Effect of surface modification on the radiation stability of diamond ohmic contacts

The ohmic contact interface between diamond and metal is essential for the application of diamond detectors.Surface modification can significantly affect the contact performance and eliminate the interface polarization effect.However,the radiation stability of a diamond detector is also sensitive to surface modification.In this work,the influence of surface modification technology on a diamond ohmic contact under high-energy radiation was investigated.Before radiation,the specific contact resistivities(ρc)between Ti/Pt/Au-hydrogen-terminated diamond(H-diamond)and Ti/Pt/Au-oxygenterminated diamond(O-diamond)were 2.0×10^(-4)W·cm^(2) and 4.3×10^(-3)Wcm^(2),respectively.After 10 MeV electron radiation,the ρc of Ti/Pt/Au H-diamond and Ti/Pt/Au O-diamond were 5.3×10^(-3)W·cm^(2)and 9.1×10^(-3)W·cm^(2),respectively.The rates of change of ρc of H-diamond and O-diamond after radiation were 2550%and 112%,respectively.The electron radiation promotes bond reconstruction of the diamond surface,resulting in an increase in ρc.

Exploring the effect and mechanisms of Epimedium on diabetic testicular injury using network pharmacology,molecular docking,and cell experiments

Background:Studying the potential targets and mechanisms of Epimedium for anti-diabetic testicular injury using network pharmacology,molecular docking,and cell experiments.Methods:Acquisition of major components and targets of Epimedium was based on TCMSP,TCMID,and Symmap databases and retrieval of diabetic testicular injury targets by OMIM,GeneCards,Pharmgkb,and Drugbank databases.Intersecting targets were obtained from the Venny 2.1.0 database and input SRTING data to construct a protein-protein interaction(PPI)network,and key targets were screened in Cytoscape 3.8.0 software.Then the Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analyses of intersecting targets were conducted through the DAVID database.Further,AutoDock software was used to verify docking between the main components and the core target proteins.In addition,a Cell Counting Kit-8(CCK-8)assay was used to determine the survival effect of quercetin,the main component of Epimedium,on TM4 sertoli-like cells exposed to palmitic acid(PA).Results:Quercetin,kaempferol and luteolin in epimedium were identified as the main components in the treatment of diabetic testicular injury.It has core target proteins including MMP9,AKT1,and TNF.The biological process mainly involves the regulation of the apoptotic signaling pathway.The key pathways of KEGG are the AGE-RAGE signaling pathway in diabetic complications,PI3K-Akt and MAPK signaling pathway.Molecular docking results showed that quercetin had the strongest binding ability to MMP9.Also,PA-challenged cells had a lower survival rate,which was alleviated by the administration of quercetin.Conclusion:Our findings suggest that Epimedium attenuates diabetes mellitus(DM)-induced testicular injury through AGE-RAGE,PI3K-Akt and MAPK signaling pathway.These insights offer a potential therapeutic strategy for managing DM-induced testicular injury,will be the basis for future clinical research.

Comparison of α particle detectors based on single-crystal diamond films grown in two types of gas atmospheres by microwave plasma-assisted chemical vapor deposition

Chemical vapor deposition(CVD)-grown diamond films have been developed as irradiation-resistant materials to replace or upgrade current detectors for use in extreme radiation environments. However, their sensitivity in practical applications has been inhibited by space charge stability issues caused by defects and impurities in pure diamond crystal materials. In this study, two high-quality CVD-grown single-crystal diamond(SCD) detectors with low content of nitrogen impurities were fabricated and characterized. The intrinsic properties of the SCD samples were characterized using Raman spectroscopy, stereomicroscopy, and X-ray diffraction with the rocking curve mode, cathode luminescence(CL), and infrared and ultraviolet-visible-near infrared spectroscopies. After packaging the detectors, the dark current and energy resolution under α particle irradiation were investigated. Dark currents of less than 5 pA at 100 V were obtained after annealing the electrodes, which is comparable with the optimal value previously reported. The detector that uses a diamond film with higher nitrogen content showed poor energy resolution, whereas the detector with more dislocations showed poor charge collection efficiency(CCE). This demonstrates that the nitrogen content in diamond has a significant effect on the energy resolution of detectors, while the dislocations in diamond largely contribute to the poor CCE of detectors.

Energy consumption of electrooxidation systems with boron-doped diamond electrodes in the pulse current mode

A pulse current technique was conducted in a boron-doped diamond （BDD） anode system for electrochemical waste- water treatment. Due to the strong generation and weak absorption of hydroxyl radicals on the diamond surface, the BDD elec- trode possesses a powerful capability of electrochemical oxidation of organic compounds, especially in the pulse current mode. The influences of pulse current parameters such as current density, pulse duty cycle, and frequency were investigated in terms of chemical oxygen demand （COD） removal, average current efficiency, and specific energy consumption. The results demon- strated that the relatively high COD removal and low specific energy consumption were obtained simultaneously only if the current density or pulse duty cycle was adjusted to a reasonable value. Increasing the frequency slightly enhanced the COD re- moval and average current efficiency. A pulse-BDD anode system showed a stronger energy saving ability than a constant-BDD anode system when the electrochemical oxidation of phenol of the two systems was compared. The results prove that the pulse current technique is more cost-effective and more suitable for a BDD anode system for real wastewater treatment. A kinetic analysis was presented to explain the above results.

