Particle properties in granular activated carbon filter during drinking water treatment

The elemental composition and bacteria attached in particles were investigated during granular activated carbon （GAC） filtration.The experimental results showed that trapped influent particles could form new,larger particles on GAC surface.The sloughing of individuals off GAC surface caused an increase in effluent particles in the size range from 5 to 25 μm.The selectivity for element removal in GAC filters caused an increasing proportion of metallic elements in the effluent particles.The distribution of molar ratio indicated a complicated composition for large particles,involving organic and inorganic substances.The organic proportion accounted for 40% of total carbon attached to the particles.Compared with dissolved carbon,there was potential for the formation of trihalomethanes by organic carbon attached to particles,especially for those with size larger than 10 μm.The pure carbon energy spectrum was found only in the GAC effluent and the size distribution of carbon fines was mainly above 10 μm.The larger carbon fines provided more space for bacterial colonization and stronger protection for attached bacteria against disinfection.The residual attached bacteria after chorine disinfection was increased to 10 2-10 3 CFU/mL within 24 hours at 25°C.

Application of Improved Deep Auto-Encoder Network in Rolling Bearing Fault Diagnosis

Since the effectiveness of extracting fault features is not high under traditional bearing fault diagnosis method, a bearing fault diagnosis method based on Deep Auto-encoder Network (DAEN) optimized by Cloud Adaptive Particle Swarm Optimization (CAPSO) was proposed. On the basis of analyzing CAPSO and DAEN, the CAPSO-DAEN fault diagnosis model is built. The model uses the randomness and stability of CAPSO algorithm to optimize the connection weight of DAEN, to reduce the constraints on the weights and extract fault features adaptively. Finally, efficient and accurate fault diagnosis can be implemented with the Softmax classifier. The results of test show that the proposed method has higher diagnostic accuracy and more stable diagnosis results than those based on the DAEN, Support Vector Machine (SVM) and the Back Propagation algorithm (BP) under appropriate parameters.

Strategies of polyhydroxyalkanoates modification for the medical application in neural regeneration/nerve tissue engineering

Neural regeneration was once considered to be impossible, especially in the central nervous system where neural regeneration comprise the generation of new neurons, glia, axons, myelin, and synapses. Until recently, neural stem cells/neural progenitor cells (NSCs/NPCs) were identified from various areas of brain and brought hopes to the neural repair and regeneration. Tissue engineering has revolutionized the current neural regeneration technology and it has become a pioneering interdisciplinary field in the areas of biomedical research. Polyhydoxyalkanoate (PHA) as one of biodegradable material has been successfully used as tissue engineering materials. It has also been applied in nerve tissue engineering due to the high biocompatibility and low cytotoxicity. Over the past 10 years, different kinds of modification strategies have been undertaken to improve the properties of PHA to fit the requirements from various fields. Several members of PHA family have been attempted for neural regeneration. This article reviewed the recent modification strategies for improving the properties of PHA and highlighted the pioneer applications in neural regeneration.

Cloning and Bioinformatics Analysis of <i>Rosa rugosa</i>TFL1 Gene (<i>RrTFL1</i>)

In order to determine if the TFL1 is related with the continuous flowering phenotype of wild Rosa rugosa from Muping, the full-length cDNA sequence of TFL1 Gene was cloned for the first time from the flower buds of wild Rosa rugosafrom Muping with RT-PCR and RACE methods and named as RrTFL1. The full-length cDNA is 973 bp with an open reading frame of 519 bp, encoding 172 amino acids. The derived protein has a molecular weight of 19.48 kD, a calculated pI of 9.13, a c100227 conserved domain at position 1-172, and belongs to PEBP family. The derived protein is a Hydrophilic protein secreted into the cytoplasmic. There is no transmembrane domain and no signal peptide cleavage site, five Ser phosphorylation sites, seven Thr phosphorylation sites, three Tyr phosphorylation sites, one O-glycosylation site, and no N-glycosylation sites. There are 24.42% α-helixes, 36.63% random coil, 27.91% extended peptide chain, and 11.05% β-corner structure. This protein and the TFL1 protein from Rosaceae plants, including Rosa chinensis, share a sequence homology of 87% - 96%. All of the proteins contain a c100227 conserved domain, two highly conserved modules D-P-D-x-P, G-x-H-R, and two functional sites His, Asp. Furthermore, their phylogenetic relationships are consistent with their traditional classifications. These results not only laid a foundation for further researching the expression and function of RrTFL1, but also cultivating new varieties of R. rugosawhich can flower continuously by gene engineering.

