Homogeneity-Breaking Instability of Periodic Solutions of Gierer-Meindardt Model

The homogeneity-breaking instability of the periodic solutions triggered by Hopf bifurcations of a diffusive Gierer-Meinhart system is studied in this paper.Sufficient conditions on the diffusion coefficients and the cross diffusion coefficients were derived to guarantee the occurrence of the aforementioned homogeneity-breaking instability.

精、微表处在高速公路养护中的应用对比研究

预防性养护是高速公路养护中必不可少的手段,在预防早期病害中,通过各种罩面技术可以有效提升高速公路的效能。本文通过分析精表处和微表处在高速公路预防性养护中的应用,并基于其施工条件,研究精表处和微表处的优缺点和适用范围,以便为相关应用提供可具参考的建议。

Photostriction effect and electric properties of La-doped PMN-PT transparent ferroelectric ceramics

Ferroelectric ceramics display a remarkable photostriction effect,which could facilitate the prevention of electromagnetic interference and promote the integration and miniaturization of actuator systems,indicating potential applications in glim-mer sensors.In this work,highly transparent La-doped 0.9Pb(Mg1/3Nb2/3)O3-0.1PbTiO3(0.9PMN-0.1PT)ceramicswere synthesized using a solid-state reaction method in an oxyge-nated atmosphere.XRD and SEM were used to analyze the phase structure of the dense samples,which displayed a pure perovskite structure,with no trace of a pyrochlore phase.With La doping,the phase transitiontemperature shows a decreasing trend,and its dielectric constant could reach up to 20,000.The P-E loop of the samples was gradually refined into a straight line with an increase in the doping amount.After La doping,the transparency of the 0.9PMN-0.1PT cera-mics was significantly enhanced and reached up to 61%at the near-infrared band.Finally,the photogenerated voltage and deformation of the La-doped 0.9PMN-0.1PT ceramics were investigated under ultraviolet light of various intensities.After 20 s of irradiation at an intensity of 800 mW/cm²,the max-imum voltage and deformation,with values of 40 V and 250 nm,respectively,were both found in the 1%La-doped 0.9PMN-0.1PT ceramics.

2022 Chinese national clinical practice guideline on Helicobacter pylori eradication treatment

Background:Helicobacter pylori(H.pylori)infection is an infectious disease with a prevalence rate of up to 50%worldwide.It can cause indigestion,gastritis,peptic ulcer,and gastric cancer.H.pylori eradication treatment can effectively control disease progression and reduce the risk of the above conditions.However,the escalating trend of antibiotic resistance presents a global challenge for H.pylori eradication.We aim to provide guidance on pharmacological treatment of H.pylori infection.Methods:This clinical practice guideline is developed following the World Health Organization’s recommended process,adopting Grading of Recommendations Assessment,Development and Evaluation in assessing evidence quality,and utilizing Evidence to Decision framework to formulate clinical recommendations,minimizing bias and increasing transparency of the clinical practice guideline development process.We used the Reporting Items for practice Guidelines in HealThcare(RIGHT)statement and The Appraisal of Guidelines for Research and Evaluation Ⅱ(AGREE Ⅱ)as reporting and conduct guides to ensure the guideline’s completeness and transparency.Results:Though decreasing in developed countries,the prevalence of H.pylori remains high in developing countries,causing a major public health burden.This clinical practice guideline contains 12 recommendations concerning pharmacological treatment for H.pylori eradication.Among them,it is worth highlighting that bismuth preparations are inexpensive,safe,and effective,consequently making bismuth quadruple therapy a preferred choice for initial and rescue treatment.In empirical treatment,high-dose dual therapy is equally effective compared with bismuth quadruple therapy.Conclusions:The 12 recommendations in this clinical practice guideline are formed with consideration for stakeholders’values and preferences,resource use,feasibility,and acceptability.Recommendations are generalizable to resource limited settings with similar antibiotic resistance pattern as China,and lower middle-income countries facing comparable sociological and technical challenges.Registration:Guidelines International Network(GIN)website,https://guidelines.ebmportal.com/node/69996.

Development of High Sensitivity Eight-Element Multiplexed Fiber Laser Acoustic Pressure Hydrophone Array and Interrogation System

Fiber laser hydrophones have got widespread concems due to the unique advantages and broad application prospects. In this paper, the research results of the eight-element multiplexed fiber laser acoustic pressure array and the interrogation system are introduced, containing low-noise distributed feedback fiber laser （DFB-FL） fabrication, sensitivity enhancement packaging, and interferometric signal demodulation. The frequency response range of the system is 10Hz-10kHz, the laser frequency acoustic pressure sensitivity reaches 115 dB re Hz/Pa, and the equivalent noise acoustic pressure is less than 60μa/Hz^1/2. The dynamic range of the system is greater than 120 dB.

