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Cell number explains the intraspecific spur-length variation in an Aquilegia species

Plant Diversity 2019年第5期41卷 307-314页

作者： Zhi-Li Zhou Yuan-Wen Duan Yan Luo Yong-Ping Yang Zhi-Qiang Zhang Institute of Tibetan Plateau Research at Kunming Kunming Institute of BotanyChinese Academy of SciencesKunming650201China University of Chinese Academy of Sciences Beijing 100049China Gardening and Horticulture Department Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMengla666303China Laboratory of Ecology and Evolutionary Biology Yunnan UniversityKunming650091China

Variations of nectar spur length allow pollinators to utilize resources in novel ways,leading to the different selective pressures on spurs and allowing taxa to diversify.However,the mechanisms underlying spur length variation remain unclear.Interspecific comparisons of spur length suggest that both cell division and anisotropic expansion could explain the changes of spur length,and that hormone-related genes contribute to the process of spur formation.In contrast,little is known about intraspecific spur length variation.In Aquilegia rockii,spur length varies strikingly,ranging from 1 mm to 18 mm.To examine the potential mechanisms underlying spur length variation in A.rockii,we observed cell morphology and analyzed RNA-seq of short-and long-spurred flowers.Scanning electron microscopy revealed that at two positions on spurs there were no differences in either cell density or cell anisotropy between short-and long-spurred flowers,suggesting that in A.rockii changes in cell number may explain variations in spur length.In addition,we screened transcriptomes of short-and long-spurred flowers for differentially expressed genes;this screen identified several genes linked to cell division(e.g.,F-box,CDKB2-2,and LST8),a finding which is consistent with our analysis of the cellular morphology of spurs.However,we did not find any highly expressed genes involved in the hormone pathway in long-spurred flowers.In contrast to previous hypotheses that anisotropic cell expansion leads to interspecific spur variation in Aquilegia,our results suggest that cell number changes and related genes are mainly responsible for spur length variations of A.rockii.Furthermore,the underlying mechanisms of similar floral traits in morphology may be quite different,enriching our understanding of the mechanisms of flower diversity in angiosperms.

关键词： Aquilegia rockii Cell number Columbine Floral polymorphism Intraspecific variation Nectar spur

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A low phase noise and low spur PLL frequency synthesizer for GNSS receivers

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Journal of Semiconductors 2014年第1期35卷 96-103页

作者：李森江金光周细凤刘江华 School of Physics and Technology Wuhan University GNSS Research Center Wuhan University Suzhou Institute Wuhan University

A low phase noise and low spur phase locked loop （PLL） frequency synthesizer for use in global navigation satellite system （GNSS） receivers is proposed. To get a low spur, the symmetrical structure of the phase frequency detector （PFD） produces four control signals, which can reach the charge pump （CP） simultaneously, and an improved CP is realized to minimize the charge sharing and the charge injection and make the current matched. Additionally, the delay is controllable owing to the programmable PFD, so the dead zone of the CP can be eliminated. The output frequency of the VCO can be adjusted continuously and precisely by using a programmable LC-TANK. The phase noise of the VCO is lowered by using appropriate MOS sizes. The proposed PLL frequency synthesizer is fabricated in a 0.18 μm mixed-signal CMOS process. The measured phase noise at 1 MHz offset from the center frequency is -127.65 dBc/Hz and the reference spur is -73.58 dBc.

关键词： PLL frequency synthesizer phase noise spur PFD CP VCO

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Investigation on meshing and dynamic characteristics of spur gears with tip relief under wear fault

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Science China(Technological Sciences) 2019年第11期62卷 1948-1960页

作者： HUANGFU YiFan CHEN KangKang MA Hui LI Xu YU Xi ZHAO BaiShun WEN BangChun School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China Key Laboratory of Vibration and Control of A ero~Propulsion Systems Ministry of Education of ChinaNortheastern UniversityShenyang 110819China Sate Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China

Combining the loaded tooth contact analysis(LTCA)method and the gear dynamic model,a wear prediction model for spur gears with tip relief is established.The simulated wear depth is verified by the experimental results in a published reference.Based on the wear profile,the mesh stiffness and the tooth root stress obtained from the proposed model are compared with those obtained from the finite element model.Relative to the finite element method,the proposed method can greatly reduce the computation time.The effects of the tip relief and surface wear on the meshing and the dynamic characteristics are discussed.The tip relief can greatly decelerate the surface wear.Appropriate tip relief and slight wear can decrease the tooth interference and reduce the system vibration.Furthermore,the effects of the rotational speed on the wear depth are also studied and it is found that the quasi-static model is applicable to wear prediction when the rotational speed is away from the harmonic resonance peak.

