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The quenching rate of the 750.4 nm actinometer line in argon by H2 and several hydrocarbons (CH4, C2H2, C2H4, C2H6) has been determined. Argon atoms at room temperature are excited by two-photon excitation at 184 nm to the 4p′[1/2]0 state, and the decay time of the fluorescence emission at 750.4 nm is measured. The quenching rates are inferred from the change of the decay time with the pressure of the quenching gas. For hydrocarbons, the quenching rates are of the order of 10−9 cm3 s−1. The radiative lifetime of the 4p′[1/2]0 is found to be 24 ns.

The first direct observation of the velocity distribution of the metastable Ar1*~2G9/2! ions in the presheath of an inductively coupled plasma has been achieved by using the Doppler shifted laser induced fluorescence technique. Drift of the ions along the electric field in the presheath is observed and distribution functions of the velocity in both parallel and perpendicular directions, relative to the E field, are deduced at 5 and 40 mTorr. Present results show that in high density plasmas the velocity distribution of the metastable ions is directly related to that of the ground state argon ions. Neutral gas temperature of around 600 K is also measured from the absorption profile of a diode laser beam, set on one of the 772.4 nm argon lines.

Most commercial CFD tools use fan curves to represent a fan. However, the presence of a blockage near inlet or exhaust of a fan and a restricted airflow direction will alter the fan performance, and the use of the original fan curve may result in erroneous results in these cases. A new approach to model fans will be presented in this paper. Using conservation of mass, momentum and energy, and the velocity triangles, this model relates velocity and pressure at fan exhaust to the corresponding values at fan inlet as well as fan geometry, rotational speed and fan blade lift and drag coefficients.Copyright © 2005 by ASME

We review an interesting case of craniocervical necrotizing fasciitis with thoracic extension in an immunocompetent 44-year-old man. The patient underwent aggressive medical and surgical management during a long hospitalization. Multiple surgical debridements, including transcervical mediastinal debridement, and eventually a thoracotomy for mediastinal abscess were required. The patient eventually recovered, and 3 months later he showed no sign of complications or recurrence. Craniocervical necrotizing fasciitis is a fulminant soft-tissue infection, usually of odontogenic origin, that requires prompt identification and treatment to ensure survival. Broad-spectrum intravenous antibiotics, aggressive surgical debridement and wound care, hyperbaric oxygen, and good intensive care are the mainstays of treatment.

SiClX (X=0–2) radicals’ concentrations have been measured by broadband ultraviolet absorption spectroscopy during the etching of 200mm diameter silicon wafers in HBr∕Cl2∕O2 plasmas. We report the variations of the concentrations of these radicals as a function of the radio frequency (rf) source power and rf-bias power. The silicon wafer etch rate is measured simultaneously. From the measured radicals densities and using electron impact ionization cross sections found in the literature, the densities of SiClX+ ions are calculated and are found to be in good agreement with ion densities measured by mass spectrometry. The upper limit for the SiCl2 radical concentration is calculated from the wafer etch rate. By comparison with the measured SiCl2 radical concentration it is concluded that SiCl2 radicals should also be produced by the reactor walls due to the etching of silicon containing species adsorbed on the reactor walls. Finally, using electron impact dissociation cross sections, the densities of SiCl an...

The 443 nm Ar+ line emission intensity in a cylindrical argon magnetoplasma excited by a 13.56 MHz helicon antenna is found to be strongly modulated at the excitation frequency. The peak in optical emission propagates in the axial direction at a velocity corresponding to that of helicon waves launched by the antenna. The spatiotemporal modulation is consistent with pulses of electrons produced by acceleration under the antenna and subsequent entrainment of these electrons over half of a trapping period in the axial electric field of the helicon wave.

Objective: To describe the new technique of transnasal endoscopic medial maxillectomy. Study Design: Study design included application of the new technique in the management of five patients with inverting papilloma; retrospective review of five patients who had lateral rhinotomy with medial maxillectomy for inverting papilloma; comparison of transnasal endoscopic medial maxillectomy to open medial maxillectomy for scope of resection, margin control, operative time, and surgical access; and detailed description of transnasal endoscopic medial maxillectomy. Methods: Charts were reviewed and tabulated for operative time, duration of follow-up, and recurrence. Pathology reports were reviewed for number and orientation of the specimens and for margin control. Results: Operative time was shorter for patients managed with transnasal endoscopic medial maxillectomy. All patients with transnasal endoscopic medial maxillectomy had one large, well-oriented specimen with margin control. There was no recurrence in either group. Conclusions: Transnasal endoscopic medial maxillectomy providing full access to the maxillary and ethmoid sinuses is described in detail. Transnasal endoscopic medial maxillectomy is an effective, reproducible technique with less operative time and morbidity and, possibly, better pathological tumor mapping than open medial maxillectomy for selected patients. Maxillary sinus involvement with inverting papilloma is not a contraindication for this technique. Strong illumination, superior resolution, and angled visualization, coupled with exact osteotomies, make transnasal endoscopic medial maxillectomy an efficacious technique for inverting papilloma with extension limited to the maxillary and ethmoid sinuses.

