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Charge-state populations for the neon-XFEL system
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作者 邓萍 蒋刚 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第6期155-163,共9页
The interaction between neon and x-ray free-electron lasers with different laser parameters is systematically studied by solving a set of coupled rate equations. As an example, the evolution of 1s~12 s~22 p~6 configur... The interaction between neon and x-ray free-electron lasers with different laser parameters is systematically studied by solving a set of coupled rate equations. As an example, the evolution of 1s~12 s~22 p~6 configuration is given under different incident photon numbers, pulse widths, and photon energies. We have also determined all of the charge-state populations as a function of three laser pulse parameters by averaging over time. The result shows that the variations of these charge-state populations demonstrate a pattern when the pulse width is shorter than 10 fs: some of the charge-states decrease rapidly,while the others rise but remain relatively constant for pulse width larger than 10 fs. The variation of the average charge with three parameters has also obtained. The average charge decreases for a pulse width shorter than 10 fs but remains basically unchanged for a pulse width longer than 10 fs. 展开更多
关键词 x-ray free electron LASERS NEON CHARGE-STATE population pulse WIDTH
区段煤柱合理宽度的数值模拟研究
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作者 王伟 梁家豪 《煤炭技术》 CAS 2019年第9期20-23,共4页
通过分析,应力降低区的区间为6 m以内的煤柱,因此煤柱宽度6 m的巷道,支护载荷相对较小,有利于巷道维护。通过不同煤柱宽度的巷道围岩变形分析,煤柱宽度为6 m时,两帮变形量最小,煤柱自身稳定性好,有利于控制煤柱变形。综合以上模拟分析,... 通过分析,应力降低区的区间为6 m以内的煤柱,因此煤柱宽度6 m的巷道,支护载荷相对较小,有利于巷道维护。通过不同煤柱宽度的巷道围岩变形分析,煤柱宽度为6 m时,两帮变形量最小,煤柱自身稳定性好,有利于控制煤柱变形。综合以上模拟分析,煤柱合理宽度为6 m。 展开更多
关键词 工作面 区段煤柱 宽度 数值模拟
水平轴风力机分裂翼型气动特性数值模拟
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作者 周伟 叶舟 +1 位作者 王治红 李春 《动力工程学报》 CAS CSCD 北大核心 2019年第6期478-485,共8页
为提高水平轴风力机的风能利用率,以NREL S809为原始翼型研究了分裂翼型缝道相对位置和缝道相对宽度对翼型流场结构、翼型气动性能、升力和阻力特性的影响。结果表明:分裂翼型缝道会对翼型周围涡的发展与变化产生影响,不仅能明显改善翼... 为提高水平轴风力机的风能利用率,以NREL S809为原始翼型研究了分裂翼型缝道相对位置和缝道相对宽度对翼型流场结构、翼型气动性能、升力和阻力特性的影响。结果表明:分裂翼型缝道会对翼型周围涡的发展与变化产生影响,不仅能明显改善翼型的失速特性,还提高了翼型的气动性能;缝道相对位置为40/90、缝道相对宽度为1.0%时分裂翼型的升力系数达到最大,与原始翼型相比,其升力系数提高约10.797%,分裂作用对于提高翼型气动性能的效果较佳。 展开更多
关键词 分裂翼型 缝道 相对位置 宽度 气动性能
Role of platelet parameters as a biomarker in diagnosis of acute appendicitis: A retrospective case-controlled study
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作者 Seyed Hamid Madani Mitra Tarlan +3 位作者 Hadi Mozafari Sedigheh Khazaei Farhad Shaveisi-Zadeh Shahab Mozafari 《急性病杂志(英文版)》 2019年第4期153-159,共7页
Objective: To investigate the diagnostic value of platelet parameters in acute appendicitis. Methods: This retrospective case-controlled study was performed among 200 healthy people and 200 patients with a primary dia... Objective: To investigate the diagnostic value of platelet parameters in acute appendicitis. Methods: This retrospective case-controlled study was performed among 200 healthy people and 200 patients with a primary diagnosis of acute appendicitis between October 2017 and June 2018. The patients were classified into three groups: the acute complicated appendicitis (suppurative and gangrenous) group, acute non-complicated appendicitis group and the control group. Red blood cell, white blood cell, lymphocyte, monocyte and platelets count, red blood cell distribution width, hemoglobin, hematocrit, mean platelet volume, platelet distribution width, and C-reactive protein were compared between the groups. Results: Thirty-nine (19.5%) patients with acute appendicitis had no complication and 161 (80.5%) developed a complication. The white blood cell count, neutrophil count and C-reactive protein serum levels were significantly higher, whereas the mean age, lymphocyte