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A new pathotype characterization of Daxing and Huangyuan populations of cereal cyst nematode(Heterodera avenae) in China 被引量:8
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作者 CUI Jiang-kuan HUANG Wen-kun +4 位作者 PENG Huan LIU Shi-ming WANG Gao-feng KONG Lin-an PENG De-liang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2015年第4期724-731,共8页
The cereal cyst nematode(CCN, Heteroder aavenae) causes serious yield loss on cereal crops, especially wheat, worldwide. Daxing population in Beijing City and Huangyuan population in Qinghai Province, China, are two... The cereal cyst nematode(CCN, Heteroder aavenae) causes serious yield loss on cereal crops, especially wheat, worldwide. Daxing population in Beijing City and Huangyuan population in Qinghai Province, China, are two CCN populations. In this study, the CCN pathotypes of Daxing and Huangyuan populations were characterized by tests on 23 standard "International Test Assortment" with the local species Wenmai 19 as the susceptible control. Tested materials were grouped by three nematode populations' virulence on resistant genes(Rha1, Rha2, Rha3, Cre1) and nonresistant genes, varieties and lines. Both Daxing and Huangyuan populations were avirulent to Ortolan(Ha1). Barley cvs. Ortolan, Siri, Morocco, Bajo Aragon 1-1, and Martin 403-2 were all resistant to both populations. Cultivars Herta, Harlan 43 and wheat Iskamish-K-2-light were all susceptible to Huangyuan population, all of them, however, were resistant to Daxing population. The other five oats were all resistant to the two tested CCN populations. Except Iskamisch K-2-light, all the other wheat cultivars(Capa, Loros×Koga, AUS 10894, and Psathias) were susceptible to Daxing population. Because the pathotypes of the two tested CCN populations in Beijing and Qinghai were not identical to any of the 13 pathotypes previously characterized by the test assortment, we classified Daxing and Huangyuan populations as the new pathotypes, named Ha91. 展开更多
关键词 cereal cyst nematode Heterodera avenae daxing population Huangyuan population PATHOTYPE
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Site classification of the eastern forest region of Daxing'an Mountains 被引量:1
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作者 扬凯 马英 +1 位作者 谷会岩 刘鹏 《Journal of Forestry Research》 SCIE CAS CSCD 1999年第2期129-130,共2页
Based on the plot data from the investigation and the theory of forest ecology and ecological system,the site classification of the eastern forest region of Daxing’an Mountains was made by mean of mathematical method... Based on the plot data from the investigation and the theory of forest ecology and ecological system,the site classification of the eastern forest region of Daxing’an Mountains was made by mean of mathematical method. The main factors were slope, thickness of soil layer, slope position and slope aspect. Grades of slope were used as the division standard for site type group. The slope aspect, slope position and thickness of soil layer were used as the division standards for site type. Altogether 7 site type groups and 15 main site types were determined the region. It provided reliable fundamental basis for the reasonable management and planting design in the area. 展开更多
