Cleaning of nitrogen-containing carbon contamination by atmospheric pressure plasma jet

Atmospheric pressure plasma jet(APPJ)was used to clean nitrogen-containing carbon films(C–N)fabricated by plasma-assisted chemical vapor deposition method employing the plasma surface interaction linear device at Sichuan University(SCU-PSI).The properties of the contaminated films on the surface of pristine and He-plasma pre-irradiated tungsten matrix,such as morphology,crystalline structure,element composition and chemical structure were characterized by scanning electron microscopy,grazing incidence x-ray diffraction and x-ray photoelectron spectroscopy.The experimental results revealed that the removal of C–N film with a thickness of tens of microns can be realized through APPJ cleaning regardless of the morphology of the substrates.Similar removal rates of 16.82 and 13.78μm min^(-1)were obtained for C–N films deposited on a smooth pristine W surface and rough fuzz-covered W surface,respectively.This is a remarkable improvement in comparison to the traditional cleaning method.However,slight surface oxidation was found after APPJ cleaning,but the degree of oxidation was acceptable with an oxidation depth increase of only 3.15 nm.Optical emission spectroscopy analysis and mass spectrometry analysis showed that C–N contamination was mainly removed through chemical reaction with reactive oxygen species during APPJ treatment using air as the working gas.These results make APPJ cleaning a potentially effective method for the rapid removal of C–N films from the wall surfaces of fusion devices.

Low-Temperature Baking Effect of the Radio-Frequency Nb_(3)Sn Thin Film Superconducting Cavity

The Nb_(3)Sn thin film cavity,having the potential to be operated at a higher temperature and higher gradient compared to the cavity made from bulk niobium,is one of the most promising key technologies for the nextgeneration radio-frequency superconducting accelerators.In our work,several 1.3 GHz single-cell TESLA-shaped Nb_(3)Sn thin film cavities,coated by the vapor diffusion method,were tested at Peking University and Institute of Modern Physics,Chinese Academy of Sciences.It was observed that the performance of the Nb_(3)Sn thin film cavities in the tests without the slow cooling down procedure and the effective magnetic field shielding was significantly improved by using a low temperature baking at 100℃for 48 hours.Although the peak electric field of the cavity remained unchanged,the rapid drop of the unloaded Q value(Q0)with the increasing accelerating field(Q-slope)was effectively eliminated,resulting in an improvement of the Q0 in the intermediate field region by~8 times.Furthermore,under better test conditions with the shielded magnetic field less than 5 mG and the slow cooling down procedure in the temperature range of 25-15 K,the Q0 was still improved by about 20%.Our study shows that the low temperature baking can be an effective supplement to the effective post-treatment for the Nb_(3)Sn thin film cavity.

Development and Performance of the First Nb_(3)Sn Thin-Film Cavity via Bronze Process

Low-temperature synthesis of Nb_(3)Sn thin-film cavity is of great significance in the field of superconducting radio frequency(SRF).The bronze process can grow only stable Nb_(3)Sn phase at 700℃,so it is considered to be the most promising process for low-temperature synthesis of Nb3Sn thin-film cavity.We successfully fabricated the worldwide first Nb_(3)Sn thin-film cavity by bronze process.We technically solved the key problems of precursor preparation,characterized and analyzed the uniformity of the Nb_(3)Sn film,and tested the performance of the cutout samples and the whole cavity of the Nb_(3)Sn film.It is obtained that the Q0value of the cavity at 4.2 K is about 1.2×10^(9),which is greater than the performance of the bulk-niobium cavity under the same conditions.This result means that the preparation of Nb_(3)Sn by bronze process has the great potential to more practical copper-based Nb_(3)Sn thin-film cavity,which is expected to achieve a substantial improvement in the performance of SRF cavity and comprehensive engineering applications.

A time sequence analysis on the informal information flow mechanism of microblogging

Microblog is a new Internet featured product, which has seen a rapid development in recent years. Researchers from different countries are making various technical analyses on microblogging applications. In this study, through using the natural language processing(NLP) and data mining, we analyzed the information content transmitted via a microblog, users' social networks and their interactions, and carried out an empirical analysis on the dissemination process of one particular piece of information via Sina Weibo.Based on the result of these analyses, we attempt to develop a better understanding about the rule and mechanism of the informal information flow in microblogging.

