-
1دورية أكاديمية2.1 W/mm Output Power Density at 10 GHz for H-Terminated Diamond MOSFETs With (111)-Oriented Surface
المؤلفون: Bing Qiao, Pengfei Dai, Xinxin Yu, Zhonghui Li, Ran Tao, Jianjun Zhou, Rui Shen, Tangsheng Chen
المصدر: IEEE Journal of the Electron Devices Society, Vol 12, Pp 51-55 (2024)
مصطلحات موضوعية: Hydrogen-terminated, (111)-oriented diamond, output power, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
الوصف: This paper presents high performance hydrogen-terminated diamond MOSFETs fabricated on a (111)-oriented single-crystal diamond substrate. The diamond surface was passivated by a high-quality Al2O3 grown by ALD at 350°C as well as a secondary passivation layer Si3N4 deposited by PECVD. After passivation, a low ohmic contact resistance $R_{c}$ of $0.5 \Omega \cdot $ mm was obtained and the 2DHG sheet density was as high as $1.0\times 10\,\,^{\mathrm{ 13}}\,\,{\mathrm{ cm}}^{-2}$ with a corresponding mobility of $104 {\mathrm{ cm}}^{2} /\text{V}\cdot \text{s}$ . The fabricated diamond MOSFET with gate length of $0.5 ~\mu \text{m}$ showcased a high current density of 750 mA/mm, a low on-resistance of $24 \Omega \cdot $ mm, and a high off-state breakdown voltage of 117 V. Thanks to the high current density and low on-resistance, a record high output power density of 2.1 W/mm was achieved at 10 GHz with drain biased at a low voltage of −30 V. These results demonstrate that the output current and output power can be improved by using a (111)-oriented diamond, which is benefit for high-frequency and high-power RF devices.
وصف الملف: electronic resource
-
2دورية أكاديمية
المؤلفون: Pengfei Dai, Shaowei Wang, Hongliang Lu
المصدر: Micromachines, Vol 15, Iss 3, p 321 (2024)
مصطلحات موضوعية: GaN HEMT, VTH drift, high temperature and high voltage, Mechanical engineering and machinery, TJ1-1570
الوصف: With the development of high-voltage and high-frequency switching circuits, GaN high-electron-mobility transistor (HEMT) devices with high bandwidth, high electron mobility, and high breakdown voltage have become an important research topic in this field. It has been found that GaN HEMT devices have a drift in threshold voltage under the conditions of temperature and gate stress changes. Under high-temperature conditions, the difference in gate contact also causes the threshold voltage to shift. The variation in the threshold voltage affects the stability of the device as well as the overall circuit performance. Therefore, in this paper, a review of previous work is presented. Temperature variation, gate stress variation, and gate contact variation are investigated to analyze the physical mechanisms that generate the threshold voltage (VTH) drift phenomenon in GaN HEMT devices. Finally, improvement methods suitable for GaN HEMT devices under high-temperature and high-voltage conditions are summarized.
وصف الملف: electronic resource
-
3دورية أكاديمية
المؤلفون: Xiaomin Wang, Feifei Chen, Pengfei Dai, Xingfeng Lin, Lei Qi
المصدر: Nursing Open, Vol 10, Iss 3, Pp 1461-1470 (2023)
مصطلحات موضوعية: coronavirus, nurses, perceived professional benefits, professional identity, psychological distress, severe acute respiratory syndrome‐related coronavirus, Nursing, RT1-120
الوصف: Abstract Aims To examine the perceived professional benefits (PPB) and associated factors among nurses during the coronavirus disease 2019 (COVID‐19) pandemic in China. Design Cross‐sectional study. Methods Using the snowball sampling method, 492 nurses (478 females, 14 males) were recruited. Data were collected using an online survey, including participants' socio‐demographic and working characteristics, psychological distress related to the COVID‐19 pandemic, dealing with professional frustration, professional self‐reflection and PPB from 1–30 April 2020. Results Nurses experienced high levels of PPB. In linear regression analysis, self‐perceived concerns about COVID‐19, emotional shock caused by it, risk perception towards their occupations, dealing with professional frustration and professional self‐reflection were positively associated with PPB among nurses. These factors explained 84% variance in PPB. Conclusions This study highlighted that although the nurses experienced psychological distress, they gained high PPB during the COVID‐19 pandemic. Additionally, to facilitate nurses' efforts to achieve professional growth, more educational resources and opportunities for engaging in reflective practices could be provided.