关键词 daxing’an MOUNTAINS FOREST SITE classification SITE TYPE GROUP SITE TYPE
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Spring habitat selection of sables in Daxing'an Mountains 被引量:1
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作者 张洪海 《Journal of Forestry Research》 SCIE CAS CSCD 1999年第2期111-114,共4页
This paper studies the habitat selection of sables (Martes. zibellina) in spring adopting radio-tracking and GPS (Global Positioning System) in Daxing’an Mountains of China. Sables liked mature and elder forest, but ... This paper studies the habitat selection of sables (Martes. zibellina) in spring adopting radio-tracking and GPS (Global Positioning System) in Daxing’an Mountains of China. Sables liked mature and elder forest, but it avoided uncovered and young growth land. In spring sables had strong selection to medium cover-degree forest, but it avoided widen ground and especial high cover-degree forest. On the contrary sables didn’t have the strong selection to shrubs cover-degree, but strong selection to dominant tree species, slope degree and slope direction, especially sable liked medium and lower slope. At the same time, sables had the strong selection to the log’s density and the crown’s cover-degree. Generally it avoided high elevation and lower slope land. 展开更多
关键词 SABLE RADIO-TRACKING GPS Habitat Selection daxing’an Mountains
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Population Characteristics of Dendrolims Superans in Daxing'an Mountains
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作者 孟庆繁 杨晓光 +3 位作者 闫绿光 洪国奇 林同 刘宽余 《Journal of Forestry Research》 SCIE CAS CSCD 1997年第4期227-230,共4页
Dendrolims superans produced one generation every two years Large larvae and small larvae exist at the sametime. lt broke out in Daxiang an Mountains in 1990. and seriously destroyed growth of Larix gmelum Rupr In ord... Dendrolims superans produced one generation every two years Large larvae and small larvae exist at the sametime. lt broke out in Daxiang an Mountains in 1990. and seriously destroyed growth of Larix gmelum Rupr In order to control D Superans.the population properties of D.superans were stedied from 1991 to 1992 including sex ratio.age distribution. pattern etc.. The sex ratio of D. superans population is The larvae age distrihution indicates that larvaeover 5 instar is less than younger larvae under 4 instar in Yongqing forest farm- but the younger larvae under 4 instar is morethan larvae over 5 instar in Hanjiayuanzi Forest Farm. The population of D. superans in Yongqing Farm has heen declining.and incrcasing in Hanjiayuanzi. Pupae and eggs are mainly distributed in middle and lower crowns layer of trees. respec-tively account for 66% and 59.5%, of total individuals. The pupae in higher cown layer is lightly regular distrihution. andclumping distribution middle and lower crowns layer of trees. The eggs in higher crown is light clumpin1g distribution. andrandom in middle and low crown of tree. 展开更多
