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Analyzing the surface passivity effect of germanium oxynitride:a comprehensive approach through first principles simulation and interface state density
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作者 Sheng-Jie Du Xiu-Xia Li +8 位作者 Yang Tian yuan-yuan liu Ke Jia Zhong-Zheng Tang Jian-Ping Cheng Zhi Deng Yu-Lan Li Zheng-Cao Li Sha-Sha Lv 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第5期74-84,共11页
High-purity germanium(HPGe)detectors,which are used for direct dark matter detection,have the advantages of a low threshold and excellent energy resolution.The surface passivation of HPGe has become crucial for achiev... High-purity germanium(HPGe)detectors,which are used for direct dark matter detection,have the advantages of a low threshold and excellent energy resolution.The surface passivation of HPGe has become crucial for achieving an extremely low energy threshold.In this study,first-principles simulations,passivation film preparation,and metal oxide semiconductor(MOS)capacitor characterization were combined to study surface passivation.Theoretical calculations of the energy band structure of the -H,-OH,and -NH_(2) passivation groups on the surface of Ge were performed,and the interface state density and potential with five different passivation groups with N/O atomic ratios were accurately analyzed to obtain a stable surface state.Based on the theoretical calculation results,the surface passivation layers of the Ge_(2)ON_(2) film were prepared via magnetron sputtering in accordance with the optimum atomic ratio structure.The microstructure,C-V,and I-V electrical properties of the layers,and the passivation effect of the Al/Ge_(2)ON_(2)/Ge MOS were characterized to test the interface state density.The mean interface state density obtained by the Terman method was 8.4×10^(11) cm^(-2) eV^(-1).The processing of germanium oxynitrogen passivation films is expected to be used in direct dark matter detection of the HPGe detector surface passivation technology to reduce the detector leakage currents. 展开更多
关键词 Surface passivation High purity germanium detector Germanium nitrogen oxide Interface state density
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Multimodal imaging diagnosis and analysis of prognostic factors in patients with adult-onset Coats disease
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作者 Wei Zhou Hui Zhou +6 位作者 yuan-yuan liu Meng-Xuan Li Xiao-Han Wu Jiao Liang Jing Hao Sheng-Nan liu Chun-Jie Jin 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第8期1469-1476,共8页
AIM:To describe the multimodal imaging features,treatment,and outcomes of patients diagnosed with adultonset Coats disease.METHODS:This retrospective study included patients first diagnosed with Coats disease at≥18 y... AIM:To describe the multimodal imaging features,treatment,and outcomes of patients diagnosed with adultonset Coats disease.METHODS:This retrospective study included patients first diagnosed with Coats disease at≥18 years of age between September 2017 and September 2021.Some patients received anti-vascular endothelial growth factor(VEGF)therapy(conbercept,0.5 mg)as the initial treatment,which was combined with laser photocoagulation as needed.All the patients underwent best corrected visual acuity(BCVA)and intraocular pressure examinations,fundus color photography,spontaneous fluorescence tests,fundus fluorescein angiography,optical coherence tomography(OCT),OCT angiography,and other examinations.BCVA alterations and multimodal image findings in the affected eyes following treatment were compared and the prognostic factors were analyzed.RESULTS:The study included 15 patients who were aged 24-72(57.33±12.61)y at presentation.Systemic hypertension was the most common associated systemic condition,occurring in 13(86.7%)patients.Baseline BCVA ranged from 2.0 to 5.0(4.0±1.1),which showed improvement following treatment(4.2±1.0).Multimodal imaging revealed retinal telangiectasis in 13 patients(86.7%),patchy hemorrhage in 5 patients(33.3%),and stage 2B disease(Shield’s staging criteria)in 11 patients(73.3%).OCT revealed that the baseline central macular thickness(CMT)ranged from 129 to 964μm(473.0±230.1μm),with 13 patients(86.7%)exhibiting a baseline CMT exceeding 250μm.Furthermore,8 patients(53.3%)presented with an epiretinal membrane at baseline or during follow-up.Hyper-reflective scars were observed on OCT in five patients(33.3%)with poor visual prognosis.Vision deteriorated in one patient who did not receive treatment.Final vision was stable in three patients who received laser treatment,whereas improvement was observed in one of two patients who received anti-VEGF therapy alone.In addition,8 of 9 patients(88.9%)who received laser treatment and conbercept exhibited stable or improved BCVA.CONCLUSION:Multimodal imaging can help diagnose adult-onset Coats disease.Anti-VEGF treatment combined with laser therapy can be an option for improving or maintaining BCVA and resolving macular edema.The final visual outcome depends on macular involvement and the disease stage. 展开更多