Long-term ultrastable frequency dissemination via a 50-km spooled fiber link using a two-section DFB laser

The stable long-distance transmission of radio-frequency(RF)signals holds significant importance from various aspects,including the comparison of optical frequency standards,remote monitoring and control,scientific research and experiments,and RF spectrum management.We demonstrate a scheme where an ultrastable frequency signal was transmitted over a 50 km coiled fiber.The optical RF signal is generated using a two-section distributed feedback(DFB)laser for direct modulation based on the reconstruction equivalent chirp(REC)technique.The 3-dB modulation bandwidth of the two-section DFB laser is 18 GHz and the residual phase noise of-122.87 dBc/Hz is achieved at 10-Hz offset frequency.We report a short-term stability of 1.62×10^(-14)at an average time of 1 s and a long-term stability of 6.55×10^(-18)at the measurement time of 62,000 s when applying current to the front section of the DFB laser.By applying power to both sections,the stability of the system improves to 4.42×10^(-18)within a testing period of 56,737 s.Despite applying temperature variations to the transmission link,long-term stability of 8.63×10^(-18)at 23.9 h can still be achieved.

A pH/ROS dual-responsive system for effective chemoimmunotherapy against melanoma via remodeling tumor immune microenvironment

Chemotherapeutics can induce immunogenic cell death(ICD)in tumor cells,offering new possibilities for cancer therapy.However,the efficiency of the immune response generated is insufficient due to the inhibitory nature of the tumor microenvironment(TME).Here,we developed a pH/reactive oxygen species(ROS)dual-response system to enhance chemoimmunotherapy for melanoma.The system productively accumulated in tumors by specific binding of phenylboronic acid(PBA)to sialic acids(SA).The nanoparticles(NPs)rapidly swelled and released quercetin(QUE)and doxorubicin(DOX)upon the stimulation of tumor microenvironment(TME).The in vitro and in vivo results consistently demonstrated that the NPs improved anti-tumor efficacy and prolonged survival of mice,significantly enhancing the effects of the combination.Our study revealed DOX was an ICD inducer,stimulating immune responses and promoting maturation of dendritic cells(DCs).Additionally,QUE served as a TME regulator by inhibiting the cyclooxygenase-2(COX2)-prostaglandin E2(PGE2)axis,which influenced various immune cells,including increasing cytotoxic T cells(CLTs)infiltration,promoting M1 macrophage polarization,and reducing regulatory T cells(Tregs)infiltration.The combination synergistically facilitated chemoimmunotherapy efficacy by remodeling the immunosuppressive microenvironment.This work presents a promising strategy to increase anti-tumor efficiency of chemotherapeutic agents.

Fermented calcium butyrate supplementation in post-peak laying hens improved ovarian function and tibia quality through the“gut-bone”axis

The compromised egg quality and leg abnormality during the end of the laying cycle(after 40 weeks)have been leading to poor animal welfare and substantial economic losses.Therefore,the effects of fermented calcium(Ca)butyrate,produced by fermentation by Clostridium butyricum,on production,eggshell quality,and tibial property of hens were explored.A total of 192 Hy-line brown laying hens at50-week-old were assigned to a basal diet or the basal diet with 300 mg/kg of the fermented Ca butyrate from 50 to 58 weeks of age.Each treatment had 6 replicates with 16 hens each.The diet supplemented with 300 mg/kg fermented Ca butyrate notably increased egg weight,ovarian follicle number,and eggshell strength(P=0.072)as compared to the basal diet,which were associated with cytokine secretion,toll-like receptor signaling pathways,and intestinal immunity based on the RNA-seq data from the granulosa.Dietary Ca butyrate inclusion decreased the expression of ileal tumor necrosis factor-alpha and serum pro-inflammatory cytokine concentration,as well as increased the content of serum immunoglobulin A when compared to the basal diet(both P<0.05).The birds that received fermented Ca butyrate diets exhibited higher villus height(P<0.05)and upregulated expression of tight junction proteins,whereas it did not alter the composition of cecal microbiota(P>0.05).In addition,the diet with fermented Ca butyrate reduced the number of osteoclasts in the proximal tibia and the level of C-terminal cross-linked telopeptide of type I collagen,a bone resorption marker(P<0.05),whereas it tended to increase the concentration of the procollagen type I N-terminal propeptide that reflects bone formation marker in serum.Moreover,the layers fed fermented Ca butyrate diets possessed higher(P<0.05)bone area and trabecular number of the proximal tibia,yield load,and ultimate load than those that consumed basal diets.Collectively,dietary fermented Ca butyrate supplementation in post-peak layer diets improved the ovarian function and tibia quality,which might be related to enhancing intestinal integrity and consequently decreasing inflammation mediated bone resorption.