关键词 Dendrolims superans daxing AN MOUNTAINS POPULATION Characteristics SPECIAL PATTERN METHODS
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Quantitative dynamics on stimulating regeneration and sowing seedlings of Larix gmelinii in Daxing'an Mountains
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作者 徐振邦 代力民 +4 位作者 陈高 潘禄 陈涛 初得志 杨善勋 《Journal of Forestry Research》 SCIE CAS CSCD 2000年第4期231-236,共6页
To understand the quantitative dynamics and death reason of stimulating regeneration seedlings is significant for stimulating the natural regeneration ofLarix gmelinii and implement of conservation project of natural ... To understand the quantitative dynamics and death reason of stimulating regeneration seedlings is significant for stimulating the natural regeneration ofLarix gmelinii and implement of conservation project of natural forest. This paper summarized location observations and directly-seeding simulation experiments of six permanent sample plots that were set up after the seed bumper harvest year ofLarix gmelinii in 1989. The study showed that stimulating natural regeneration seedlings had a large mortality in the first three years, especially in the first year of seedling emergence. After three years seedlings died less and stepped into the stable regeneration stage. A large number of seedlings died of sunscald as the primary death reason. For those areas of good site conditions and rich soil, damping-off would cause seedlings to death in large quantities. The task of stimulating regeneration is mainly to get rid of the litter (forest floor) on burned areas. By means of promoting measures, emergence rate of sown seeds would be several times and dozens of times higher than that of seed shedding on the condition of retention of forest floor. Promoting the regeneration need to select the suitable site against great slope and low-lying lands; at the same time, be careful of the avoidance of frost heaving by depression water. 展开更多
关键词 Larix gmelinii LARCH Stimulating natural regeneration SEEDLINGS Burn area daxing’an Mountains
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Classification,metallogenesis and exploration of silver deposits in Daxing’anling of Inner Mongolia and its adjacent areas
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作者 Biao Jiang Deng-hong Wang +12 位作者 Yu-chuan Chen Tong Zhang Xiu-lang Pu Wen-wen Ma Yan Wang Guang Wu Li-wen Wu Tong Zhang Xue-jiao Li Jie Yan Yu-shan Zuo Hong-jun Sun Zhi-yuan Li 《China Geology》 CAS 2022年第4期595-613,共19页
By the end of 2020,83 silver deposits(or ore occurrences),including four super-large-scale deposits,nine large-scale deposits,33 medium-scale deposits and 37 small-scale deposits or ore occurrences,have been proved.Th... By the end of 2020,83 silver deposits(or ore occurrences),including four super-large-scale deposits,nine large-scale deposits,33 medium-scale deposits and 37 small-scale deposits or ore occurrences,have been proved.The amount of silver metal exceeds 86000 t with average grade of 100 g/t,which makes