关键词 adult-onset Coats disease multimodal imaging anti-vascular endothelial growth factor conbercept
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Diagenetic evolution and effects on reservoir development of the Dengying and Longwangmiao formations,Central Sichuan Basin,Southwestern China 被引量:1
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作者 Lei Jiang An-Ping Hu +7 位作者 Yong-Liang Ou Da-Wei liu Yong-Jie Hu You-Jun Tang Peng Sun yuan-yuan liu Zi-Chen Wang Chun-Fang Cai 《Petroleum Science》 SCIE EI CAS CSCD 2023年第6期3379-3393,共15页
The deeply buried Lower Cambrian Longwangmiao Formation and Upper Ediacaran Dengying Formation from the Sichuan Basin,China,have a total natural gas reserve up to 3×10^(12)m^(3).The complex diagenetic evolution a... The deeply buried Lower Cambrian Longwangmiao Formation and Upper Ediacaran Dengying Formation from the Sichuan Basin,China,have a total natural gas reserve up to 3×10^(12)m^(3).The complex diagenetic evolution and their impacts on the present-day reservoir quality have not been systematically elucidated,hampering the current exploration.Crucially,the integration and comparation diagenetic study on these two formations,which may be able to shed new lights on reservoir formation mechanism,are yet to be systemically evaluated.By compiling geochemistry data,including carbonate U-Pb ages and petrophysics data,coupled with new petrology,trace elements,and strontium isotope data,of various types of diagenetic carbonates,this study aims to decipher the potential links between diagenesis and reservoir development of both formations.Intriguingly,similar diagenetic sequence,which contains five distinctive dolomite phases,is established in both formations.The matrix dolomite(D1)and early dolomite cement(D2)were likely formed by reflux dolomitization,as inferred by their nearly syn-depositional U-Pb ages and elevatedδ^(18)O caused by seawater evaporation.The subsequent moderate burial dolomite cement(D3)was most plausibly the product of burial compaction as indicated by its lighterδ^(18)O and slightly younger U-Pb ages compared with D1 and D2.Whereas deep burial dolomite cements(D4 and D5)yield markedly depletedδ^(18)O,elevated ^(87)Sr/^(86)Sr,along with much younger U-Pb ages and higher precipitation temperatures,suggesting that they were likely linked to hydrothermal fluids.Despite the wide occurrence of meteoric and organic acids leaching and thermochemical sulfate reduction,they may have only played a subsidiary role on these reservoirs development.Instead,superior reservoir quality is tightly linked to tectonics as inferred by higher reservoir quality closely related to the well-developed fractures and faults filled with abundant hydrothermal minerals.Notably,good reservoirs in both formations are mainly attributed to high permeability caused by tectonics.Hence,this new contribution emphasizes the crucial role of tectonics on spatially explicit reservoir prediction of deep to ultra-deep(up to>8000 m)carbonates in the Sichuan Basin,as well as other sedimentary basin analogues in China. 展开更多
关键词 Carbonate reservoir DIAGENESIS DOLOMITIZATION Meteoric water Oil charge Hydrothermal fluids Tectonic-driven fractures Deep to ultra-deep exploration
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晚期支气管腺样囊性癌化疗有效1例 被引量:3
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作者 王雨薇 叶程远 +2 位作者 刘媛媛 李义慧 王建功 《中国现代医学杂志》 CAS 2019年第10期125-126,共2页
1临床资料患者男性,66岁,患右支气管腺样囊性癌6 年7 个月,为进一步治疗入住河北省唐山市人民医院。患者于2010 年11 月无诱因出现咳嗽、咳少量白痰。痰中有少量暗红色血丝,无胸痛、无呼吸困难、无头痛及头晕等不适,未引起足够重视。
关键词 气管肿瘤 复发 肿瘤转移 抗肿瘤联合化疗方案 放疗
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Recent advances of sonodynamic therapy in cancer treatment 被引量:24
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作者 Guo-Yun Wan Yang liu +3 位作者 Bo-Wei Chen yuan-yuan liu Yin-Song Wang Ning Zhang 《Cancer Biology & Medicine》 SCIE CAS CSCD 2016年第3期325-338,共14页
Sonodynamic therapy(SDT) is an emerging approach that involves a combination of low-intensity ultrasound and specialized chemical agents known as sonosensitizers. Ultrasound can penetrate deeply into tissues and can b... Sonodynamic therapy(SDT) is an emerging approach that involves a combination of low-intensity ultrasound and specialized chemical agents known as sonosensitizers. Ultrasound can penetrate deeply into tissues and can be focused into a small region of a tumor to activate a sonosensitizer which offers the possibility of non-invasively eradicating solid tumors in a site-directed manner.In this article, we critically reviewed the currently accepted mechanisms of sonodynamic action and summarized the classification of sonosensitizers. At the same time, the breath of evidence from SDT-based studies suggests that SDT is promising for cancer treatment. 展开更多
