applicable to quick phase imaging.

As an innovative optical processing technology based on the chemical reaction, inductively coupled atmospheric pressure plasma processing (IC-APPP) technology has the advantages of high processing efficiency, non-mechanical damage and low cost. Inductively coupled plasma jet (ICP) can be characterized by the high temperature and enthalpy, which is the prerequisite of high material removal rate in optical processing. Thermal analysis is critical to characterize the IC-APPP of optics. Based on the energy balance theory in the low-temperature plasma processing, the heat transfer process of substrate was analyzed and boundary conditions in the model were proposed. The gas temperature of the impinging jet was obtained by the simulation of plasma jet characteristics using finite element analysis, which acts as the input to the heat transfer model of IC-APPP process. Experiments were carried out to validate the accuracy of model and thermal effect on the removal rate was analyzed for IC-APPP. Results suggest that there exist varying degrees of nonlinearity with different temperature ranges in the IC-APPP.

Inductively coupled atmospheric pressure plasma processing (IC-APPP) is a novel polishing technique for silica-based optics to quickly mitigate the surface or subsurface damage due to its high efficiency and low cost. However, theoretically uniform removal of materials is difficult to achieve because of complex thermal effect. In this paper, numerical modelling and experimental study of global temperature field in IC-APPP is presented. First, a transient heat transfer model is established using finite element analysis to study the characteristics of temperature field distribution during the process. Then, the effects of substrate geometry and processing parameters are systematically analyzed. Finally, conformal polishing experiments are carried out to illustrate the correlation between the effectiveness of uniform removal and the temperature field. The surface shape can be maintained well with optimal processing parameters in IC-APPP.

The continuous phase plate (CPP) is the vital diffractive optical element involved in laser beam shaping and smoothing in high-power laser systems. The high gradients, small spatial periods, and complex features make it difficult to achieve high accuracy when manufacturing such systems. A high-accuracy and high-efficiency surface topography manufacturing method for CPP is presented in this paper. The atmospheric pressure plasma jet (APPJ) system is presented and the removal characteristics are studied to obtain the optimal processing parameters. An optimized iterative algorithm based on the dwell point matrix and a fast Fourier transform (FFT) is proposed to improve the accuracy and efficiency in the dwell time calculation process. A 120 mm × 120 mm CPP surface topography with a 1326.2 nm peak-to-valley (PV) value is fabricated with four iteration steps after approximately 1.6 h of plasma processing. The residual figure error between the prescribed surface topography and plasma-processed surface topography is 28.08 nm root mean square (RMS). The far-field distribution characteristic of the plasma-fabricated surface is analyzed, for which the energy radius deviation is 11 μm at 90% encircled energy. The experimental results demonstrates the potential of the APPJ approach for the manufacturing of complex surface topographies.

This paper reported a general noninterferometric high-accuracy quantitative phase imaging (QPI) method for arbitrary complex valued objects. Given by a typical 4f optical configuration as the imaging system, three frames of small-window phase modulation are applied on the object Fourier spectrum so that redistributed intensity patterns are produced on the image plane, in which the object phase emerges at different degree. Then, an algebraic relationship that connects the object phase with the output intensity is established to provide us with an approximate closed form phase recovery. Further, an efficient iterative optimization strategy is developed to turn that approximate solution into an accurate one. Due to the linear convergence property of the iteration, a high accuracy phase recovery is achieved without requiring heavy iterations. The feasibility and accuracy of the proposed method are verified by both numerical simulations and experiments on diverse phase objects., Regular paper, 6 Figures, 1 Tables

The Atmospheric pressure plasma jet (APPJ) is a very efficient tool that can be employed in the damage-free optical manufacturing. The deep understanding of the temperature field and flow pattern inside the discharge can be a useful tool for optimizing these devices. In this paper, simulation analysis and experiment research on the surface temperature distribution are presented. Through FLUENT finite element analysis software and the heat transfer theory in the flow field, the surface jet characteristics of components are analyzed. Combined with the temperature measurement experiments, the characteristics of surface temperature field modeling are verified, which provides an analysis basis for the comparative study of subsequent temperature and thermal deformation.

