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不同围压下岩石中泊松比的各向异性 被引量:55
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作者 刘斌 席道瑛 +3 位作者 葛宁洁 王宝善 H. Kern T. popp 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2002年第6期880-890,共11页
由弹性波纵横波速比计算得到的泊松比 ,在利用地震波反演地下结构和物质组成时 ,可以提供比单纯地利用纵波或者横波波速更强的约束 .为了研究不同岩石中泊松比及其各向异性随围压的变化 ,选取 1 9块典型的岩石样品 ,在不同围压下沿相互... 由弹性波纵横波速比计算得到的泊松比 ,在利用地震波反演地下结构和物质组成时 ,可以提供比单纯地利用纵波或者横波波速更强的约束 .为了研究不同岩石中泊松比及其各向异性随围压的变化 ,选取 1 9块典型的岩石样品 ,在不同围压下沿相互正交的 3个方向同时测量纵、横波速度 ,并通过计算得到了泊松比及其各向异性 .结果表明 ,在大部分样品中泊松比各向异性与纵波速度各向异性有一定的相关性 ,但在有的样品中泊松比各向异性与纵波速度各向异性没有明显的关系 ,甚至表现出完全相反的变化规律 .由于泊松比也表现出很强的各向异性 ,在排除微裂隙的影响后有的仍可以达到 30 %以上 ,在利用实际地震波传播数据通过泊松比反演地下物质结构时必须考虑其各向异性的影响 . 展开更多
关键词 围压 超声波速 泊松比 各向异性 反演 地震波 弹性波
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不同围压下孔隙度不同的干燥及水饱和岩样中的纵横波速度及衰减 被引量:45
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作者 刘斌 H.Kern T.popp 《地球物理学报》 SCIE EI CAS CSCD 北大核心 1998年第4期537-546,共10页
选择具有不同孔隙度的三种岩石样品,在最高达600MPa (干燥样品)或300MPa (水饱和样品)的不同围压条件下,同时测量了在其中传播的纵、横波的速度及衰减。对于低孔隙度的花岗岩,干燥和水饱和样品的 Q 值几乎没有差别,但与干燥样品相比,水... 选择具有不同孔隙度的三种岩石样品,在最高达600MPa (干燥样品)或300MPa (水饱和样品)的不同围压条件下,同时测量了在其中传播的纵、横波的速度及衰减。对于低孔隙度的花岗岩,干燥和水饱和样品的 Q 值几乎没有差别,但与干燥样品相比,水饱和样品中的纵波速度较高而横波速度稍低。对于中等孔隙度的杂砂岩,干燥样品和水饱和样品的波速和 Q 值及其随围压的变化有明显的不同。在高孔隙度的砂岩中这种不同更加显著。综合分析同时测得的纵、横波速度和 Q 值可以发现,当围压增加时,低孔隙度的花岗岩中同体应变相关的能量损失与同剪切应变相关的能量损失之比减小,但在中等孔隙度的杂砂岩和高孔隙度的砂岩中这一比值增大;同时,水饱和样品中的这一比值要比干燥样品中的大,而且它们之间的差别同样品的孔隙度正相关。 展开更多
关键词 超声波速 围压 水饱和 孔隙度 岩样 纵横波速度
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不同温压条件下蛇纹岩和角闪岩中波速与衰减的各向异性 被引量:32
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作者 刘斌 葛宁洁 +1 位作者 H.Kern T.popp 《地球物理学报》 SCIE EI CAS CSCD 北大核心 1998年第3期371-381,共11页
在实验室中研究了蛇纹岩和角闪岩样品在不同温压条件下的纵、横波速度和Q值.这两种岩样对应的主要组成矿物叶蛇纹石和普通角闪石都具有很强的晶格优选方位(LPO).随着围压的增加,波速和Q值均增大,但是在相互正交的三个方向上(垂... 在实验室中研究了蛇纹岩和角闪岩样品在不同温压条件下的纵、横波速度和Q值.这两种岩样对应的主要组成矿物叶蛇纹石和普通角闪石都具有很强的晶格优选方位(LPO).随着围压的增加,波速和Q值均增大,但是在相互正交的三个方向上(垂直或平行于层理面及线理方向)增大的速度并不相同,这与微裂隙的逐渐闭合密切相关.在600MPa的围压下升高温度直到600℃以上,由于微裂隙的热扩张受到约束,波速和Q值下降幅度很小.观测到的波速和Q值的各向异性具有不同的机理,波速各向异性主要与定向分布的微裂隙和主要矿物的LPO等构造因素有关;高围压下纵波Q值各向异性与速度各向异性正好相反,可能是由于形成层理面的定向排列的平板状矿物晶体沿不同方向边界之间接触程度不同造成的. 展开更多
关键词 蛇纹岩 角闪岩 波速 衰减 各向异性 温压条件
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围压作用下岩石样品中微裂纹的闭合 被引量:9
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作者 刘斌 王宝善 +2 位作者 季卫国 H.Kern T.popp 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2001年第3期421-428,共8页
岩石中普遍存在的微裂纹对其物理性质有十分显著的影响 .为了得到不同围压条件下岩样内部微裂纹形态的变化 ,选取几种具有明显层理的岩石圈岩石样品 ,在不同围压下沿相互正交的三个方向对纵横波速度和线应变等进行了测量 ,根据O’Connel... 岩石中普遍存在的微裂纹对其物理性质有十分显著的影响 .为了得到不同围压条件下岩样内部微裂纹形态的变化 ,选取几种具有明显层理的岩石圈岩石样品 ,在不同围压下沿相互正交的三个方向对纵横波速度和线应变等进行了测量 ,根据O’Connell模型通过计算得出有效泊松比、裂纹密度、裂纹孔隙度和裂纹的c/a比值 (a为硬币形裂纹半长轴的长度 ,c为其半宽度 ) .结果表明 ,随着围压的增加 ,在垂直于层理面的方向上裂纹闭合最快但c/a比值不减反增 .结合显微组构分析可知 ,岩石中的裂纹表面实际上是凸凹不平的 ,在围压增加引起裂纹闭合过程中一条裂纹可以变成几个 ,长度成倍减小但宽度变化不大 ,所以在垂直于层理面的方向上c/a比值随围压增加而增大 .但另两个方向上的变化明显不同 ,应该与模型本身的适用范围有关 .通过同时测量纵、横波速度 ,计算c/a比值 。 展开更多
关键词 裂纹长宽比 泊松比 地震波速 裂纹密度 围压作用 岩石圈
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地球内核的地震波速各向异性与其自转有关 被引量:9
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作者 刘斌 张群山 +3 位作者 王宝善 傅容珊 H.Kern T.popp 《科学通报》 EI CAS CSCD 北大核心 1999年第11期1209-1211,共3页
