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泥炭沼泽学若干基本概念的再认识 被引量:12
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作者 卜兆君 王升忠 谢宗航 《东北师大学报(自然科学版)》 CAS CSCD 北大核心 2005年第2期105-110,共6页
 综合国内外有关研究成果,比较和区别了泥炭沼泽学的若干基本概念.泥炭沼泽是自然或人为干扰较少的积累泥炭的生态系统,而泥炭地则可以有较强人为干扰.雨养泥炭沼泽营养补给主要源于大气降水,矿养泥炭沼泽则主要接受地表水和地下水补给...  综合国内外有关研究成果,比较和区别了泥炭沼泽学的若干基本概念.泥炭沼泽是自然或人为干扰较少的积累泥炭的生态系统,而泥炭地则可以有较强人为干扰.雨养泥炭沼泽营养补给主要源于大气降水,矿养泥炭沼泽则主要接受地表水和地下水补给.部分木本植物沼泽和挺水植物沼泽属于泥炭沼泽的范畴,但在北半球,挺水植物沼泽并非主要的积累泥炭的湿地类型.低、中和高位泥炭沼泽是针对泥炭沼泽的地貌形态而言的,不应与泥炭沼泽的发育阶段建立普遍而严格的联系.富、中和贫营养泥炭沼泽概念的使用应慎重,只有通过水化学测试才能准确确定泥炭沼泽的营养状况.同时浅析了造成泥炭沼泽学中若干概念混淆或误解的主要原因. 展开更多
关键词 泥炭沼泽 雨养泥炭沼泽 矿养泥炭沼泽 木本植物沼泽 挺水植物沼泽
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酮咯酸氨丁三醇复合芬太尼用于胸科手术术后镇痛的观察 被引量:12
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作者 李红新 詹锦六 劳燕萍 《临床肺科杂志》 2011年第8期1188-1189,共2页
目的观察酮咯酸氨丁三醇复合芬太尼用于胸科手术的镇痛效果。方法择期行胸科手术患者75例,随机分为A、B、C三组,术毕行PC IA镇痛。A组镇痛药物为酮咯酸氨丁三醇4 mg/kg,B组为酮咯酸氨丁三醇3 mg/kg、芬太尼4 ug/kg,C组为芬太尼10ug/kg,... 目的观察酮咯酸氨丁三醇复合芬太尼用于胸科手术的镇痛效果。方法择期行胸科手术患者75例,随机分为A、B、C三组,术毕行PC IA镇痛。A组镇痛药物为酮咯酸氨丁三醇4 mg/kg,B组为酮咯酸氨丁三醇3 mg/kg、芬太尼4 ug/kg,C组为芬太尼10ug/kg,均用0.9%生理盐水稀释至100m l。记录0、8、16、24h VAS评分及不良反应。结果术后0 h A、B组评分低于C组(P<0.05);术后8、16、24h B组C组评分低于A组(P<0.05);A、B组术后24h出现不良反应例数少于C组(P<0.05)。结论酮咯酸氨丁三醇复合芬太尼用于胸科手术后PCIA效果良好,降低了芬太尼所致不良反应的发生率。 展开更多
关键词 酮咯酸氨丁三醇 芬太尼 术后镇痛
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吉林省敦化地区晚全新世泥炭沼泽孢粉组合特征及古植被 被引量:8
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作者 赵红艳 周道玮 《应用生态学报》 CAS CSCD 北大核心 2006年第2期197-200,共4页
对大桥泥炭地的孢粉进行了分析和年龄测定,根据孢粉组合、地层特征和^14C年龄将剖面划分为4个孢粉带,分别为2195±70~2045±70yr B.P.松为主的松.云冷杉-榛-栎-苔草组合带、2045±70~1745±70yr B.P.苔草为主... 对大桥泥炭地的孢粉进行了分析和年龄测定,根据孢粉组合、地层特征和^14C年龄将剖面划分为4个孢粉带,分别为2195±70~2045±70yr B.P.松为主的松.云冷杉-榛-栎-苔草组合带、2045±70~1745±70yr B.P.苔草为主的松-桦-榛-胡桃-苔草组合带、1745±70~705±70yr B.P.松-榛.鹅耳枥-苔草.毛茛组合带和705±70yr B.P.~1950yr A.D.松-云冷杉-桦-苔草组合带.周围植被由温带山地针叶林(类似现今海拔1100m以上)、温带针阔混交林下部(类似现今海拔400~600m)和温带针阔混交林中部(类似现今海拔600~800m)过渡到温带针阔混交林上部(类似现今海拔800~1100m).相应地,泥炭沼泽经历了孕育期、蓬勃发展期、继续扩张期和消亡期. 展开更多
关键词 泥炭沼泽 孢粉组合 古植被 晚全新世 长白山区
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ANSYS在永磁电机转子强度接触有限元分析中的应用 被引量:10
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作者 姜彤 李殿起 韩立 《机械设计与制造》 北大核心 2008年第11期87-89,共3页
扼要地介绍了ANSYS有限元软件求解接触问题时涉及到的基本概念和原理,介绍了接触有限元分析的具体步骤。应用大型有限元分析软件ANSYS,考虑永磁电机转子中永磁体和转子铁心的接触非线性状态,对永磁电机转子进行了三维有限元分析,得出了... 扼要地介绍了ANSYS有限元软件求解接触问题时涉及到的基本概念和原理,介绍了接触有限元分析的具体步骤。应用大型有限元分析软件ANSYS,考虑永磁电机转子中永磁体和转子铁心的接触非线性状态,对永磁电机转子进行了三维有限元分析,得出了永磁电机转子的应力分布情况。整个分析求解过程也为类似的接触有限元分析提供了参考。 展开更多
关键词 永磁电机 转子 接触 有限元 分析
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经方度量衡之“分”探讨 被引量:9
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作者 董艳 王阶 《时珍国医国药》 CAS CSCD 北大核心 2017年第2期421-422,共2页
经方的桴鼓之效与其药物剂量密不可分,正如清·王清任《医林改错》所言:"药味要紧,分两更要紧",而正确把握经方剂量的关键在于古今度量衡的换算,故近年来人们对经方剂量单位问题研究颇多,尤以"两""斤"... 经方的桴鼓之效与其药物剂量密不可分,正如清·王清任《医林改错》所言:"药味要紧,分两更要紧",而正确把握经方剂量的关键在于古今度量衡的换算,故近年来人们对经方剂量单位问题研究颇多,尤以"两""斤"及"尺"为著,唯独"分"这一单位阐述较少,而争议较多,故本文主要探讨度量衡"分"的几种不同含义,并结合经方原文阐述其实际意义。 展开更多
