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反冲洗用喷射器流场模拟及结构优化

煤矿机电 2024年第1期45卷 67-70页

作者：唐琨陶震魏逸中煤科工集团上海有限公司上海200030

为提高反冲洗喷射器的工作性能,采用工作流场模拟分析和试验验证相结合的方法,在此基础上,通过改变喷射器结构尺寸及工作参数,分析其对性能的影响,包括灵敏度的影响,最后利用Workbench中多目标优化得到最佳的工作点。

关键词： Fluent数值模拟反冲洗用喷射器水泵试验灵敏度分析多目标参数优化

彝良县沙木沟石英砂岩矿床地质特征及成因浅析

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云南地质 2024年第1期43卷 71-75页

作者：何永波唐永昆云南省有色地质局三一〇队云南大理671000

彝良沙木沟石英砂岩矿赋存于泥盆系中统缩头山组中,属陆源碎屑来源滨海相沉积型石英砂岩矿床,单斜层状产出。沿矿体走向和倾斜方向均具较大的找矿潜力。受上扬子陆块隆起区控制,为古陆隆起滨海前滨带反复冲洗沉积形成。矿石中Fe_(2)O_(3... 详细信息

彝良沙木沟石英砂岩矿赋存于泥盆系中统缩头山组中,属陆源碎屑来源滨海相沉积型石英砂岩矿床,单斜层状产出。沿矿体走向和倾斜方向均具较大的找矿潜力。受上扬子陆块隆起区控制,为古陆隆起滨海前滨带反复冲洗沉积形成。矿石中Fe_(2)O_(3)含量略大于一般工业指标,其他指标与一般工业指标要求一致,其矿石可达到平板玻璃用硅质原料一级品要求。

关键词：石英砂岩矿缩头山组地质特征成因浅析沙木沟石英砂岩矿云南彝良

An Adaptive Transmission Scheme in Cooperative Relay Networks with Energy Accumulation

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Chinese Journal of Electronics 2019年第1期28卷 152-161页

作者： tang kun SHI Ronghua GUO Yabo SHI Heyuan DONG Jian School of Information Science and Engineering Central South University School of Insurance and Economics University of International Business and Economics School of Software Tsinghua University

We investigate a wireless-powered cooperative relay network, where an energy constrained relay node accumulates the energy harvested from radio frequency signals, and then assists source signal transmission. An adaptive cooperative transmission scheme for cooperative relay network is developed. The relay helps to transmit the source signal only if it has harvested enough energy and the channels between source and relay do not suffer from an outage. Before each transmission block, one out of two transmission modes, i.e., Half-duplex(HD) or Full-duplex(FD), is dynamically adopted based on the maximal instantaneous capacity of the system. A closed-form expression for the exact outage probability of the system with the proposed scheme is derived. Monte Carlo simulations are run to validate the accuracy of the mathematical analysis, and numerical results show that the proposed protocol outperforms the existing fixed cooperative transmission modes.

关键词： Cooperative relay networks Wireless energy harvesting Full-duplex relaying Half-duplex relaying Outage probability

氮添加增加中国陆生植物生物量并降低其氮利用效率

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植物生态学报 2024年第2期48卷 147-157页

作者：耿雪琪唐亚坤王丽娜邓旭张泽凌周莹中国科学院教育部水土保持与生态环境研究中心中国科学院水利部水土保持研究所陕西杨凌712100 中国科学院大学北京100049 西北农林科技大学水土保持科学与工程学院陕西杨凌712100

研究植物整体和地上、地下部分生物量和氮利用效率(NUE)对氮添加的响应,有助于了解全球氮沉降背景下中国陆地生态系统植物碳、氮循环的变化。然而氮添加对植物生物量和NUE的影响是否一致,影响这种响应的主要因素仍不清楚。该研究收集整... 详细信息

研究植物整体和地上、地下部分生物量和氮利用效率(NUE)对氮添加的响应,有助于了解全球氮沉降背景下中国陆地生态系统植物碳、氮循环的变化。然而氮添加对植物生物量和NUE的影响是否一致,影响这种响应的主要因素仍不清楚。该研究收集整理了94篇已发表论文中有关中国氮添加实验的相关数据,使用meta分析定量评估了氮添加对植物生物量分配和NUE的影响及其主要影响因素。结果表明:(1)氮添加在显著增加植物整体、地上和地下生物量的同时,也显著降低了不同部分的NUE,但植物地上生物量的增加幅度(34.0%)高于地下生物量(5.3%),而地下部分NUE(29.9%)的下降幅度高于地上部分NUE(15.4%);(2)植物整体和不同部分生物量及其NUE对氮添加的响应在不同生态系统类型、氮肥形式、施氮水平、持续时间和水分条件下均存在显著差异,且草地和荒漠生态系统对氮添加的响应明显高于其他生态系统类型;(3)影响植物整体、地上和地下生物量效应值的最主要因素均为土壤总氮含量,植物整体和地上部分NUE的最主要影响因素均为施氮量,而影响地下部分NUE效应值的最主要因素为氮肥形式。总之,植物生物量和NUE在氮添加条件下的变化趋势相反,两者分别主要受土壤总氮含量和施氮水平的影响。