地球内核相对于外部地球存在差异转动 ,固体内核表面相对于液态外核运动的线速度在赤道上最大 ,在两极为零 .因此内核生长速度在赤道附近比两极处快 .引力作用将驱动其内部的物质由赤道向两极流动使其保持近似球形 .与这一流动相应的轴... 地球内核相对于外部地球存在差异转动 ,固体内核表面相对于液态外核运动的线速度在赤道上最大 ,在两极为零 .因此内核生长速度在赤道附近比两极处快 .引力作用将驱动其内部的物质由赤道向两极流动使其保持近似球形 .与这一流动相应的轴对称应力场使得六方紧密堆积 (hcp)铁晶体的c轴沿内核自转轴方向排列 。 展开更多
关键词 地球内核 自转 晶体定向排列 各向异性 地震波速
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Risk of hepatitis B virus reactivation in cancer patients undergoing treatment with tyrosine kinase-inhibitors
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作者 Bansi P Savaliya Ramin Shekouhi +6 位作者 Fatima Mubarak Harsheen K Manaise Paola Berrios Jimenez Gabrielle Kowkabany Reed A popp Kyle popp Emmanuel Gabriel 《World Journal of Gastroenterology》 SCIE CAS 2024年第24期3052-3058,共7页
This editorial commented on an article in the World Journal of Gastroenterology titled“Risks of Reactivation of Hepatitis B Virus in Oncological Patients Using Tyrosine Kinase-Inhibitors:Case Report and Literature An... This editorial commented on an article in the World Journal of Gastroenterology titled“Risks of Reactivation of Hepatitis B Virus in Oncological Patients Using Tyrosine Kinase-Inhibitors:Case Report and Literature Analysis”by Colapietro et al.In this editorial,we focused on providing a more comprehensive exploration of hepatitis B virus reactivation(HBVr)associated with the usage of tyrosine kinase inhibitors(TKIs).It includes insights into the mechanisms underlying HBV reactivation,the temporal relationship between TKIs and HBV reactivation,and preventive measures.The aim is to understand the need for nucleos(t)ide analogs(NAT)and serial blood tests for early recognition of reactivation and acute liver injury,along with management strategies.TKIs are considered to be an intermediate(1%-10%)of HBVr.Current guidelines stipulate that patients receiving therapy with high or moderate risks of reactivation or recent cancer diagnosis must have at least tested hepatitis B surface antigen,anti-hepatitis B core antigen(HBc),and anti-hepatitis B surface antibody.Anti-HBc screening in highly endemic areas means people with negative tests should be vaccinated against HBV.Nucleoside or nucleotide analogs(NAs)like entecavir(ETV),tenofovir disoproxil fumarate(TDF),and tenofovir alafenamide(TAF)form the basis of HBV reactivation prophylaxis and treatment during immunosuppression.Conversely,lamivudine,telbivudine,and adefovir are generally discouraged due to their reduced antiviral efficacy and higher risk of fostering drug-resistant viral strains.However,these less effective NAs may still be utilized in cases where ETV,TDF,and TAF are not feasible treatment options. 展开更多
关键词 Hepatitis B virus REACTIVATION Chronic hepatitis B Tyrosine-kinase inhibitor IMMUNOMODULATORS IMMUNOSUPPRESSANT Nucleoside analogue Hemato-oncology
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围术期神经肌肉阻滞的管理:欧洲麻醉和重症监护学会临床指南
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作者 Thomas Fuchs-Buder Carolina S.Romero +11 位作者 Heidrun Lewald Massimo Lamperti Arash Afshari Ana-Marjia Hristovska Denis Schmartz Jochen Hinkelbein Dan Longrois Maria popp Hans Dde Boer Massimiliano Sorbello Radmilo Jankovic Peter Kranke 《中华麻醉学杂志》 CAS CSCD 北大核心 2024年第6期641-656,共16页