An accurate quantitative phase imaging technique with three phase shifts on focal plane is proposed. Without approximation to exp(iϕ), the new method is applicable to arbitrary complex-valued objects and can obtain accurate object reconstruction.

Surface distortion reduces the astronomical observation efficiency of large radio telescopes. Based on even-odd phase expansion, we present a semi-analytical phase retrieval algorithm for antennas equipped with an active surface system to detect its surface distortion. In the method, the odd-part distortion is solved directly from the focused far-field pattern, and the even-part is solved by adding a defocused scanning. We propose a window-shape defocusing scheme that is superior to the conventional defocusing scheme of moving sub-reflector. When the antenna is slightly distorted (aperture phase aberration

Wavefront aberration in optical imaging system reduces the image quality. The Gerchberg and Saxton algorithm is commonly applied to detect the wavefront from far-field intensities. Based on ‘alternating projection’, the algorithm is very sensitive to the initial phase guess, and can easily fall into a local optimal solution. In this paper, we propose an effective method based on phase modulation to obtain a favorable initial phase which ensures the GS iteration converge to the closely optimal solution. In the method, after the infocus image, add a suitable ‘phase mask’ to the incident beam and record the second far-field image. From the difference of the two images, a good approximation to the far-field phase can be solved directly, which reveals many crucial features of the exact far-field phase. With this value as the initial input, the GS iteration or other iterative Fourier algorithms would be able to achieve nearly global optimal phase retrieval.

Subsurface damage (SSD) is a defect that is inevitably induced during mechanical processes, such as grinding and polishing. This defect dramatically reduces the mechanical strength and the laser damage thresholds of optical elements. Compared with traditional mechanical machining, atmospheric pressure plasma processing (APPP) is a relatively novel technology that induces almost no SSD during the processing of silica-based optical materials. In this paper, a form of APPP, inductively coupled plasma (ICP), is used to process fused silica substrates with fluorocarbon precursor under atmospheric pressure. The surface morphology evolution of ICP-processed substrates was observed and characterized by confocal laser scanning microscope (CLSM), field emission scanning electron microscope (SEM), and atomic force microscopy (AFM). The results show that the roughness evolves with the etching depth, and the roughness evolution is a single-peaked curve. This curve results from the opening and the coalescing of surface cracks and fractures. The coalescence procedure of these microstructures was simulated with two common etched pits on a polished fused silica surface. Understanding the roughness evolution of plasma-processed surface might be helpful in optimizing the optical fabrication chain that contains APPP.

Surface deformations of large reflector antennas highly depend on elevation angle. This paper adopted a scheme with the ability to conduct measurement at any elevation angle: carrying an emission source, an unmanned aerial vehicle (UAV) scans the antenna on a near-field plane, meanwhile the antenna stays stationary. Near-field amplitude is measured in the scheme. To recover the deformation from the measured amplitude, this paper proposed a novel algorithm by deriving the deformation-amplitude equation, which reveals the relation between the surface deformation and the near-field amplitude. By the algorithm, a precise deformation recovery can be reached at a low frequency (

The surface chemical composition and atomic emission spectroscopy of F atoms and CF 2 molecules involved in the processing of Atmospheric Pressure Plasma Jet (APPJ) produced from CF 4 precursor has been explored. The XPS spectra illustrated that small amount of radicals including C-CF n and CF-CF n could be introduced onto the fused silica surface during the CF 4 plasma process, the fluorocarbon radicals were generated during CF 4 plasma ionization. Moreover, the relative concentrations of excited state species of F atoms and CF 2 molecules, which play significant role in remove and fluorocarbon radicals, were acquired for CF 4 plasma. The densities of F atoms increased dramatically with increasing applied RF power, whereas CF 2 molecules decreased monotonically over the same power range, the subsequent electron impacted decomposition of plasma species after CF 4 precursor fragmentation. The spectrum of the F atoms and CF 2 molecules fallowed the same tendency with the increasing concentration of gas CF 4 , reaching the maximum at the 20sccm and 15sccm respectively, and then the emission intensity of reactive atoms decreased with more CF 4 molecules participating. Addition certain amount O 2 into CF 4 plasma resulted in promoting CF 4 dissociation, O 2 can easily react with the dissociation product of CF 2 molecules, which inhibit the compound of the F atoms, so with the increasing concentration of O 2 , the concentration of the CF 2 molecules decreased and the emission intensities of F atoms showed the maximum at the O 2 /CF 4 ratio of 20%. These results have led to the development of a scheme that illustrates the mechanisms of surface chemistry reaction and the affection of plasma parameters in CF 4 plasma systems with respect to F and CF 2 gas-phase species.