We have developed a new method for measuring electric field magnitude using 2+1 photon laser‐induced fluorescence of ground‐state hydrogen atoms. The atoms are excited to the n=2 level by two 243‐nm photons, then further excited to the n=6 level by one photon at 410 nm and detected by cascaded Hα fluorescence. The electric field magnitude is deduced from the Stark splitting of the n=6 level. The method was calibrated using H atoms from a distant source flowing through a region of known electric field. Results are presented for field profiles in dc discharges in 0.3 and 1 Torr pure H2.

The time-resolved OH density in a nanosecond pulsed filamentary discharge in an atmospheric pressure He–H2O(0.05%) mixture is measured using laser induced fluorescence. The lifetime of the excited OH(A) state is found to be strongly time dependent during the plasma pulse, with the shortest decay time occurring at the moment the plasma is switched off. The measured LIF intensity is corrected for this time-resolved quenching and calibrated using Rayleigh scattering. Time-resolved electron density , He (3S1) metastable density , gas temperature and optical emission are presented and used in the interpretation of the observed time dependence of the OH density. Based on these experimental data, it is shown that for the present discharge conditions, OH is mainly produced by charge transfer reactions to water followed by dissociative recombination of the water ion. In addition, two often encountered issues with the calibration of OH LIF are highlighted with an example.

Chylothorax is a serious condition with a high rate of morbidity that may lead to death. Although it is encountered more frequently with certain thoracic procedures, it is considered to be a rare complication of neck dissection. Different forms of management have been postulated; however, no consensus of treatment has been achieved. A case of severe bilateral chylothorax that developed after bilateral neck dissection in a patient with laryngeal carcinoma is presented. Somatostatin injection was successful after total parenteral nutrition failed to control the chylothorax. On the basis of this case and the review of the literature discussed here, we advocate the use of somatostatin with other conservative measures in the management of chylothorax.

Ion and neutral temperatures are measured by high‐resolution laser‐induced fluorescence spectroscopy both in the source and downstream of an electron cyclotron resonance discharge through mixtures of Ar, Ar/Ne, and Ar/He. Contrary to previous reports, both ions and neutrals are found to be cold. In the source, ion temperatures perpendicular to the magnetic field are ≤0.5 eV; downstream they are ∼0.25 eV. Neutral temperatures in the source and downstream are 0.068 and 0.030 eV, respectively.

Electron cyclotron resonance plasma sources are gaining widespread use in plasma processing because they offer high ion flux with controllable energy and thereby high etching and deposition rates with minimal damage. However, it is unclear how ion energy distributions evolve from source to wafer as a function of plasma parameters such as pressure, microwave power, and magnetic field strength. Therefore, we used Doppler broadened and shifted laser‐induced fluorescent line profiles to measure Ar+ metastable ion velocity distributions downstream from a divergent magnetic field electron cyclotron resonance source. Spatially resolved distributions, measured at positions above and across a wafer platen, differ markedly from shifted Maxwell–Boltzmann functions. Ions are accelerated along the magnetic field direction by a weak (∼0.5 V/cm), ambipolar electrostatic field. The ion energy component perpendicular to the electric field corresponds to a temperature of only 0.46±0.10 eV. On the edges of the platen, the m...