近来的研究表明,由于围术期神经肌肉阻滞管理不当,肌肉松弛药(肌松药)残留阻滞及其术后并发症的发生率居高不下。需要重视神经肌肉功能监测仪、肌松药及其拮抗剂的合理应用,以利于改善神经肌肉阻滞管理。欧洲麻醉和重症监护学会(Europea... 近来的研究表明,由于围术期神经肌肉阻滞管理不当,肌肉松弛药(肌松药)残留阻滞及其术后并发症的发生率居高不下。需要重视神经肌肉功能监测仪、肌松药及其拮抗剂的合理应用,以利于改善神经肌肉阻滞管理。欧洲麻醉和重症监护学会(European Society of Anaesthesiology and Intensive Care,ESAIC)首次发布围术期神经肌肉阻滞管理临床指南,旨在为临床医生提供最佳医疗管理的循证建议,以提高围术期患者安全。本指南主要聚焦在3个临床问题:肌松药是否有助于成人气管插管?神经肌肉阻滞深度是否影响腹部手术患者的预后?肌松药残留阻滞的诊断和治疗策略有哪些?根据PICO原则(患者、干预、对照、结局;patient,intervention,comparator,outcome;PICO)构建临床问题并进行文献检索。初始纳入的临床研究为24 000篇,采用逐步筛选策略,最终临床研究88篇纳入指南分析。应用GRADE方法学(Grading of Recommendations,Assessment,Development and Evaluation,GRADE)对结局指标证据、质量等级进行评价。运用两轮德尔菲法收集专家组建议并形成统一推荐:R1推荐应用肌松药辅助气管插管(1A)。R2推荐应用肌松药以减少气管插管导致的咽部和(或)喉部损伤(1C)。R3推荐在快速顺序诱导插管(rapid sequence induction intubation,RSII)时使用短效肌松药,例如琥珀胆碱1 mg/kg或罗库溴铵0.9~1.2 mg/kg(1B)。R4推荐在需要改善外科手术条件时,加深神经肌肉阻滞深度(1B)。R5尚无足够的证据推荐深度神经肌肉阻滞可减轻术后疼痛或降低围术期并发症的发生率(2C)。R6推荐在拇内收肌处刺激尺神经,定量监测神经肌肉阻滞深度以排除肌松药残留阻滞(1B)。R7推荐应用舒更葡糖钠逆转甾体类肌松药(罗库溴铵、维库溴铵)诱导的深、中及浅度神经肌肉阻滞(1A)。R8推荐在使用新斯的明前,TOFr自行恢复至>0.2,并继续定量监测神经肌肉功能,直至TOFr超过0.9 展开更多
关键词 神经肌肉阻滞 神经肌肉功能 肌松药 临床指南 罗库溴铵 琥珀胆碱 外科手术 定量监测
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Corn and Soybean Growth as Affected by Wastewater-Derived Struvite-Phosphorus Sources and Irrigation Water Types
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作者 Machaela Morrison Kristofor R. Brye +2 位作者 Gerson Drescher Jennie popp Lisa S. Wood 《Agricultural Sciences》 2024年第4期472-504,共33页
Struvite (MgNH<sub>4</sub>PO<sub>4</sub>·6H<sub>2</sub>O) produced synthetically from a stock solution of known phosphorus (P) and nitrogen (N) concentrations has been shown to... Struvite (MgNH<sub>4</sub>PO<sub>4</sub>·6H<sub>2</sub>O) produced synthetically from a stock solution of known phosphorus (P) and nitrogen (N) concentrations has been shown to be an effective, alternative fertilizer-P source for various crops, but little is known about the potential agronomic effectiveness of struvite created from an actual municipal wastewater source. The objective of this study was to evaluate the effects of soil [i.e., Creldon silt loam (Oxyaquic Fragiudalf) and Calloway silt loam (Aquic Fraglossudalf) series], fertilizer-P source [i.e., synthetically produced electrochemically precipitated struvite (ECSTsyn), real-wastewater-derived ECST (ECSTreal), chemically precipitated struvite (CPST), monoammonium phosphate (MAP), and an unamended control (UC)], and irrigation water type (i.e., tapwater and struvite-removed wastewater) on corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] growth and N, P, and magnesium (Mg) uptake in a 60-day, greenhouse potted-plant study. Crop growth and N, P, and Mg uptakes for the struvite treatments (i.e., CPST, ECSTsyn, and ECSTreal) were generally similar to or at least 1.2 times greater than MAP. The ECSTsyn material commonly had up to five times greater N, P, and Mg uptake in corn and soybean than any other fertilizer-P source. Struvite-removed wastewater resulted in at least 1.3 times lower dry matter and N, P, and Mg uptake than tapwater. Similar corn and soybean results from the struvite fertilizers among the various soil-water type combinations compared to MAP suggest that struvite generates similar crop responses as at least one widely used, commercially available, multi-nutrient fertilizer-P source. 展开更多