关键词 经方 度量衡
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发动机飞轮壳强度有限元分析 被引量:8
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作者 刘晓明 杨晓翔 韦铁平 《机械设计与制造》 北大核心 2015年第11期239-242,共4页
根据某公司提供的出现断裂的飞轮壳模型,利用有限元法对飞轮壳结构进行两种不同受力情况下的强度分析。首先,通过ANSA与ANSYS软件接口,准确建立飞轮壳结构的有限元计算模型,对其进行静力学分析,计算出两种受力情况下多种不同工况飞轮壳... 根据某公司提供的出现断裂的飞轮壳模型,利用有限元法对飞轮壳结构进行两种不同受力情况下的强度分析。首先,通过ANSA与ANSYS软件接口,准确建立飞轮壳结构的有限元计算模型,对其进行静力学分析,计算出两种受力情况下多种不同工况飞轮壳的应力分布规律。其次,将仿真分析结果与裂纹实际发生位置进行对比,得到与实际情况最接近的加载方式。最后,根据模拟结果分析飞轮壳断裂的原因。分析结果为飞轮壳的设计与改进提供有益的参考,可节省产品开发周期。 展开更多
关键词 飞轮壳 裂纹 有限元法 强度分析
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Plant Programmed Cell Death Caused by an Autoactive Form of Prf Is Suppressed by Co-Expression of the Prf LRR Domain 被引量:4
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作者 Xinran Du Min Miao +4 位作者 Xinrong Ma Yongsheng Liu Joseph C. Kuhl Gregory B. Martin Fangming Xiao 《Molecular Plant》 SCIE CAS CSCD 2012年第5期1058-1067,共10页
In tomato, the NBARC-LRR resistance (R) protein Prf acts in concert with the Pto or Fen kinase to determine immunity against Pseudomonas syringae pv. tomato (Pst). Prf-mediated defense signaling is initiated by th... In tomato, the NBARC-LRR resistance (R) protein Prf acts in concert with the Pto or Fen kinase to determine immunity against Pseudomonas syringae pv. tomato (Pst). Prf-mediated defense signaling is initiated by the recognition of two sequence-unrelated Pst-secreted effector proteins, AvrPto and AvrPtoB, by tomato Pto or Fen. Prf detects these inter- actions and activates signaling leading to host defense responses including localized programmed cell death (PCD) that is associated with the arrest of Pst growth. We found that Prf variants with single amino acid substitutions at D1416 in the IHD motif (isoleucine-histidine-aspartic acid) in the NBARC domain cause effector-independent PCD when transiently expressed in leaves of Nicotiana benthamiana, suggesting D1416 plays an important role in activation of Prf. The N-ter- minal region of Prf (NPrf) and the LRR domain are required for this autoactive Prf cell death signaling but dispensable for accumulation of the PrfD1416V protein. Significantly, co-expression of the Prf LRR but not NPrf, with PrfD1416v, AvrPto/Pto, AvrPtoB/Pto, an autoactive form of Pro (PtoY207D), or Fen completely suppresses PCD. However, the Prf LRR does not in- terfere with PCD caused by Rpi-blblD475v a distinct R protein-mediated PCD signaling event, or that caused by overex- pression of MAPKKKα, a protein acting downstream of Prf. Furthermore, we found the PrfD1416V protein is unable to accumulate in plant cells when co-expressed with the Prf LRR domain, likely explaining the cell death suppression. The mechanism for the LRR-induced degradation of PrfD1416V is unknown but may involve interference in the intramo- lecular interactions of Prf or to binding of the unattached LRR to other host proteins that are needed for Prf stability. 展开更多