In order to reveal the plasma etching processes on fused silica, the surface characterizations of fused silica after Ar/CF 4 atmospheric pressure plasma processing were investigated. The morphology and chemistry evolution of fused silica surface were analyzed by AFM and XPS respectively. The AFM micrographs exhibited the three-dimensional surface topography and the RMS roughness changed with the increase of the material removal depth. The surfaces appeared to become smoother when the plasma etching occurred on the surface top layer. However, after the chemically modified layer was removed, etching resulted in the formation of a series of pits. During extended etching, the individual pits coalesced with one another, and the coalescence provided a means of reducing the depth of subsurface damage and the RMS roughness. The XPS results illustrated that small amount of radicals including C-CF n and CF-CF n could be introduced onto the fused silica surface during the Ar/CF 4 plasma process, the fluorocarbon radicals were generated during CF 4 plasma ionization. And the changes in relative concentration of the fluorocarbon radicals C-CF n with the removal depth were also studied.

International audience; The SMART CITY is an important field for ubiquitous computing (UC), ambient intelligence (AmI), connected vehicles (CV), and the User Interface approach. Data vitalization related to in-city data collection and their appropriate diffusion to city actors (private and professional) and their services is the main issue. In the context of Hotspot-based Internet, Location-based services and Internet of Things, we study User-oriented systems with four typical variants related to transportation and customer behavior: a dynamic lane allocation system, a system for urban goods delivery, bus shelter-based communication, and street and store consumer adapted guidance and advertising.

The surface chemistry reaction involved in the processing of Atmospheric Pressure Plasma Jet (APPJ) produced from CF 4 precursor has been explored. The atomic emission spectroscopy of F atoms and CF 2 molecules was investigated as they contribute to substrate etching and FC film formation during APPJ processing. Optical emission spectroscopy (OES) spectra were acquired for CF 4 plasma, relative concentrations of excited state species of F atoms and CF 2 molecules were also dependent upon plasma parameters. The densities of F atoms increased dramatically with increasing applied RF power, whereas CF 2 molecules decreased monotonically over the same power range, the subsequent electron impacted decomposition of plasma species after CF 4 precursor fragmentation. The spectrum of the F atoms and CF 2 molecules fallowed the same tendency with the increasing concentration of gas CF 4 , reaching the maximum at the 20sccm and 15sccm respectively, and then the emission intensity of reactive atoms decreased with more CF 4 molecules participating. Addition certain amount O 2 into CF 4 plasma resulted in promoting CF 4 dissociation, O 2 can easily react with the dissociation product of CF 2 molecules, which inhibit the compound of the F atoms, so with the increasing concentration of O 2 , the concentration of the CF 2 molecules decreased and the emission intensities of F atoms showed the maximum at the O 2 /CF 4 ratio of 20%. These results have led to the development of a scheme that illustrates the mechanisms of surface chemistry reaction and the affection of plasma parameters in CF 4 plasma systems with respect to F and CF 2 gas-phase species.