关键词 Sonodynamic therapy sonosensitizer CANCER ULTRASOUND reactive oxygen species
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Effect of Lactobacillus rhamnosus GG supernatant on serotonin transporter expression in rats with post-infectious irritable bowel syndrome 被引量:10
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作者 Ya-nan Cao Li-juan Feng +7 位作者 yuan-yuan liu Kui jiang Mao-jun Zhang Yi-xin Gu Bang-Mao Wang jia Gao Ze-Lan Wang Yu-Ming Wang 《World Journal of Gastroenterology》 SCIE CAS 2018年第3期338-350,共13页
AIM To evaluate the effect of Lactobacillus rhamnosus GG supernatant(LGG-s) on the expression of serotonin transporter(SERT) in rats with post-infectious irritable bowel syndrome(PI-IBS).METHODS Campylobacter jejuni 8... AIM To evaluate the effect of Lactobacillus rhamnosus GG supernatant(LGG-s) on the expression of serotonin transporter(SERT) in rats with post-infectious irritable bowel syndrome(PI-IBS).METHODS Campylobacter jejuni 81-176(1010 CFU/m L) was used to induce intestinal infection to develop a PI-IBS model. After evaluation of the post-infectious phase by biochemical tests, Dn A agarose gel electrophoresis, abdominal withdrawal reflex(AWR) test, and the intestinal motility test, four PI-IBS groups received different concentrations of LGG-s for 4 wk. The treatments were maintained for 1.0, 2.0, 3.0 or 4.0 wk during the experiment, and the colons and brains were removed for later use each week. SERT m Rn A and protein levels were detected by real-time PCR and Western blot, respectively.RESULTS The levels of SERT m Rn A and protein in intestinal tissue were higher in rats treated with LGG-s than in control rats and PI-IBS rats gavaged with PBS during the whole study. Undiluted LGG-s up-regulated SERT m Rn A level by 2.67 times compared with the control group by week 2, and SERT m Rn A expression kept increasing later. Double-diluted LGG-s was similar to undiluted-LGG-s, resulting in high levels of SERT m Rn A. Triple-diluted LGG-s up-regulated SERT m Rn A expression level by 6.9-times compared with the control group, but SERT m Rn A expression decreased rapidly at the end of the second week. At the first week, SERT protein levels were basically comparable in rats treated with undiluted LGG-s, double-diluted LGG-s, and triplediluted LGG-s, which were higher than those in the control group and PBS-treated PI-IBS group. SERT protein levels in the intestine were also comparable in rats treated with undiluted LGG-s, double-diluted LGG-s, and triple-diluted LGG-s by the second and third weeks. SERT m Rn A and protein levels in the brain had no statistical difference in the groups during the experiment.CONCLUSION LGG-s can up-regulate SERT m Rn A and protein levels in intestinal tissue but has no influence in brain tissue in rats with PI-IBS. 展开更多
关键词 SEROTONIN TRANSPORTER intestinal infection LACTOBACILLUS rhamnosus SUPERNATANT IRRITABLE BOWEL syndrome
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Corrosion and wear resistance of AZ31 Mg alloy treated by duplex process of magnetron sputtering and plasma electrolytic oxidation 被引量:11
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作者 Bing-jian WEI Yu-lin CHENG +2 位作者 yuan-yuan liu Zhun-da ZHU Ying-liang CHENG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第8期2287-2306,共20页
In order to improve the wear and corrosion resistance of AZ31 magnesium alloy,a magnetron-sputtered Al layer with a thickness of 11μm was firstly applied on the alloy,and then treated by plasma electrolytic oxidation... In order to improve the wear and corrosion resistance of AZ31 magnesium alloy,a magnetron-sputtered Al layer with a thickness of 11μm was firstly applied on the alloy,and then treated by plasma electrolytic oxidation(PEO)in an aluminate and silicate electrolytes,respectively.The performance of PEO coatings was investigated by dry sliding wear and electrochemical corrosion tests.The aluminate coating exhibits excellent wear resistance under both 10 and 20 N loads.The silicate coating only shows low wear rate under 10 N,but it was destroyed under 20 N.Corrosion tests show that the Al layer after magnetron sputtering treatment alone cannot afford good protection to the Mg substrate.However,the duplex layer of PEO/Al can significantly improve the corrosion resistance of AZ31 alloy.Electrochemical tests show that the aluminate and silicate coatings have corrosion current densities of-1.6×10^(-6) and-1.1×10^(-6) A/cm^(2),respectively,which are two orders lower than that of the un-coated AZ31 alloy.However,immersion tests and electrochemical impedance spectroscopy(EIS)show that the aluminate coating exhibits better long-term corrosion protection than silicate coating. 展开更多
关键词 AZ31 magnesium alloy magnetron sputtering plasma electrolytic oxidation dry sliding wear CORROSION
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Synthesis,characterization,and theoretical study of N,S-codoped nano-TiO_2 with photocatalytic activities 被引量:8