关键词 NBARC-LRR resistance protein PRF Pto fen AvrPto AvrPtoB cell death.
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Liuzhou Luosifen goes global
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作者 王莹 《疯狂英语(新读写)》 2024年第9期48-49,77,共3页
Activity 1.Think about the following questions and write down your answers before reading the text.1.Have you ever tried Liuzhou Luosifen?If so,what did you think of it?2.What makes Liuzhou Luosifen unique compared to... Activity 1.Think about the following questions and write down your answers before reading the text.1.Have you ever tried Liuzhou Luosifen?If so,what did you think of it?2.What makes Liuzhou Luosifen unique compared to other types of noodles? 展开更多
关键词 tried fen Liuzhou
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Independent and Combined Associations of Sleep Duration, Bedtime, and Polygenic Risk Score with the Risk of Hearing Loss among Middle-Aged and Old Chinese: The Dongfeng–Tongji Cohort Study
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作者 Miao Liu Haiqing Zhang +8 位作者 Zhichao Wang Tingting Mo Xuefeng Lai Yaling He Minghui Jiang Meian He Weijia Kong Tangchun Wu Xiaomin Zhang 《Research》 SCIE EI CSCD 2024年第1期721-733,共13页
Evidence available on the independent and combined associations of sleep duration,bedtime,and genetic predisposition with hearing loss was lacking.The present study included 15,827 participants from the Dongfeng–Tong... Evidence available on the independent and combined associations of sleep duration,bedtime,and genetic predisposition with hearing loss was lacking.The present study included 15,827 participants from the Dongfeng–Tongji cohort study.Genetic risk was characterized by polygenic risk score(PRS)based on 37 genetic loci related to hearing loss.We conducted multivariate logistic regression models to assess the odds ratio(OR)for hearing loss with sleep duration and bedtime,as well as the joint association and interaction with PRS.Results showed that hearing loss was independently associated with sleeping≥9 h/night compared to the recommended 7 to<8 h/night,and with bedtime≤9:00 p.m.and>9:00 p.m.to 10:00 p.m.compared to those with bedtime>10:00 p.m.to 11:00 p.m.,with estimated ORs of 1.25,1.27,and 1.16,respectively. 展开更多
关键词 Middle hearing fen
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论我国现代货币单位“元、角、分”体系的确立 被引量:2
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作者 张宁 《史学月刊》 CSSCI 北大核心 2005年第2期43-48,共6页
18世纪中叶以降 ,中国货币制度的近代化渐次展开。新的货币单位———“元、角、分”体系随之出现 ,在与传统货币单位的竞争中不断发展 ,1910年成为法定货币单位。通过北洋政府和国民党政府的努力 ,“元、角、分”体系的地位最终得以确... 18世纪中叶以降 ,中国货币制度的近代化渐次展开。新的货币单位———“元、角、分”体系随之出现 ,在与传统货币单位的竞争中不断发展 ,1910年成为法定货币单位。通过北洋政府和国民党政府的努力 ,“元、角、分”体系的地位最终得以确立 。 展开更多
关键词 货币制度 近代化
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Natural Variation of Pto and Fen Genes and Marker-Assisted Selection for Resistance to Bacterial Speck in Tomato 被引量:2