关键词 ARKANSAS Corn Production Soybean Production STRUVITE Recovered Nutrients
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鸡胚完整脑的光子发射和光激发光研究 被引量:6
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作者 张锦珠 于文斗 +2 位作者 孙彤 Fritz-Albert popp 《中国科学(C辑)》 CSCD 1996年第6期481-486,共6页
利用自制的单光子记录系统,对离体的浸于DMEM培养液中的鸡胚的完整脑所进行的光子发射测量显示出整脑与培养液相比有光子发射.完整脑的光子发射强度与胚龄,鸡胚的健康状况和离体后脑组织的新鲜程度有关.在对完整脑的光激发光测量中观察... 利用自制的单光子记录系统,对离体的浸于DMEM培养液中的鸡胚的完整脑所进行的光子发射测量显示出整脑与培养液相比有光子发射.完整脑的光子发射强度与胚龄,鸡胚的健康状况和离体后脑组织的新鲜程度有关.在对完整脑的光激发光测量中观察到一种短寿命的延迟发光,它的衰减过程不服从指数衰减规律而表现出双曲线衰减行为.从生物光子发射归因于生物体内的非定位的相干性电磁场及Frohlish的生命系统中存在着长距离的相干性的理论,讨论了利用生物光子发射研究细胞间通讯、生物的调节及生物与环境关系的意义,以及所检测的光子发射与生物系统自身的相干性电磁场的关系,并提出应从环境对生物系统自身场的影响来理解所测的生物光子发射. 展开更多
关键词 生物光学 光子发射 光激发光 鸡胚 完整脑组织
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Wavelength-tunable multi-point pump semiconductor disk laser based on an intra-cavity transmission grating
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作者 冯健 佟存柱 +8 位作者 赵宇飞 Andreas popp Berthold Schmidt 汪丽杰 孟博 陆寰宇 王延靖 张新 王立军 《Chinese Optics Letters》 SCIE EI CAS CSCD 2023年第2期33-39,共7页
We report a wavelength-tunable multi-point pump scheme of the semiconductor disk lasers(SDLs).By designing an external cavity of SDL with an intra-cavity transmission grating,multiple pump gain regions share the same ... We report a wavelength-tunable multi-point pump scheme of the semiconductor disk lasers(SDLs).By designing an external cavity of SDL with an intra-cavity transmission grating,multiple pump gain regions share the same resonator.The effect of the intra-cavity grating on the output laser power,wavelength,and beam quality was investigated.The emission wavelength could be tuned over a bandwidth of~18 nm.With multi-point pumping,we achieve the laser output power with almost no loss,and further improvement is limited by the thermal effect.The changes in the beam are due to the mode selectivity by the intra-cavity grating. 展开更多
关键词 semiconductor disk laser wavelength tuning transmission grating multi-point pump
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Runoff-Water Properties from Various Soils as Affected by Struvite-Phosphorus Source and Water Type
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作者 Machaela Morrison Kristofor R. Brye +2 位作者 Gerson Drescher Jennie popp Lisa S. Wood 《Journal of Environmental Protection》 2023年第10期789-823,共35页