关键词： spur gears tip relief surface wear mesh stiffness dynamic characteristics

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苹果Co基因的SSR标记定位(简报)

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实验生物学报 2005年第3期38卷 272-275页

作者：田义轲王彩虹戴洪义张继澍西北农林科技大学生命科学学院杨陵712100 莱阳农学院园艺系莱阳265200

柱型苹果,其特征是节间高度短缩,腋芽萌发为大量的短枝,很少或无侧生延长新梢,呈自然单干形g-4].柱型苹果几乎不需要修剪,非常适合于高密度栽植[5],可以极大地提高土地利用率.因此,柱型苹果是苹果株型育种的一个重要基因资源.

关键词： SSR 标记定位 Co基因 analysis apple 苹果 plant group the and form spur was to tes map

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Profile Modification for Increasing the Tooth Strength in spur Gear Using CAD

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Engineering（科研） 2010年第9期2卷 740-749页

作者： Shanmugasundaram Sankar Maasanamuthu Sundar Raj Muthusamy Nataraj 不详

This paper examines the tooth failure in spur gears. Corrective measures are taken to avoid tooth damage by introducing profile modification in root fillet. In general, spur gear with less than 17 numbers of teeth had the problem of undercutting during gear manufacturing process which minimizes the strength of gear at root. In this study, a novel design method, namely circular root fillet instead of the standard trochoidal root fillet is introduced in spur gear and analyzed using ANSYS version 11.0 software. The strength of these modified teeth is studied in comparison with the standard design. The analysis demonstrates that the novel design exhibit higher bending strength over the standard trochoidal root fillet gear. The result reveals that the circular root fillet design is particularly suitable for lesser number of teeth in pinion and where as the trochoidal root fillet gear is more opt for higher number of teeth.

关键词： Bending Stress Circular Root Fillet Deflection Profile Modification spur Gear Trochoidal Root Fillet

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LOCAL SCOUR DEPTH AROUND spurS IN THE LOWER YELLOW RIVER

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International Journal of Sediment Research 2002年第3期17卷 244-249页

作者： Baishan ZHANG,Jiye MA,Zhilin WEI Wuhan 430072 China. Department of Civil Engineering Beijing University of Aeronautics 37 Xueyuan Road Beijing100083 China Henan Bureau of Yellow River Zhengzhou 450003 China. Wuhan University

A formula for the computations of local scour depth at the head of spurs is derived according to the equilibrium principle of incipient motion of sediment particle. The proposed formula is verified with laboratory data and field measurements. In the derivation of this formula, two different scour resistance forces, the cohesive force and the gravitational force, are considered, and the integrated coefficient is calibrated using data from the Lower Yellow River.

关键词： spur Scour depth Lower Yellow River

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The Impact of Subungual Osteochondroma Deformans on Severely Mycotic Toenails

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Journal of Cosmetics, Dermatological Sciences and Applications 2019年第1期9卷 56-65页

作者： Christopher Brian Stewart Maryellen Ann Waltz Central Virginia Foot & Ankle Laser Center Charlottesville VA USA

Background: We examined 94 toenails exhibiting clinical signs of severe onychomycosis taking into account multiple contributing factors, not the least of which was Subungual Osteochondroma Deformans (SOD). We hypothesize that SOD plays a significant role in both the etiology and treatment of onychomycosis. Methods/Results: A retrospective post-treatment outcome analysis was performed comparing two groups of severely mycotic toenails. The first group of 25 fungal nails showed 54.31% improvement following treatment by both surgical nail avulsion and a 1064 YAG laser-based Nail Restoration algorithm. The second group of 69 fungal nails was not only treated using the same nail avulsion/laser-based algorithm but was also evaluated for SOD lesions which were surgically removed when present, resulting in 95.31% improvement. The overall incidence of SOD lesions in the second group of severely mycotic toenails was 73.91%. Conclusion: We submit that at 73.91% Subungual Osteochondroma Deformans has an under-reported and under-appreciated association with toenail fungus. Generally, we find that our success rates in treating severe toenail fungus using our laser-based Nail Restoration Protocols are much higher when SOD lesions are surgically removed.

关键词： Subungual Osteochondroma Deformans Onychomycosis Laser Toenail Topical Surgery Bone spur

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A Static Phase Offset Reduction Technique for Multiplying Delay-Locked Loop

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Circuits and Systems 2015年第1期6卷 13-19页

作者： Xinjie Wang Tadeusz Kwasniewski Department of Electronics Carleton University Ottawa Canada

Static phase offset (SPO) in conventional multiplying delay-locked loops (MDLLs) dramatically degrades the deterministic jitter performance. To overcome the issue, this paper presents a new SPO reduction technique for MDLLs. The technique is based on the observation that the SPO of MDLL is mainly caused by the non-idealities on charge pump (e.g. sink and source current mismatch), and control line (e.g. gate leakage of loop filter and voltage controlled delay line (VCDL) control circuit). With a high gain stage inserting between phase detector/phase frequency detector (PD/PFD) and charge pump, the equivalent SPO has been decreased by a factor equal to the gain of the gain stage. The effectiveness of the proposed technique is validated by a Simulink model of MDLL. The equivalent SPO is measured by the power level of reference spur.