Understanding synergistic catalysis on Pt–Cu diatomic sites via operando X-ray absorption spectroscopy in sulfur redox reactions

Sulfur redox reactions render lithium–sulfur(Li–S)batteries with an energy density of>500Whkg−1 but suffer a low practical capacity and fast capacity fade due to sluggish sulfur redox reaction(SRR)kinetics,which lies in the complex reaction process that involves a series of reaction intermediates and proceeds via a cascade reaction.Here,we present a Pt–Cu dual-atom catalyst(Pt/Cu-NG)as an electrocatalyst for sulfur redox reactions.Pt/Cu-NG enabled the rapid conversion of soluble polysulfide intermediates into insoluble Li2S2/Li2S,and consequently,it prevented the accumulation and shuttling of lithium polysulfides,thus outperforming the corresponding single-atom catalysts(SACs)with individual Pt or Cu sites.Operando X-ray absorption spectroscopy and density functional theory calculations revealed that a synergistic effect between the paired Pt and Cu atoms modifies the electronic structure of the Pt site through d-orbital interactions,resulting in an optimal moderate interaction of the metal atom with the different sulfide species.This optimal interaction enhanced charge transfer kinetics and promoted sulfur redox reactions.Our work thus provides important insights on the atomic scale into the synergistic effects operative in dual-atom catalysts and will thus pave the way to electrocatalysts with enhanced efficiency for high-performance Li–S batteries.

Directly modulated 25 Gbaud/s tunable in-series DFB laser array for WDM systems

In this Letter,we proposed and experimentally demonstrated a directly modulated tunable laser based on the multi-wavelength distributed feedback(DFB)laser array.The lasers are placed in series to avoid the usage of an optical combiner and additional power loss.A three-section design is utilized to reduce the interference from other lasers and improve the electro-optic response bandwidth.Besides,the reconstruction-equivalent-chirp technique is used to simplify the grating fabrication and precisely control the grating phase.We realized 12 channels with 100 GHz spacing with high side mode suppression ratios of above 50 dB.The output power of all the channels is above 14 mW.The 3 dB electro-optic bandwidth is above 20 GHz at a bias current of 100 mA for all four lasers.A 25 Gb/s data transmission over a standard single-mode fiber of up to 10 km is demonstrated for all 12 channels,and 50 Gb/s data per wavelength is obtained through the four-level pulse amplitude modulation.The proposed directly modulated tunable in-series DFB laser array shows the potential for a compact and low-cost light source for wavelength division multiplexing(WDM)systems,such as next-generation front-haul networks and passive optical networks.

能量配比系数对铝合金激光-MIG复合焊接气孔的影响

为研究能量配比系数(激光功率与电弧功率的比值)对铝合金激光-MIG复合焊接气孔的影响,采用X射线无损检测与金相显微组织观察法对6 mm厚6061铝合金激光-MIG复合焊接接头在能量配比系数为4.0、3.5、3.1下的气孔进行了分析。结果发现:激光功率对焊缝横截面底部熔宽的影响显著,增大电弧功率能有效增大复合作用区域的深度;在较高的能量配比系数下,焊缝内部气孔的直径较大,但其数量较少,气孔率较低;在焊缝横截面上,气孔主要分布在焊缝上部,下部较少;但是当能量配比系数降低至3.1时,气孔的分布趋于均匀,下部气孔数量增加显著,且工艺气孔的数量也有所增加。结果表明,提高激光功率的能量占比有利于降低气孔率。

耐高温聚酰亚胺泡沫材料

聚酰亚胺泡沫具有低介电、隔热、吸声、高比强度以及高经济效益等诸多优点,因而近些年来在航空、航天、船舶航舰、能源与环境保护等领域有着广泛的应用。聚酰亚胺泡沫按照泡孔结构分为软质开孔泡沫和硬质闭孔泡沫两大类,其通常是由芳香族二酐与芳香族二胺通过缩聚反应制备得到分子量可控的聚酯铵盐,再将其作为前驱体经过热发泡制备得到最终的聚酰亚胺泡沫。前驱体的化学结构对最终的聚酰亚胺泡沫的机械性能和热性能都有非常显著的影响,同时前驱体的分子量也会对泡沫的密度、机械性能和热性能有非常显著的影响。聚酰亚胺泡沫的研究进展,特别是其化学结构、性能和应用都会在本文中逐一阐述。

