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Objective To compare the disinfection effect of 3% (v/v) hydrogen peroxide and 500 mg/L chlorine-containing disinfectants in the independent waterway of a periodontal ultrasonic scaler to provide a reference for clinical waterway disinfection management in stomatology departments. Methods The 18 ultrasonic scalers were randomly divided into 3 groups of 6 units: the control group, experimental group 1 (3% hydrogen peroxide disinfectant group), and experimental group 2 (500 mg/L chlorine-containing disinfectant group). The replaceable parts of the independent waterway pipes of the 3 groups of ultrasonic scalers were replaced, and the water supply was supplied with sterile distilled water (DW). In the control group, special treatment was not applied to the nonreplaceable pipe part. In experimental group 1, the 3% hydrogen peroxide was used to disinfect nonreplaceable pipelines. In experimental group 2, the nonreplaceable part was disinfected with the 500 mg/L chlorine-containing disinfectant. The water sample was taken from the outlet of the scaler working part in the three groups for monitoring before disinfection, immediately after disinfection and 10 consecutive days after disinfection. Bacteria in the water samples were cultured for the colony counts. Then, the bacterial culture data were compared between groups. The qualified criterion of the water sample was that the number of bacterial colonies was less than or equal to 100 CFU/mL. After disinfection, a bacterial species mass spectrometry identification analysis was carried out when the number of bacterial colonies in each group exceeded the standard for the first time. Biofilms from the inner wall of the tube in the three groups were observed under an electron microscope on the 10th day after disinfection. Results There were no significant differences between the three groups before disinfection (F = 2.549, P = 0.111). The number of bacterial colonies in the spout of 6 scalers in the control group all exceeded the standard, and three kinds of bacteria were cultured: Sphingomonas melonis, Herbaspirillum huttiense, and Ralstonia pickettii. Compared with those in the control group, the number of bacterial colonies in experimental group 1 decreased significantly for 1-2 days after disinfection (P

Gingival recessions (GRs) result in root hypersensitivity, root surface caries, and esthetic problems. Various root coverage surgeries are being developed for periodontal plastic therapy. The tunnel technique (TUN) is one of the most widely applied surgeries due to its features of being minimally invasive, practical, excellent outcomes and long-term stability; however, there are still some limitations of this technique. The history and evolution from the envelope flap to TUN, including its efficiency when compared with coronally advanced flaps with a connective tissue graft (CTG), are reviewed in this paper. The limitations of TUN are discussed in consideration of our clinical experience; for example, there is high technique sensitivity when TUN is applied in GR>5 mm because of the great difficulty in covering the grafts. The advantages of surgical access, including vertical incisions in the vestibule, “W” type and pinhole access, are discussed for different situations. Mattress sutures and sling sutures in a single tooth or multiple teeth are applied in TUN. The different types of grafts, such as CTG, platelet-rich plasma, articular dermal matrix and xenogeneic collagen matrix, are described. Mechanical, chemical and biological conditioning of the root surface are recommended during surgery. Protecting the surgical area and taking antibiotics postoperatively are also very important. Finally, the modifications when TUN is applied with other kinds of techniques are discussed, including lateral closed TUN, laterally positioned flaps, double papilla flaps and frenuloplasty. Minimally invasive, esthetic, long-term stability and simplified techniques are the development trends of TUN in the future.

Cotton fiber is a kind of cellulosic fiber and is widely used in textile. To legitimately determine the parameters of compressive force properties of cotton fiber assembly, axial stress was set up through a uniaxial quasi-static loading experiment on cotton fiber assembly. The constitutive model was built for cotton fiber assembly with viscoelastic plastic theory to calculate its mechanical parameters. The results showed that the viscoelasto plastic model was established to characterize the mechanical response. The constitutive model of stress and time had been adopted at the compression and relaxation processes. The viscoelastic constitutive model can be used to describe the densifying process. Loading cycles, compression velocity, and humidity on the parameters were also investigated by analyzing the E1, E2, η2, loading cycles, and humidity showed significant influence on mechanical parameters. The E1, E2, and η2 values of Stage II were lower than others because the cotton fiber assembly of Stage II was an unsteady structure. The E1 values were almost higher than the E2 values, the E1, E2, and η2 values of Stage III and recovery were much higher than others. The senior viscoelastic stage of cotton fiber assembly mainly showed elastic deformation from loose and disordered fiber structures.

