Nonlinear spectral cleaning effect in cross-polarized wave generation

The underlying mechanism of the spectral cleaning effect of the cross-polarized wave（XPW） generation process was theoretically investigated. This study shows that the spectral noise of an input spectrum can be removed in the XPW generation process and that the spectral cleaning effect depends on the characteristics of the input pulses, such as the chirp and Fourier-transform-limited duration of the initial pulse, and the modulation amplitude and frequency of the spectral noise. Though these factors codetermine the output spectrum of the XPW generation process, the spectral cleaning effect is mainly affected by the initial pulse chirp. The smoothing of the spectrum in the XPW generation process leads to a significant enhancement of the coherent contrast.

Effect of a disposable endoscope precleaning kit in the cleaning procedure of gastrointestinal endoscope:A multi-center observational study

BACKGROUND Precleaning is a key step in endoscopic reprocessing.AIM To develop an effective and economic endoscope cleaning method by using a disposable endoscope bedside precleaning kit.METHODS Altogether,228 used gastrointestinal endoscopes were selected from five high-volume endoscopy units and precleaned by a traditional precleaning bucket(group T)or a disposable endoscope bedside precleaning kit(group D).Each group was further subdivided based on the replacement frequency of the cleaning solution,which was replaced every time in subgroups T1 and D1 and every several times in subgroups Ts and Ds.The adenosine triphosphate(ATP)level and residual proteins were measured three times:Before and after precleaning and after manual cleaning.RESULTS After precleaning,the precleaning kit significantly reduced the ATP levels(P=0.034)and has a more stable ATP clearance rate than the traditional precleaning bucket.The precleaning kit also saved a quarter of the cost of enzymatic detergent used during the precleaning process.After manual cleaning,the ATP levels were also significantly lower in the precleaning kit group than in the traditional precleaning bucket group(P<0.05).Meanwhile,the number of uses of the cleaning solution(up to four times)has no significant impact on the cleaning effect(P>0.05).CONCLUSION Considering its economic cost and cleaning effect,the use of a disposable endoscope bedside precleaning kit can be an optimal option in the precleaning stage with the cleaning solution being replaced several times in the manual cleaning stage.

Spatiotemporal mode-locked multimode fiber laser with dissipative four-wave mixing effect

The high degree of freedom and novel nonlinear phenomena of multimode fiber are attracting attention. In this work,we demonstrate a spatiotemporal mode-locked multimode fiber laser, which relies on microfiber knot resonance(MKR) via dissipative four-wave-mixing(DFMW) to achieve high-repetition-rate pulses. Apart from that, DFMW mode locking with switchable central wavelengths can also be obtained. It was further found that high pulse energy induced nonlinear effect of the dominant mode-locking mechanism transforming from DFMW to nonlinear Kerr beam cleaning effect(NL-KBC). The experimental results are valuable for further comprehending the dynamic characteristics of spatiotemporal mode-locked multimode fiber lasers, facilitating them much more accessible for applications.

典型生物非光滑理论及其仿生应用

对典型的哺乳动物体表、植物表皮毛、表皮腊、土壤动物体表、水生鱼类表面的非光滑表面进行特征描述;并对非光滑类型进行分类;阐述了仿生脱附的基本理论;对其在工业、农业及航空领域应用现状及前景进行了综述。

Toward a non-invasive cleaning of the wall painting using polyelectrolyte hydrogel

Developing advanced cleaning systems for the removal of unwanted layers from painted surfaces is still a challenging issue that needs to be addressed in the field of cultural heritage.In this work,we proposed the use of novel polyelectrolyte hydrogels prepared via free radical polymerization and freeze-thaw methods.Zwitterionic sulfobetaine methacrylate(SBMA)was crosslinked with methylacryloyloxyethyl trimethylammonium(DMC)through covalent bonding to yield zwitterionic polyelectrolyte poly(SBMA-co-DMC)(PSD).Introducing PSD into the polyvinyl alcohol/carboxymethyl chitosan(PVA/CMC)hydrogel network enhanced the intermolecular electrostatic interactions and changed the porous structure and swelling behaviors,thus leading to improved mechanical properties.The adsorption ability of the PVA/CMC/PSD polyelectrolyte hydrogels toward dyes(rhodamine B and congo red)and metal ions(Cu^(2+)and K^(+))varied with increasing amounts of PSD,which could be attributed to cationic PSD tuning the net charges in the hydrogel.The cleaning effectiveness of the PVA/CMC/PSD polyelectrolyte hydrogels was assessed on wall painting mock-ups coated with soil,red paint,and soluble salts,using microscopic and spectroscopic analyses.The results showed that the hydrogel adhered to rough surfaces and removed unwanted substances effectively without leaving determinable residues,providing a possible safe and efficient method for the cleaning of important artifacts.