Daxing’anling region one of the the most important silver ore belt in China.However,the metallogenic characteristics and metallogenesis need to be clarified.The silver deposits in the study area are classified into three main types,which are magmatic hydrothermal vein type,continental volcano-subvolcanic type and skarn type,respectively.The supergiant deposits include the Shuangjianzishan deposit(silver metal amount of 15214 t with average grade of 138 g/t),the Baiyinchagandongshan deposit(silver metal amount of 9446 t with average grade of 187 g/t),the Huaobaote deposit(silver metal amount of 6852 t with average grade of 170 g/t),and the Fuxingtun deposit(silver metal amount of 5240 t with average grade of 196 g/t).The silver deposits are mainly distributed in the central and south of the Daxing’anling area,and mainly formed in the Yanshanian period.The silver polymetallic deposits in the Daxinganling area are significantly controlled by regional faults and the junction zone of volcanic rock basins and their margins.The north-east trending deep faults are the most important ore-controlling structures in this area.The distribution of silver polymetallic deposits along the main faults is obvious,and the intersection area of multiple groups of faults often form important mine catchments.The Permian is the most important ore-bearing formation in this area,but some important silver polymetallic deposits occur in Mesozoic volcanic basins or pre-Mesozoic strata.The magmatic rocks related to mineralization are mainly intermediate acidic or acidic intrusions,intermediate acidic lavas,pyroclastic rocks,and small intrusions of ultra-shallow or shallow facies of the Yanshanian Period.The mineralization element combination is mainly determined by the elemental geochemical background of surrounding rocks or source layers.In addition,the type of deposit,the distance from the mineralization center,and the degree of differentiation of ore-forming rock mass are also important influence factors.The article analyzes the prospecting prospects of each silver deposit type in the study area,discusses the relationship between mineralization center and deep prospecting,and proposes that porphyry silver deposits should be paid attention to.In the prospecting and exploration of silver deposits,comprehensive evaluation and multi-target prospecting need to be strengthened because silver can coexist or be associated with a variety of metals. 展开更多
关键词 Silver deposit Deposit type Porphyry silver deposit Supergiant silver deposit METALLOGENESIS Mineral exploration engineering Prospecting direction daxing’anling Inner Mongolia
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Research on Grade Renewing of Cultivated Land at County Level:A Case Study of Daxing District,Beijing
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作者 MA Jian-hui JIN Jing +2 位作者 WU Ke-ning KOU Zong-miao FU Bo 《Asian Agricultural Research》 2012年第12期55-60,65,共7页
