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Background/Purpose Ludwig's angina (LA) still presents regularly and various characteristics are documented, but patients admitted to the Intensive Care Unit (ICU) has not been studied. The purpose of this study was to investigate the clinical characteristics and outcomes of patients with LA who were admitted to ICU. Materials and methods We retrospectively reviewed all 29 patients with LA who were admitted to the ICU of a university hospital from January 2013 to October 2018. Results were evaluated via descriptive analysis. The Log–Rank test was used to analyze the hospital/ICU length of stay (LOS). Results The male: female ratio was 2.63:1. Mean age was 53.41 ± 16.57 years (range 8–78 years). Concomitant conditions comprised diabetes mellitus in 10 patients (34.48%), and hypertension in six (20.69%). The main reason for ICU admission was surgical (44.83%). The mean Acute Physiology, Age, Chronic Health Evaluation II (APACHE II) and the Sequential Organ Failure Assessment (SOFA) scores were 13.52 ± 3.18 and 3.83 ± 2.89, respectively. Twenty-eight patients (96.55%) received respiratory support. Sixteen patients (55.17%) had positive bacterial culture results. Fourteen bacterial strains were detected, most of which were gram-positive (72.72%). Mean LOS was 6.89 ± 14.39 days (range 0.5–73 days), and 24.79 ± 16 days in the hospital. The ICU mortality rate was 10.34%. Compared with LA patients without descending necrotizing mediastinitis (DNM), those with DNM had longer ICU and hospital LOS. The laboratory investigations were higher. Conclusion LA patients in ICU were predominantly male, with a wide range age, high incidence of complications, long hospital LOS.

Artificially-structured functional materials (AFMs) are artificial media that combine the advantages of nature materials and artificial structures to produce excellent and unexpected properties. Ferroelectric materials have key features in possessing spontaneous polarizations, which can be switched by using electric field, temperature, and strain. This review article attempts to provide a comprehensive insight into the current development of ferroelectric composite AFMs, and to introduce a developing subject in realizing multifield controls for tunable functional devices. Some typical ferroelectric materials and their multifield tunable mechanisms are summarized in detail. The incorporation of ferroelectric materials can yield various designs of AFMs to modulate electromagnetic waves. Recent progress of typical designs with different tuning strategies for active AFMs are illustrated and compared, including the metamaterials, metasurfaces, heterojunctions, superlattices, and their hybrid designs. This scientific subject involves interesting research topics of electromagnetism, electronics, optoelectronics, and ferroelectrics, which is significant to bring novel functionalities via multifield controls.

The KxNa1-xNbO3 nanopowders with cubic-like morphology and an average size of about 50 nm were synthesized by sol-gel auto-combustion method. And then, the ceramics were prepared and the phase transition, microstructure and electrical properties of the KxNa1-xNbO3 ceramics were investigated. Pure perovskite phases of the KxNa1-xNbO3 ceramics were confirmed by XRD patterns and the K0.50Na0.50NbO3 ceramics show the coexistence of orthorhombic and monoclinic structures. SEM micrographs show that all samples have bimodal grain size distributions and the number of the small grains decrease with increasing K+ content in the bimodal grain size distribution system. The K0.50Na0.50NbO3 ceramics with the uniform grain size and the maximum density show excellent electrical properties with er=467.40, tan δ=0.020, d33=128 pC/N and kp=0.32 at the room temperature, demonstrating that the properties of the K0.50Na0.50NbO3 powers prepared by sol-gel auto-combustion are excellent and the ceramics are promising lead-free piezoelectric materials.

The effects of dwell time on the phase structure, microstructure, and electrical properties were investigated for the 0.98(K0.5Na0.5)NbO3-0.02LaFeO3 ceramics (abbreviated as 0.98KNN–0.02LF). All the ceramics sintered for different dwell time are of pure phase and the peak intensity of the 0.98KNN–0.02LF ceramics becomes stronger with a longer dwell time. Denser microstructures with larger grain size are developed for the sample with a longer dwell time. The maximum dielectric permittivity decreases with increasing the dwell time, and the deteriorative dielectric properties are due to the increasing grain size and the domain wall motion. Ferroelectric properties results indicate that 2Pr value slightly decreases with increasing the dwell time, while the 2Ec value increases. Consequently, the 0.98KNN–0.02LF ceramic sintered at 1150 °C for 2 h shows optimum dielectric properties (ɛr=2253 and tan δ