وصف الملف: electronic resource
العلاقة: https://doaj.org/toc/2054-1058Test
-
4دورية أكاديمية
المؤلفون: Xiao Li, Fei Li, Fei Ye, Haotian Guo, Wentao Chen, Jia Jin, Yiran Wang, Pengfei Dai, Huili Shi, Hongru Tao, Wenzhen Dang, Yiluan Ding, Mingchen Wang, Hualiang Jiang, Kaixian Chen, Naixia Zhang, Dong Gao, Yuanyuan Zhang, Cheng Luo
المصدر: Cell Reports, Vol 42, Iss 7, Pp 112798- (2023)
مصطلحات موضوعية: CP: Cancer, Biology (General), QH301-705.5
الوصف: Summary: In castration-resistant prostate cancer (CRPC), clinical response to androgen receptor (AR) antagonists is limited mainly due to AR-variants expression and restored AR signaling. The metabolite spermine is most abundant in prostate and it decreases as prostate cancer progresses, but its functions remain poorly understood. Here, we show spermine inhibits full-length androgen receptor (AR-FL) and androgen receptor splice variant 7 (AR-V7) signaling and suppresses CRPC cell proliferation by directly binding and inhibiting protein arginine methyltransferase PRMT1. Spermine reduces H4R3me2a modification at the AR locus and suppresses AR binding as well as H3K27ac modification levels at AR target genes. Spermine supplementation restrains CRPC growth in vivo. PRMT1 inhibition also suppresses AR-FL and AR-V7 signaling and reduces CRPC growth. Collectively, we demonstrate spermine as an anticancer metabolite by inhibiting PRMT1 to transcriptionally inhibit AR-FL and AR-V7 signaling in CRPC, and we indicate spermine and PRMT1 inhibition as powerful strategies overcoming limitations of current AR-based therapies in CRPC.
وصف الملف: electronic resource
العلاقة: http://www.sciencedirect.com/science/article/pii/S2211124723008094Test; https://doaj.org/toc/2211-1247Test
-
5دورية أكاديمية
المؤلفون: Wei Gao, Pengfei Dai, Yuqian Wang, Yurong Zhang
المصدر: BMC Geriatrics, Vol 22, Iss 1, Pp 1-10 (2022)
مصطلحات موضوعية: Cross-sectional study, Walking impairment, Depression, Visual impairment, Cognitive function, Older adults, Geriatrics, RC952-954.6
الوصف: Abstract Background Walking impairment, a common health problem among older adults, has been linked to poor vision and mental health. This study aimed to investigate the associations of walking impairment with visual impairment, depression, and cognitive function in older adults. Methods A total of 1,489 adults aged 60 years and older who had participated in the National Health and Examination Survey (NHANES) 2013–2014 in the United States were included. Multivariate logistic regression models were used to examine the associations of walking impairment with visual impairment, depression, and four subdomains of cognitive function. Sample weights were used to ensure the generalizability of the results. Results Among all the participants (median age = 68 years; 53.7% women), 17.5% reported walking impairment. Walking impairment was significantly associated with visual impairment (adjusted odds ratio [aOR] = 2.76; 95% CI: 1.47–5.20) and depression (aOR = 4.66; 95% CI: 3.11–6.99). Walking impairment was only associated with the Digit Symbol Substitution (DSST) subdomain of cognitive function in total participants (aOR = 0.97; 95% CI: 0.95–0.99) and in non-Hispanic white adults (aOR = 0.96; 95% CI: 0.94–0.98). Participants with two or three impairment indicators had a higher OR of walking impairment (aOR = 3.64, 95% CI = 2.46–5.38) than those with 0–1 (reference group) impairment indicator. Conclusions Walking impairment was associated with visual impairment, depression, and cognitive impairment in American older adults and also positively associated with the number of impairment indicators. The association between walking impairment and cognitive impairment varied according to race. Evaluations of vision, cognition, and depression should be conducted among older adults with walking impairment, and the needs of older adults should be provided in the evaluations alongside information on the biological aspects of their particular race.