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作者 SUN Wan-yu ZHAO Wan-ying WANG Yuan-yuan PEI Cheng-cheng YANG Wen-cai 《Agricultural Sciences in China》 CAS CSCD 2011年第6期827-837,共11页
The resistance in tomato plants to bacterial speck caused by Pseudomonas syringae pv. tomato is triggered by the interactions between the plant resistance protein Pto and the pathogen avirulence proteins AvrPto or Avr... The resistance in tomato plants to bacterial speck caused by Pseudomonas syringae pv. tomato is triggered by the interactions between the plant resistance protein Pto and the pathogen avirulence proteins AvrPto or AvrPtoB. Fen is a gene encoding closely related functional protein kinases as the Pto gene. To investigate the status of resistance to the pathogen and natural variation of Pto and Fen genes in tomato, 67 lines including 29 growing in China were subject to disease resistance evaluation and fenthion-sensitivity test. Alleles of Pto and Fen were amplified from genomic DNA of 25 tomato lines using polymerase chain reaction (PCR) and sequences were determined by sequencing the PCR products. The results indicated that none of the 29 cultivars/hybrids growing in China were resistant to bacterial speck race 0 strain DC3000. Seven of eight tomato lines resistant to DC3000 were also fenthion-sensitive. Analysis of deduced amino acid sequences identified three novel residue substitutions between Pto and pto, and one new substitution identified between Fen and fen. A PCR-based marker was developed and successfully used to select plants with resistance to DC3000. 展开更多
关键词 TOMATO bacterial speck PTO fen natural variation marker-assisted selection
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Impact of Ecological Corridor Construction on Urban Space-A Case Study of Fen River Park in Taiyuan City 被引量:2
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作者 ZHAO Fang 《Journal of Landscape Research》 2013年第4期23-24,28,共3页
With the city development and construction, ecological corridor has become one of the most attractive areas in urban districts. Ecological corridor has produced not only ecological benefits, but also economic benefits... With the city development and construction, ecological corridor has become one of the most attractive areas in urban districts. Ecological corridor has produced not only ecological benefits, but also economic benefits and social benefits, especially banded ecological park. By analyzing the impact of Fen River Park on leisure space, living space, communication space, commercial space of Taiyuan, and expounding shortcomings of constructing Fen River Ecological Corridor, countermeasures and suggestions were put forward. 展开更多
关键词 Urban space CORRIDOR IMPACT study fen RIVER PARK
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宁化客家方言的被动标记
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作者 巫细水 覃东生 《牡丹江教育学院学报》 2023年第8期13-17,97,共6页