Lithium-ion batteries (LIBs) are extensively used in electric vehicles and portable electronics due to their high energy density. However, conventional carbonate electrolytes suffer from potential Li plating at high current density and high flammability, which hinder their fast charging capability. Herein, a multi-functional electrolyte additive, namely ethoxy(pentafluoro)cyclotriphosphazene (PFPN), is explored to realize extreme fast charging of graphite‖LiFePO4 (LFP) cells with enhanced safety. The addition of PFPN into the baseline electrolyte comprising 1 M lithium bisfluorosulfonimide salt (LiFSI) in 1,3-dioxolane not only enhances the bulk ionic conductivity but also promotes the generation of a robust and ionic-conductive solid electrolyte interphase, hence enabling superior fast-charging performance of LIBs. In addition, the PFPN additive improves the nonflammability of electrolytes and inhibits the corrosion of Al foil caused by the LiFSI salt. As a result, graphite anodes deliver reversible capacities of 314.2 mA h g−1 and 164.4 mA h g−1 at 20C and 50C, respectively. Furthermore, the graphite‖LFP full pouch cells maintain a reversible capacity of 127.9 mA h g−1 and a high capacity retention of 99.68% over 500 cycles under 1C. This work provides a viable pathway to designing fast-charging electrolytes with remarkable cycling stability and excellent flame retardancy. [ABSTRACT FROM AUTHOR]

In this work, nitrogen‐defective g‐C3N4 with different nitrogen defect densities is synthesized for ciprofloxacin photocatalytic degradation. Compared with pristine g‐C3N4, g‐C3N4 etched with NaBH4 for 1 h exhibits an approximately ten‐fold increase in the rate constant of ciprofloxacin (CIP) degradation. The combined experimental analysis and theoretical calculations reveal that nitrogen defects can be incorporated into g‐C3N4 in all nitrogen sites and that C─N═C is the most susceptible site. By incorporating nitrogen defects to induce defect states between the conduction band (CB) and valence band (VB), the electronic and band structures are tuned. The induced defect states can be downshifted to approach the valance band, reaching increased nitrogen defect density within optimum ranges to accommodate excited electrons to narrow the bandgap, extend the light absorption capability, and enhance the charge carrier separation and transfer efficiency. The g‐C3N4 etched by NaBH4 for 2 h with over‐introduced nitrogen defects exhibits a declined performance due to a deteriorated structure, and the over‐downshifted defect states turn out to be a new recombination center for charge carriers. [ABSTRACT FROM AUTHOR]

This paper provides a simulation model for the electronic paper display device, the model can quickly and efficiently simulate the initial steady state of the electronic ink system, thus improving the efficiency of device development. It mainly includes the following contents: Obtaining the parameters of the model, then the built‐in electric field strength is calculated through the model parameter information and the pre‐ constructed built‐in electric field model. The motion of each charged particle is simulated to obtain the simulation relationship between the display gray scale and the applied electric field force. Finally, it make various charged particles reach the force equilibrium state, so as to realize the simulation of the voltage‐gray scale relationship of electronic ink system. [ABSTRACT FROM AUTHOR]

In this study, an 11‐layer thin film with the thickness of 0.58 μm is designed to be placed under the red and green pixels. This film exhibits a blue light reflectance of 95% and a transmittance of 99% for red and green light. Additionally, the thickness of the RCF and GCF is reduced from the original 2 μm to 1 μm. Experimental results demonstrate a 19.9% increase in backlight transmittance and a color gamut reaching 118% sRGB. [ABSTRACT FROM AUTHOR]

Folded optical path designs have been widely applied in Virtual Reality (Pancake VR) displays in recent years. Compared with the traditional straight‐through and Fresnel optical path design, the Pancake design has obvious advantages in smaller size and clearer virtual image. However, the Pancake optical path uses polarization devices to fold the optical path and, light undergoes multiple refractions and reflections between lens groups, thus inevitably introducing stray light. This stray light greatly reduces the contrast ratio even if taking high‐contrasting Mini‐LED backlight LCD as panel, and seriously affects the user experience. In this paper, we first analyze the causes of stray light in the Pancake design and then propose an effective optical design method. In addition, an effective process scheme for improving image contrast is proposed by analyzing the impact of lens and tube reflectivity. Further, a prototype of the Pancake VR optical module is successfully implemented with low stray light and high contrast ratio. [ABSTRACT FROM AUTHOR]