count, monocyte count, red blood cell distribution width and platelet count were significantly lower in acute appendicitis patients with and without complications compared with the control group. Moreover, combined analysis of best diagnostic parameters (white blood cell, neutrophil and lymphocyte counts) showed that combined parallel sensitivity and specificity were 98.7% and 42.7%, respectively. Conclusions: White blood cell, lymphocyte counts and neutrophil count could be used for diagnosis of acute appendicitis. More over the utility of mean platelet volume for differential diagnosis might be overestimated. 展开更多
关键词 Acute APPENDICITIS DIAGNOSIS COMPLICATION Mean PLATELET volume PLATELET Distribution width PLATELET COUNT
面向MES的冷轧带钢全工序材料设计 预览
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作者 李显 周明科 叶姜 《四川冶金》 CAS 2019年第4期44-46,共3页
本介绍了MES中的冷轧带钢全工序材料设计。在面向订单的新型生产模式下,结合客户订单的差异化需求,从厚度、宽度、重量等方面进行冷轧合同的转炉、热轧、冷轧全工序材料设计,达到对各生产工序进行管控,方便组织生产的目的。
关键词 MES 冷轧带钢 厚度 宽度 重量 材料设计
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Climate forcing of tree growth in dry Afromontane forest fragments of Northern Ethiopia: evidence from multi-species responses 预览
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作者 Zenebe Girmay Siyum J.O.Ayoade +1 位作者 M.A.Onilude Motuma Tolera Feyissa 《森林生态系统:英文版》 CSCD 2019年第2期132-148,共17页
Background: Climate-induced challenge remains a growing concern in the dry tropics, threatening carbon sink potential of tropical dry forests. Hence, understanding their responses to the changing climate is of high pr... Background: Climate-induced challenge remains a growing concern in the dry tropics, threatening carbon sink potential of tropical dry forests. Hence, understanding their responses to the changing climate is of high priority to facilitate sustainable management of the remnant dry forests. In this study, we examined the long-term climate-growth relations of main tree species in the remnant dry Afromontane forests in northern Ethiopia. The aim of this study was to assess the dendrochronological potential of selected dry Afromontane tree species and to study the influence of climatic variables (temperature and rainfall) on radial growth. It was hypothesized that there are potential tree species with discernible annual growth rings owing to the uni-modality of rainfall in the region. Ring width measurements were based on increment core samples and stem discs collected from a total of 106 trees belonging to three tree species (Juniperus procera, Olea europaea p. cuspidate and Podocarpus falcatus). Thesubsp. collected samples were prepared, crossdated, and analyzed using standard dendrochronological methods. The formation of annual growth rings of the study species was verified based on successful crossdatability and by correlating tree-ring widths with rainfall. Results: The results showed that all the sampled tree species form distinct growth boundaries though differences in the distinctiveness were observed among the species. Positive and significant correlations were found between the tree-ring widths and rainfall, implying that rainfall plays a vital role in determining tree growth in the region. The study confirmed the formation of annual growth rings through successful crossdating, thus highlighted the potential applicability of dendroclimatic studies in the region. Conclusions: Overall, the results proved the strong linkage between tree-ring chronologies and climate variability in the study region, which further strengthens the potential of dendrochronological studies developing in Ethiopia, and also has great i 展开更多
关键词 Climate-growth relationship CLIMATE change DRY AFROMONTANE forest Restoration TREE-RING WIDTH
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太湖乔木林河岸植被缓冲带截留氮素效率 预览