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作者 Hong-tao Gao yuan-yuan liu +2 位作者 Cui-hong Ding Dong-mei Dai Guang-jun liu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2011年第5期606-614,共9页
Nitrogen and sulfur doped titanium dioxide photocatalysts were prepared by the sol-gel method.The products were characterized by X-ray diffraction (XRD),transmission electron microscopy (TEM),and UV-visible diffus... Nitrogen and sulfur doped titanium dioxide photocatalysts were prepared by the sol-gel method.The products were characterized by X-ray diffraction (XRD),transmission electron microscopy (TEM),and UV-visible diffuse reflectance spectra (DRS).Photocatalytic activities of the samples were investigated on the degradation of methyl orange (MO).The effect of the dopants on the electronic structure of TiO2 was studied by the first-principles calculations based on the density functional theory (DFT).The orbital hybridization resulted in energy gap narrowing and electronic delocalization in the crystal of doped TiO2.Mobile electrons of varied energetic states could offer enhanced electron transfer,together with optical absorption improvement.The results show that the doping elements of N and S play a cooperative role in the modification of electronic structure,which enhances the photocatalytic performance.The experimentally observed absorption edges of N-doped TiO2,S-doped TiO2,and N,S-codoped TiO2 are 420,413,and 429 nm,respectively,which can be explained by the theoretical calculation results. 展开更多
关键词 titanium dioxide DOPING electronic structure red shift PHOTOCATALYSIS nanoparticles
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High-efficiency trace Na extraction from crystal quartz ore used for fused silica-——A pretreatment technology 被引量:5
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作者 Min Lin Zhen-yu Pei +4 位作者 yuan-yuan liu Zhang-jie Xia Kang Xiong Shao-min Lei En-wen Wang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2017年第10期1075-1086,共12页
Trace Na sources, extraction dynamics of trace Na, and influences of calcination temperature on quartz lattice, fluid inclusions, and muscovite were studied in detail herein for trace Na extraction from the quartz ore... Trace Na sources, extraction dynamics of trace Na, and influences of calcination temperature on quartz lattice, fluid inclusions, and muscovite were studied in detail herein for trace Na extraction from the quartz ore with water leaching at 90℃. Experimental results suggested that the trace Na sources included quartz lattice, fluid inclusions, and muscovite. The extraction rate of the trace Na in quartz ores can reach 31.0wt% after calcination at 900℃ for 5 h and water leaching at 90℃ for 24 h. The extraction process consisting of the dissolution of unfree Na and diffusion of free Na was dominated by calcination temperature. Calcination at 900℃ for 5 h was effective for extraction of the trace Na in fluid inclusions and muscovite. The extraction of the trace Na was mainly affected by the decrepitation of fluid inclusions when the calcination temperature ranged from 400 to 600℃ and by the damage of muscovite when the calcination temperature ranged from 600 to 900℃. Based on the extraction rates at different calcination temperatures, approximately 20.1wt% of the trace Na occurred in fluid inclusions, approximately 10.9wt% existed in muscovite, and 69.0wt% mainly occurred in quartz lattice. 展开更多
关键词 TRACE sodium EXTRACTION QUARTZ ORE fluid inclusion MUSCOVITE decrepitation CALCINATION water leaching
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3D stress simulation and parameter design during twin-roll casting of 304 stainless steel based on the Anand model 被引量:4
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作者 Jing Guo yuan-yuan liu +2 位作者 Li-gang liu Yue Zhang Qing-xiang Yang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2014年第7期666-673,共8页
This study first investigated cracks on the surface of an actual steel strip. Formulating the Anand model in ANSYS software, we then simulated the stress field in the molten pool of type 304 stainless steel during the... This study first investigated cracks on the surface of an actual steel strip. Formulating the Anand model in ANSYS software, we then simulated the stress field in the molten pool of type 304 stainless steel during the twin-roll casting process. Parameters affecting the stress distribution in the molten pool were analyzed in detail and optimized. After twin-roll casting, a large number of transgranular and intergranular cracks resided on the surface of the thin steel strip, and followed a tortuous path. In the molten pool, stress was enhanced at the exit and at the roller contact positions. The stress at the exit decreased with increasing casting speed and pouring temperature. To ensure high quality of the fabricated strips, the casting speed and pouring temperature should be controlled above 0.7 m/s and 1520℃, respectively. 展开更多
