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.

Double Position Servo Synchronous Drive System Based on Cross-Coupling Integrated Feedforward Control for Broacher

Synchronization errors directly deteriorate the machining accuracy of metal parts and the existed method cannot keep high synchronization precision because of external disturbances. A new double position servo synchronous driving scheme based on semi-closed-loop cross- coupling integrated feedforward control is proposed. The scheme comprises a position error cross-coupling feedfor-ward control and a load torque identification with feed- forward control. A digital integrated simulation system for the dual servo synchronous drive system is established. Using a 20 t servo broacher, performance analysis of the scheme is conducted based on this simulation system and the simulation results show that systems with traditional parallel or single control have problems when the work- table works with an unbalanced load. However, the system with proposed scheme shows good synchronous perfor- mance and positional accuracy. Broaching tests are performed and the experimental results show that the maximum dual axis synchronization error of the system is only 8μm during acceleration and deceleration processes and the error between the actual running position and the given position is almost zero. A double position servo synchronous driving scheme is presented based on crosscoupled integrated feedforward compensation control, which can improve the synchronization precision.

Continuous compositional spread investigation of SiC-based thin films prepared by MW-ECR plasma enhanced magnetron co-sputtering

A kind of combinatorial material methodology,also known as continuous compositional spread method,was employed to investigate the relationship between the optical band gap and composition of SiC thin films.A wide range of SixCy thin films with different carbon contents have been successfully deposited in a single deposition by carefully arranging the sample position on the substrate holder.The films were characterized by surface profiler,x-ray photoelectron spectroscopy,ultraviolet-visible spectroscopy,fourier transform infrared spectroscopy and Raman spectroscopy.The carbon content y increases linearly from 0.28 to 0.72 while the sample position changed from 85 to 175 mm,the optical band gap changed between 1.27 and 1.99 eV,the maximum value corresponded to the stoichiometric SiC sample at the position of 130 mm,which has the highest Si?C bond density of 11.7×10^22 cm^-3.The C poor and C rich SixCy samples with y value less and larger than 0.5 were obtained while samples deviated from the position 130 mm,the optical band gap decreased with the Si?C bond density.

环保“费改税”对中国医药制造业绿色创新的影响研究

企业发展使得人们的生活水平不断提升,但同时也对生活环境带来了更大的负担,为了实现我国经济高质量可持续发展,政府不断推出和完善环保政策,鼓励企业在发展的同时,增加对环境的关注。中国于2018年1月1日正式实施环保“费改税”政策,对企业排污施加更大的环境合法性压力,以期达到促进企业绿色创新的效果,为了对政策实施效果进行评估,本文以2015~2021年沪深两市A股医药制造业上市公司为研究对象,采用双重差分法对环保“费改税”政策的绿色创新影响效果进行考察,并应用中介效应检验法分析企业内部研发投入和外部融资限制发挥的中介作用。研究发现:①环保“费改税”政策显著促进了医药制造企业绿色创新。②规模越大的企业绿色创新水平越高;政府补贴对医药制造业企业绿色创新呈现显著负相关关系,在一定程度上抑制了企业绿色创新。③企业R&D投入在环保“费改税”政策与医药制造业企业绿色创新的关系中发挥着部分中介作用。④环保“费改税”政策通过减轻企业融资约束间接促进企业绿色创新。基于以上研究结论,本文提出以下政策建议:政府应因地制宜,对不同的企业,选择合理恰当的税额标准;加强对政府补贴的监督管理,丰富完善补贴方式,使其能够更加有效地促进企业实质性绿色创新;规范和完善企业绿色创新的融资机制,缓解企业融资困境;企业应建立健全投资管理体系以提升研发投资效率等。

Remarkable difference of phospholipid molecular chirality in regulating PrP aggregation and cell responses

Prion diseases are fatal neurodegenerative diseases that can cause severe dementia.The misfolding and accumulation of the prion peptide (PrP)_(106–126) is crucial,and this process is closely relevant to biological membranes.However,how PrP_(106–126)aggregation is affected by the molecular chirality of phospholipid membrane is unknown.Thus,in this study,a pair of L-and D-aspartic acid (Asp)-modified 1,2-dipalmitoyl-sn–glycero-3-phosphoethanolamine (DPPE) were synthesized to construct chiral liposomes.We discover that L-Asp-DPPE liposomes strongly inhibit the oligomerization and amyloidogenesis of PrP_(106–126),whether acting on monomers or oligomers,which rescues cytotoxicity induced by PrP_(106–126).By comparison,D-Asp-DPPE liposomes inhibit peptide oligomerization only at a high concentration and cannot prevent amyloidogenesis when acting on oligomers,which lead to pronounced cytotoxicity.Apoptosis experiment,dynamic change of intracellular Ca^(2+)(_(i)Ca^(2+)) and Ca^(2+)release from endoplasmic reticulum(ER),reactive oxygen species (ROS) production,adsorption dynamics and affinity tests,and fluorescent imaging clearly disclose that molecular chirality of the liposomes dominates conformational transition of PrP_(106–126)from random coil to β-sheet,binding and adsorption of the monomers and oligomers,and subsequent fibrillation process,resulting in distinct inhibition effect in Ca^(2+)overload and release,ROS production and cell apoptosis.This work is the first to report that interfacial molecular chirality is a potentially crucial influence on the fibrillation process of PrP_(106–126) and its cell responses,whereas the convergence of chiral amino acids and liposomes can be considered potential inhibitors in prion diseases.

Sensing Mechanism of Excited-State Intermolecular Hydrogen Bond for Phthalimide: Indispensable Role of Dimethyl Sulfoxide

Excited-state hydrogen bond strongly affects the intramolecular charge conversion process,which is very suitable for the design and development of high-performance fluorescent probes.However,as one of the most common solvents or additives used in sensing,the role of dimethyl sulfoxide(DMSO)in the system of the excited-state hydrogen bond is seldom explored.As the goal of this research,we investigated the sensing mechanism of a C0RM3-green fluorescent probe system for carbon monoxide releasing molecule(CORM-3)detection and tracking in vivo,through quantum chemistry calculations based on density-functional-theory(DFT)/time-dependent density-functional-theory(TDDFT)methods.Based on the analysis of the solvent effect of DMSO by the reduced density gradient function and IR spectroscopy,we provided a new strategy to explain the fluorescence mechanism.Subsequently,we verified the result through the potential energy curve of Phthalimide(PTI,the reduced product of C0RM3-green).The excited-state hydrogen bond between PTI and DMSO promotes radiation transition and leads to obvious difference in the photophysical properties of PTI and PTI-DMSO.