Struvite (MgNH<sub>4</sub>PO<sub>4</sub>?6H<sub>2</sub>O) can be produced from municipal wastewater and has been shown to be an alternative fertilizer-phosphorus (P) source for vari... Struvite (MgNH<sub>4</sub>PO<sub>4</sub>?6H<sub>2</sub>O) can be produced from municipal wastewater and has been shown to be an alternative fertilizer-phosphorus (P) source for various crops, but little is known about the runoff-water-quality implications from soil-applied struvite. The objective of this study was to evaluate the effects of soil [Creldon (Oxyaquic Fragiudalfs), Dapue (Fluventic Hapludolls), Roxana (Typic Udifluvents), and Calloway (Aquic Fraglossudalfs) series], fertilizer-P source [synthetically produced electrochemically precipitated struvite (ECSTsyn), real-wastewater-derived ECST (ECSTreal), chemically precipitated struvite (CPST), and monoammonium phosphate (MAP)], and water source (rainwater, groundwater, and struvite-removed real wastewater) over time on runoff-water-quality parameters from laboratory-conducted, rainfall-runoff simulations. Mesh tea bags containing each soil-fertilizer treatment combination were rained on with each water source (Trial 1), incubated for 6 months, and rained on again (Trial 2) to evaluate runoff-water quality. Struvite fertilizers had similar runoff-water-quality properties to those from MAP. In Trial 1, runoff total P (TP) concentration differences (i.e., soil-fertilizer-water-type response minus control response minus blank response) from ECSTsyn or ECSTreal were 1 to 5 times larger than MAP and CPST for all water-soil-fertilizer-P source treatment combinations, except for the Creldon-groundwater and Roxana-wastewater combinations. In both trials, runoff TP decreased over time in all water-soil and soil-fertilizer-P source treatment combinations, except for the Roxana-CPST combination where TP increased over time by 46%. The similar water-quality responses from the struvite fertilizers among the various soils and water types compared to MAP suggest that struvite has similar runoff-water-quality implications as at least one widely used, commercially available fertilizer-P source. 展开更多
关键词 Rainfall Simulation RUNOFF STRUVITE PHOSPHORUS Water Quality
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内核地震波速各向异性的成因 被引量:5
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作者 刘斌 张群山 +2 位作者 王宝善 傅容珊 H.Kern T.popp 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2000年第3期312-321,共10页
地球内核是轴对称各向异性的,其对称轴与地球的极轴之间有11°左右的夹角,本 文根据地球内核相对于外部地球有差异转动这一观测结果,利用晶体生长理论,对内核地震波 速度各向异性的成因进行了探讨.当从熔融状态结晶时,晶体... 地球内核是轴对称各向异性的,其对称轴与地球的极轴之间有11°左右的夹角,本 文根据地球内核相对于外部地球有差异转动这一观测结果,利用晶体生长理论,对内核地震波 速度各向异性的成因进行了探讨.当从熔融状态结晶时,晶体的生长速度与晶体和熔融态之 间相对运动的线速度成正比涸此当固态内核在液态外核中生长时,沿赤道方向的生长速度比 两极方向快.在万有引力场的作用下内核始终保持近似球形,生长速度较快的赤道附近的物 质会向两极区域流动,形成轴对称的流变场。这一轴对称的流变场伴随着轴对称的应力场,使 得构成地球内核的hcp型铁晶体的c轴沿着内核自转轴的方向排列,导致观测到的地球内核地 震波速度各向异性。作为推论,内核相对于外部地球可能同时存在着进动和章动。 展开更多
关键词 地球内核 地震波 波速 各向异性
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长江流域油菜田土壤硫肥力现状研究 被引量:6
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作者 李录久 巨晓棠 +5 位作者 张福锁 孙义祥 孙礼胜 郭熙盛 张祥明 Thomas popp 《土壤通报》 CAS CSCD 北大核心 2005年第4期564-567,共4页
选择长江流域油菜产区研究安徽省土壤缺S现状和油菜植株硫营养状况。结果表明,安徽省长江流域油菜产区,土壤有效S平均含量15.31mgkg-1,缺S状况较为严重,缺S土壤所占比例高达63.10%,潜在性缺S土壤所占比例为35.48%。主要土壤类型中灰潮土... 选择长江流域油菜产区研究安徽省土壤缺S现状和油菜植株硫营养状况。结果表明,安徽省长江流域油菜产区,土壤有效S平均含量15.31mgkg-1,缺S状况较为严重,缺S土壤所占比例高达63.10%,潜在性缺S土壤所占比例为35.48%。主要土壤类型中灰潮土缺S状况最为严重,有效S不足的土壤所占比例高达80%。油菜植株全S含量为5.08~20.18gkg-1,平均10.02gkg-1。花和叶含S量较高,全S含量平均为11.06gkg-1和11.00gkg-1,茎杆含S量较低,全S平均含量仅8.00gkg-1。油菜花朵和叶片全S含量多在8~16gkg-1,茎杆含S量在6~10gkg-1之间。花、叶、茎全S含量(y)与土壤有效S含量(x)之间呈极显著二次曲线正相关,回归方程分别为y1=3.79782+0.88501x-0.02265x2(R2=0.4156**,F=9.96,n=31),y2=3.6548+0.86280x-0.02111x2(R2=0.26569**,F=5.07),y3=3.78016+0.45330x-0.00981x2(R2=0.34399**,F=7.32)。 展开更多