To create a scientific way to renew the grades of cultivated land at county level, monitoring points were set up according to the monitoring control regions and grade types of cultivated land in Daxing District, Beiji... To create a scientific way to renew the grades of cultivated land at county level, monitoring points were set up according to the monitoring control regions and grade types of cultivated land in Daxing District, Beijing, and soil samples were collected to carry out chemical analysis. Afterwards, the input and output data of cultivated land in each village were surveyed to renew the grades of cultivated land. The results indicate that the average natural grade of cultivated land was 8.4, which was equal to that of 2004; the average utilization grade was 8.1, which was slightly higher than that of 2004; the average economic grade was 9.9, which was lower than that of 2004. It is concluded that it is scientific to renew cultivated land grades through scientifically setting monitoring points according to the monitoring control regions and grade types of cultivated land. 展开更多
关键词 LAND management GRADE renewing of CULTIVATED LAND
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Daxing'anling Prefecture:unspoiled Land and a Green Source
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《China Today》 2001年第4期72-77,共6页
关键词 daxing’anling Prefecture:unspoiled Land and a Green Source
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Beijing Daxing Airport is Finally Open
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作者 高洁 《疯狂英语(初中天地)》 2020年第1期16-17,共2页
关键词 Beijing daxing Airport is Finally Open
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基于MIDAS的DAX网络发布技术在油田WebGIS中的应用研究 被引量:2
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作者 刘显德 李欣 +2 位作者 曹闻渊 孙宁 许少华 《微型电脑应用》 2002年第10期11-12,8,共3页
提出了基于 MIDAS的 DAX网络发布技术在Web GIS中的设计方法。该方法在一个共享的中间层上封装了商业规则 ,集中的实现了应用服务器所要实现的功能 ,使客户程序将重点放在显示数据和与用户交互上。将这项技术应用于油田中的地质图绘制方... 提出了基于 MIDAS的 DAX网络发布技术在Web GIS中的设计方法。该方法在一个共享的中间层上封装了商业规则 ,集中的实现了应用服务器所要实现的功能 ,使客户程序将重点放在显示数据和与用户交互上。将这项技术应用于油田中的地质图绘制方面 ,解决了油田中多层分布式异构数据库的访问、管理和地质图件的动态生成问题。研制开发的“基于 Web GIS地质图绘制软件包”在大庆油田推广使用 ,取得了良好的效果。 展开更多
关键词 MIDAS dax 网络发布 WEBGIS 网络地理信息系统 油田勘探
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荧光定量PCR检测牛性别相关基因DAX1表达的标准质粒和标准曲线的构建 被引量:2
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作者 徐超 杜卫华 +5 位作者 王宗礼 余大为 王栋 郝海生 赵学明 朱化彬 《中国畜牧兽医》 CAS 北大核心 2010年第9期94-99,共6页
本研究根据GenBank中登录的剂量敏感的性别反转-先天性肾上腺发育不良基因1(dosage-sensitive sex reversal,adrenal hypoplasia critical region,on chromosome X,gene 1,DAX1)设计引物,构建包含DAX1基因cDNA片段的质粒,作为中国荷斯坦... 本研究根据GenBank中登录的剂量敏感的性别反转-先天性肾上腺发育不良基因1(dosage-sensitive sex reversal,adrenal hypoplasia critical region,on chromosome X,gene 1,DAX1)设计引物,构建包含DAX1基因cDNA片段的质粒,作为中国荷斯坦牛DAX1基因mRNA定量检测的标准品,建立了DAX1基因mRNA表达实时荧光定量PCR检测方法。结果表明,该方法特异性好,检测灵敏度达102拷贝,线性范围为102~106拷贝,阈值循环数(Ct)与PCR体系中起始模板量的对数值间有着良好的线性关系(r=0.99975),扩增效率高(E=100%),可以作为检测牛DAX1基因mRNA定量检测方法。 展开更多
关键词 牛生殖嵴 dax1 荧光定量PCR TAQMAN探针 标准曲线
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2个先天性肾上腺发育不良家系中DAX-1基因的新突变 被引量:1
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作者 郭茂华 秦贵军 +3 位作者 栗夏连 吉鸿飞 马笑堃 王丹萍 《河南医学研究》 CAS 2013年第6期801-804,共4页