1.3 GHz超导腔的电化学青铜法铌三锡镀膜技术

由于射频超导腔具有高品质因数Q0,大束流孔径等诸多优势,已被加速器行业广泛应用。目前纯铌腔的性能已经接近理论极限,使用Nb3Sn薄膜腔代替纯铌腔是突破这一限制的有效手段。铌三锡具有较高的超导转变温度和过热磁场,理论预期可以大幅度提高SRF腔体工作温度和加速梯度。目前,Nb3Sn薄膜制备技术蓬勃发展,其中锡蒸汽扩散法已经比较成熟,已制备出初步满足工程需求的铌基铌三锡薄膜射频超导腔。但是由于反应温度在1100℃以上,锡蒸汽扩散法无法摆脱纯铌基底,因此不可避免地在机械稳定性、导热性等方面有缺陷,难以满足未来高可靠性加速器的应用。青铜法广泛应用于铌三锡线缆的制备,热处理温度不高于700℃,具有制备铜基铌三锡镀膜腔的潜力。此外,电化学镀膜与其他方式相比,具有成本低、反应过程容易控制、常温常压等明显优势。本工作将上述两种工艺结合起来,研究了电化学方式在1.3 GHz铌基超导腔上镀青铜前驱体,之后热处理合成铌三锡薄膜腔。垂测结果表明,4.2 K下的薄膜腔本征Q0为6×108左右且仍具很大提升空间。

FHA domain of AGGF1 is essential for its nucleocytoplasmic transport and angiogenesis

Angiogenic factor with G-patch and FHA domains 1(AGGF1) exhibits a dynamic distribution from the nucleus to the cytoplasm in endothelial cells during angiogenesis, but the biological significance and underlying mechanism of this nucleocytoplasmic transport remains unknown. Here, we demonstrate that the dynamic distribution is essential for AGGF1 to execute its angiogenic function. To search the structural bases for this nucleocytoplasmic transport, we characterized three potential nuclear localization regions, one potential nuclear export region, forkhead-associated(FHA), and G-patch domains to determine their effects on nucleocytoplasmic transport and angiogenesis, and we show that AGGF1 remains intact during the dynamic subcellular distribution and the region from 260 to 288 amino acids acts as a signal for its nuclear localization. The distribution of AGGF1 in cytoplasm needs both FHA domain and 14-3-3α/β. Binding of AGGF1 via FHA domain to 14-3-3α/β is required to complete the transport. Thus, we for the first time established structural bases for the nucleocytoplasmic transport of AGGF1 and revealed that the FHA domain of AGGF1 is essential for its nucleocytoplasmic transport and angiogenesis.

Insulin-resistance and depression cohort data mining to identify nutraceutical related DNA methylation biomarker for type 2 diabetes

Insulin-resistance(IR)is one of the most important precursors of type 2 diabetes(T2D).Recent evidence suggests an association of depression with the onset of T2D.Accumu-lating evidence shows that depression and T2D share common biological origins,and DNA methylation examination might reveal the link between lifestyle,disease risk,and potential therapeutic targets for T2D.Here we hypothesize that integrative mining of IR and depression cohort data will facilitate predictive biomarkers identification for T2D.We utilized a newly proposed method to extract gene-level information from probe level data on genome-wide DNA methylation array.We identified a set of genes associated with IR and depression in clin-ical cohorts.By overlapping the IR-related nutraceutical-gene network with depression net-works,we identified a common subnetwork centered with Vitamin D Receptor(VDR)gene.Preliminary clinical validation of gene methylation set in a small cohort of T2D patients and controls was established using the Sequenome matrix-assisted laser desorption ionization-time flight mass spectrometry.A set of sites in the promoter regions of VDR showed a signifi-cant difference between T2D patients and controls.Using a logistic regression model,the optimal prediction performance of these sites was AUC Z 0.902,and an odds ratio Z 19.76.Thus,monitoring the methylation status of specific VDR promoter region might help stratify the high-risk individuals who could potentially benefit from vitamin D dietary sup-plementation.Our results highlight the link between IR and depression,and the DNA methyl-ation analysis might facilitate the search for their shared mechanisms in the etiology of T2D.