The Tian Ma Telescope (TM) is the largest fully steerable radio telescope in Asia. It has a primary reflector of 65-m in diameter with a shaped Cassegrain configuration. The primary reflector of the TM is an active surface with 1104 actuators for the 1008 surface panels. The panels of the telescope are divided into 18 rings, and 24 fan sections. Each section includes three sub-sections. The active surface system adopts TCP/IP Ethernet network and RS-485 bus as a dominating mode of communication. The control software works on the Windows system, and adopts the object-oriented technology. The photogrammetry and phase-coherent holography has been used to set the surface to about 0.3mm at the rigging angle. The FEM model is testing now. The Out-of-Focus holography and other techniques will be used to modify the dynamic surface deformation.

In coherent diffraction imaging, modulus is recorded and phase is lost. Phase retrieval is to recover the lost phase from the recorded modulus. Iterative Fourier algorithm (IFA) solves this problem by imposing modulus constraints to make the phase converge. Here we show a modulus angle joint phase retrieval method. When both amplitude and phase modulation are applied, the angle relationship, which denotes the Fourier phase difference, can be exactly derived from the measured intensities. Based on this angle relationship, a new form of IFA called angle iteration is developed, which exhibits a faster but unstable convergence compared with tradition IFA (modulus iteration). By modulus-angle combined iteration, the proposed method reaches a quick and stable convergence. With the same intensity measurements, it drops nearly 80% the phase retrieval errors by traditional IFA but costs the same CPU time. This work reveals the fact that changing the constraint format would improve the original iteration process.

The material of Zerodur is widely used in high performance optics because of its excellent thermal stability characteristics. This paper deals with the development of an APPJ (Atmospheric Pressure Plasma Jet) chemical machining process for defect free and high efficiency machining of Zerodur. The APPJ chemical machining mechanism for multi-phase multi-composite materials is presented. The chemical property of the plasma jet is investigated via the atom emission spectrum analysis method and the experimental results of Zerodur material removal function and surface roughness variation with different processing parameters are discussed. Scientific explanations for the experimental observations are given.

This paper investigates robust stability of linear time-invariant (LTI) uncertain sampled-data control systems with generalized sampled-data hold functions (GSHFs). A new sufficient condition for robust stability of such systems is developed. Unlike that of most of the previous works, it directly uses the data of the continuous-time plant and therefore it is less conservative. The condition is expressed in terms of the spectral radius of a certain matrix and is shown to be a unimodal function of a free parameter. This property enabled us to use standard one-dimensional optimization algorithm to perform the proposed test. Copyright © 2006 John Wiley & Sons, Ltd.

Robotic yoyo playing is a challenging, open-loop unstable game, which requires dynamic dexterity to stabilize. The switching control strategy proposed here stabilizes the yoyo by determining when to start its activation. A straightforward implementation is presented and demonstrated, using continuous state estimation provided by visual feedback and the previously developed dynamic model. The discrete return map associated with the original continuous system is analyzed and shown to possess a single physically relevant fixed point. Stability is guaranteed as long as the control parameter, which determines the magnitude of the acceleration, is above a certain level. The stabilizing power of the proposed control algorithm is successfully demonstrated on a real-time robotic yoyo playing system. Theoretical predictions regarding the fixed point of the return map are confirmed experimentally, providing further support for our modeling and analysis.

This paper focuses on modeling the dynamics of a yoyo—a popular toy, which presents a challenging task for robotic control. A dynamic two-degree-of-freedom (DOF) model of the yoyo with a unilateral constraint is first proposed. The flight of the yoyo is naturally split into four phases, namely, a free-motion phase, a constrained-motion phase, a bottom phase, and a transition phase. It is shown that the energy loss is mainly due to a sequence of collisions that occur between the yoyo and the string during the bottom and transition phases. The dynamics in the bottom and transition phases is simplified by a single impulsive effect with an equivalent restitution coefficient, which depends only on the mass, inertia and axle radius of the yoyo. The resulting one-DOF model captures the energy loss while greatly simplifying the dynamic model, and thus facilitating the analysis and design of yoyo control. Both models are verified by experiments conducted on three different yoyos.

