Internal phase control of fiber laser array based on photodetector array

Coherent beam combining(CBC) of fiber laser array is a promising technique to realize high output power while maintaining near diffraction-limited beam quality. To implement CBC, an appropriate phase control feedback structure should be established to realize phase-locking. In this paper, an innovative internal active phase control CBC fiber laser array based on photodetector array is proposed. The dynamic phase noises of the laser amplifiers are compensated before being emitted into free space. And the static phase difference compensation of emitting laser array is realized by interference measurement based on photodetector array. The principle of the technique is illustrated and corresponding simulations are carried out, and a CBC system with four laser channels is built to verify the technique. When the phase controllers are turned on, the phase deviation of the laser array is less than λ/20, and ~ 95% fringe contrast of the irradiation distribution is obtained. The technique proposed in this paper could provide a reference for the system design of a massive high-power CBC system.

MY RESEARCH ON PHASE TRANSITION AND INTERNAL FRICTION

In 1945, I began my campus life as a physics major in Zhongyang (National) University.I graduated from the University in July 1949 and obtained my MS degree when it was renamed Nanjing University in the same year.The next year,I worked as a teaching assistant at Nanjing College of Pharmacy.From 1950 to 1981.I taught physics at Nanjing University in the status of a teaching assistant first,then a lecturer and

A double-network porous hydrogel based on high internal phase emulsions as a vehicle for potassium sucrose octasulfate delivery accelerates diabetic wound healing

Diabetic wounds are a difficult medical challenge.Excessive secretion of matrix metalloproteinase-9(MMP-9)in diabetic wounds further degrades the extracellular matrix and growth factors and causes severe vascular damage,which seriously hinders diabetic wound healing.To solve these issues,a double-network porous hydrogel composed of poly(methyl methacrylate-co-acrylamide)(p(MMA-co-AM))and polyvinyl alcohol(PVA)was constructed by the high internal phase emulsion(HIPE)technique for the delivery of potassium sucrose octasulfate(PSO),a drug that can inhibit MMPs,increase angiogenesis and improve microcirculation.The hydrogel possessed a typical polyHIPE hierarchical microstructure with interconnected porous morphologies,high porosity,high specific surface area,excellent mechanical properties and suitable swelling properties.Meanwhile,the p(MMA-co-AM)/PVA@PSO hydrogel showed high drug-loading performance and effective PSO release.In addition,both in vitro and in vivo studies showed that the p(MMA-co-AM)/PVA@PSO hydrogel had good biocompatibility and significantly accelerated diabetic wound healing by inhibiting excessive MMP-9 in diabetic wounds,increasing growth factor secretion,improving vascularization,increasing collagen deposition and promoting re-epithelialization.Therefore,this study provided a reliable therapeutic strategy for diabetic wound healing,some theoretical basis and new insights for the rational design and preparation of wound hydrogel dressings with high porosity,high drug-loading performance and excellent mechanical properties.

Facile synthesis of metal-organic frameworks embedded in interconnected macroporous polymer as a dual acid-base bifunctional catalyst for efficient conversion of cellulose to 5-hydroxymethylfurfural

5-Hydroxymethylfurfural(5-HMF),as a key platform compound for the conversion of biomass to various biomass-derived chemicals and biofuels,has been attracted extensive attention.In this research,using Pickering high internal phase emulsions(Pickering HIPEs)as template and functional metal-organic frameworks(MOFs,UiO-66-SO;H and UiO-66-NH;)/Tween 85 as co-stabilizers to synthesis the dual acid-base bifunctional macroporous polymer catalyst by one-pot process,which has excellent catalytic activity in the cascade reaction of converting cellulose to 5-HMF.The effects of the emulsion parameters including the amount of surfactant(ranging from 0.5%to 2.0%(mass)),the internal phase volume fraction(ranging from 75%to 90%)and the acid/base Pickering particles mass ratio(ranging from 0:6 to 6:0)on the morphology and catalytic performance of solid catalyst were systematically researched.The results of catalytic experiments suggested that the connected large pore size of catalyst can effectively improve the cellulose conversion,and the synergistic effect of acid and base active sites can effectively improve the 5-HMF yield.The highest 5-HMF yield,about 40.5%,can be obtained by using polymer/MOFs composite as catalyst(Poly-P12,the pore size of(53.3±11.3)μm,the acid density of 1.99 mmol·g^(-1)and the base density of 1.13 mol·g^(-1))under the optimal reaction conditions(130℃,3 h).Herein,the polymer/MOFs composite with open-cell structure was prepared by the Pickering HIPEs templating method,which provided a favorable experimental basis and theoretical reference for achieving efficient production of high addedvalue product from abundant biomass.