(1-X)K0.5Na0.5NbO3–xBiGaO3[(1-X)KNN-Xbg] Lead-Free Ceramics with Different Additive of Bigao3 Were Synthesized by Conventional Solid-State Sintering Technique. Dielectric, Piezoelectric and Ferroelectric Properties of (1-X)KNN-Xbg Lead-Free Ceramics Were Studied. it Is Found that the Piezoelectric Properties Was Improved due to the Additive Bigao3，The Ceramics X=0.01 near Room Temperature Exhibit Excellent Electrical Properties D33=152pC/N, TC=372 °C. these Results Indicate that Bigao3 Adjusted K0.5Na0.5NbO3-Based Ceramics Materials Are Promising Lead-Free Piezoelectric Ceramic Candidates for Practical Applications.

For Na0.5K0.5NbO3(KNN)-based lead-free piezoelectric ceramics, an important phenomenon was found that the piezoelectric properties can be improved remarkably for equivalence substitution while it can’t be improved remarkably for non-equivalence substitution. To find out the real reason for this phenomenon, Li+ and La3+ were used to modify KNN lead-free piezoelectric ceramics by conventional sintering technique. The relaxor characteristic was detected for La3+ modified KNN lead-free piezoelectric ceramics, and this caused low piezoelectric properties. However, the relaxor characteristic can not be detected for Li+ modified KNN lead-free piezoelectric ceramics, and the piezoelectric properties is higher than that of La3+ modified KNN lead-free piezoelectric ceramics. Accordingly, the relaxor characteristic has important effect on structure and electric properties. The results show that equivalence and non-equivalence substitution have important and different effect on structure and performance of KNN ceramics.

To improve the temperature stability of PMN(Pb(Mg1/3Nb2/3)O3)-based ceramics, PMN-based composite ceramics were prepared by co-sintering two kinds of ceramics with different curie temperature. One unit is MHT(0.82PMN (Pb (Mg1/3Nb2/3) O3) -0.18PT (PbTiO3) (the curie temperature Tm=74°C)), and the other unit is MLT (0.88PMN (Pb (Mg1/3Nb2/3) O3)-0.12BT (BaTiO3) (the curie temperature Tm=-50°C)). The effects of the sintering temperature and the ratio of high and low Tm units on dielectric temperature stability were studied. The results show that the temperature stability can be improved greatly by co-sintering and coating method. The results show that PMN(Pb(Mg1/3Nb2/3)O3)-based composite ceramics are promising candidate for practical applications.

Lead magnesium niobate-lead titannate single crystal (abbreviated as PMNT) was used to fabricate PMNT/polymer 1-3-2 piezoelectric composite with different volume fractions of PMNT, by dicing single crystal PMNT along mutually perpendicular two directions on the surface and then filling polymer into grooves. The piezoelectric, dielectric and electromechanical properties of the novel composite were determined. It was demonstrated that a thickness electromechanical coupling coefficient of the composites could reach as high as 0.75 and acoustic impendence decreased to 14.9 Mrayls (lower than 30 Mrayls of PMNT). The pulse-echo waveforms of the composites without backing were also measured. It showed a -6dB bandwidth of 88% at the center frequency of 0.95MHz.

Si/C/B powders were synthesized by carbothermal reduction of xerogels containing boride. Colorless, transparent and monolithic gel was obtained by using tetraethoxysilane, saccharose, tributyl borate, ethanol and distilled water as starting materials. When the xerogel was fired at 1 600 °C in the static argon atmosphere, the XRD pattern commences to show the crystallite peak corresponding with C. β-SiC was synthesized at 1 700 °C, but amorphous remainders could not be eliminated completely. The XRD results show that the boron possibly enters into the silica network, leading to the formation of borosiloxane. Microstructure of β-SiC powders consists of agglomerated particles with diameters ranging from 30 to 100 nm. Though the samples prepared at 1 600 °C and 1 700 °C have better dielectric loss tangent than the sample at 1 500 °C due to exiting crystalline material, the dielectric constant and dielectric loss tangent of three samples reveal lower values.

