碳纤维表面处理对含硅芳炔树脂复合材料的界面增强

含硅芳炔(PSA)树脂是一类具有优异耐热性的树脂基体,其纤维复合材料可应用于航空航天领域,但是PSA树脂与纤维的复合材料存在界面结合较弱的问题。文中针对这个问题,以T300碳纤维/PSA树脂复合材料为对象开展研究。首先,对T300碳纤维布进行高温处理,并进行了热重分析、红外光谱、X射线光电子能谱及扫描电镜表征;其次,制备了T300/PSA树脂复合材料,探究了其性能变化;最后,用端炔基苯并噁嗪(BA)偶联剂涂敷高温处理后的碳纤维布,再与PSA树脂复合,研究了复合材料性能变化。结果表明,高温处理的T300碳纤维/PSA树脂复合材料力学性能提高,高温处理的T300碳纤维布再经BA偶联剂涂敷,其PSA树脂复合材料的力学性能可进一步提高,常温弯曲强度提高到了413.1 MPa,提升幅度为53.9%;450℃弯曲强度提高到了295.5 MPa,提升幅度为44.3%。

Palladium nanoparticles/wool keratin-assisted carbon composite-modified flexible and disposable electrochemical solid-state pH sensor

Several p H-dependent processes and reactions take place in the human body;hence,the p H of body fluids is the best indicator of disturbed health conditions.However,accurate and real-time diagnosis of the p H of body fluids is complicated because of limited commercially available p H sensors.Hence,we aimed to prepare a flexible,transparent,disposable,userfriendly,and economic strip-based solid-state p H sensor using palladium nanoparticles(Pd NPs)/N-doped carbon(NC)composite material.The Pd NPs/NC composite material was synthesized using wool keratin(WK)as a precursor.The insitu prepared Pd NPs played a key role in the controlled switching of protein structure to the N-doped carbon skeleton withπ–πarrangement at the mesoscale level,which mimics the A–B type polymeric structure,and hence,is highly susceptible to H+ions.The optimized carbonization condition in the presence of Pd NPs showed that the material obtained using a modified Ag/Ag Cl reference electrode had the highest p H sensitivity with excellent stability and durability.The optimized p H sensor showed high specificity and selectivity with a sensitivity of 55 m V/p H unit and a relative standard deviation of 0.79%.This study is the first to synthesize Pd NPs using WK as a stabilizing and reducing agent.The applicability of the sensor was investigated for biological samples,namely,saliva and gastric juices.The proposed protocol and material have implications in solid-state chemistry,where biological material will be the best choice for the synthesis of materials with anticipated performance.

Genomic prediction of Fusarium head blight resistance in early stages using advanced breeding lines in hard winter wheat

Fusarium head blight(FHB),also known as scab,is a devastating fungal disease of wheat that causes significant losses in grain yield and quality.Quantitative inheritance and cumbersome phenotyping make FHB resistance a challenging trait for direct selection in wheat breeding.Genomic selection to predict FHB resistance traits has shown promise in several studies.Here,we used univariate and multivariate genomic prediction models to evaluate the prediction accuracy(PA)for different FHB traits using 476elite and advanced breeding lines developed by South Dakota State University hard winter wheat breeding program.These breeding lines were assessed for FHB disease index(DIS),and percentage of Fusarium damaged kernels(FDK)in three FHB nurseries in 2018,2019,and 2020(TP18,TP19,and TP20)and were evaluated as training populations(TP)for genomic prediction(GP)of FHB traits.We observed a moderate PA using univariate models for DIS(0.39 and 0.35)and FDK(0.35 and 0.37)using TP19 and TP20,respectively,while slightly higher PA was observed(0.41 for DIS and 0.38 for FDK)when TP19 and TP20(TP19+20)were combined to leverage the advantage of a large training population.Although GP with multivariate approach including plant height and days to heading as covariates did not significantly improve PA for DIS and FDK over univariate models,PA for DON increased by 20%using DIS,FDK,DTH as covariates using multi-trait model in 2020.Finally,we used TP19,TP20,and TP19+20 in forward prediction to calculate genomic-estimated breeding values(GEBVs)for DIS and FDK in preliminary breeding lines at an early stage of the breeding program.We observed moderate PA of up to 0.59 for DIS and 0.54for FDK,demonstrating the promise in genomic prediction for FHB resistance in earlier stages using advanced lines.Our results suggest GP for expensive FHB traits like DON and FDK can facilitate the rejection of highly susceptible materials at an early stage in a breeding program.

An Analysis of Theme Positioning of Tourism-oriented Characteristic Towns——A Case Study of Jiangwan Town,Jiangxi Province

The tourism-oriented characteristic town is a main part of China's tourism development.Tourism-oriented characteristic towns take up the largest proportion in the characteristic towns and have the largest development potential and value.Taking Jiangwan Town of Jiangxi Province as an example,this paper analyzed the factors influencing the development of tourism-oriented characteristic towns,including natural resources,regional conditions,market demands and perceived value.It refined and built the theme of Jiangwan Town: ecological history and culture tourism,a scenic spot of Fujian,Zhejiang and Anhui provinces,and experience-type farm culture and traditional ancient culture tourism.