基于动态光散射技术研究群体自驱动Janus颗粒的增强型布朗运动行为

自驱动Janus颗粒是两侧具有不同性质并可进行自驱运动的非均质颗粒的统称.本文以标称直径为1μm的Pt-SiO_2型自驱动Janus颗粒(以下简称Janus颗粒)为研究对象,利用动态光散射技术(dynamic light scattering, DLS)研究了其在纯水及不同浓度H2O2溶液中的运动行为.实验结果表明:群体Janus颗粒在H2O2溶液中的运动行为表现为增强型布朗运动.随着H_2O_2溶液浓度的增加,DLS测得群体Janus颗粒的有效扩散系数增大且都大于其在纯水中布朗运动时的扩散系数,且其弛豫时间逐渐减小.此外,根据DLS测得的自相关函数反演算推导得到了群体Janus颗粒在极短时间间隔内的均方位移.其结果表明:在相同观测时间间隔下,随着H_2O_2溶液浓度的增大,均方位移增加;在相同浓度的H_2O_2溶液中,随着观测时间间隔的增加,均方位移增加.最后,分析了单粒子追踪技术(single particle tracking,SPT)与DLS两种方法用于研究Janus颗粒运动行为的特点与区别,并指出观测时间间隔是影响DLS和SPT两种方法实验结果的关键因素.

空心玻璃微珠/ZnIn_2S_4纳米复合微球的制备及性能

以空心玻璃微珠为载体,通过水热法实现了六方相型ZnIn_2S_4在空心玻璃微珠表面的可控自组装,从而制备出空心玻璃微珠/ZnIn_2S_4核壳复合微球.采用X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射光谱(UV-Vis)、光电子能谱分析(XPS)技术对复合微球的表征,研究了微珠表面活化处理对表面包覆ZnIn_2S_4晶体结构、形貌、光学性质及催化性能的影响.结果表明,空心玻璃微珠分别通过硅烷偶联剂γ-氨丙基三乙氧基硅烷(KH550)和双氧水活化预处理后,其表面负载ZnIn_2S_4更为均匀,呈层状纳米花瓣结构,并对有机污染物罗丹明B(RhB)有着良好的降解效果.

Numerical analysis for impacts of nozzle end-clearances on aerodynamic performance and forced response in a VNT turbine

It has been well known that nozzle end-clearances in a Variable Nozzle Turbine（VNT）are unfavorable for aerodynamic performance, especially at small openings, and efforts to further decrease size of the clearances are very hard due to thermal expansion. In this paper, both the different sizes of nozzle end-clearances and the various ratios of their distribution at the hub and shroud sides were modelled and investigated by performing 3D Computational Fluid Dynamics（CFD） and Finite Element Analysis（FEA） simulations with a code of transferring the aerodynamic pressure from the CFD results to the FEA calculations. It was found that increasing the size of the nozzle end-clearances divided equally at the hub and shroud sides deteriorates turbine efficiency and turbine wheel reliability, yet increases turbine flow capacity. And, when the total nozzle endclearances remain the same, varying nozzle end-clearances＇ distribution at the hub and shroud sides not only shifts operation point of a VNT turbine, but also affects the turbine wheel vibration stress.Compared with nozzle hub clearance, the shroud clearance is more sensitive to both aerodynamic performance and reliability of a VNT turbine. Consequently, a possibility is put forward to improve VNT turbine efficiency meanwhile decrease vibration stress by optimizing nozzle end-clearances＇ distribution.

Demodulation of the multi-peak fiber Bragg grating sensor based on partial wavelength scan

Until now, a high-efficiency demodulation method for fiber Bragg grating(FBG) sensors has been a challenge.In this Letter, by employing multi-peak FBGs, an FBG sensor with a partial wavelength scan is proposed and initially demonstrated. By demodulating a near-symmetrical multi-peak FBG and an asymmetrical multi-peak FBG in the strain experiment, sensor sensitivities of 1.02 pm/με and 1.01 pm/με are measured for the interrogation system, respectively. The average demodulation deviations for the two sensors are 1.81% and 0.4%,respectively. The proposed method is expected to realize high-efficiency and low-cost FBG interrogators.