文章主要考察了宁化客家方言的三个被动标记“分[p n 44]”、“畀[pei 31]”、“得[t 5]”。描写了其在宁化客家方言中的基本用法,同时,探讨了宁化客家方言中被动句的基本类型、构成成分的主要特征以及被动句式的语义色彩,并探究了宁化... 文章主要考察了宁化客家方言的三个被动标记“分[p n 44]”、“畀[pei 31]”、“得[t 5]”。描写了其在宁化客家方言中的基本用法,同时,探讨了宁化客家方言中被动句的基本类型、构成成分的主要特征以及被动句式的语义色彩,并探究了宁化客家方言被动标记的语法化来源和归纳其语法化路径。 展开更多
关键词 宁化客家方言 被动标记 “分” “畀” “得”
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载荷频率对690(TT)合金腐蚀疲劳裂纹扩展行为的影响 被引量:4
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作者 付正鸿 陈辉 +4 位作者 苟国庆 肖军 邱绍宇 刘锦云 查五生 《材料热处理学报》 EI CAS CSCD 北大核心 2016年第2期36-41,共6页
通过研究载荷频率变化对690(TT)合金在含饱和氧的模拟压水堆一回路水环境中腐蚀疲劳裂纹扩展行为的影响,得到以下结论:随着载荷频率的降低,裂纹扩展速率(CGR)和环境影响因子(F_(en))均随之增大;裂纹扩展路径为穿晶型,在频率较低或应力比... 通过研究载荷频率变化对690(TT)合金在含饱和氧的模拟压水堆一回路水环境中腐蚀疲劳裂纹扩展行为的影响,得到以下结论:随着载荷频率的降低,裂纹扩展速率(CGR)和环境影响因子(F_(en))均随之增大;裂纹扩展路径为穿晶型,在频率较低或应力比R较大时出现较多的支裂纹;断口呈典型的腐蚀疲劳断裂特征,裂纹在三维空间中扩展,可观察较多的微裂纹。 展开更多
关键词 690(TT)合金 载荷频率 腐蚀疲劳裂纹扩展 环境影响因子
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Day Tripper:Shenzhen's Dafen Oil Painting Village
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作者 Rakini Bergundy 《城市漫步(GBA版)》 2023年第8期16-17,共2页
Aswe embarked on our half-day escapadetotheenigmaticDafen Oil PaintingVillage,awhirlwindof emotions swirled within us.Excitement mingled witha tingeof skepticism;could this renowned art factory truly live up to the my... Aswe embarked on our half-day escapadetotheenigmaticDafen Oil PaintingVillage,awhirlwindof emotions swirled within us.Excitement mingled witha tingeof skepticism;could this renowned art factory truly live up to the mystical allure we had heard about?In the late1980s,anentrepreneurial trade painternamed Huang Jiangmade a daringmove,relocating his business from HongKong to the outskirts of Shenzhen.Little did he know that this decision would set Dafenona remarkable trajectory to become the world's art factory. 展开更多
关键词 fen PAINTING locating
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恒加速度离心机转臂的稳健设计方法 被引量:4
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作者 冉光斌 《机械设计与制造》 北大核心 2008年第5期5-7,共3页
在对恒加速度离心机转臂结构参数取值范围粗略估计的基础上,安排以Pro/E软件实现的正交数值实验,并用正交多项式拟合出各主要参数对转臂重量、转臂所受最大应力和转臂最大位移的响应面模型。然后,以转臂的重量为优化目标,而以转臂所受... 在对恒加速度离心机转臂结构参数取值范围粗略估计的基础上,安排以Pro/E软件实现的正交数值实验,并用正交多项式拟合出各主要参数对转臂重量、转臂所受最大应力和转臂最大位移的响应面模型。然后,以转臂的重量为优化目标,而以转臂所受的最大应力和最大位移量为约束条件,对响应面模型进行优化,找出转臂最合理的结构参数组合,并用有限元软件对优化结构所受最大应力和最大位移进行验证。计算结果表明转臂以Pro/E为基础的稳健设计,可提高设计效率,并得到满意的设计结果。 展开更多
关键词 稳健设计 PRO/E 有限元法 响应面法
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Fe_n,Co_n和Ni_n(n=2~4)分子团簇的自旋极化效应 被引量:1
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作者 江海 阎世英 周旭波 《青岛大学学报(自然科学版)》 CAS 2010年第1期50-53,共4页
采用密度泛函理论中的交换关联函数B3P86,对Fen,Con和Nin(n=2~4)分子团簇进行了几何结构的优化。对于每一个分子体系,为了能找到具有最低能量的结构,分别考虑多种同分异构体和不同的多重度,最终得到它们的基态结构、键长和键能... 采用密度泛函理论中的交换关联函数B3P86,对Fen,Con和Nin(n=2~4)分子团簇进行了几何结构的优化。对于每一个分子体系,为了能找到具有最低能量的结构,分别考虑多种同分异构体和不同的多重度,最终得到它们的基态结构、键长和键能。结果表明:Fen,Con和Nin(n=2~4)分子的最低能量随着多重性的增加而降低,这种电子自旋的非平衡性显示出自旋极化效应。 展开更多
关键词 fen CON Nin 自旋极化 密度泛函理论
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荀子“分”思想对孔孟儒家思想的推拓——兼论荀子“分”思想的时代意义 被引量:3