Tailoring the electronic structure of PdAg_(x) alloy nanowires for high oxygen reduction reaction

Lowering the cost while maintaining the highly catalytic performance is greatly beneficial for the development of commercial fuel cells and metal-air batteries.Compared with platinum,palladium holds a stronger oxygen affinity and high abundance on earth,endowing it a promising alternative to platinum in anion-exchange membrane fuel cells.However,the sluggish oxygen reduction reaction of palladium still remains a great issue and requires the design of stable and efficient palladium-based electrocatalysts.Here,we report the solvothermal/hydrothermal reduction method to prepare a series of PdAg_(x)nanowires.The prepared PdAg_(x)NWs exhibit hollow structure,which greatly improves the utilization of Pd atoms,offering an outstanding ORR performance.Specifically,PdAg_(2)NWs exhibit an onset potential of 0.92 V and mass activity of 350.7 mA mgPd^(-1)at 0.7 V vs.RHE for ORR in 0.1 M KOH solution.This work provides a novel approach for the construction of hollow NWs and their subsequent applications in other electrocatalytic reactions.

Photoacoustic/ultrasound dual-modal imaging of human nails: A pilot study

Traditional diagnostic techniques including visual examination,ultrasound(US),and magnetic resonance imaging(MRI)have limitations of in-depth information for the detection of nail disorders,resolution,and practicality.This pilot study,for thefirst time,evaluates a dualmodality imaging system that combines photoacoustic tomography(PAT)with the US for the multiparametric quantitative assessment of human nail.The study involved a small cohort offive healthy volunteers who underwent PAT/US imaging for acquiring the nail unit data.The PAT/US dual-modality imaging successfully revealed thefine anatomical structures and microvascular distribution within the nail and nail bed.Moreover,this system utilized multispectral PAT to analyze functional tissue parameters,including oxygenated hemoglobin,deoxyhemoglobin,oxygen saturation,and collagen under tourniquet and cold stimulus tests to evaluate changes in the microcirculation of the nail bed.The quantitative analysis of multispectral PAT reconstructed images demonstrated heightened sensitivity in detecting alterations in blood oxygenation levels and collagen content within the nail bed,under simulated different physiological conditions.This pilot study highlights the potential of PAT/US dual-modality imaging as a real-time,noninvasive diagnostic modality for evaluating human nail health and for early detection of nail bed pathologies.

Binary titanium alloys as dental implant materials—a review

Titanium(Ti)has been used for long in dentistry and medicine for implant purpose.During the years,not only the commercially pure Ti but also some alloys such as binary and tertiary Ti alloys were used.The aim of this review is to describe and compare the current literature on binary Ti alloys,including Ti-Zr,Ti-In,Ti-Ag,Ti-Cu,Ti-Au,Ti-Pd,Ti-Nb,Ti-Mn,Ti-Mo,Ti-Cr,Ti-Co,Ti-Sn,Ti-Ge and Ti-Ga,in particular to mechanical,chemical and biological parameters related to implant application.Literature was searched using the PubMed and Web of Science databases,as well as google without limiting the year,but with principle key terms such as‘Ti alloy’,‘binary Ti’,‘Ti-X’(with X is the alloy element),‘dental implant’and‘medical implant’.Only laboratory studies that intentionally for implant or biomedical applications were included.According to available literatures,we might conclude that most of the binary Ti alloys with alloying<20%elements of Zr,In,Ag,Cu,Au,Pd,Nb,Mn,Cr,Mo,Sn and Co have high potential as implant materials,due to good mechanical performance without compromising the biocompatibility and biological behaviour compare to cp-Ti.

Associations of Residential Greenness with Depression and Anxiety in Rural Chinese Adults

BACKGROUND Depression and anxiety are top contributors to non-fatal health loss globally.Several studies have indicated the association between residential greenness and mental health.METHOD The participants(n=27,366)were recruited from four counties in Henan Province,China during 2015–2017.Symptoms of depression and anxiety were evaluated using the Patient Health Questionnaire-2(PHQ-2)and the Generalized Anxiety Disorder-2(GAD-2)in the baseline survey.The level of residential greenness during the 3-year period before the baseline survey was assessed using the Moderate Resolution Imaging Spectroradiometer(MODIS)Normalized Difference Vegetation Index(NDVI)and Enhanced Vegetation Index(EVI).The mixed-effect linear regression model was applied to examine the associations of residential greenness with depression and anxiety.RESULTS The results of adjusted models showed that the score of PHQ-2(Dscore and 95%confidence interval[CI])decreased by-0.024(-0.041,-0.006)and-0.022(-0.038,-0.004)with an interquartile range(IQR)increase in NDVI and EVI within a 1,000-m buffer radius,respectively.The score of GAD-2(Dscore and 95%CI)decreased by-0.024(-0.040,-0.006)and-0.028(-0.044,-0.011),in relation to an IQR increase in NDVI and EVI within a 1,000-m buffer radius,respectively.CONCLUSIONS A higher level of residential greenness was significantly associated with lower risk of depression and anxiety in rural areas of Henan Province.Improving residential greenness accessibility may help to promote the mental health of rural populations.