Objectives: To study immunotherapy for advanced head and neck squamous cell carcinoma using AT-84, a spontaneously arising murine tumor. We examined the draining lymph nodes (DLNs) for generation of potential therapeutic lymphocytes in head and neck squamous cell carcinoma. Design: Experimental randomized control trial. Intervention: Therapeutic T cells from DLNs were generated by the sequential activation of the in vivoprimed DLN cells with 2C11, an anti-CD3 antibody, and interleukin-2 (IL-2). Immunotherapy of mice bearing lung metastases was carried out in various experiments with low-dose systemic IL-2 and activated DLN cells. Using a 4-hour radioactive chromium Cr 51 release assay, in vitro cytotoxicity of these cells also was examined. Results: Mice immunized with this tumor failed to reject the growth of a subsequent challenge with the tumor. Immunotherapy with low-dose systemic IL-2 resulted in a mean reduction of 79% in the number of lung metastases. Adoptive immunotherapy with activated DLN cells was effective in all experiments, with a mean reduction of 59% in the number of metastases in immunodeficient mice. However, DLN cells were not directly cytotoxic to the tumor cells in in vitro assays, unlike control lymphokine-activated killer cells. Conclusions: AT-84 is a nonimmunogenic tumor similar to many human malignant neoplasms, making this a suitable model for immunotherapy. Low-dose systemic IL-2 was effective in reduction of established metastasis in this model. Activated DLN cells show reproducible in vivo therapeutic efficacy despite lack of in vitro cytotoxicity. Use of DLN cells as sources of therapeutic T cells in patients with head and neck squamous cell carcinoma deserves exploration because they are readily obtainable and because conventional treatment is of limited benefit. Arch Otolaryngol Head Neck Surg. 1997;123:25-30

International audience; Absolute OH densities are obtained in a radio-frequency-driven Ar-H2O atmospheric-pressure plasma jet by laser-induced fluorescence (LIF), calibrated by Rayleigh scattering and by UV broadband absorption. The measurements are carried out in ambient air and the effect of air entrainment into the Ar jet is measured by analyzing the time-resolved fluorescence signals. The OH densities are obtained for different water vapor concentrations admixed to the Ar and as a function of the axial distance from the nozzle. A sensitivity analysis to deduce the accuracy of the model-calculated OH density from the LIF measurement is reported. It is found that the UV absorption and the LIF results correspond within experimental accuracy close to the nozzle and deviate in the far effluent. The possible reasons are discussed. The OH densities found in the plasma jet are in the range (0.1-2.5) × 1021 m-3 depending on the water concentration and plasma conditions.

The 9th Workshop on Frontiers in Low Temperature Plasma Diagnostics (FLTPD) was held in Zinnowitz, near Greifswald, Germany. FLTPD is a biennial European event in which scientists working on low-temperature plasmas present their recent results, pointing out in particular the originality of the diagnostic techniques used. The idea of starting this series of workshops was born in a discussion between Frieder Dobele, Bill Graham and myself when travelling together from Bar Harbor, USA (after the 6th LAPD) to Montreal, Canada in October 1993. It became evident that we had been lacking a European meeting that could bring together experts in the field of low-temperature plasma diagnostics and create the possibility to share the knowledge of these diagnostics with new generations of scientists. The first FLTPD was held in Les Houches, France, in February 1995 and since then it has been organized in the spring of all odd-numbered years in different European countries, as shown in the following table. YearLocationChair of LOC 1995Les Houches, FranceJ Derouard 1997Bad Honnef, GermanyF Dobele 1999Saillon, SwitzerlandCh Hollenstein 2001Rolduc, NetherlandsR van de Sanden 2003Speccia, ItalyS De Benedictis 2005Les Houches, FranceN Sadeghi 2007Cumbria, UKM Bowden 2009Blansko, Czech RepublicF Krcma 2011Zinnowitz, GermanyJ Ropke To encourage brainstorming and extended discussions among participants, FLTPD meetings have always been organized in isolated locations with the number of attendees limited to about 70. Workshops extend over three and a half days with about 10 expert presentations by invited speakers (a few from overseas) and short oral or poster contributions. This special issue of Plasma Sources Science and Technology contains 11 articles representative of contributions to the last FLTPD in Zinnowitz. These peer-reviewed articles, which bring the 9th FLTPD to a wider audience, represent a snapshot of current topics in low-temperature plasma diagnostics. However, no attempt is made to give a full review of the field, which is in fact much wider and still rapidly developing. I hope, nevertheless, that readers will find this compilation useful and stimulating for their research and that the special edition will serve as a convenient reference source. My special thanks go to the Scientific Committee for their important contributions to the success of the workshop in selecting invited speakers. I also am particularly grateful to the Editorial Board of Plasma Sources Science and Technology for the publication of this special issue.