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作者 朱晓成 吴永波 +1 位作者 余昱莹 李文霞 《浙江农林大学学报》 CAS CSCD 北大核心 2019年第3期565-572,共8页
为研究河岸植被缓冲带对氮素的截留效率,以太湖流域平缓坡地上人工林河岸缓冲带作为研究对象,分析了不同河岸缓冲带宽度(5,15,30,40 m),不同植物类型(‘南林95’杨 Populus × euramericana‘Nanlin 95’林、中山杉Taxodium hybrid ... 为研究河岸植被缓冲带对氮素的截留效率,以太湖流域平缓坡地上人工林河岸缓冲带作为研究对象,分析了不同河岸缓冲带宽度(5,15,30,40 m),不同植物类型(‘南林95’杨 Populus × euramericana‘Nanlin 95’林、中山杉Taxodium hybrid ‘Zhongshanshan’林、南林杨95-中山杉混交林)对不同深度径流水及土壤中氮素的截留效果。结果表明:15 m宽的河岸缓冲带即能很好地截留各形态氮素,40 m缓冲带对径流水中硝态氮、铵态氮、总氮的截留率分别达68.8%,68.7%和66.0%;同一宽度条件下,缓冲带对40 cm深径流水中铵态氮、总氮的截留率较高,分别达71.4%和69.1%,对20 cm深径流水中硝态氮截留率较高,达70.6%;森林土壤对铵态氮和硝态氮的截留主要在中层土壤,对总氮截留主要在表层土壤;杨树林缓冲带对径流水中铵态氮和硝态氮的截留率较高(P<0.05),达77.4%和66.3%;杨树-中山杉混交林缓冲带对总氮的截留率较高(P<0.05),达73.0%;植物叶片(r =-0.53)全氮和土壤总氮(r =-0.59)均与径流水中总氮呈负相关关系。图8参26。 展开更多
关键词 生态学 河岸缓冲带 宽度 植物类型 氮素 截留率
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The effect of the beam shapes on the doubly-clamped piezoelectric energy harvester 预览
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作者 Lei JIN Shiqiao GAO Xiyang ZHANG 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第9期1361-1374,共14页
For a piezoelectric energy harvester composed of a doubly-clamped beam with arbitrary width shapes and a proof mass, the influence of beam shapes and electrode arrangements on different electric outputs is analyzed. T... For a piezoelectric energy harvester composed of a doubly-clamped beam with arbitrary width shapes and a proof mass, the influence of beam shapes and electrode arrangements on different electric outputs is analyzed. The output performances of piezoelectric energy harvesters with rectangular shape, concave trapezoidal shape, and concave parabolic shape are compared, and an optimization way is given. The experimental results validate the effectiveness of the methods. 展开更多
关键词 doubly-clamped WIDTH shape PIEZOELECTRIC energy HARVESTER electrode connection
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Experimental investigation on the optical remote sensing images of internal solitary waves with a smooth surface 预览
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作者 Yuan Mei Jing Wang +2 位作者 Songsong Huang Haidi Mu Xu Chen 《海洋学报:英文版》 SCIE CAS CSCD 2019年第6期124-131,共8页
The parameter inversion of internal solitary waves (ISWs) based on optical remote sensing images is a key work. A new approach is proposed and demonstrated for simulating the optical remote sensing images of ISWs with... The parameter inversion of internal solitary waves (ISWs) based on optical remote sensing images is a key work. A new approach is proposed and demonstrated for simulating the optical remote sensing images of ISWs with a smooth surface in the laboratory. An optical remote sensing simulation system used to detect ISWs is constructed by a two-dimensional ISW flume, a LED (light emitting diode) light source and two CCD (charge coupled device) cameras. The optical remote sensing images of the horizontal surface and ISWs propagation images of a vertical side are detected simultaneously, which aims to explore the response of optical remote sensing corresponding to ISWs with the smooth surface. The results show that during the propagation of ISWs, dark pattern images are obtained by CCD 1 camera. The characteristics of the dark patterns vary along with the incident angle of the light source. The characteristic parameters of the optical remote sensing images correspond to the wave factors of vertical profiles. The experiment also shows a positive correlation between the dark pattern width and the half wave width under different amplitudes of ISWs. The system has the advantages of clear phenomenon and high repeatability, which provides the scientific basis for quantitative investigation on imaging mechanism of ISW by optical remote sensing. 展开更多
关键词 internal SOLITARY WAVE optical remote sensing image DARK pattern HALF WAVE WIDTH WAVE factors