关键词： meta分析土壤总氮氮添加生物量分配氮利用效率生态系统类型

Attention-Based Adaptive Intra Refresh Method for Robust Video Coding

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Tsinghua Science and Technology 2012年第1期17卷 67-72页

作者： Xiaolong Wang Huijuan Cui kun tang Department of Electronic Engineering Tsinghua UniversityBeijing 100084China

Intra refresh is an efficient and simple technique for suppressing temporal error propagation in video transmission over error-prone networks. However, most existing intra refresh algorithms do not make good use of the visual perceptual mechanism of the Human Visual System （HVS）. This paper presents an intra refresh algorithm based on an attention model and a loss impact model. Intra refresh rates are allowed to vary for different image regions according to the HVS characteristic and the channel conditions to protect the most important macro-blocks against packet loss. A joint source-channel rate-distortion model was de- veloped taking into account the HVS characteristic to achieve an optimal end-to-end distortion for a better subjective quality. Tests demonstrate that, for the same bit rate and packet loss rate, this method provides a much better subjective feeling than existing intra refresh methods.

关键词： human visual system (HVS) attention-based model intra refresh H.264/AVC

Realtime robust speech communication based on iterative joint source-channel decoding and demodulation algorithm for MELP vocoder

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High Technology Letters 2010年第2期16卷 111-116页

作者：彭坦 Cui Huijuan tang kun Tsinghua National Laboratory for Information Science and Technology State Key laboratory on Microwave and Digital Communications Department of Electronic Engineering Tsinghua University Beijing 100084 P.R. China

Realtime speech communications require high efficient compression algorithms to encode speech signals. As the compressed speech parameters are highly sensitive to transmission errors, robust source and channel decoding and demodulation schemes are both important and of practical use. In this paper, an it- erative joint souree-channel decoding and demodulation algorithm is proposed for mixed excited linear pre- diction （MELP） vocoder by both exploiting the residual redundancy and passing soft information through- out the receiver while introducing systematic global iteration process to further enhance the performance. Being fully compatible with existing transmitter structure, the proposed algorithm does not introduce addi- tional bandwidth expansion and transmission delay. Simulations show substantial error correcting perfor- mance and synthesized speech quality improvement over conventional separate designed systems in delay and bandwidth constraint channels by using the joint source-channel decoding and demodulation （JSCCM） algorithm.

关键词： speech coding joint souree-channel coding and modulation (JSCCM) iterative decoding

Leading-edge flow separation control over an airfoil using a symmetrical dielectric barrier discharge plasma actuator

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Chinese Journal of Aeronautics 2019年第5期32卷 1190-1203页

作者： Xin ZHANG Huaxing LI Yong HUANG kun tang Wanbo WANG School of Aeronautics Northwestern Polytechnical University Low Speed Aerodynamics Institute China Aerodynamics Research and Development Center

In order to promote an in-depth understanding of the mechanism of leading-edge flow separation control over an airfoil using a symmetrical Dielectric Barrier Discharge(DBD) plasma actuator excited by a steady-mode excitation, an experimental investigation of an SC(2)-0714 supercritical airfoil with a symmetrical DBD plasma actuator was performed in a closed chamber and a low-speed wind tunnel. The plasma actuator was mounted at the leading edge of the ***-resolved Particle Image Velocimetry(PIV) results of the near-wall region in quiescent air suggested that the symmetrical DBD plasma actuator could induce some coherent structures in the separated shear layer, and these structures were linked to a dominant frequency of f0= 39 Hz when the peak-to-peak voltage of the plasma actuator was 9.8 kV. In addition, an analysis of flow structures without and with plasma actuation around the upper side of the airfoil at an angle of attack of18° for a wind speed of 3 m/s(Reynolds number Re = 20000) indicated that the dynamic process of leading-edge flow separation control over an airfoil could be divided into three stages. Initially, this plasma actuator could reinforce the shedding vortices in the separated shear layer. Then, these vortical structures could deflect the separated flow towards the wall by promoting the mixing between the outside flow with a high kinetic energy and the flow near the surface. After that, the plasma actuator induced a series of rolling vortices in the vicinity of the suction side of the airfoil, and these vortical structures could transfer momentum from the leading edge of the airfoil to the separated region, resulting in a reattachment of the separated flow around the airfoil.