Consideration of ion transport in high density, low pressure plasma systems is important for meeting process requirements in the manufacturing of ultra-large-scale integrated circuits. The ion energy and angular distributions at the boundary between the plasma and the wafer, the sheath, influence etching selectivity, linewidth control, plasma-induced damage, and microscopic etching uniformity. These distributions, in turn, are easily altered by changing the magnetic field profile and/or the neutral gas pressure. Using Doppler-shifted laser-induced fluorescence, metastable ion velocity distribution functions in helicon-wave-excited Ar plasmas are measured. Two magnetic field configurations are examined. For a magnetic "mirror," where the field exhibits a maximum and a saddle point in the source, the plasma is observed to be asymmetric and nonuniform: this leads to broadened velocity distributions and significant ion drift from one region of the plasma to another. As the pressure is increased in the mirror field configuration, the transverse ion "temperature" exhibits a maximum as a function of pressure and, when etching is ion-flux limited, either decreasing or increasing the pressure should result in improved linewidth control. The plasma is more symmetric when the magnetic field is reversed in the source and again downstream. With this double cusp configuration, the transverse ion temperature decreases monotonically with pressure, and improved linewidth control in the ion-flux limit would be obtained by operating at higher pressure.

Objectives In select hosts fungal species may become invasive and opportunistic, resulting in severe morbidity and mortality. We report a rare case of invasive Aspergillus, diagnosed on initial presentation as chronic fungal otitis externa.

International audience; Laser scattering experiments were performed in high pressure (100s of Torr) parallel-plate, slot-type DC microdischarges operating in argon or nitrogen. Laser Thomson Scattering (LTS) and Rotational Raman Scattering were employed in a novel, backscattering, confocal configuration. LTS allows direct and simultaneous measurement of both electron density (ne) and electron temperature (Te). For 50 mA current and over the pressure range of 300 - 700 Torr, LTS yielded Te = 0.9 ± 0.3 eV and ne = (6 ± 3)*1013 cm-3, in reasonable agreement with the predictions of a mathematical model. Rotational Raman spectroscopy (RRS) was employed for absolute calibration of the LTS signal. RRS was also applied to measure the 3D gas temperature (Tg) in nitrogen DC microdischarges. In addition, diode laser absorption spectroscopy was employed to measure the density of argon metastables (1s5 in Paschen notations) in argon microdischarges. The gas temperature, extracted from the width of the absorption profile, was compared with Tg values obtained by optical emission spectroscopy.

International audience; Optical emisssion spectroscopy was employed to study a high pressure (100 s of Torr), slot-type (600 μm interelectrode gap), argon dc microdischarge, with added traces of nitrogen. Spatially resolved gas temperature profiles were obtained by analyzing rovibrational bands of the N2 first positive system. The gas temperature peaked near the cathode and increased with current. The contribution of Stark broadening to the hydrogen Hβ emission lineshape was used to extract the electron density. The axial distribution of electron density as well as visual observation revealed that the microdischarge positive column was highly constricted. The electron density near the sheath edge increased with both pressure and current.

For applications in ultra-large scale integration, low pressure, high density plasmas are being developed for etching and deposition of thin films. To control critical parameters such as the flux and energy distribution of ions impacting surfaces, it is necessary to understand how these parameters are influenced by physical and electromagnetic design. In this work, we report measurements of ion velocity distributions in Ar/He and Cl2/He electron cyclotron resonance plasmas. Using Doppler-shifted laser-induced fluorescence spectroscopy, we measure metastable Ar and Cl ion velocity distributions parallel and perpendicular to the magnetic field as a function of magnetic field amplitude, pressure, and microwave power. We also examine the effects of the wafer platen on the distribution functions by repeating the measurements after removing the platen. We find nearly isotropic ion velocity distributions when the source is operated as a magnetic mirror and the He partial pressure is low; higher He pressures tend to cool the parallel velocity distribution. Downstream, we consistently observe bimodal ion velocity distributions: the fast component, created in the source, follows magnetic flux lines into the reactor; the slow component, created mostly where the plasma expands from the source into the reaction chamber, is more isotropic. The relative amplitudes of these two components, the average ion energy, and the ion energy distribution are easily controlled by changing pressure and magnetic field.

