Plasma diagnosis of tetrahedral amorphous carbon films by filtered cathodic vacuum arc deposition

Filtered cathodic vacuum arc(FCVA)deposition is regarded as an important technique for the synthesis of tetrahedral amorphous carbon(ta-C)films due to its high ionization rate,high deposition rate and effective filtration of macroparticles.Probing the plasma characteristics of arc discharge contributes to understanding the deposition mechanism of ta-C films on a microscopic level.This work focuses on the plasma diagnosis of an FCVA discharge using a Langmuir dualprobe system with a discrete Fourier transform smoothing method.During the ta-C film deposition,the arc current of graphite cathodes and deposition pressure vary from 30 to 90 A and from 0.3 to 0.9 Pa,respectively.The plasma density increases with arc current but decreases with pressure.The carbon plasma density generated by the arc discharge is around the order of10^(10)cm^(-3).The electron temperature varies in the range of 2-3.5 eV.As the number of cathodic arc sources and the current of the focused magnetic coil increase,the plasma density increases.The ratio of the intensity of the D-Raman peak and G-Raman peak(I_(D)/I_(G))of the ta-C films increases with increasing plasma density,resulting in a decrease in film hardness.It is indicated that the mechanical properties of ta-C films depend not only on the ion energy but also on the carbon plasma density.

低能电子束辐射交联改性PP/LLDPE五层共挤POF热收缩膜的性能

通过低能电子束辐射改性聚丙烯(PP)/线型低密度聚乙烯(LLDPE)五层共挤聚烯烃(POF)热收缩膜,制备耐温性强、收缩温度窗口宽的POF交联热收缩膜。文中研究了辐照气氛和吸收剂量对POF热收缩膜结构、力学性能和热收缩性能的影响。结果表明,在氮气和空气气氛辐照后,POF热收缩膜的结构、力学性能和热收缩性能未有明显差别。POF热收缩膜交联度和耐温性均随着吸收剂量增加而增加。POF热收缩膜的断裂伸长率随吸收剂量增加无明显变化;拉伸强度随吸收剂量增加先增加再降低。低能电子束辐照交联改善了POF热收缩膜低温收缩性能,增宽了热收缩温度窗口。

电子束辐照烯烃嵌段共聚物制备二重形状记忆弹性体

在真空氛围中对烯烃嵌段共聚物(OBC)进行电子束辐照.探讨了吸收剂量对OBC交联程度、力学性能、结晶和二重形状记忆效应的影响.通过应力?应变拉伸性能测试、X射线衍射(XRD)和拉伸恢复等方法对辐照样品的力学性能、晶体结构和二重形状记忆效应进行表征.结果表明:随着吸收剂量的增加,OBC凝胶含量增加,断裂伸长率逐渐降低,100%定伸强度增加,而在剂量50~150kGy时,拉伸强度随剂量的增加而增加,在更高剂量时开始降低;XRD测试表明,交联主要发生在无定形区域,重结晶的样品晶型结构没有发生改变,高剂量下三维交联结构部分抑制可结晶聚乙烯链段的扩散和重排,从而结晶度稍微降低;拉伸恢复测试表明,在剂量50kGy以上时,样品都有二重形状记忆效应,形状固定率和形状回复率均在93%以上.

Research progress in assessment and strategies for sustainable food system within planetary boundaries

Meeting the increasing food demand in a manner that ensures both resources and environmental sustainability poses a global challenge.The conceptual framework of planetary boundaries(PBs)has emerged as a crucial reference in the study of sustainable food system,with specific focuses on key dimensions such as land use change,freshwater use,nitrogen(N)and phosphorus(P)cycles,and greenhouse gas(GHG)emissions.In this study,we summarized the threshold applications of PBs in sustainable food system research at both the global and national(China)scales.Based on these thresholds,we evaluated the sustainability conditions of the food system,considering resources such as cropland,freshwater,N and P applications,as well as environmental impacts including N and P losses,and GHG emissions.In addition,we explored the impacts of single or combined management strategies on sustainable food systems.These strategies included dietary changes,improvements in technologies and management,reductions in food loss and waste,and optimization in agricultural production distribution.Finally,we outlined future research directions in sustainable food system,including enhancing research on the interaction mechanisms among PBs elements within food systems,conducting downscaling studies of PBs elements at national and regional levels,and ensuring the rationality of policy-making for sustainable food systems in China.This study can provide a theoretical foundation and strategies guidance for sustainable food system and agricultural land use management in the future both globally and in China.

Pivotal roles of tumor-draining lymph nodes in the abscopal effects from combined immunotherapy and radiotherapy

Background:Currently,due to synergy enhancement of anti-tumor effects and potent stimulation of abscopal effects,combination therapy with irradiation and programmed cell death protein 1/programmed death-ligand 1(PD-1/PD-L1)immune checkpoint inhibition(immuno-radiotherapy,iRT)has revolutionized the therapeutic guidelines.It has been demonstrated that tumor-draining lymph nodes(TDLN)are essential for effective antitumor immunity induced by radiotherapy,immunotherapy,or iRT.Given that the function of TDLN in iRT remains unclear,this study aimed to investigate the function and mechanism of TDLN in iRT-induced abscopal effects.Methods:The function of TDLN was evaluated using unilateral or bilateral MC38 and B16F10 subcutaneous tumor models with or without indicated TDLN.The flow cytometry,multiple immunofluorescence analysis,and NanoString analysis were utilized to detect the composition and function of the immune cells in the primary and abscopal tumor microenvironment.Additionally,we tempted to interrogate the possible mechanisms via RNA-sequencing of tumor-infiltrating lymphocytes and TDLN.Results:TDLN deficiency impaired the control of tumor growth by monotherapy.Bilateral TDLN removal rather than unilateral TDLN removal substantially curtailed iRT-stimulated anti-tumor and abscopal effects.Furthermore,in the absence of TDLN,the infiltration of CD45+and CD8+T cells was substantially reduced in both primary and abscopal tumors,and the anti-tumor function of CD8+T cells was attenuated as well.Additionally,the polarization of tumor-associated macrophages in primary and abscopal tumors were found to be dependent on intact bilateral TDLN.RNA-sequencing data indicated that impaired infiltration and anti-tumor effects of immune cells partially attributed to the altered secretion of components from the tumor microenvironment.Conclusions:TDLN play a critical role in iRT by promoting the infiltration of CD8+T cells and maintaining the M1/M2 macrophage ratio.

Nitrogen-doped carbon black supported Pd nanoparticles as an effective catalyst for formic acid electro-oxidation reaction

Pd nanoparticles supported on nitrogen doped carbon black （Vulcan XC-72R） with two different levels of doping were prepared by the microwave-assisted ethylene glycol reduction process and used as catalyst for the formic acid electro-oxidation （FAEO）. The results indicate that the different nitrogen doping contents in Pd/N-C catalysts have a significant effect on the performance of FAEO. A higher N content facilitates the uniform dispersion of Pd nanoparticles on carbon black with narrow particle size distribution. Furthermore, the electrochemical results show that the catalyst with a higher N-doping content possesses a higher catalytic activity and a long-term stability for FAEO. The peak current density of the Pd/N-C （high） catalyst is 1.27 and 2.31 times that of the Pd/N-C （low） and homemade Pd/C-H catalyst. The present paper may provide a simple method for preparation of high-performance anode catalyst for direct formic acid fuel cells （DFAFCs）.