وصف الملف: electronic resource
العلاقة: https://doaj.org/toc/1471-2318Test
-
6دورية أكاديمية
المؤلفون: Fenghou Shi, Zhujing Pan, Pengfei Dai, Yongbao Shen, Yizeng Lu, Biao Han
المصدر: Forests, Vol 14, Iss 7, p 1294 (2023)
مصطلحات موضوعية: Phoebe sheareri, waterlogging stress, leaf anatomical structure, leaf ultrastructure, Plant ecology, QK900-989
الوصف: Phoebe sheareri is an excellent roadside tree with a wide distribution range and high ornamental value. Excessive moisture can affect the external morphology, the microstructure, and the ultrastructure of the leaf. Little is known at present regarding the leaf structure of P. sheareri under waterlogging stress. In this paper, the external morphology of leaves, the microstructure of leaf epidermis, and the ultrastructure of mesophyll cells of P. sheareri seedlings under waterlogging stress and drainage were dynamically observed. Waterlogging stress contributed to the yellowing and wilting of P. sheareri seedling leaves, the gradual closing of leaf epidermal stomata, increasing density of leaf stomata, gradual loosening of the arrangement of leaf cell structure, and merging of leaf palisade tissue cells. Waterlogging stress forced the structure of the chloroplast membranes to blur, gradually causing swelling, and deformation, with plasmolysis occurring in severe cases. During waterlogging, the basal lamellae were disorganized, and the mitochondrial membrane structure was damaged. The damaged state of the leaves was not relieved after drainage. Waterlogging stress not only inhibited the growth of leaves, but also accelerated the closure of stomata, disordered the arrangement of palisade tissue and spongy tissue gradually, and damaged the internal organelles of mesophyll cells.
وصف الملف: electronic resource
-
7دورية أكاديمية
المؤلفون: Zhe Liu, Quan Sun, Pengfei Dai, Jinyin Lei, Boling Zeng, Lingjuan Wang, Haojun Xie, Jingyao Wang
المصدر: Atmosphere, Vol 14, Iss 6, p 963 (2023)
مصطلحات موضوعية: wind erosion climate erosion forces, spatial and temporal evolution, center of gravity migration, driving factors, Ningxia region, Meteorology. Climatology, QC851-999
الوصف: Wind erosion is one of the major meteorological hazards in Ningxia, and climate change has caused changes in wind erosion–climatic erosion activity in recent years. This study uses the wind erosion climate factor (C) proposed by the Food and Agriculture Organization of the United Nations to assess the impact of climate change on wind erosion–climate erosion, and the results show that (1) the distribution of wind erosion degree in Ningxia region is central > northern > southern. Seasonally, it is higher in spring and winter, and lower in summer and autumn. (2) Climate change has more influence on spring, autumn and winter, and less influence on summer. (3) The center of gravity is mainly located at the junction of central and northern Ningxia, and the center of gravity migrates through four migration stages—northeast–southwest–northeast–southwest—on the annual scale, and four migration stages—northwest–northeast–southeast—on the seasonal and monthly scales. The migration rate in the cold season is greater than that in the warm season. (4) The wind erosion climate factor index is influenced by sunshine hours, average temperature, average humidity, average wind speed and total precipitation, and the degree of influence has spatial and temporal variability, among which the wind erosion climate factor index is the most sensitive to the influence of average wind speed. (5) The wind erosion climate factor indices are positively correlated with NAO, AO, PDO and SOI indices, and negatively correlated with MEI and ENSO indices, and there are resonance cycles of different time scales.
وصف الملف: electronic resource
-
8دورية أكاديمية
المؤلفون: Jichao Li, Hongxia Lian, Airong Zheng, Jiangfan Zhang, Pengfei Dai, Yan Niu, Tengyun Gao, Ming Li, Liyang Zhang, Tong Fu
المصدر: Frontiers in Veterinary Science, Vol 9 (2022)
مصطلحات موضوعية: calves, roughages, growth, nutrient digestibility, rumen fermentation, bacterial community, Veterinary medicine, SF600-1100
الوصف: This study aimed to assess the effects of feeding with different forage sources and starter concentrations on growth performance, nutrient digestibility, ruminal fermentation, and the microbial community in weaned Holstein calves. A total of 54 Holstein calves (body weight (BW) = 77.50 ± 5.07 kg; age = 70 ± 2.54 days) were assigned to 1 of 3 treatment groups (n = 18/group) that were offered diets with different forages: (1) peanut vine (PV), (2) oat hay (OH), or (3) an alfalfa hay + oat hay combination (alfalfa hay:oat hay =1:1, AO). Starter and forage intakes were recorded daily, while BW and growth parameters were assessed at 15-day intervals. The apparent digestibility of nutrients was determined. Ruminal fluid samples were collected and used to detect relevant indicators. A difference was observed for the forage × age interaction for all feed, nutrient intake, BW, ADG, and body structure parameters (P < 0.05). The final BW, average daily feed intake (ADFI), and average daily gain of the PV calves were higher than those of calves from the other groups (P < 0.05). The ruminal propionate concentration evidently increased in calves of the AO group (P < 0.05). The abundances of Rikenellaceae_RC9_gut_group and Shuttleworthia showed distinct responses to feeding with different forages (P < 0.05) at the genus level. The relative abundance of Shuttleworthia was negatively related to rumen pH and acid detergent fiber digestibility (P < 0.05) and strongly positively related to propionate concentration (P < 0.01). A positive correlation was found between Ruminococcus_1 abundance and butyrate concentration and neutral detergent fiber digestibility (P < 0.05). The relative abundances of Succiniclasticum and Prevotella_7 were negatively related to butyrate concentration (P < 0.05). In conclusion, there was an interaction between the factors (forage × age). The peanut vine used as a forage source promoted a higher starter concentrate intake compared to other diets and increased with the calves' age. The growth performance and rumen bacterial community of the calves were further improved. These results indicate that peanut vine can be used as the main source of forage in the diets of weaned calves.