The working diagnosis was chronic aerophagia, exacerbated by carbonated drinks, leading to an acute airway obstruction and syncope. To relieve the obstruction, we counteracted the pressure of the ballooning posterior tracheal wall by placing the patient on continuous positive airway pressure (CPAP) and decompressing the upper gastrointestinal (GI) tract with a nasogastric tube. The patient’s stridor and dyspnea almost immediately improved. Achalasia (and other esophageal motility disorders) and obstructing lesions of the GI tract were considered in this patient. During the subsequent hospitalization, CT scans of the neck and chest and barium swallow with small bowel followthrough redemonstrated a massively dilated esophagus and stomach, without any masses. GI motility studies were also completed and revealed esophageal aperistalsis without evidence of achalasia. A 24-hour Holter monitoring eliminated likely cardiac causes for the syncopal event. The patient’s psychiatrist was consulted, and his medications were rearranged in an effort to decrease the number of neuroleptic substances. After several days of CPAP and nasogastric desufflation, the patient’s stridor resolved. Repeat bronchoscopy displayed improvement in the airway with less ballooning of the posterior wall; however, the esophagus and stomach remained persistently dilated on subsequent imaging. We were able to wean the patient off of CPAP and remove the nasogastric tube by day 7. He was ultimately discharged on hospital day 30 (extended for social service reasons), with instructions to avoid carbonated drinks. DISCUSSION

International audience; The temporal characteristics of the Xe+ ion axial velocity distribution function (VDF) were recorded in the course of low-frequency discharge current oscillations (~14 kHz) of the 5 kW class PPS®X000 Hall thruster. The evolution in time of the ion axial velocity component is monitored by means of a laser induced fluorescence diagnostic tool with a time resolution of 100 ns. As the number of fluorescence photons is very low during such a short time period, a homemade pulse-counting lock-in system was used to perform real-time discrimination between background photons and fluorescence photons. The evolution in time of the ion VDF was observed at three locations along the thruster channel axis after a fast shutdown of the thruster power. The anode discharge current is switched off at 2 kHz during 5 μs without any synchronization with the current oscillation cycle. This approach allows to examine the temporal behavior of the ion VDF during decay and ignition of the discharge as well as during forced and natural plasma oscillations. Measurements show that the distribution function of the axial component of the Xe+ ion does change periodically in time with a frequency close to the current oscillation frequency in both forced and natural cases. The ion density and the mean velocity are found to oscillate, whereas the velocity dispersion stays constant, which indicates that ionization and acceleration layers have identical dynamics. Finally, variations over time in the electric field are for the first time experimentally evidenced in a crossed-field discharge.

Laser Thomson scattering in a novel, backscattered configuration was employed to measure the electron temperature (Te) and electron density (ne) in argon dc microdischarges, with an interelectrode gap of 600μm. Measurements were performed at the center of the gap that corresponds to the positive column. For 50mA microdischarge current and over the pressure range of 300–700Torr, the plasma parameters were found to be Te=0.9±0.3eV and ne=(6±3)×1013cm−3, in reasonable agreement with the predictions of a mathematical model.

It is shown that the spectrum attributed in the work of Shun’ko and Belkin [J. Appl. Phys. 102, 083304 (2007)] to the 557 nm forbidden transition of oxygen, O(S10→D12), induced by collision with argon atoms is probably the chemiluminescence from the O+NO reaction. Also, given the less than 0.1 ms lifetime of O(S10) atoms in the gas flow, they cannot survive during the transport to the surface, and hence they cannot be responsible for the observed cleaning effect.

Magnetic neutral loop discharges (NLDs) can be operated at significantly lower pressures than conventional radio-frequency (rf) inductively coupled plasmas (ICPs). These low pressure conditions are favourable for technological applications, in particular anisotropic etching. An ICP–NLD has been designed providing excellent diagnostics access for detailed investigations of fundamental mechanisms. Spatially resolved Langmuir probe measurements have been performed in the plasma production region (NL region) as well as in the remote application region downstream from the NL region. Depending on the NL gradient two different operation modes have been observed exhibiting different opportunities for control of plasma uniformity. The efficient operation at comparatively low pressures results in ionization degrees exceeding 1%. In this regime neutral dynamics has to be considered and can influence neutral gas and process uniformity. Neutral gas depletion through elevated gas temperatures and high ionization rates have been quantified. At pressures above 0.1 Pa, gas heating is the dominant depletion mechanism. At lower pressures neutral gas is predominantly depleted through high ionization rates and rapid transport of ions by ambipolar diffusion along the magnetic field lines. Non-uniform profiles of the ionization rate can, therefore, result in localized neutral gas depletion and non-uniform processing. We have also investigated the electron dynamics within the radio-frequency cycle using phase resolved optical emission spectroscopy and Thomson scattering. In these measurements electron drift phenomena along the NL torus have been identified.