Atmospheric Pressure Plasma Processing (APPP) using inductively coupled plasma has demonstrated that it can achieve comparable removal rate on the optical surface of fused silica under the atmosphere pressure and has the advantage of inducing no sub-surface damage for its non-contact and chemical etching mechanism. APPP technology is a cost effective way, compared with traditional mechanical polishing, magnetorheological finishing and ion beam figuring. Thus, due to these advantages, this technology is being tested to fabricate large aperture optics of fused silica to help shorten the polishing time in optics fabrication chain. Now our group proposes to use inductively coupled plasma processing technology to fabricate ground surface of fused silica directly after the grinding stage. In this paper, form control method and several processing parameters are investigated to evaluate the removal efficiency and the surface quality, including the robustness of removal function, velocity control mode and tool path strategy. However, because of the high heat flux of inductively coupled plasma, the removal depth with time can be non-linear and the ground surface evolvement will be affected. The heat polishing phenomenon is founded. The value of surface roughness is reduced greatly, which is very helpful to reduce the time of follow-up mechanical polishing. Finally, conformal and deterministic polishing experiments are analyzed and discussed. The form error is less 3%, before and after the APPP, when 10μm depth of uniform removal is achieved on a 60×60mm ground fused silica. Also, a basin feature is fabricated to demonstrate the figuring capability and stability. Thus, APPP is a promising technology in processing the large aperture optics.

International audience; Public screens are common in modern society, and provide information services to audiences. However, as more and more screens are installed, it becomes a burden for users to find information concerning themselves quickly. This is because screens cannot understand what users really need, they only display pre-designed information related to a certain location. To ensure better cohabitation between people and screens, one solution is to make screens understand users rather than make users understand screens. Given that it is difficult, even for humans, to interpret other people's intentions, it is far harder for screens to understand users. We need first to decide which kinds of information about users could be helpful for a screen to estimate to users' needs. In this paper, we study a public interactive screen, which can speculate as to users' intentions by interpreting their proxemic attributes (such as dis- tance, movement, etc.) and context information (identity, locations, etc.). Based on proxemic interaction semantics, we built an interactive pub- lic screen, which: 1) could interpret users' needs in advance and display relevant information; 2) be available for multi-users and display distinct information to them; 3) be open for data exchanges with users' mobile devices. Through a lab study, we demonstrate that the screen presented in this paper is more attractive to users and could provide users with useful information more rapidly and precisely than traditional screens.

The removal function is one of the key factors in achieving ultra-precision machining results by computer controlled optic surface principle. In the atmospheric pressure plasma jet machining process,the distribution of active radicals on the workpiece surface is one of the major factors that affect the removal function. However, the distribution of jet pressure on the workpiece surface affects the distribution of active radicals. The pressure distribution of the plasma jet effluent on the workpiece surface has been simulated according to jet theory. The spatial density distribution of active radicals is measured with atomic emission spectroscopy. The results show that there is a relationship between the activeradical distribution and the jet pressure distribution. Finally, based onexperimental data, the material removal function model has been developed by curve fitting, and in this model, the reactive gas flux and the distance between the nozzle and the workpiece is defined/calculated/obtained by the parametersof the removal function.

International audience; Miniaturization of smart devices and sensors, as well as widespread use of new interaction modalities make Ambient Intelligence (AmI) not a pro-spect for the future but an impending reality of existence. This requires methods for solving the issues on how to integrate interaction devices into a context-aware environment. We thus designed a middleware to provide a promising ap-proach. Our middleware adopts a two-layer structure. The lower layer is the en-terprise service bus, which is in charge of integrating context sensors and inter-action devices, and of discovering context. The higher layer is the versatile con-text interpreter, which is responsible for context inference, expressive query, and persistent storage. Finally, we implemented the prototype of this middle-ware on the street and store marketing scenario.

Proxemics is the terminology used to describe spatial relationships among humans while communicating with each other. It could be interesting to apply the proxemics theory to the domain of human computer interaction, namely proxemic interaction. Computers, unlike people, find it hard to interpret instantly and precisely the user's nonverbal hints, such as body postures, movement, and distance. With the development of computer vision, these tasks can be performed with simple devices. In this paper, we build the abstract model for calculation in proxemic interaction, and further illustrate the prototype based on research life in the lab. We then describe evolution of the prototype through investigation of proxemic interaction. Finally, we ask users for their opinion via a preliminary user study and usability test. Our study shows that users are attracted by this kind of interaction, and especially by the application scenario in the lab with a large public screen.