Comparative study of oxidation ability between boron-doped diamond (BDD) and lead oxide (PbO_2) electrodes

The electrochemical oxidation capabilities of two high-performance electrodes,the boron-doped diamond film on Ti （Ti/BDD） and the lead oxide film on Ti （Ti/PbO2）,were discussed.Hydroxyl radicals （·HO） generated on the electrode surface were detected by using p-nitrosodimethylaniline （RNO） as the trapping reagent.Electrochemical oxidation measurements,including the chemical oxygen demand （COD） removal and the current efficiency （CE）,were carried out via the degradation of p-nitrophenol （PNP） under the galvanostatic condition.The results indicate that an indirect reaction,which is attributed to free hydroxyl radicals with high activation,conducts on the Ti/BDD electrode,while the absorbed hydroxyl radicals generated at the Ti/PbO2 surface results in low degradation efficiency.Due to quick mineralization which combusts PNP to CO2 and H2O absolutely by the active hydroxyl radical directly,the CE obtained on the Ti/BDD electrode is much higher than that on the Ti/PbO2 electrode,notwithstanding the number of hydroxyl radicals produced on PbO2 is higher than that on the BDD surface.

Enhanced deposition of Zn O films by Li doping using radio frequency reactive magnetron sputtering

Radio frequency(RF) reactive magnetron sputtering was utilized to deposit Li-doped and undoped zinc oxide(Zn O) films on silicon wafers. Various Ar/O2 gas ratios by volume and sputtering powers were selected for each deposition process. The results demonstrate that the enhanced Zn O films are obtained via Li doping. The average deposition rate for doped Zn O films is twice more than that of the undoped films. Both atomic force microscopy and scanning electron microscopy studies indicate that Li doping significantly contributes to the higher degree of crystallinity of wurtzite–Zn O. X-ray diffraction analysis demonstrates that Li doping promotes the(002) preferential orientation in Li-doped Zn O films. However, an increase in the Zn O lattice constant, broadening of the(002) peak and a decrease in the peak integral area are observed in some Li-doped samples, especially as the form of Li2 O. This implies that doping with Li expands the crystal structure and thus induces the additional strain in the crystal lattice. The oriented-growth Li-doped Zn O will make significant applications in future surface acoustic wave devices.

Optical characterization of single-crystal diamond grown by DC arc plasma jet CVD

Optical centers of single-crystal diamond grown by DC arc plasma jet chemical vapor deposition(CVD) were examined using a low-temperature photoluminescence(PL) technique. The results show that most of the nitrogen-vacancy(NV) complexes are present as NV-centers, although some H2 and H3 centers and B-aggregates are also present in the single-crystal diamond because of nitrogen aggregation resulting from high N_2 incorporation and the high mobility of vacancies under growth temperatures of 950–1000°C. Furthermore, emissions of radiation-induced defects were also detected at 389, 467.5, 550, and 588.6 nm in the PL spectra. The reason for the formation of these radiation-induced defects is not clear. Although a Ni-based alloy was used during the diamond growth, Ni-related emissions were not detected in the PL spectra. In addition, the silicon-vacancy(Si-V)-related emission line at 737 nm, which has been observed in the spectra of many previously reported microwave plasma chemical vapor deposition(MPCVD) synthetic diamonds, was absent in the PL spectra of the single-crystal diamond prepared in this work. The high density of NV-centers, along with the absence of Ni-related defects and Si-V centers, makes the single-crystal diamond grown by DC arc plasma jet CVD a promising material for applications in quantum computing.

Orientation variation along growth direction of millimeter free-standing CVD diamond thinned by mechanical grinding

A free-standing diamond film with millimeter thickness prepared by DC arc plasma jet was thinned successively by mechanical grinding. The orientation and quality of the diamond films with different thicknesses were characterized by X-ray diffraction and Raman spectroscopy, respectively. The results show a random grain-orientatinn distribution during the initial growth stage. As the film thickness increases, the preferred orientation of the diamond film changes from （111） to （220）, due to the competitive growth mechanism. Twinning generated during the nucleation stage appears to stabilize the preferential growth along the 〈110〉 direction. The interplanar spacing of the （220） plane is enlarged as the film thickness increases, which is caused by the increase of non-diamond-phase carbon and impurities under the cyclic gas. In addition, the quality of the diamond film is barely degraded during the growth process. Furthermore, the peak shift demonstrates a significant inhomogeneity of stress along the film growth direction, which results from competitive growth.

研究2Hz和100Hz电针对2型糖尿病神经痛大鼠的镇痛作用以及对背根神经节致痛相关蛋白表达的影响（英文）

目的:研究2和100 Hz电针对2型糖尿病神经痛(DNP)大鼠的镇痛作用,以及对DNP大鼠背根神经节(DRG)上P2X3受体和降钙素相关基因肽(CGRP)表达的影响。创新点:本研究首次选用2型DNP大鼠模型来研究电针治疗DNP的优势频率。研究证明2 Hz电针对2型DNP大鼠的镇痛作用以及对DRG上高表达的P2X3抑制作用优于100 Hz,为电针治疗DNP及其频率选择提供科学依据和阐释。方法:将雄性SD大鼠分为对照组(腹腔注射柠檬酸钠缓冲液)和模型组(高脂高糖饲养联合腹腔注射35 mg/kg链脲佐菌素(STZ))。模型组根据采用不同的电针频率分为以下三组:DNP组、DNP+2 Hz电针组、DNP+100 Hz电针组。采用足底测试仪检测大鼠足跖热痛阈(PWL),用酶联免疫吸附测定(ELISA)试剂盒检测大鼠空腹胰岛素(FINS)含量,用免疫荧光法检测DRG上的P2X3受体和CGRP的表达水平。结论:2和100 Hz电针对2型DNP均有明显的镇痛作用,且2 Hz电针对2型DNP的镇痛作用优于100 Hz电针(图2)。免疫荧光实验结果显示,2和100 Hz电针均能明显下调DRG中P2X3受体和CGRP的高表达(图3和4),且2 Hz电针对DRG中P2X3受体的抑制作用优于100 Hz电针(图3)。综上所述,2 Hz电针是治疗2型DNP较为理想的治疗手段。