Objective To demonstrate an anatomic basis for endoscopic medial maxillectomy with excision of the lateral nasal wall to the nasal floor, including the inferior turbinate, and nasolacrimal duct. Transnasal endoscopic medial maxillectomy involves complete resection of the lateral nasal wall with boundaries that are inferior to the nasal floor; superior to the cribriform plate and fovea ethmoidalis; anterior to the anterior maxillary wall, including the nasolacrimal duct; and posterior to within 5 mm of the eustachian tube. Transnasal endoscopic medial maxillectomy provides exposure for endoscopic resection of the orbital wall, pterygopalatine fossa, pterygoid plates, nasopharynx, and anterior skull base when indicated. Design Volumetric analysis of the maxillary sinus was performed on axial and coronal computed tomographic scans of 19 adult patients for a total of 38 maxillary sinuses. Setting Tertiary care medical center. Patients Nineteen adult patients with tumors of the head (but outside the sinonasal region). Interventions Radiographic analysis. Main Outcome Measures The total volume of the maxillary sinus, volume above and below the superior attachment of the inferior turbinate, and volume anterior to the nasolacrimal duct were measured. Results The mean (SD) total volume of the maxillary sinus was 20.1 (4.2) cm 3 , whereas its volume inferior to the superior attachment of the inferior turbinate was 12.9 (3.7) cm 3 and anterior to the nasolacrimal duct was 1.1 (0.6) cm 3 . The mean (SD) volume of the maxillary sinus inferior to the superior attachment of the inferior turbinate was 64% (12%), whereas the nasolacrimal duct obscured the transnasal anterior exposure of the maxillary sinus. Conclusion Without excision of the lateral nasal wall inferiorly to the nasal floor and anteriorly, including the nasolacrimal duct, over half of the maxillary sinus would be inaccessible for procedures directed at neoplasms within the maxillary sinus.

The nickel atom density was measured in an inductively coupled argon plasma with an internal Ni coil, as a function of pressure and power, using optical absorption spectroscopy. Nickel atoms were sputtered from the coil and from a separate Ni target under optional target bias. A fraction of the atoms was ionized in the high-density plasma. The gas temperature was determined by analyzing the rovibrational spectra of the second positive system of nitrogen actinometer gas. The electron density was determined by optical emission spectroscopy in combination with a global model. For a pressure of 8–20mTorr and coil power of 40–200W, the Ni atom density ranged from 2.7×109to1.5×1010cm−3, increasing strongly with pressure. The Ni atom density first increased with power but saturated at high power levels. The measured Ni atom density agreed fairly well with the predictions of a global model, in particular, at the higher pressures. The model also predicted that the Ni+ ion density greatly increased at higher powers...

International audience; During silicon gate etching in low pressure high density HBr/Cl2/O2 plasma, SiOClx layers are deposited on the reactor walls. These layers are at the origin of process drifts. However their chemical composition, deposition mechanism and their influence on the plasma chemistry remains poorly understood. In this study, the chemical composition of this layer has been investigated by a “plasma etching-sputtering” technique: the silicon oxychloride layer deposited on the reactor walls during the etching of a 200 mm diam silicon wafer has been subsequently submitted to an Ar plasma with the addition of a few % SF6. During the slow etch process of this layer, time-resolved optical emission spectroscopy and mass spectrometry have been used to follow the time evolution of the gas phase concentration of different atoms and radicals, the etch products of the SiOClx layer. The results give insight into the chemical nature of the deposited layer and of its variation as a function of the depth. In particular, it will be shown that these layers are chlorine-rich and not oxidelike. Also, their composition is not homogeneous through their depth. In a second set of experiments, the SiOClx layer has been exposed to an Ar/O2 plasma providing information on the oxidation mechanism of the Si–Cl bonds and thus on the SiOClx film deposition mechanism in HBr/Cl2/O2 plasmas. This oxidation mechanism is acting through the entire volume of the 10 nm thick layers and proceeds by substitution of Cl atoms of SiCl bonds by O atoms, resulting in desorption of a large amount of Cl atoms from the chamber walls during the layer oxidation. Finally, the layer on the chamber walls has been exposed to an Ar/Cl2 plasma, demonstrating that SiOClx layers are not etched significantly by Cl atoms.