关键词 stainless steel strip metal roll casting STRESS surface cracks numerical analysis
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Effect of temperature on leaching behavior of copper minerals with different occurrence states in complex copper oxide ores 被引量:4
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作者 Gai-rong WANG yuan-yuan liu +3 位作者 Lin-lin TONG Zhe-nan JIN Guo-bao CHEN Hong-ying YANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2019年第10期2192-2201,共10页
The effect of temperature on leaching behavior of copper minerals with different occurrence states in complex copper oxide ores was carried out by phase analysis means of XRD, optical microscopy and SEM-EDS. The resul... The effect of temperature on leaching behavior of copper minerals with different occurrence states in complex copper oxide ores was carried out by phase analysis means of XRD, optical microscopy and SEM-EDS. The results indicated that at ambient temperature, the easily leached copper oxide minerals were completely dissolved, while the bonded copper minerals were insoluble. At lukewarm temperature of 40℃, it was mainly the dissolution of copper in isomorphism state. With increasing temperature to 60℃, the copper leaching rate in the adsorbed state was significantly accelerated. In addition, when the temperature increased to 80℃, the isomorphic copper was completely leached, leaving 11.2% adsorbed copper un-leached. However, the copper in feldspar-quartz-copper-iron colloid state was not dissolved throughout the leaching process. Overall, the leaching rates of copper in different copper minerals decreased in the order: malachite, pseudo-malachite > chrysocolla > copper-bearing chlorite > copper-bearing muscovite > copper-bearing biotite > copper-bearing limonite > feldspar-quartz-copper-iron colloid. 展开更多
关键词 complex copper oxide ores occurrence state TEMPERATURE leaching behavior copper minerals
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Study on the mechanical activation of malachite and the leaching of complex copper ore in the Luanshya mining area, Zambia 被引量:4
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作者 Gai-rong Wang Hong-ying Yang +2 位作者 yuan-yuan liu Lin-lin Tong Ali Auwalu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2020年第3期292-300,共9页
Mechanical activation(MA) of malachite was carried out by dry planetary grinding(DPG) and wet Isa grinding(WIG) methods. When the rotational speed was increased to 400 r/min in DPG, the specific surface area of malach... Mechanical activation(MA) of malachite was carried out by dry planetary grinding(DPG) and wet Isa grinding(WIG) methods. When the rotational speed was increased to 400 r/min in DPG, the specific surface area of malachite reached the maximum and the particle size reached the minimum of 0.7–100 μm. Agglomeration occurred between mineral particles when the rotational speed was increased to 580 r/min in DPG.However, no agglomeration was observed among particles with sizes 0.4–3 μm in WIG. X-ray diffraction analysis showed that, at a 580 r/min rotational speed in DPG, the amorphization degree of malachite was 53.12%, whereas that in WIG was 71.40%, indicating that MA led to amorphization and distortion of crystal structures. In addition, in the Fourier transform infrared(FT-IR) spectra of activated malachite, the bands associated with –OH, CO_3^(2-)and metal lattice vibrations of Cu–O and Cu–OH were weakened, and a new H–O–H bending mode and peaks of gaseous CO_2 appeared, indicating that MA decreased the band energy, enhanced dihydroxylation, and increased the chemical reactivity of the malachite.Furthermore, the leaching behavior of copper ore was greatly improved by MA. 展开更多
关键词 MALACHITE mechanical activation crystal structure copper ore Zambia
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Evaluation of the passivation effect and the first-principles calculation on surface termination of germanium detector 被引量:3
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作者 Sha-Sha Lv yuan-yuan liu +3 位作者 Wei-You Tang Li He Xiu-Xia Li Jian-Ping Cheng 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2021年第9期40-51,共12页