关键词 土壤有效S含量 油菜含S量 长江流域
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An examination of thematic research,development,and trends in remote sensing applied to conservation agriculture
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作者 Zobaer Ahmed Aaron Shew +3 位作者 Lawton Nalley Michael popp V.Steven Green Kristofor Brye 《International Soil and Water Conservation Research》 SCIE CSCD 2024年第1期77-95,共19页
Conservation agriculture seeks to reduce environmental degradation through sustainable management of agricultural land.Since the 1990s,agricultural research has been conducted using remote sensing technologies;however... Conservation agriculture seeks to reduce environmental degradation through sustainable management of agricultural land.Since the 1990s,agricultural research has been conducted using remote sensing technologies;however,few previous reviews have been conducted focused on different conservation management practices.Most of the previous literature has focused on the application of remote sensing in agriculture without focusing exclusively on conservation practices,with some only providing a narrative review,others using biophysical remote sensing for quantitative estimates of the bio-geo-chemical-physical properties of soils and crops,and few others focused on single agricultural management practices.This paper used the preferred reporting items for systematic review(PRISMA)methodology to examine the last 30 years of thematic research,development,and trends associated with remote sensing technologies and methods applied to conservation agriculture research at various spatial and temporal scales.A set of predefined key concepts and keywords were applied in three databases:Scopus,Web of Science,and Google Scholar.A total of 188 articles were compiled for initial examination,where 68 articles were selected for final analysis and grouped into cover crops,crop residue,crop rotation,mulching,and tillage practices.Publications on conservation agriculture research using remote sensing have been increasing since 1991 and peaked at 10 publications in 2020.Among the 68 articles,94%used a pixel-based,while only 6%used an object-based classification method.Prior to 2005,tillage practices were abundantly studied,then crop residue was a focused theme between 2004 and 2012.From 2012 to 2020,the focus shifted again to cover crops.Ten spectral indices were used in 76%of the 68 studies.This examination offered a summary of the new potential and identifies crucial future research needs and directions that could improve the contribution of remote sensing to the provision of long-term operational services for various conservation agricult 展开更多
关键词 Remote sensing Conservation agriculture Classification algorithm Spatial resolution SATELLITE Spectral indices PRISMA
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沉积岩中波速、衰减及渗透率随压力的变化 被引量:2