To establish and characterize the first pediatric normative database for the Multi-Dimensional Voice Program, a computerized voice analysis system, and to compare the normative data with the vocal profiles of patients with vocal fold nodules.A cross-sectional, observational design was used to establish the normative database. The comparative study was completed using a case-control design.University-based outpatient pediatric otolaryngology clinic.One hundred control subjects (50 boys and 50 girls) aged 4 to 18 years contributed to the normative database. The voices of 26 patients (19 boys and 7 girls) with bilateral vocal fold nodules were also analyzed.Demographic data, including sex, age, height, weight, body mass index, and cigarette smoke exposure, were obtained. The Multi-Dimensional Voice Program extracted up to 33 acoustic variables from each voice analysis.The mean (SEM) values of each of the acoustic variables are presented. At age 12 years, boys experience a dramatic decrease in fundamental frequency measurements. The voices of patients with vocal fold nodules had significantly elevated frequency perturbation measurements compared with control subjects (P.001).The vocal profile of children is uniform across all girls and prepubescent boys. Patients with vocal fold nodules demonstrated a consistent acoustic profile characterized by an elevation in frequency perturbation measurements. Normal acoustic reference ranges may be used to detect various vocal fold pathologic abnormalities and to monitor the effects of voice therapy.

Anisotropic etching of silicon gates is a key step in today’s integrated circuit fabrication. For sub-100 nm gate dimensions, one of the main issues is to precisely control the shape of the etched feature. This requires a detailed knowledge of the various physicochemical mechanisms involved in anisotropic plasma etching. Since silicon etching in high-density plasmas is strongly ion assisted, the identities of the ions bombarding the wafer is a key parameter that governs the etch rates and the etched profiles. In the present article, mass spectrometry has been used to investigate the chemical composition of the ion flux bombarding the reactor walls of an industrial inductively coupled plasma used for 200-mm-diam silicon wafer processing. The plasma chemistries investigated are HBr/Cl2/O2 and HBr/Cl2/O2/CF4 mixtures optimized for sub-100 nm gate processes. Quantitative ion mass spectra show that under those conditions the ion flux contains up to 50% of SiClXBrY+ (X,Y=0–2) ions, although Cl+, Cl2+, and Br+ i...

Threshold ionization mass spectrometry method has been applied to the study of the neutral radicals present in a microwave generated CF4 plasma. Calibration of the mass spectrometry signals by comparison with the ion signals produced by the dissociative ionization of CF4 allows the estimation of the absolute concentration of the radicals in a 15 mTorr plasma, with an emphasis on the cases of atomic fluorine and CFx (x = 1–3) radicals. The effect, on the gas phase composition, of the introduction of a silicon sample in the plasma chamber is also investigated. Among these effects, the introduction of silicon leads to decrease the concentration of the F and H atoms as well as HF molecules, and to increase the concentration of the SiF3 and CFx radicals.

High‐density plasmas are being used in the manufacture of electronic devices and systems because they provide high throughput at low pressure and low ion energy. Low pressure is desirable for maximizing process uniformity over large substrates while low ion energy is desirable for minimizing process‐induced damage. However, the optimal design for a high density plasma reactor is unclear and the technology has largely developed empirically: many alternatives for magnetic and geometric design are offered for the same processing applications. In this talk we discuss diagnostic measurements of high density plasma reactors and how they can be used in developing improved reactor designs and in providing insight into materials processing. Laser‐induced fluorescence measurements of metastable ion velocity distributions are made in both Ar and Cl2 electron cyclotron resonance and helicon plasmas. The effects of magnetic field configuration, power, and pressure on the energy and angular distributions of the ions wi...

The present work reports an economically attractive improvement in the area of producing particulate slow release nitrogen fertilizer using lignin as a waste effluent of pulp and paper manufacturing process. An improved coating of modified lignin was applied on the surfaces of the individual urea particles. The Kraft and Sulfite black liquors obtained from two different paper pulping units and were used as sources of sulfate and sulfite lignin, respectively. Chemical modification of extracted lignin was performed through acetylation reaction by acetic acid/sodium metabisulfite to increase its hydrophobicity character. In a separate experiment, a thin layer of synthesized acetylated lignin was coated on granular urea by fluidized-bed technique. The nitrogen release of synthesized fertilizer in the water and soil was examined by the Kjeldahl method. The analysis of FTIR spectra indicated the changes in the functional groups of acetylated lignin. Petrographic photography and scanning electron microscopy (SEM) analyses demonstrated a uniform and homogeneous covering of the urea surface. The 7 day nitrogen release rate of urea coated by acetylated lignin in soil was obtained 36.3 and 45.3 % for Kraft and Sulfite lignin, respectively, whereas this value was 59 % for sulfur coated urea. Using industrial wastewater as source of lignin gives satisfactory results for industrial applications and yields a quality green fertilizer product with reduced operation difficulties while considerably preserving the environment.