The point-contact high-purity germanium detector(HPGe)has the advantages of low background,low energy threshold,and high energy resolution and can be applied in the detection of rare-event physics.However,the performa... The point-contact high-purity germanium detector(HPGe)has the advantages of low background,low energy threshold,and high energy resolution and can be applied in the detection of rare-event physics.However,the performance of HPGe must be further improved to achieve superior energy resolution,low noise,and long-term reliability.In this study,we combine computational simulations and experimental comparisons to deeply understand the passivation mechanism of Ge.The surface passivation effect is calculated and inferred from the band structure and density of interface states,and further con-firmed by the minority carrier lifetime.The first-principles method based on the density functional theory was adopted to systematically study the lattice structure,band structure,and density of state(DOS)of four different systems:Ge–H,Ge–Ge-NH 2,Ge-OH,and Ge-SiO_(x).The electronic char-acteristics of the Ge(100)unit cell with different passi-vation groups and Si/O atomic ratios were compared.This shows that H,N,and O atoms can effectively reduce the surface DOS of the Ge atoms.The passivation effect of the SiO_(x) group varied with increasing O atoms and Si/O atomic ratios.Experimentally,SiO and SiO_(2) passivation films were fabricated by electron beam evaporation on a Ge substrate,and the valence state of Si and resistivity was measured to characterize the film.The minority carrier lifetime of Ge-SiO_(2) is 21.3 ls,which is approximately quadruple that of Ge-SiO.The passivation effect and mechanism are discussed in terms of hopping conduction and surface defect density.This study builds a relationship between the passivation effect and different termination groups,and provides technical support for the potential passivation layer,which can be applied in Ge detectors with ultralow energy thresholds and especially in HPGe for rare-event physics detection experiments in future. 展开更多
关键词 Germanium detector PASSIVATION Surface termination
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Surface metallization of PTFE and PTFE composites by ion implantation for low-background electronic substrates in rare-event detection experiments 被引量:2
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作者 Shao-Jun Zhang yuan-yuan liu +5 位作者 Sha-Sha Lv Jian-Ping Cheng Bin Liao Pan Pang Zhi Deng Li He 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2022年第7期37-47,共11页
Polytetrafluoroethylene(PTFE)is a low-background polymer that is applied to several applications in rare-event detection and underground low-background experiments.PTFE-based electronic substrates are important for re... Polytetrafluoroethylene(PTFE)is a low-background polymer that is applied to several applications in rare-event detection and underground low-background experiments.PTFE-based electronic substrates are important for reducing the detection limit of high-purity germanium detectors and scintillator calorimeters,which are widely applied in dark matter and 0υββdetection experiments.The traditional adhesive bonding method between PTFE and copper is not conducive to working in liquid nitrogen and extremely low-temperature environments.To avoid adhesive bonding,PTFE must be processed for surface metallization owing to the mismatch between the PTFE and copper conductive layer.Low-background PTFE matrix composites(m-PTFE)were selected to improve the electrical and mechanical properties of PTFE by introducing SiO_(2)/TiO_(2) particles.The microstructures,surface elements,and electrical properties of PTFE and m-PTFE were characterized and analyzed following ion implantation.PTFE and m-PTFE surfaces were found to be broken,degraded,and cross-linked by ion implantation,resulting in C=C conjugated double bonds,increased surface energy,and increased surface roughness.Comparably,the surface roughness,bond strength,and conjugated double bonds of m-PTFE were significantly more intense than those of PTFE.Moreover,the interface bonding theory between PTFE and the metal copper foil was analyzed using the direct metallization principle.Therefore,the peel strength of the optimized electronic substrates was higher than that of the industrial standard at extremely low temperatures,while maintaining excellent electrical properties. 展开更多
关键词 Surface modification Polytetrafluoroethylene Ion implantation Surface metallization Low temperature resistance
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High-responsivity solar-blind photodetector based on MOCVD-grown Si-dopedβ-Ga_(2)O_(3)thin film 被引量:2
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作者 Yu-Song Zhi Wei-Yu Jiang +9 位作者 Zeng liu yuan-yuan liu Xu-Long Chu Jia-Hang liu Shan Li Zu-Yong Yan Yue-Hui Wang Pei-Gang Li Zhen-Ping Wu Wei-Hua Tang 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第5期595-601,共7页
Si-dopedβ-Ga_(2)O_(3)films are fabricated through metal-organic chemical vapor deposition(MOCVD).Solar-blind ultraviolet(UV)photodetector(PD)based on the films is fabricated by standard photolithography,and the photo... Si-dopedβ-Ga_(2)O_(3)films are fabricated through metal-organic chemical vapor deposition(MOCVD).Solar-blind ultraviolet(UV)photodetector(PD)based on the films is fabricated by standard photolithography,and the photodetection properties are investigated.The results show that the photocurrent increases to 11.2 mA under 200μW·cm^(-2)254 nm illumination and±20 V bias,leading to photo-responsivity as high as 788 A·W^(-1).The Si-dopedβ-Ga2O3-based PD is promised to perform solar-blind photodetection with high performance. 展开更多