Selective conversion of cellulose to hexitols over bi-functional Ru-supported sulfated zirconia and silica-zirconia catalysts

We report a process of selective conversion of microcrystalline cellulose to hexitols over bi-functional Ru-supported sulfated zirconia and silica-zirconia catalysts. A 58.1% yield of hexitols and a 71.0% conversion of cellulose were achieved over Ru/SZSi（100：15）-773 catalyst at 443 K. The as-synthesized catalysts were characterized by X-ray diffraction （XRD）, BET, thermogravimetric analysis and pyridine adsorption Fourier transform infrared spectroscopy （FTIR）. XRD results indicated that the sulfated catalysts were pure tetragonal phase of ZrO2 when calcined at 773 K. Monoclinic zirconia appeared at the calcination temperature of 873 K, and the content of monoclinic phase increased with the elevating temperature. Compared with sulfated zirconia catalyst, sulfated silica-zirconia catalysts possessed a higher ratio of Bronsted to Lewis on the surface of catalysts, as shown from pyridine adsorption FTIR results. The reaction results indicated that the tetragonal zirconia, which is necessary for the formation of superacidity, was the active phase to cellulose conversion. The higher amounts of Bronsted acid sites can remarkably accelerate the cellulose depolymerization and promote side reactions that convert C5-C6 alcohols into the unknown soluble degradation products.

Characteristics Research on Self-Amplified Distributed Feedback Fiber Laser

A distributed feedback （DFB） fiber laser with a ratio of the backward to forward output power of 1：100 was composed by a 45-ram-length asymmetrical phase-shifted fiber grating fabricated on the 50-mm erbium-doped photosensitive fiber. Forward output laser was amplified using a certain length of Nufern EDFL-980-Hp erbium-doped fiber to absorb the surplus pump power after the active phase-shifted fiber grating and get population inversion. By using OptiSystem software, the best fiber length of the EDFL to get the highest gain was simulated. In order to keep the amplified laser with the narrow line-width and low noise, a narrow-band light filter consisting of a fiber Bragg grating （FBG） with the same Bragg wavelength as the laser and an optical circulator was used to filter the amplified spontaneous emission （ASE） noise of the out-cavity erbium-doped fiber. The designed laser structure sufficiently utilized the pump power, and a DFB fiber laser with the 32.5-mW output power, l l.5-kHz line width, and -87-dB/Hz relative intensity noise （R1N） at 300 mW of 980 nm pump power was brought out.

Multi-Wavelength Narrow Linewidth Fiber Laser Based on Distributed Feedback Fiber Lasers

A narrow linewidth laser configuration based on distributed feedback fiber lasers （DFB-FL） with eight wavelengths in the international telecommunication union （ITU） grid is presented and realized. In this laser configuration, eight phase-shifted gratings in series are bidirectionally pumped by two 980-nm laser diodes （LDs）. The final laser output with over 10-mW power for each wavelength can be obtained, and the maximum power difference within eight wavelengths is 1.2 dB. The laser configuration with multiple wavelengths and uniform power outputs can be very useful in large scaled optical fiber hydrophone fields.

Study on the Characters of Phase-Shifted Fiber Bragg Grating in Asymmetric Perturbation and Its Application in Fiber Laser Acoustic Sensor

A n-phase-shifted fiber Bragg grating theoretical model is established, and the effects of an asymmetric and symmetrical perturbation field on a phase-shifted fiber Bragg grating are investigated in this paper. The trends of wavelength shifting caused by effective refraction index of phase shift grating in symmetric and asymmetric acoustic field are investigated in detail. Then, the fiber laser acoustic sensors packaged in asymmetric and symmetrical structures are designed and tested, respectively. The results show that the acoustic response of the wavelength of the distributed feedback （DFB） fiber laser （FL） in an asymmetric packaging structure is much more sensitive than in that in the symmetrical structure. The sensor packaged in the asymmetrical structure has a better low frequency （0Hz-500Hz） performance and a higher sensitivity than that in the symmetrical structure, and the sensitivity is improved about 15dB in average and 32.7dB in maximum. It provides a new method to improve the sensitivity of the fiber acoustic sensor.

Changing Patterns in Digestive Diseases Mortality in Urban and Rural Areas—China,1987-2021

What is already known about this topic?Digestive diseases(DDs)are a global health concern with a substantial epidemiological and economic impact,given their high prevalence.What is added by this report?This study investigated the trends in mortality related to DDs in China from 1987 to 2021,focusing on the urban-rural divide.Additionally,it aimed to determine the specific impacts of age,period,and cohort on DDs mortality.What are the implications for public health practice?There is a need to prioritize and allocate more resources toward the future management of DDs in order to effectively address the challenges posed by urbanization and aging populations.