Glucose-responsive erythrocyte-bound nanoparticles for continuously modulated insulin release

Glucose-responsive closed-loop insulin delivery systems represent a promising treatment strategy for diabetes,but current systems generally cannot achieve long-term effects.In this study,we designed an erythrocyte-biomimetic glucose-responsive system(EGRS)by coupling glucose-responsive nanoparticles(GRNs)to red blood cells;these nanoparticles exhibited the dual functions of glucose-responsiveness and persistent presence in circulation.GRNs are generated by encapsulating with insulin through ion crosslinking,followed by coloading with glucose oxidase(GOx)and catalase(CAT),a process that endows the nanoparticles with glucose-responsiveness.Simultaneously,the GRNs are coupled with red blood cells to camouflage them from the immune system,therefore,these erythrocyte-coupled GRNs can circulate in the blood for a long time.Under conditions of hyperglycemia,GOx acts on blood glucose to produce gluconic acid,which causes the rupture of GRNs and efficient release of insulin.Conversely,insulin is only released at the basic rate during hypoglycemia.Thus,EGRS can efficiently and continuously respond to hyperglycemia to maintain blood glucose levels within the normal range.

Metal-free visible-light-induced oxidative cyclization reaction of 1,6-enynes and arylsulfinic acids leading to sulfonylated benzofurans

A new and convenient visible-light-induced method has been developed for the synthesis of sulfonylated benzofurans via oxidative cyclization reaction of 1,6-enynes and arylsulfinic acids.This reaction was carried out under metal-free and mild conditions,in which the C-S,C-C and C=O bonds could be sequentially formed in one pot operation.

Rapid and simple spectrophotometric determination of persulfate in water by microwave assisted decolorization of Methylene Blue

A rapid and simple method for determination of persulfate in aqueous solution was developed. The method is based on the rapid reaction of persulfate with Methylene Blue（MB） via domestic microwave activation, which can promote the activation of persulfate and decolorize MB quickly. The depletion of MB at 644 nm（the maximum absorption wavelength of MB） is in proportion to the increasing concentration of persulfate in aqueous solution. Linear calibration curve was obtained in the range 0-1.5 mmol/L, with a limit of detection of 0.0028 mmol/L. The reaction time is rapid（within 60 sec）, which is much shorter than that used for conventional methods. Compared with existing analytical methods, it need not any additives, especially colorful Fe2＋, and need not any pretreatment for samples, such as p H adjustment.

On the mechanical aspect of additive manufactured polyether-ether-ketone scaffold for repair of large bone defects

Polyether-ether-ketone(PEEK)is widely used in producing prosthesis and have gained great attention for repair of large bone defect in recent years with the development of additive manufacturing.This is due to its excellent biocompatibility,good heat and chemical stability and similar mechanical properties which mimics natural bone.In this study,three replicates of rectilinear scaffolds were designed for compression,tension,three-point bending and torsion test with unit cell size of 0.8 mm,a pore size of 0.4 mm,strut thickness of 0.4 mm and nominal porosity of 50%.Stress-strain graphs were developed from experimental and finite element analysis models.Experimental Young’s modulus and yield strength of the scaffolds were measured from the slop of the stress-strain graph to be 395 and 19.50 MPa respectively for compression,427 and 6.96 MPa respectively for tension,257 and 25.30 MPa respectively for three-point bending and 231 and 12.83 MPa respectively for torsion test.The finite element model was found to be in good agreement with the experimental results.Ductile fracture of the struct subjected to tensile strain was the main failure mode of the PEEK scaffold,which stems from the low crystallinity of additive manufacturing PEEK.The mechanical properties of porous PEEK are close to those of cancellous bone and thus are expected to be used in additive manufacturing PEEK bone implants in the future,but the lower yield strength poses a design challenge.

Concomitant functionalization of two different ketones by merging Brønsted acid catalysis and radical relay coupling

n the previous literature, incorporation of functional groups at the α-position of unactivated carbonylcompounds was mainly restricted to one kind of corresponding precursor. Herein, we report the concomitant functionalization of two distinct α-C–H bonds of carbonyls integrated with unactivated olefins andtert-butyl hydroperoxide selectively and efficiently in one pot by merging Brønsted acid catalysis andradical relay coupling, which delivers an array of structurally valuable unsymmetrical peroxy 1,9-diketonesin moderate to good yields under metal-free conditions.