目的:探讨2个X-连锁先天性肾上腺发育不良家系的临床特征,检测患者及其家属中是否存在DAX-1基因突变。方法:对2个家系中4例患者分别进行相关医学检查获取临床资料,并取得所有患者及其家系成员的外周血标本;提取全血基因组DNA,PCR扩增DA... 目的:探讨2个X-连锁先天性肾上腺发育不良家系的临床特征,检测患者及其家属中是否存在DAX-1基因突变。方法:对2个家系中4例患者分别进行相关医学检查获取临床资料,并取得所有患者及其家系成员的外周血标本;提取全血基因组DNA,PCR扩增DAX-1基因的2个外显子,包括外显子和内含子边界,扩增产物经纯化后直接测序进行基因检测。测序结果在核苷酸序列数据库进行比较分析。结果:1个家系中的3例患者(均为青春期前发病)DAX-1基因第1外显子处均存在119-120insT半合子移码突变,家系中有2例女性为此突变的杂合子;另1个家系中的1例患者(青春期发病)DAX-1基因第1外显子处存在993delC半合子移码突变,家系中有3例女性为此突变的杂合子。结论:在2个中国先天性肾上腺发育不良家系中发现DAX-1新的移码突变119-120insT和993delC。 展开更多
关键词 dax-1基因突变 先天性肾上腺发育不良 低促性腺激素性性腺功能减退
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内蒙古大兴安岭林火时空动态的变化特征
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作者 班擎宇 贾超 +1 位作者 王悦宇博 张恒 《林业工程学报》 CSCD 北大核心 2024年第2期116-123,共8页
内蒙古大兴安岭森林火灾频发,研究其季节性变化趋势及空间动态分布特征,对今后该地区森林防火期划分和防火资源的合理分配具有重要意义。利用Mann-Kendall趋势检验法、滑动t检验法对1981—2018年内蒙古大兴安岭森林火灾数据进行趋势和... 内蒙古大兴安岭森林火灾频发,研究其季节性变化趋势及空间动态分布特征,对今后该地区森林防火期划分和防火资源的合理分配具有重要意义。利用Mann-Kendall趋势检验法、滑动t检验法对1981—2018年内蒙古大兴安岭森林火灾数据进行趋势和突变分析,使用分位数回归法研究影响森林火灾过火面积的时间与空间因素,得出内蒙古大兴安岭森林火灾在时间和空间上的动态变化特征。结果表明:内蒙古大兴安岭森林火灾整体呈先下降(1981—1999年)再上升(2000—2007年)又下降(2008—2018年)的趋势。森林火灾主要发生在春、夏、秋三季,春季森林火灾变化较复杂,波动明显,在1991年发生突变;秋季森林火灾波动较平缓,但在1994年发生突变;2004—2011年期间夏季森林火灾明显增长,火险期向夏季发生偏移和延长;冬季发生火灾较少。森林火灾过火面积与火灾持续时间呈正相关,尤其在高分位点处,正相关性更加显著。内蒙古大兴安岭森林火灾主要发生在鄂伦春自治旗等地,从空间横向动态变化来看,整体呈现由西南向东北递增的趋势;从空间纵向动态变化来看,海拔对森林火灾过火面积的影响并不显著。建议应加强内蒙古大兴安岭东北地区及春、夏两季的林火监测和防火宣传,适当调整森林防火期和防火资源时空分配,将有助于减少内蒙古大兴安岭森林火灾的发生。 展开更多
关键词 内蒙古大兴安岭 森林火灾 过火面积 时空分布 林火监测 防火期
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ERA5资料在蓟州复杂地形下的检验与应用
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作者 邹双泽 白爱娟 +3 位作者 何科 金海东 黄金颖 金波 《海洋气象学报》 2024年第1期118-128,共11页
以复杂地形的天津蓟州为例,通过对比距离蓟州最近的大兴探空站资料与欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts, ECMWF)第五代大气再分析(ECMWF Reanalysis v5,ERA5)资料的差异,对基于ERA5资料生成的... 以复杂地形的天津蓟州为例,通过对比距离蓟州最近的大兴探空站资料与欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts, ECMWF)第五代大气再分析(ECMWF Reanalysis v5,ERA5)资料的差异,对基于ERA5资料生成的强对流指数在蓟州的适用性进行检验和评估。结果表明:(1)ERA5资料与大兴探空站探测的位势高度、气温和风速在对流层高度吻合,说明ERA5资料能够描述蓟州高空气象条件,且对低空的表现能力比高空准确,各要素中大气湿度的表现相对较差;(2)基于ERA5生成的对流指数中,与强对流天气密切相关的对流有效位能(convective available potential energy, CAPE)、K指数、沙瓦特指数(Showalter index, SI)和大气可降水量(precipitable water, PW)与大兴探空站对应参数的相关系数分别达到0.66、0.90、0.93和0.99,表明利用ERA5构建的对流指数能够揭示大气不稳定层结条件;(3)ERA5对流指数变化与蓟州降水过程相对应,ERA5能够反映天气的变化和发展,为强对流潜势分析提供参考。 展开更多
关键词 蓟州 大兴探空站 ERA5资料 高空探测 强对流指数
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大兴安岭沿麓黑土区翻耕农田微立垡覆盖阻风减蚀技术创新与应用
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作者 张向前 师晶晶 +6 位作者 戎美仁 路战远 任永峰 程玉臣 张德健 孟天天 郝楠森 《北方农业学报》 2024年第2期107-114,共8页
大兴安岭沿麓是我国重要的农畜产品生产基地,由于长期过度耕作和单一翻耕等不合理的耕作方式,加速了该地区农田风蚀退化、质量下降和产能降低,因此,减少土壤风蚀、提升农田地力和作物产量是农业可持续发展亟待解决的问题。文章综述了不... 大兴安岭沿麓是我国重要的农畜产品生产基地,由于长期过度耕作和单一翻耕等不合理的耕作方式,加速了该地区农田风蚀退化、质量下降和产能降低,因此,减少土壤风蚀、提升农田地力和作物产量是农业可持续发展亟待解决的问题。文章综述了不同类型生态区传统翻耕、长期免耕、合理轮耕技术及其应用效果,论述了翻耕地微立垡覆盖阻风减蚀核心技术的内容及其对土壤风蚀、蓄水保墒、作物生长与产量等方面的影响,明确了微立垡覆盖是大兴安岭沿麓黑土区翻耕地冬春季风蚀防控的关键技术和途径。翻耕地微立垡覆盖阻风减蚀技术大面积应用效果显著,破解了长期以来翻耕农田裸露风蚀重、水土流失损失大导致农田逐步退化的科技难题,为大兴安岭沿麓及其生态类型相似区翻耕农田风蚀防控研究提供了重要支撑。 展开更多
关键词 大兴安岭沿麓 黑土区 翻耕农田 微立垡覆盖 阻风减蚀技术
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高分辨率InSAR技术在北京大兴国际机场形变监测中的应用