关键词 Si-dopedβ-Ga_(2)O_(3) metal-organic chemical vapor deposition(MOCVD) solar-blind high responsivity
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Experimental investigation on the radiation background inside body counters 被引量:2
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作者 Yu Wang yuan-yuan liu +8 位作者 Bin Wu Xiang-Peng Meng Jian-Ping Cheng Ying Wang Li-Jiao Wang Yun-Shi Xiao Qin-Jian Cao Jian-Feng Zhang Fei Tuo 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2022年第2期66-78,共13页
In vivo measurement of radioactivity based on various body counters is arguably the leading measure used to determine the distribution and activity of radionuclides in human subjects,such as I-131 in the thyroid,Am-24... In vivo measurement of radioactivity based on various body counters is arguably the leading measure used to determine the distribution and activity of radionuclides in human subjects,such as I-131 in the thyroid,Am-241 in the lungs,and Pb-210 in the skull.Throughout the measurements,the radiation background is the key factor that determines the sensitivity of the counter.Therefore,to facilitate in vivo measurements,a well-designed shielding room is required to create a low-background environment.However,because the compositions of the radiation background are quite complicated,the respective contributions from each source remain obscure,which places a considerable burden on seeking an optimized design of shielding rooms that strikes the optimum balance between the construction cost and background suppression effect.In this study,we conducted a systematic experimental investigation on the radiation background outside and inside four representative body counters with assorted designs using a variety of radiation detectors,including high-purity germanium detectors,CdZnTe detector,radon emanometer,and gamma-ray dosimeter.By carefully controlling the experimental conditions and synergetic analysis of the measurement results,in conjunction with previous studies,we separated and determined the relative contributions induced by environmental radiation(4%),airborne radon and its daughters(2%),the normal radioactivity of human subjects arising from K-40(58%),cosmic rays(12%),and radioactivity in shielding materials and measuring instruments(24%).Furthermore,based on these results,we discuss practical guidelines to design a shielding room for body counters. 展开更多
关键词 Body counter Radiation background Shielding room In vivo measurement
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基于开缝引射流的离心泵空化流动研究 被引量:3
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作者 刘媛媛 王维军 李泰龙 《风机技术》 2019年第6期18-22,共5页
为确定不同形式的开缝对离心泵的影响,采用引射流技术对其进行了六种开缝设计,采用RNG k-ε湍流模型和改进的Kubota空化模型对其空化流动进行了数值求解。结果表明:在大流量工况下运行时,离心泵外特性突降的原因在于叶片发生空化后附着... 为确定不同形式的开缝对离心泵的影响,采用引射流技术对其进行了六种开缝设计,采用RNG k-ε湍流模型和改进的Kubota空化模型对其空化流动进行了数值求解。结果表明:在大流量工况下运行时,离心泵外特性突降的原因在于叶片发生空化后附着空化改变了叶片型线,堵住了整个流道,造成了叶片做功能力逐步丧失;选择合理的开缝宽度和角度,可以使叶轮流道内的流动更加均匀,湍流减小,提高泵的效率,还可以改善离心泵的空化性能,延缓空化的发生,降低泵的必需空化余量。 展开更多
关键词 空化 扬程 离心泵 开缝 湍流
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Clinical efficacy of intravitreal corticoid as an adjunctive therapy to anti-VEGF treatment of neovascular age-related macular degeneration:a Meta-analysis 被引量:1
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作者 Bo-Hao Cui Wei Zhou +4 位作者 Wen-Wen Wang Hao Yang Ya-Lan Dong yuan-yuan liu Hua Yan 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2021年第7期1092-1099,共8页
AIM:To evaluate the efficacy and safety of intravitreal cor ticoid as an adjunctive therapy to anti-vascular endothelial growth factor(VEGF)treatment of neovascular age-related macular degeneration(nvAMD).METHODS:Four... AIM:To evaluate the efficacy and safety of intravitreal cor ticoid as an adjunctive therapy to anti-vascular endothelial growth factor(VEGF)treatment of neovascular age-related macular degeneration(nvAMD).METHODS:Four databases including Pub Med,Embase,Cochrane Library,and the clinicaltrials.gov were comprehensively searched for studies comparing intravitreal corticoid plus anti-VEGF(IVC/IVA)vs anti-VEGF monotherapy(IVA)in patients with nvAMD.GRADE profiler was used to assess the quality of outcomes.Best-corrected visual acuity(BCVA),central macular thickness(CMT)and adverse events including the occurrence of severe elevation of intraocular pressure(IOP)and the progress of cataract were extracted from the eligible studies.Review Manager(Rev Man)5.3 was used to analyze the data.RESULTS:There was no statistic difference of mean change in BCVA at 6 and 12 mo between IVC/IVA and IVA group[95%confidence interval(CI):-2.28 to 4.24,P=0.55;95%CI:-3.01 to 8.70,P=0.34].No statistic difference was found in the change of CMT between two groups at 6 mo time point(95%CI:-17.98 to 16.42,P=0.93)while the CMT reduction in IVC/IVA group was significantly more obvious than IVA group at 12 mo time point[mean difference(MD)=-44.08,95%CI:-80.52 to-7.63,P=0.02].The risk of occurrence of severe elevation of IOP in the IVC/IVA group was higher than that in the IVA group(95%CI:1.92 to 9.48;P=0.0004).Cataract progression risk was calculated no statistic difference between two groups(95%CI:0.74 to 4.66;P=0.18).CONCLUSION:No visual or anatomical benefits are observed in IVC/IVA group at 6 mo.At 12 mo,the CMT of the IVC/IVA group is significantly lower than that of the IVA group.Risk of severe elevation of IOP is significantly higher when treated by IVC/IVA. 展开更多