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生态学价值视角下的城市河流绿道宽度研究进展 预览
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作者 王芳 汪耀龙 谢祥财 《中国城市林业》 2019年第1期57-61,共5页
城市河流绿道作为河流廊道在城市生态保护方面发挥重要作用,而设置合理的绿道宽度能使河流绿道的生态价值更加凸显,是城市河流生态建设中的重要一环。文章从保土控污、生物保护和改善微气候3方面就绿道宽度对河流生态功能的影响进行综述... 城市河流绿道作为河流廊道在城市生态保护方面发挥重要作用,而设置合理的绿道宽度能使河流绿道的生态价值更加凸显,是城市河流生态建设中的重要一环。文章从保土控污、生物保护和改善微气候3方面就绿道宽度对河流生态功能的影响进行综述,总结当前研究中存在的问题并提出建议,以期为城市河流绿道在城市生态环境层面的规划提供参考。 展开更多
关键词 城市河流绿道 宽度 生态 环境
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Calculation of the infrared frequency and the damping constant (full width at half maximum) for metal organic frameworks
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作者 M Kurt H Yurtseven +1 位作者 A Kurt S Aksoy 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第6期324-331,共8页
The ρ(NH2) infrared(IR) frequencies and the corresponding full width at half maximum(FWHM) values for(CH3)2 NH2 FeⅢ M Ⅱ(HCOO)6(DMFe M, M = Ni, Zn, Cu, Fe, and Mg) are analyzed at various temperatures by using the e... The ρ(NH2) infrared(IR) frequencies and the corresponding full width at half maximum(FWHM) values for(CH3)2 NH2 FeⅢ M Ⅱ(HCOO)6(DMFe M, M = Ni, Zn, Cu, Fe, and Mg) are analyzed at various temperatures by using the experimental data from the literature. For the analysis of the IR frequencies of the ρ(NH2) mode which is associated with the structural phase transitions in those metal structures, the temperature dependence of the mode frequency is assumed as an order parameter and the IR frequencies are calculated by using the molecular field theory. Also, the temperature dependence of the IR frequencies and of the damping constant as calculated from the models of pseudospin(dynamic disorder of dimethylammonium(DMA+) cations)–phonon coupling(PS) and of the energy fluctuation(EF), is fitted to the observed data for the wavenumber and FWHM of the ρ(NH2) IR mode of the niccolites studied here. We find that the observed behavior of the IR frequencies and the FWHM of this mode can be described adequately by the models studied for the crystalline structures of interest. This method of calculating the frequencies(IR and Raman) and FWHM of modes which are responsible for the phase transitions can also be applied to some other metal organic frameworks. 展开更多
关键词 infrared(IR) FREQUENCY full WIDTH at half maximum(FWHM) phase TRANSITIONS ρ(NH2) mode niccolites
Effect of wire tension on different output responses during wire electric discharge machining on AISI 304 stainless steel 预览
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作者 Tina Chaudhary Arshad Noor Siddiquee Arindam Kumar Chanda 《Defence Technology(防务技术)》 CAS CSCD 2019年第4期541-544,共4页
WEDM is used in machining conductive materials where it is required to obtained complicated and intricate shapes with high accuracy.Various applications are in the field of automobile,medical industries,aerospace etc.... WEDM is used in machining conductive materials where it is required to obtained complicated and intricate shapes with high accuracy.Various applications are in the field of automobile,medical industries,aerospace etc.WEDM is an economical machining option with short product development cycle.Surface roughness,kerf width,Material removal rate,Recast layer hardness and surface microhardness in WEDM are most important responses.In this paper,effect of varied Wire tension on SR,KW,MRR,RCL hardness and surface microhardness on AISI 304 have been investigated.Pulse on time,pulse off time,current and dielectric fluid are taken as fixed parameter.Results show that Wire tension influences the SR,MRR and Surface microhardness and has no effect on kerf width in case of Stainless steel304. 展开更多
关键词 WIRE EDM WIRE tension Material removal rate Surface ROUGHNESS KERF WIDTH Micro-hardness