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作者 赵霞 马新岩 +1 位作者 余虔 王招冰 《自然资源遥感》 CSCD 北大核心 2024年第1期49-57,共9页
北京大兴国际机场位于大兴榆垡—礼贤地区,是北京市五大区域地面沉降区之一,不均匀的形变会对机场的安全稳定运行产生影响。文章基于时间序列InSAR技术,利用2019年9月—2021年11月间39景高分辨率COSMO-SkyMed SAR影像,获取了北京大兴国... 北京大兴国际机场位于大兴榆垡—礼贤地区,是北京市五大区域地面沉降区之一,不均匀的形变会对机场的安全稳定运行产生影响。文章基于时间序列InSAR技术,利用2019年9月—2021年11月间39景高分辨率COSMO-SkyMed SAR影像,获取了北京大兴国际机场形变信息的时空特征,监测结果精度较高,与水准监测结果基本吻合。结果表明,北京大兴国际机场的沉降在2019—2021年持续发展,最大沉降速率为-47.5 mm/a,最大累积沉降量达到-103.84 mm,4条跑道均存在不均匀沉降。进一步详细分析了跑道在时间、空间上的形变特征,以及航站楼、维修机坪、油罐区、公务机坪等其他形变较大区域的形变信息,并结合地基处理方式对影响沉降的驱动因素进一步分析。文章可为大兴机场的安全平稳运营提供参考。 展开更多
关键词 时序InSAR 形变监测 北京大兴国际机场 COSMO-SkyMed 影响因素
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DAX-1基因突变导致先天性肾上腺发育不良的临床分析
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作者 樊大贝 李志臻 张好好 《河南医学研究》 CAS 2020年第14期2500-2503,共4页
目的分析X连锁先天性肾上腺发育不良的临床表现和分子水平改变情况,讨论基因突变和临床表型变化的关系及可能机制。方法搜集先证者和家系成员的临床资料,明确诊断先证者的疾病名称;根据病史绘制系谱图分析遗传方式,运用二代测序方法检... 目的分析X连锁先天性肾上腺发育不良的临床表现和分子水平改变情况,讨论基因突变和临床表型变化的关系及可能机制。方法搜集先证者和家系成员的临床资料,明确诊断先证者的疾病名称;根据病史绘制系谱图分析遗传方式,运用二代测序方法检测基因突变。结合先证者的临床表现和体内激素分泌的结果,给予药物治疗后连续观察3个月先证者的临床表现、体内激素水平的变化及影像学的改变。结果先证者确诊为X连锁先天性肾上腺发育不良,此家系为常染色体隐性遗传,通过基因测序发现DAX-1基因新的突变位点(c.214G>C)。经过3个月的糖皮质激素和盐皮质激素治疗后,观察该患者对应的临床表现、生化指标和激素指标等均明显转好,趋于康复水平。结论新的DAX-1基因突变位点c.214G>C可造成X连锁先天性肾上腺发育不良,通过药物治疗可缓解患者临床症状。 展开更多
关键词 先天性肾上腺发育不良 dax-1基因 错义突变 药物治疗
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大兴安岭东部林区天然林主要树种胸径生长模型构建
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作者 高明 刘奇峰 +1 位作者 朱万才 潘研 《现代农业研究》 2024年第6期95-99,共5页
预测大兴安岭地区天然林主要树种胸径生长对未来该地区森林动态监测和规划管理具有重要意义。本研究以大兴安岭东部林区全区1034块三期连续清查数据为研究对象,使用5种常见的模型形式作为基础模型,对8个天然树种调查数据进行拟合,最终... 预测大兴安岭地区天然林主要树种胸径生长对未来该地区森林动态监测和规划管理具有重要意义。本研究以大兴安岭东部林区全区1034块三期连续清查数据为研究对象,使用5种常见的模型形式作为基础模型,对8个天然树种调查数据进行拟合,最终构建了8个天然主要树种的胸径预测模型。使用总相对误差(R_(S)),决定系数(R~2)、平均相对误差(■)、预估精度(P)、L值(L)5个指标对8种天然林主要树种的5个拟合模型的拟合效果进行评估。最终结果表明M1模型是樟子松、山杨和黑桦的最优胸径预测模型,M5模型是兴安落叶松、河岸杨柳、云杉、白桦和柞木的最优胸径预测模型。本研究所构建的大兴安岭地区天然林8个主要树种的胸径生长模型拟合效果较好,能有效为未来森林生长动态预测提供支持。 展开更多
关键词 大兴安岭 胸径生长模型 天然林
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特大城市平原区高速公路纵断设计要点——北京市大兴国际机场北线高速设计实践
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作者 尹传军 《黑龙江交通科技》 2024年第7期6-10,共5页
为进一步明确特大城市平原区高速公路纵断设计比选重点和影响因素,以北京市大兴国际机场北线高速设计实践为例,重点通过磁大路—京台高速段、上跨京九铁路段、上跨芦求路南延路段和穿越现状深坑段4处典型段落阐述了纵断比选过程,得出影... 为进一步明确特大城市平原区高速公路纵断设计比选重点和影响因素,以北京市大兴国际机场北线高速设计实践为例,重点通过磁大路—京台高速段、上跨京九铁路段、上跨芦求路南延路段和穿越现状深坑段4处典型段落阐述了纵断比选过程,得出影响特大城市平原区高速公路纵断设计各因素的重要程度由大到小依次为:总体规划、地区经济发展、技术可行性、永久基本农田、对其他工程的影响、运营风险、工程造价、环境景观影响。总结特大城市平原区高速公路纵断设计要点,为其它同类工程设计提供参考。 展开更多
关键词 道路工程 纵断设计 大兴国际机场北线高速公路
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全年制冷系统冷却塔防絮研究
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作者 曹培隆 《科学技术创新》 2024年第2期81-84,共4页
信息数据机房内信息设备运行期间产生大量的热量,为确保机房温湿度环境,保障信息设备运行安全,通常设计全年制冷系统为末端信息机房提供冷源供应。在北京,每年3月-5月为“飘絮”季,大量的杨絮、柳絮极易吸入冷却塔进行循环系统,导致冷... 信息数据机房内信息设备运行期间产生大量的热量,为确保机房温湿度环境,保障信息设备运行安全,通常设计全年制冷系统为末端信息机房提供冷源供应。在北京,每年3月-5月为“飘絮”季,大量的杨絮、柳絮极易吸入冷却塔进行循环系统,导致冷水机组出现“无水流”停机故障,影响系统能源供应,严重时可能导致末端信息机房设备超温、数据丢失等严重情况。为此,本文以北京大兴国际机场信息中心ITC全年制冷系统为实例,开展对冷却塔防絮装置的一系列研究,研发出一套立体式防絮装置,并对防护效果与影响风量之间的平衡关系开展试验研究,实现最佳的防絮效果。 展开更多
关键词 数据机房 全年制冷系统 冷却塔 防絮 大兴机场
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