Coherent combining of a fiber laser array via cascaded internal phase control technique

We experimentally demonstrated a cascaded internal phase control technique.A laser array with 12 channels was divided into three sub-arrays and a stage array,and phases of the sub-arrays and the stage array were locked by four phase controllers based on the stochastic parallel gradient descent(SPGD)algorithm,respectively.In this way,the phases of the whole array were locked,and the visibility of the interference pattern of the whole emitted laser array in the far field was∼93%.In addition,the technique has the advantage of element expanding and can be further used in the high-power coherent beam combination(CBC)system due to its compact spatial structure.

Investigation of internal phases of linear SBS modified bitumen at the nanoscale using AFM PF-QNM

Currently,few studies explore the internal phases of styrene-butadiene-styrene(SBS)modified bitumen at the nanoscale,though the surface phases of SBS modified bitumen have been deeply understood through a lot of research.The present study uses the atomic force microscopy(AFM)peak force quantitative nanomechanical mode(PF-QNM)to investigate the nanomechanical properties of the interior of linear SBS modified bitumen and corresponding mastics at the nanoscale.Firstly,the suitable experimental methods for the interior of bitumen and mastics are explored.Then,the phase relationship between surfaces and interiors of linear SBS modified bitumen is determined by analyzing nanomechanical properties.On this basis,in comparison with the internal phases of base bitumen,the effect of modifiers on phases is deeply investigated.Finally,the internal phases of linear SBS modified bituminous mastics are further investigated.The results reveal that the interior of linear SBS modified bitumen only has two phases,which form in a manner like periphase and paraphase on the surface.In contrast to base bitumen,linear SBS modified bitumen does not create new phases and change the properties of original phases in the interior,but affects the proportion of A-phase and B-phase and presents the homogenization.Furthermore,due to the influence of preparation methods,only the bitumen area away from the fillers can be imaged by AFM PF-QNM.It can be found that the addition of mineral fillers also slightly changes the internal phase distribution of linear SBS modified bitumen,while the effect is less than that of fillers on base bitumen.

Characteristics,formation mechanism and stability of high internal phase emulsions stabilized by porcine plasma protein (PPP) / carrageenan (CG) hybrid particles

High internal phase emulsions (HIPEs) stabilized by nanoparticles based on biomacromolecules are challenging issues in recent decade.Herein,a newly developed HIPE was investigated by using heat-denatured porcine plasma protein (PPP) nanoparticles at pH 6.5 as emulsifier,and its emulsifying stability could be significantly enhanced by compounding carrageenan (CG).In the miscible system,PPP and CG formed hybrid particles through non-covalent interaction,and the sizes and zeta-potentials of the particles increased significantly along with addition of CG (from 0 to 0.7%,w/v),reached up to about 3.6 μm and −53 mV at 0.5% (w/v),respectively.CG weakened the ability of PPP to lower interfacial tension of oil/water (O/W),but increased the apparent viscosity of the system.The results from CLSM,rheology and stability experiments indicated a significant increasing trend of the HIPEs stability and solid-like characteristics along with addition of CG.Compared with the controls including bovine serum albumin (BSA),BSA-CG and CG alone,PPP-CG hybrid particles had good performance in fabricating and stabilizing the HIPEs.The work revealed the novel function of PPP as emulsifier of HIPEs and so offered the theoretical direction for application of PPP as a mass by-product,as well as an excellent HIPEs system for food,medicine and cosmetics fields.

Porous Metal-Organic Framework-Polymer Composites Using High Internal Phase Emulsion Templates: A Review

As promising engineering materials for green and sustainable processes, porous metalorganic framework(MOF)-polymer composites show great potential in applications, including adsorption, separation, catalysis, and bioengineering. Owing to the mild and scalable operation, porous polymeric materials derived from high internal phase emulsion templates(polyHIPE) have received great interests in recent decades. In this contribution, research progress of the preparation of porous MOF@polyHIPE composites and their applications are reviewed, highlighting how can MOF particles be shaped by HIPE templates, in particular the polymerizable ones. Four different emulsion templates stabilized by MOFs and the applications of corresponding MOF@polyHIPE are included. Hopefully,both the state-of-art and future directions present herein can give rise to the development of highperformance porous MOF@polyHIPEs.