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Fine-Mapping of qTGW1.2a, a Quantitative Trait Locus for 1000-Grain Weight in Rice 预览
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作者 WANG Wenhui WANG Linlin +2 位作者 ZHU Yujun FAN Yeyang ZHUANG Jieyun 《水稻科学:英文版》 CSCD 2019年第4期220-228,I0002-I0004,I0010,I0015共14页
Thousand-grain weight (TGW) is a key component of grain yield in rice. This study was conducted to validate and fine-map qTGW1.2a, a quantitative trait locus for grain weight and grain size previously located in a 933... Thousand-grain weight (TGW) is a key component of grain yield in rice. This study was conducted to validate and fine-map qTGW1.2a, a quantitative trait locus for grain weight and grain size previously located in a 933.6-kb region on the long arm of rice chromosome 1. Firstly, three residual heterozygotes (RHs) were selected from a BC2F11 population of the indica rice cross Zhenshan 97 (ZS97)///ZS97//ZS97/Milyang 46. The heterozygous segments in these RHs were arranged successively in physical positions, forming one set of sequential residual heterozygotes (SeqRHs). In each of the populations derived, non-recombinant homozygotes were identified to produce near isogenic lines (NILs) comprising the two homozygous genotypes. The NILs were tested for grain weight, grain length and grain width. QTL analyses for the three traits were performed. Then, the updated QTL location was followed for a new run of SeqRHs identification-NIL development-QTL mapping. Altogether, 11 NIL populations derived from four sets of SeqRHs were developed and used. qTGW1.2a was finally delimitated into a 77.5-kb region containing 13 annotated genes. In the six populations segregating this QTL, which were in four generations and were tested across four years, the allelic direction of qTGW1.2a remained consistent and the genetic effects were stable. For TGW, the additive effects ranged from 0.23 to 0.38 g and the proportions of phenotypic variance explained ranged from 26.15% to 41.65%. These results provide a good foundation for the cloning and functional analysis of qTGW1.2a. 展开更多
关键词 fine mapping GRAIN weight MINOR effect quantitative TRAIT LOCUS RICE GRAIN length GRAIN width
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双浮体波浪能装置的振荡和能量转换特性研究 预览
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作者 张亮 金鹏 +2 位作者 周斌珍 政雄波 刘恒序 《船舶与海洋工程学报:英文版》 CSCD 2019年第1期54-63,共10页
In this study, we investigated the hydrodynamic and energy conversion performance of a double-float wave energy converter(WEC) based on the linear theory of water waves. The generator power take-off(PTO) system is mod... In this study, we investigated the hydrodynamic and energy conversion performance of a double-float wave energy converter(WEC) based on the linear theory of water waves. The generator power take-off(PTO) system is modeled as a combination of a linear viscous damping and a linear spring. Using the frequency domain method, the optimal damping coefficient of the generator PTO system is derived to achieve the optimal conversion efficiency(capture width ratio).Based on the potential flow theory and the higher-order boundary element method(HOBEM), we constructed a threedimensional model of double-float WEC to study its hydrodynamic performance and response in the time domain. Only the heave motion of the two-body system is considered and a virtual function is introduced to decouple the motions of the floats. The energy conversion character of the double-float WEC is also evaluated. The investigation is carried out over a wide range of incident wave frequency. By analyzing the effects of the incident wave frequency, we derive the PTO’s damping coefficient for the double-float WEC’s capture width ratio and the relationships between the capture width ratio and the natural frequencies of the lower and upper floats. In addition, it is capable to modify the natural frequencies of the two floats by changing the stiffness coefficients of the PTO and mooring systems. We found that the natural frequencies of the device can directly influence the peak frequency of the capture width, which may provide an important reference for the design of WECs. 展开更多