关键词 age-related macular degeneration DEXAMETHASONE TRIAMCINOLONE anti-vascular endothelial growth factor META-ANALYSIS
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Timely vitrectomy without intraocular lens removal for acute endophthalmitis after cataract surgery 被引量:1
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作者 Hai-Xia Guo Ruo-Tian Xie +5 位作者 Yun Wang Cai-Yun You yuan-yuan liu Xiang-Da Meng Jin-Guo Yu Hua Yan 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2022年第6期1011-1014,共4页
AIM:To investigate the clinical features,causative organisms and effects of timely vitrectomy and silicone oil tamponade without intraocular lens(IOL)removal in the treatment of acute-onset endophthalmitis after catar... AIM:To investigate the clinical features,causative organisms and effects of timely vitrectomy and silicone oil tamponade without intraocular lens(IOL)removal in the treatment of acute-onset endophthalmitis after cataract surgery(APCE).METHODS:We retrospectively analyzed the clinical features and microbiological factors in 10 eyes of 10 patients with APCE at Tianjin Medical University General Hospital from January 2010 to December 2018.Data on the clinical features,causative organisms,visual acuity,intraocular pressure(IOP)and complications were collected.The mean follow-up period was 25.5 mo.RESULTS:The mean age of the patients was 71.4 y.The mean time between cataract surgery and the onset of endophthalmitis was 2.0 d.Preoperative visual acuity ranged from no light perception to hand motion.After vitrectomy,the visual acuity increased in nine eyes(90%),and was unchanged in one eye(10%).A significant difference was observed between the mean preoperative(36.3±7.1 mm Hg)and postoperative IOP(14.9±4.3 mm Hg,P<0.05).Staphylococcus epidermidis was isolated in 5 eyes,S.aureus in 2 eyes,and Enterococcus in 1 eye.Postoperative complications mainly included fibrin exudates in the anterior chamber at the early stages in all eyes and temporary IOP elevation in one eye.No retinal detachment or ocular atrophy was observed during the follow-up period.CONCLUSION:Under systemic antibiotic treatment and timely diagnosis,vitrectomy and silicone oil tamponade without IOL removal is a safe and effective method for APCE. 展开更多
关键词 VITRECTOMY silicone oil ENDOPHTHALMITIS CATARACT intraocular lens
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Investigation on microstructures and properties of semi-solid Al_(80)Mg_(5)Li_(5)Zn_(5)Cu_(5)light-weight high-entropy alloy during isothermal heat treatment process 被引量:1
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作者 Yong Hu yuan-yuan liu +3 位作者 Long-zhi Zhao Yan-chuan Tang Hai-tao Jiao De-jia liu 《China Foundry》 SCIE CAS 2022年第6期519-527,共9页
The Al_(80)Mg_(5)Li_(5)Zn_(5)Cu_(5)light-weight high-entropy alloy with globular microstructure was fabricated by isothermal heat treatment.The effects of isothermal temperatures and holding times on the semi-solid mi... The Al_(80)Mg_(5)Li_(5)Zn_(5)Cu_(5)light-weight high-entropy alloy with globular microstructure was fabricated by isothermal heat treatment.The effects of isothermal temperatures and holding times on the semi-solid microstructure evolution were investigated.The results indicate that,with increase of the isothermal temperature,the average grain size increases and the spheroidization time shortens.With prolongation of holding time,the shape factor increases firstly and then decreases,and the average grain size decreases at first and then increases when the isothermal temperature is below 520°C,however it increases gradually at 540℃.The optimal semi-solid microstructure is obtained at 520℃ for 30 min,whose shape factor and average grain size are 0.90 and 56.4μm,respectively.Compared with as-cast Al_(80)Mg_(5)Li_(5)Zn_(5)Cu_(5) light-weight high-entropy alloy,the compressive strength and plasticity of semi-solid Al_(80)Mg_(5)Li_(5)Zn_(5)Cu_(5) light-weight high-entropy alloy are increased by 36%and 108%,respectively.The formation of semi-solid microstructures includes three stages:melting separation,spheroidization,and coarsening growth.The sluggish diffusion effect of Al_(80)Mg_(5)Li_(5)Zn_(5)Cu_(5) light-weight high-entropy alloy leads to a low coarsening rate,resulting in slow grain growth. 展开更多
关键词 light-weight high-entropy alloy SEMI-SOLID isothermal heat treatment microstructure
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