وصف الملف: electronic resource
العلاقة: https://www.frontiersin.org/articles/10.3389/fvets.2022.864320/fullTest; https://doaj.org/toc/2297-1769Test
-
9دورية أكاديمية
المؤلفون: Fei Li, Ming Han, Pengfei Dai, Wei Xu, Juan He, Xiaoting Tao, Yang Wu, Xinyuan Tong, Xinyi Xia, Wangxin Guo, Yunjiao Zhou, Yunguang Li, Yiqin Zhu, Xiaoyu Zhang, Zhuang Liu, Rebiguli Aji, Xia Cai, Yutang Li, Di Qu, Yu Chen, Shibo Jiang, Qiao Wang, Hongbin Ji, Youhua Xie, Yihua Sun, Lu Lu, Dong Gao
المصدر: Nature Communications, Vol 12, Iss 1, Pp 1-14 (2021)
مصطلحات موضوعية: Science
الوصف: Enzalutamide, an approved drug for prostate cancer, acts on TMPRSS2 expression, a key mediator for SARS-CoV-2 infection. Here, the authors characterize the anti-SARS-CoV-2 effects of Enzalutamide in prostate cancer cells, lung cancer cells, human lung organoids and in hACE2-transduced Tmprss2 knockout mice and show lack antiviral action in human lung cells and human lung organoids, likely due to the AR-independent TMPRSS2 expression in mouse and human lung epithelial cells.
وصف الملف: electronic resource
العلاقة: https://doaj.org/toc/2041-1723Test
-
10دورية أكاديمية
المؤلفون: Fengjiu Yang, Jinzhe Liu, Zheng Lu, Pengfei Dai, Tomoya Nakamura, Shenghao Wang, Luyang Chen, Atsushi Wakamiya, Kazunari Matsuda
المصدر: Advanced Science, Vol 7, Iss 6, Pp n/a-n/a (2020)
مصطلحات موضوعية: bending durability, nanoporous Au films, perovskite solar cells, recycled utilization, reduce fabrication costs, Science
الوصف: Abstract Perovskite solar cells (PSCs) using metal electrodes have been regarded as promising candidates for next‐generation photovoltaic devices because of their high efficiency, low fabrication temperature, and low cost potential. However, the complicated and rigorous thermal deposition process of metal contact electrodes remains a challenging issue for reducing the energy pay‐back period in commercial PSCs, as the ubiquitous one‐time use of a contact electrode wastes limited resources and pollutes the environment. Here, a nanoporous Au film electrode fabricated by a simple dry transfer process is introduced to replace the thermally evaporated Au electrode in PSCs. A high power conversion efficiency (PCE) of 19.0% is demonstrated in PSCs with the nanoporous Au film electrode. Moreover, the electrode is recycled more than 12 times to realize a further reduced fabrication cost of PSCs and noble metal materials consumption and to prevent environmental pollution. When the nanoporous Au electrode is applied to flexible PSCs, a PCE of 17.3% and superior bending durability of ≈98.5% after 1000 cycles of harsh bending tests are achieved. The nanoscale pores and the capability of the porous structure to impede crack generation and propagation enable the nanoporous Au electrode to be recycled and result in excellent bending durability.
وصف الملف: electronic resource
العلاقة: https://doaj.org/toc/2198-3844Test
النص الكامل