关键词 Double-float WEC Energy conversion CAPTURE WIDTH ratio Optimal DAMPING RESONANCE
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GB/T406—2018《棉本色布》的解析 预览
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作者 魏伟 田金家 《棉纺织技术》 CAS 北大核心 2019年第8期76-79,共4页
解析GB/T 406—2018《棉本色布》标准。对照2008版标准,介绍了GB/T 406—2018《棉本色布》的主要技术变化;对标准测试项目的分类、测评项目的要求与规范限的配合、织物断裂强力的考核及贸易型标准的适用等进行了分析探讨,并提出了相应... 解析GB/T 406—2018《棉本色布》标准。对照2008版标准,介绍了GB/T 406—2018《棉本色布》的主要技术变化;对标准测试项目的分类、测评项目的要求与规范限的配合、织物断裂强力的考核及贸易型标准的适用等进行了分析探讨,并提出了相应建议。认为:按照贸易型标准规则,根据纺织品具体用途与具体需要制订不同的织物断裂强力考核方式是更科学合理、经济实用的方法。 展开更多
关键词 棉本色布 产品标识 织物组织 幅宽 断裂强力 织物密度 贸易型标准
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提高校本培训的“五度” 预览
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作者 陆一平 赵芳 《江苏教育研究》 2019年第20期33-37,共5页
校本培训是一种更加关注教师教育教学实践需要,以提升教师实践能力为目标的培训形式。常州市武进区星辰实验学校通过建构校本培训框架,增加校本培训的亮度;通过对培训过程进行全程考核,提高校本培训的效度;通过组织教师多维研修,拓展校... 校本培训是一种更加关注教师教育教学实践需要,以提升教师实践能力为目标的培训形式。常州市武进区星辰实验学校通过建构校本培训框架,增加校本培训的亮度;通过对培训过程进行全程考核,提高校本培训的效度;通过组织教师多维研修,拓展校本培训的广度;通过开辟多元培训路径,丰富校本培训的向度;通过总结教师研修成果,深化校本培训的深度。 展开更多
关键词 校本培训 亮度 效度 广度 向度 深度
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Experimental Study on Conversion Efficiency of A Floating OWC Pentagonal Backward Bent Duct Buoy Wave Energy Converter 预览
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作者 LI Meng WU Ru-kang +1 位作者 WU Bi-jun ZHANG Yun-qiu 《中国海洋工程:英文版》 SCIE EI CSCD 2019年第3期297-308,共12页
Wave tank tests were carried out to evaluate the total efficiency of a floating OWC Pentagonal Backward Bent Duct Buoy (PBBDB). Two kinds of turbine generators were used in tests. The incident wave power, pneumatic po... Wave tank tests were carried out to evaluate the total efficiency of a floating OWC Pentagonal Backward Bent Duct Buoy (PBBDB). Two kinds of turbine generators were used in tests. The incident wave power, pneumatic power and electricity were measured. The test results show that the primary efficiency can reach up to 185.98% in regular waves and 85.86% in irregular waves. The total efficiency from wave to wire with Wells turbine-generator set is 33.43% in regular waves and 15.82% in irregular waves. The peak total efficiency of the PBBDB with check valves equipped with the impulse turbine-generator set is 41.68% in regular waves and 27.10% in irregular waves. The efficiency of the turbine-generator set is about 30% in the tests. Obviously, the total efficiency can be further improved with the increasing of turbine efficiency. 展开更多
关键词 wave energy OSCILLATING Water Column (OWC) PBBDB Capture Width Ratio (CWR) total efficiency
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Determination of optimal grid opening width for herringbone water-sediment separation structures based on sediment separation efficiency
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作者 XIE Xiang-ping WEI Fang-qiang +1 位作者 WANG Xiao-jun YANG Hong-juan 《山地科学学报:英文版》 SCIE CSCD 2019年第3期619-629,共11页
The herringbone water-sediment separation structure(HWSSS) was developed to prevent debris flows. This paper mainly focuses on evaluating the sediment separation efficiency of HWSSS in debris flow prevention and deter... The herringbone water-sediment separation structure(HWSSS) was developed to prevent debris flows. This paper mainly focuses on evaluating the sediment separation efficiency of HWSSS in debris flow prevention and determining the grid opening width D, a crucial structure parameter for HWSSS design. Theoretical analysis on the total sediment separation rate Pt reveals that the efficiency of sediment