Adsorption of tetrodotoxin by flexible shape-memory polymers synthesized from silica-stabilized Pickering high internal phase emulsion

Flexible shape-memory polymers were synthesized by Pickering high internal phase emulsion(HIPE)polymerization and used to adsorb and separate tetrodotoxin(TTX)from an aqueous solution.SiO_(2)nanoparticles were used to stabilize the Pickering oil-in-water(O/W)HIPEs.We introduced imidazolium-modified bromobutyl rubber(IBR)with excellent mechanical properties and high viscosity into the emulsion system as the shape-memory monomer.The properties,such as shape memory and morphology,were characterized by various methods,and batches of static adsorption experiments were conducted to analyze the adsorption performance of SiO_(2)@IBR on TTX.The characterization revealed that the SiO_(2)@IBR had a porous structure and good shape memory.Thus,the combination of SiO_(2)particles and IBR prevented shedding of SiO_(2)and enhanced the mechanical and adsorption properties of SiO_(2)@IBR.The results of the adsorption experiments indicated that the SiO_(2)@IBR had good adsorption of TTX.Both the Langmuir and Freundlich models fitted the isothermal adsorption experiment process.The TTX adsorption capacity of SiO_(2)@IBR was about 290.44 mg/g at 308 K.The fitting results of the pseudo-first-order and pseudosecond-order kinetic models showed that the adsorption process involved both chemical bonding and physical adsorption.After 10 adsorption and desorption experiments,the adsorption capacity of SiO_(2)@IBR decreased less than 0.03%,indicating that it had good adsorption and regeneration performance.

Preparation and Application of Polymerized High Internal Phase Emulsion Monoliths for the Preconcentration and Determination of Malachite Green and Leucomalachite Green in Water Samples

Polymerized high internal phase emulsion(polyHIPE)monoliths were prepared and applied as adsorbent materials for solid-phase extraction(SPE)of malachite green(MG)and leucomalachite green(LMG)from water samples.The polyHIPE monoliths were prepared by post-functionalization of monolithic surface with 6-aminocaproic acid(ACA)via ring opening reaction of epoxy groups in glycidyl methacrylate(GMA)-based polyHIPEs,and then applied to the preconcentration and determination of trace MG and LMG in environmental water samples by combing with high-performance liquid chromatog-raphy(HPLC).Taking MG and LMG as targets,main factors affecting SPE performance of the polyHIPE monoliths were investigated.Under the optimized conditions,the ACA-functionalized polyHIPE monoliths could effectively preconcentrate MG and LMG from 150 mL of water samples,and the recoveries of MG and LMG at three spiked levels were ranged from 84.8 to 97.4%with the relative standard deviations(RSDs)lower than 6%.The proposed method exhibited good linearity in the range of 2-200 ng mL^(-1),with low limits of detection of 17.0 and 8.7 pg mL^(-1)for MG and LMG,respectively.In addi-tion,the prepared ACA-modified polyHIPE monolith showed good durability and stability,and it could be reused for 200 cycles without obvious losing the extraction performance.

Emulsion‐templated synthesis of 3D evaporators for efficient solar steam generation

Interfacial solar steam generation holds great promise in water desalination thanks to its high energy efficiency by heating only the top layer of water for evaporation.While three‐dimensional(3D)evaporators have been proven to increase the evaporation rate by harnessing the energy from the surroundings,further development is still required in terms of convenient fabrication with potential scalability.Herein,we propose to overcome this challenge by using a high internal phase emulsion(HIPE)to template the synthesis of 3D hierarchically porous evaporators.The HIPE‐templated synthesis combined with a molding process can efficiently fabricate the desired 3D shape without wasting any materials and generate a hierarchically porous internal structure for continuous water supply.Engineering the overall shape and internal pores produces a 3D evaporator that can suppress conduction heat loss and efficiently collect thermal energy from its surroundings,boosting the evaporation rate to 2.82 kg/(m2 h)under 1‐sun illumination,which is significantly higher than conventional 2D evaporators.HIPE‐templating synthesis is an easy but effective way to produce various porous polymers,promising for a wide range of applications where easy production,excellent shape control,and potential scalability are critical.

Pickering emulsions stabilized by biocompatible particles:A review of preparation,bioapplication,and perspective

The phenomenon of adsorption of solid particles at fluid interfaces to stabilize emulsions or foams have been known for more than a century.Today,particle-stabilized emulsions,often referred to as Pickering emulsions,are receiving growing attention as they are encountered in oil recovery and have long been used in personal care products and food industry.Over the past 10 years the focus of the Pickering emulsion has also increasingly shifted to biomedical applications with thanks to novel syntheses of a wide range of biocompatible particle stabilizers.Here,a brief overview of the development of biocompatible particles is given for Pickering emulsion stabilization,including alginate,poly(lactic-co-gIycolic acid)(PLGA),and protein-based particles.The materials prepared by templating from emulsion stabilized with biocompatible particles include colloidal capsules and hierarchically porous materials.It is hoped that the understanding gained from the recent intense activity in the field will enable more researchers to modify existing materials and design new formulations,which would be beneficial for exploring more biological applications.