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作者 陈伟 《齐鲁学刊》 CSSCI 北大核心 2011年第1期12-16,共5页
"分"是荀子政治法律思想研究中被忽视的关键范畴,是其思想的重要落脚点。在先秦时期,荀子第一个把"分"发展成型构思想体系的基石性概念,"分"也体现了荀子有异于孔孟儒家的独特致思取向。荀子的"分&q... "分"是荀子政治法律思想研究中被忽视的关键范畴,是其思想的重要落脚点。在先秦时期,荀子第一个把"分"发展成型构思想体系的基石性概念,"分"也体现了荀子有异于孔孟儒家的独特致思取向。荀子的"分"思想是对孔孟儒家思想的重要推拓,在当代社会仍然具有重要的时代意义。 展开更多
关键词 荀子 孔孟儒家
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Pig Manure Systems in Germany and China and the Impact on Nutrient Flow 被引量:3
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作者 F. Schuchardtl, T. Jiang T. Jiang +1 位作者 G. X. Li R. Mendoza Huaitalla 《Journal of Agricultural Science and Technology(A)》 2011年第6期858-865,共8页
Germany and China use different stable systems for fattening pigs. Widespread systems in Germany are closed stables with slatted or partly slatted floor, which produce liquid manure (a mixture of urine, faeces, and c... Germany and China use different stable systems for fattening pigs. Widespread systems in Germany are closed stables with slatted or partly slatted floor, which produce liquid manure (a mixture of urine, faeces, and cleaning water) whereas in China open stables with closed concrete floors are used with separate collection of faeces and urine. Based on data from literature and own analyses nutrient flows of both systems are calculated. The Chinese manure system or mechanized belt or V-shaped pit floor systems with faeces/urine separation are more effective to separate solids, nutrients, carbon, and heavy metal than mechanical separation from liquid manure. The separation rates can be up to 88% for the solids, 67% for nitrogen, 93% for phosphorus, 60% for potassium, 94% for magnesium, 97% for cupper, and 98% for zinc. The faeces can be used for composting to produce a market product. 展开更多
关键词 Pig manure China GERMANY nutrient flow fattening pigs gan qing fen.
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A finite-element simulation of 2008 Wenchuan earthquake and implications for numerical earthquake prediction
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作者 Zhu Shoubiao 《Geodesy and Geodynamics》 2011年第2期39-42,共4页
The dynamic process of the 2008 Wenehuan earthquake is simulated by finite-element method ( FEM), and the results suggest that we may be able to estimate the occurrence time, location, and magnitude of similar earth... The dynamic process of the 2008 Wenehuan earthquake is simulated by finite-element method ( FEM), and the results suggest that we may be able to estimate the occurrence time, location, and magnitude of similar earthquakes in the future. Thus a numerical earthquake prediction (NEP) program is proposed; the reliability of it is dependent on its gradual refinement and the parameters used in the models. 展开更多
关键词 fen simulation numerical earthquake prediction Wenchuan earthquake
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