Electric-field-induced mixing between e and f ?-doublet states of an NaK (B1 ?) molecule has been used to determine the amplitude of the local electric field inside a discharge. This nonperturbative technique is based on the laser-induced fluorescence spectroscopy of NaK (B - X) transition with a tunable CW laser. Electric fields of a few volts per centimeter up to several kilovolts per centimeter can be measured with a spatial resolution of 0.1 mm.

Background Nasopharyngeal carcinoma (NPC) is a solid tumor of the head and neck. Multimodal therapy is highly effective when NPC is detected early. However, due to the location of the tumor and the absence of clinical signs, early detection is difficult, making a biomarker for the early detection of NPC a priority. The dysregulation of small non-coding RNAs (miRNAs) during carcinogenesis is the focus of much current biomarker research. Herein, we examine several miRNA discovery methods using two sample matrices to identify circulating miRNAs (c-miRNAs) associated with NPC. Methods We tested two miRNA discovery workflows on two sample sources for miRNAs associated with NPC. In the first workflow, we assumed that NPC tumor tissue would be enriched for miRNAs, so we compared miRNA expression in FFPE from NPC cases and controls using microarray and RNA-Seq technologies. Candidate miRNAs from both technologies were verified by qPCR in FFPE and sera from an independent NPC sample set. In a second workflow, we directly interrogated NPC case and control sera by RNA-Seq for c-miRNAs associated with NPC, with candidate c-miRNAs verified by qPCR in the sera from the same independent NPC sample set. Results Both microarray and RNA-Seq narrowed the miRNA signature to 1-5% of the known mature human miRNAs. Moreover, these two methods produced similar results when applied to the same sample type (FFPE), with RNA-Seq additionally indicating “unknown” miRNAs associated with NPC. However, we found different miRNA profiles in NPC sera compared to FFPE using RNA-Seq, with the few overlapping miRNAs found to be significantly up-regulated in FFPE significantly down-regulated in sera (and vice versa). Despite the different miRNA profiles found in FFPE and sera, both profiles strongly associated with NPC, providing two potential sources for biomarker signatures for NPC. Conclusions We determined that the direct interrogation of sera by RNA-Seq was the most informative method for identifying a c-miRNA signature associated with NPC. We also showed that there are different miRNA expression profiles associated with NPC for tumor tissue and sera. These results reflect on the methods and meaning of miRNA biomarkers for NPC in tissue and peripheral blood.

Plasma-reactor walls interactions during etching processes by an inductively coupled plasma are an important cause of process drift in the semiconductor industry. By using a simple technique based on X-ray photoelectron spectroscopy analyses of the reactor walls coating, we have investigated the mechanism responsible for the formation of a deposit on the reactor walls after metal gate stack etching processes, and the associated reactor cleaning strategies. We show that, in the most typical etch and clean processes, reactor walls are inevitably exposed to F-based plasma leading to the formation and accumulation of AlFx residues on the Al2O3 reactor walls, hence to process drifts. These residues can be removed by SiCl4 or BCl3 based plasmas. We have also investigated a new cleaning/conditioning strategy of plasma etching reactors, in which the chamber walls are coated by a carbon-rich film between each wafer, allowing reproducible processing conditions to be achieved while preventing the AlFx issue. The influence of the reactor wall composition on the chemistry of chlorine-based plasmas is studied by numerous plasma diagnostic techniques and the importance of the cycling of etch by-products between the reactor walls and the gas phase is highlighted., Les interactions entre les plasmas créés par couplage inductif et les parois du réacteur sont responsables du manque de reproductibilité des procédés de gravure par plasma auquel est confrontée l'industrie microélectronique. Nous avons mis en évidence le mécanisme global de formation des dépôts sur les parois du réacteur pendant la gravure de divers matériaux grâce à une technique d'analyse des parois basée sur la spectroscopie de photoélectrons X. L'utilisation de plasmas à base de fluor est inévitable pour retirer ces dépôts et ainsi obtenir une reproductibilité satisfaisante, mais elle conduit à la formation de matériau AlFx sur les parois en Al2O3 des réacteurs - et ainsi à des dérives de procédés - à moins de lui associer un nettoyage par plasma à base de SiCl4 (ou de BCl3). Nous avons également étudié une stratégie de conditionnement des parois du réacteur avec du carbone qui permet d'améliorer la reproductibilité des procédés de gravure tout en supprimant le problème d'apparition de l'AlFx. L'impact de la nature chimique des parois du réacteur sur la physico-chimie des plasmas à base de chlore est détaillé et le rôle majeur du recyclage des espèces sur les parois du réacteur est mis en évidence.