关键词： Airfoil Dielectric Barrier Discharge(DBD) Flow control Particle Image Velocimetry(PIV) Plasma actuator

Screening for differentially expressed genes in Anoectochilus roxburghii (Orchidaceae) during symbiosis with the mycorrhizal fungus Epulorhiza sp.

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Science China(Life Sciences) 2012年第2期55卷 164-171页

作者： LI Biao tang MingJuan tang kun ZHAO LiFang GUO ShunXing Center of Biotechnology Institute of Medicinal Plant DevelopmentChinese Academy of Medical SciencesBeijing 100193China College of Bioinformation Chongqing University of Posts&TelecommunicationsChongqing 400065China

Mycorrhizal fungi promote the growth and development of plants, including medicinal plants. The mechanisms by which this growth promotion occurs are of theoretical interest and practical importance to agriculture. Here, an endophytic fungus （AR-18） was isolated from roots of the orchid Anoectochilus roxburghii growing in the wild, and identified as Epulorhiza sp. Tissue-cultured seedlings of A. roxburghii were inoculated with AR-l 8 and co-cultured for 60 d. Endotrophic mycorrhiza formed and the growth of A. roxburghii was markedly promoted by the fungus. To identify genes in A. roxburghii that were differentially expressed during the symbiosis with AR-18, we used the differential display reverse transcription polymerase chain reac- tion （DDRT-PCR） method to compare the transcriptomes between seedlings inoculated with the fungus and control seedlings. We amplified 52 DDRT-PCR bands using 15 primer combinations of three anchor primers and five arbitrary primers, and nine bands were re-amplified by double primers. Reverse Northern blot analyses were used to further screen the bands. Five clones were up-regulated in the symbiotic interaction, including genes encoding a uracil phosphoribosyltransferase （UPRTs; EC 2.***.2.9） and a hypothetical protein. One gene encoding an amino acid transmembrane transporter was down-regulated, and one gene encoding a tRNA-Lys （trnK） and a maturase K （matK） pseudogene were expressed only in the inoculated seedlings. The possible roles of the above genes, especially the UPRTs and marK genes, are discussed in relation to the fungal interaction. This study is the first of its type in A. roxburghii.

关键词： Anoectochilus roxburghii orchid mycorrhizal symbiosis Epulorhiza sp. differential display-PCR (DD-PCR) gene screening

骨钉骨膜联合髂骨松质骨植骨术修复替牙期唇腭裂牙槽突裂效果评价

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上海口腔医学 2024年第4期33卷 426-431页

作者：唐坤伦何晓玲陈丹电子科技大学医学院附属妇女儿童医院·成都市妇女儿童中心医院口腔科四川成都610091

目的:评价骨钉骨膜联合髂骨松质骨植骨术修复替牙期唇腭裂牙槽突裂的效果。方法:回顾性分析2020年1月—2023年12月收治的62例替牙期唇腭裂牙槽突裂患儿的临床资料,按照术式分为对照组(单纯髂骨松质骨植骨,n=42)和试验组(骨钉骨膜联合髂... 详细信息

目的:评价骨钉骨膜联合髂骨松质骨植骨术修复替牙期唇腭裂牙槽突裂的效果。方法:回顾性分析2020年1月—2023年12月收治的62例替牙期唇腭裂牙槽突裂患儿的临床资料,按照术式分为对照组(单纯髂骨松质骨植骨,n=42)和试验组(骨钉骨膜联合髂骨松质骨植骨,n=40)。比较2组植骨区存活骨量体积、移植骨整体和不同植骨区吸收率、植骨成功率、植骨成活率及并发症发生情况。采用SPSS 25.0软件包对数据进行统计学分析。结果:试验组术后3、9个月植骨区存活骨量体积显著大于对照组(P0.05)。试验组术后3、9个月及3~9个月的移植骨吸收率显著小于对照组(P0.05)。试验组术后3、9个月鼻腔侧1/2区、牙槽嵴侧1/2区、唇侧1/2区和腭侧1/2区移植骨吸收率显著低于对照组,且2组牙槽嵴侧1/2区移植骨吸收率显著高于鼻腔侧1/2区,腭侧1/2区显著高于唇侧1/2区(P<0.05)。试验组植骨成功率、植骨成活率显著高于对照组(P<0.05),并发症发生率显著低于对照组(P<0.05)。结论:骨钉骨膜联合髂骨松质骨植骨术可有效修复替牙期唇腭裂牙槽突裂,降低骨吸收率和并发症,提高成骨效果。术后骨量吸收主要发生于术后3个月内,且主要发生于牙槽嵴顶区、腭侧区。

关键词：骨钉骨膜髂骨松质骨植骨术唇腭裂牙槽突裂