Aim of software testing is to find out software defects and evaluate the software quality. In order to explain the software testing can really elevate the software quality, it is necessary to assess the quality of software testing itself. This paper discusses the definition of software testing quality, and further builds the framework model of software testing quality (STQFM) and the metrics model of software testing quality (SFTMM). The availability of the models is verified by example application.

The nonlinear friction characteristics in line cylinder pneumatic servo control system are analyzed. The friction can be seen as the disturbance in the global sliding mode variable structure control (SMVSC). The system is robust during the whole response process, by changing controller structure or adjusting control parameters to suppress the disturbance. Numerical simulation shows that the SMVSC scheme has better dynamic and static performance and robustness than that of the PD scheme. Finally, the feasibility of the SMVSC is validated through experiments on the ball & plate XY trajectory pneumatic control system, and it has precise tracking performance.

Different networks of coupled oscillators were developed for open-loop control of periodic motion. However, some tasks, like yo-yo playing, are open-loop unstable and require proper phase locking to stabilize. Given the phase-locking property of coupled oscillators, we investigate their application to closed-loop control of open-loop unstable systems, concentrating on the challenging task of yo-yo control. In particular, we focus on pulse-coupling, where the yo-yo sends a feedback upon reaching the bottom of the string and the onset of the oscillatory cycle is used to trigger the movement. Four networks involving either a stand-alone or a circuit level oscillator with either excitatory or inhibitory couplings are considered. Working curve analysis indicates that three of the networks cannot stabilize the yo-yo. The fourth network, which is based on a circuit-level oscillator, is analyzed using the return map and the region of stability is determined and verified by simulations. The resulting pulse-coupled oscillatory control provides a model-free control strategy that operates with an easy-to-measure low-rate feedback.

The capabilities of an oscillator-based controller are compared with that of a model-based controller for stabilizing a yoyo in this paper. It is shown that the oscillator-based controller can operate with a once per cycle feedback, while the model-based controller requires high-rate state feedback. However, a consequence upon the oscillator-based control with low-rate feedback is a smaller stability regime in its parameter space. Hence it may be necessary to use the model-based controller with high-freq feedback to stabilize the system initially. Once the system is stabilized, it is possible to switch to the oscillator-based controller, which can keep the system stable against minor disturbances even with low-rate feedback. This is demonstrated in the context of yoyo-control, which is periodic and open-loop unstable

Open-loop unstable rhythmic tasks, like yoyo playing, require proper phase locking to stabilize. Given the phase-locking property of coupled oscillators and their successful application to open-loop control of rhythmic motion, we investigate their application to closed-loop control of a yoyo. In particular, we focus on pulse coupling, where the yoyo sends a feedback pulse upon reaching the bottom of the string and the onset of the oscillatory cycle is used to trigger the movement. A necessary condition for stable control is derived and applied to disqualify the simply-coupled stand-alone leaky integrate-and-fire oscillator. In contrast, an alternative circuit-level oscillator, known as a phase-locked loop, is proposed. The results are verified by numerical simulations and demonstrate that the proposed pulse-coupled oscillatory control provides a model-free control strategy that operates with an easy-to-measure low-rate feedback.

We investigate reactive fluorine atom spectroscopic characterization in atmospheric pressure of He/SF6 plasma using atomic emission spectrometry. As input radio frequency (RF) power levels are raised from 140 to 220 W, the emission spectra of 685.60 (3p4D-3s4P transition) and 739.87 nm (3p4P-3s4P transition) increase significantly. Moreover, an optimal value of SF6 volume concentration in the production of fluorine radicals, which is 0.8% is achieved. Addition of certain amounts of O2 into He/SF6 plasma results in the promotion of SF6 dissociation. Emission intensities of fluorine atoms show the maximum at the O2/SF6 ratio of 0.4.