The piezoelectric ceramics xPb(Mn1/3Sb2/3)O3-(1-x)Pb(Zr1/2Ti1/2)O3 (abbreviated as PMS-PZT) were synthesized by traditional ceramics process. The effect of sintering temperature and the amount of Pb(Mn1/3Sb2/3) O3(abbreviated as PMS) on phase structure, microstructure, piezoelectric and dielectric properties of PMS-PZT ceramics was investigated. The results show that the pure perovskite phase is in all ceramics specimens, the phase structure of PMS-PZT ceramics changes from tetragonal phase to single rhombohedral phase with the increasing amount of PMS. The dielectric constant ɛr, Curie temperature Tc, electromechanical coupling factor kp and piezoelectric constant d33 decrease, whereas the mechanical quality factor Qm and dielectric loss tanδ increase with the increasing amount of PMS in system. The optimum sintering temperature is 1 200–1 250 °C. It is concluded that the PMS-PZT (x=0.07) ceramics sintered at 1 250 °C is suitable for high-power piezoelectric transformer. These properties include ɛr=674.8, tanδ=0.005 25, kp = 0.658, Qm=1 520, d33=230 pC/N, Tc=275 °C.

The lead-free piezoelectric ceramics (l- x (K 0.5 Na 0.5 )NbO 3 - x LiNbO 3 (abbreviated as KNLN) were synthesized by a traditional solid state reaction. The effects of Li + on the sintering characteristic, the phase structure and piezoelectric properties of KNLN ceramics were investigated. The sintering temperature of KNN-based ceramics is decreased by doping Li + and the range of the sintering temperature is narrow. The KNLN ceramics exhibit an enhanced piezoelectric properties with the piezoelectric constant d 33 value of 180-200 pC/N, The electromechanical coupling coefficients k p is 35%-40%. The results show that (l- x )(K 0.5 Na 0.5 )-NbO 3 - x LiNbO 3 ( x =0.05, 0.06) is a promising high-temperature lead free piezoelectric ceramic.

The lead-free piezoelectric ceramics (K0.5Na0.5)NbO3 (abbreviated as KNN) with the relative density of 97.6% were synthesized by press-less sintering owing to the careful control of processing conditions. The phase structure of KNN ceramics was analyzed. The results show that the pure perovskite phase with orthorhombic symmetry is in all ceramics specimens. The effect of poling conditions on the piezoelectric properties of KNN ceramics was investigated. The results show that the piezoelectric constant d33 and electromechanical coupling factor kp, increase with poling field, poling temperature and poling time increasing, then decrease because of electric broken. Take into account of poling conditions and piezoelectric properties of pure KNN ceramics, the optimum poling conditions for pure KNN ceramics are poling field of 4 kV/mm, poling temperature of 140 °C and poling time of 20–25 min.

In order to obtain the characteristics of argon/air plasma assistant combustion actuators, experiments of three different actuators with normal, paratactic and meshy electrode configurations were respectively performed in argon/air mixture firstly, the results showed that the shape of electrode has little influence on the discharge characteristics. Then normal electrode was applied to study spectrum and discharge characteristics under the condition of 100% air and 10% argon/90% air. The comparison showed that, though in mixture the law of discharge characteristic was the same as that of pure air, discharge current and emission spectrum were strengthened, and initial discharge voltage reduced from 27 to 24 kV.

The changing law between interelectrode current, discharge characteristic and jet characteristic of plasma ignitor under different inlet Ar pressure and working current was researched by adopting self-made plasma ignitor. Still, four channels CCD spectrometer was adopted to measure the spectrum characteristic at the exit of ignitor and electron temperature of plasma was calculated according to the spectrum characteristic. The results show that the interelectrode current gradually reduced with rising inlet Ar pressure; The jet length of plasma ignitor firstly increased then reduced with rising inlet Ar flowrate, and also increased with rising working current; The working current of plasma ignitor reduced with rising inlet Ar flowrate, and increased with rising source output current; the electron temperature of plasma ignitor jet increased with rising working current and reduced with rising Ar flowrate. The research results are of certain guidance meanings and reference values for the practical application of plasma ignition system in aeroengine.

The emission spectra of air dielectric barrier discharge were measured through dielectric barrier discharge experiment system, and the influence of argon fraction on the emission spectra of air dielectric barrier discharge was studied in the present paper. In the wavelength range of 280-500 nm, the second positive band system of nitrogen N2 (C3 pi(u)-B 3 pi(g)) and the first negative band system of nitrogen ion N2+ (B 3sigma(u)(+) -X 2 sigma(g)+) were found. Adding 10% argon under the same conditions, initial discharge voltage reduced from 26 to 23 kV, both dielectric barrier discharge and its emission spectra intensity were enhanced, and the full width at half maximum increased. With increasing argon fraction, the trends of each nitrogen second positive band system line were different and two nitrogen ion first negative band system lines (391.44 and 427.81 nm) were reduced.