separation is much related with sediment grain size distribution(GSD) and grid opening width. The lower limit of Pt is deduced from the perspective of safety consideration by transforming debris flow into sediment-laden flow. Hydraulic model tests were carried out. Based on the regression analysis of the experimental data, the quantitative relationships between Pt and D and GSD characteristic values were finally established. A procedure for determining optimal grid opening width is proposed based on these analyses. These results are of significance in evaluating sediment separation effect by HWSSS in debris flow prevention and contribute to a more explicit methodology for design of HWSSS. 展开更多
关键词 Debris flow Water-sediment SEPARATION Structure design SEDIMENT SEPARATION efficiency GRID OPENING WIDTH
沿空掘巷煤柱的合理留设宽度 预览
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作者 白渌斐 《山东煤炭科技》 2019年第2期24-25,30共3页
为了最大程度地解决煤炭资源短缺的问题,通过理论分析计算得出采空区实体煤侧极限平衡区的范围,并应用"O-X"形破坏理论,得出沿空巷道位置和窄煤柱宽度,从而保证巷道煤柱承受较小载荷,利于巷道稳定,增加煤炭资源回收率,提高矿... 为了最大程度地解决煤炭资源短缺的问题,通过理论分析计算得出采空区实体煤侧极限平衡区的范围,并应用"O-X"形破坏理论,得出沿空巷道位置和窄煤柱宽度,从而保证巷道煤柱承受较小载荷,利于巷道稳定,增加煤炭资源回收率,提高矿井效益. 展开更多
关键词 沿空掘巷 煤柱 宽度
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R/S ratio in lead Ⅱ,and the prognostic significance of red cell distribution width in acute coronary syndrome 预览
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作者 Abuzer Coskun Sevki Hakan Eren 《世界临床病例杂志》 2019年第16期2217-2226,共10页
BACKGROUND In spite of developing medical technologies to discover the etiopathogenesis of diseases and developments in the treatment of coronary artery disease,acute coronary syndromes (ACS) continue to be the main c... BACKGROUND In spite of developing medical technologies to discover the etiopathogenesis of diseases and developments in the treatment of coronary artery disease,acute coronary syndromes (ACS) continue to be the main cause of mortality and morbidity worldwide.New cardiac biomarkers and techniques are needed to help provide rapid diagnosis in order to evaluate risk in coronary artery patients.AIM To evaluate the effects of R to S ratio (RSR) in the electrocardiograph of patients with ACS,from the point of the arising complication after myocardial infarction (MI),to three-vessel disease (TVD) and mortality.METHODS The data of 1,296 patients with ACS,who presented to the emergency department of our hospital with chest pain between January 2014 and December 2018 and were admitted to the cardiology clinic,were retrospectively included in this cross-sectional cohort study.Patients with an RSR value less than Ⅰ were assigned to group I,while those with an RSR value greater than Ⅰ were assigned to group Ⅱ.RESULTS In our study,466 (35.9%) of the 1,296 patients,357 (38.3%) in group 1 and 109 (29.9%) in group 2,were female,with a mean age of 61.56 ± 9.42.ST-elevation MI 573 (44.2%),unstable angina (UA) 502 (38.7%) and non ST-elevation MI 220 (17%) were more prevalent in group I.Acute anterior MI 263 (20.3) in group I,and acute inferior MI 184 (14.2) in group Ⅱ was higher.Ischemic heart failure was the most common complication.In group Ⅱ,the red cell distribution width (RDW) was 15.42 ± 1.82,the gensini score was 48.39 ± 36.44,the left ventricular ejection fraction was 41.17 ± 10.41,the TVD was 111 (8.5),and the mortality rate was 72 (5.6),which was significantly higher than group Ⅰ RDW;in MI with ST and non- ST-elevation,in TVD,mortality and complications were high and low in UA.In single and multivariate regression analyses,the variables were associated with ACS risk.CONCLUSION RSR levels may be an auxiliary predictive value in ACS in terms of complications developing after MI,TVD,and mortality. 展开更多
关键词 Acute CORONARY SYNDROME EMERGENCY DEPARTMENT R/S RATIO Red cell distribution WIDTH
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