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作者 刘斌 杨晓勇 +3 位作者 王宝善 席道瑛 T.popp H.Kern 《石油地球物理勘探》 EI CSCD 北大核心 2000年第1期129-135,共7页
在三轴围压容器内对泥岩、粉砂岩、砂岩和杂砂岩中的弹性波速度、衰减和渗透率进行了测量,并对样品作了显微组构分析。实验发现,由于砂岩的孔隙率大,矿物颗粒的分选度和磨圆度较好,颗粒间孔隙的连通性很好,其渗透率最高;粉砂岩中晶体颗... 在三轴围压容器内对泥岩、粉砂岩、砂岩和杂砂岩中的弹性波速度、衰减和渗透率进行了测量,并对样品作了显微组构分析。实验发现,由于砂岩的孔隙率大,矿物颗粒的分选度和磨圆度较好,颗粒间孔隙的连通性很好,其渗透率最高;粉砂岩中晶体颗粒尺寸比砂岩的小,颗粒间的孔隙也较小,连通性受到影响,因此渗透率比砂岩的低;泥岩的渗透率更低,因为它的矿物颗粒更细小且固结性较差,很容易将连通的孔隙堵塞;杂砂岩是由分选性差、未经磨圆的碎砾通过基质胶结形成的,孔隙间的连通性很低,它的渗透率最小。随着围压和轴向差异应力的变化,四种样品中的波速、衰减和渗透率均发生不同形式的变化,反映了岩样组构特别是微裂隙的变化情况。 展开更多
关键词 沉积岩 渗透率 波速度 压力变化 油气层物理
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Genetic determination of irritable bowel syndrome 被引量:4
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作者 Cristina Hotoleanu Radu popp +2 位作者 Adrian Pavel Trifa Laurentiu Nedelcu Dan L Dumitrascu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第43期6636-6640,共5页
Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder. According to the Rome m criteria, IBS is defined as recurrent abdominal pain or discomfort for at least 3 d per month during the previ... Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder. According to the Rome m criteria, IBS is defined as recurrent abdominal pain or discomfort for at least 3 d per month during the previous 3 mo associated with two or more of the following symptoms: improvement with defecation, onset associated with a change in the frequency of stool and/or onset associated with a change in form or appearance of stool. There is growing evidence regarding the genetic contribution in IBS, however the precise etiology of IBS is still unknown. The evaluation of the genetic influence is based on twin studies, familial aggregation and genetic epidemiological investigations. Most studies showed a concordance for IBS significantly greater in monozygotic than in dizygotic twins. The majority of the studies have shown that familial aggregation may represent exposures to a similar environment, as well as the influence of genetic factors. Whereas no specific gene has been identified in association with IBS, recent studies have noticed the importance of polymorphisms in the promoter region of the serotonin reuptake transporter gene, G-protein beta 3 subunit gene (C825T), cholecystokinin receptor (CCKAR gene 779T〉C), and high-producer tumor necrosis factor genotype. Further studies are necessary to determine how genetic factors influence the clinical manifestations and therapeutical response in IBS patients. 展开更多
关键词 Irritable bowel syndrome Genetic factors Gene polymorphisms Twin studies Familial aggregation
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利用光子发射研究海洋甲藻间的细胞通讯 被引量:3
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作者 张锦珠 于文斗 Fritz-Albert popp 《科学通报》 EI CAS CSCD 北大核心 1994年第20期1904-1906,共3页
细胞通讯,或称细胞信息传递的研究,已成为分子生物学、细胞生物学、细胞生物物理学研究的热点,引起了许多生物学家乃至物理学家们的兴趣,因为人们认识到对许多重要的生命现象,例如生长发育、细胞分化、肿瘤发生、神经信息加工等的解释,... 细胞通讯,或称细胞信息传递的研究,已成为分子生物学、细胞生物学、细胞生物物理学研究的热点,引起了许多生物学家乃至物理学家们的兴趣,因为人们认识到对许多重要的生命现象,例如生长发育、细胞分化、肿瘤发生、神经信息加工等的解释,归根到底还要在对细胞通讯的研究中得到解答.近年来,人们对细胞的化学信号传递的研究取得了一些新进展,但是长距离的细胞间的通讯在理论上仍要依赖于物理方式. 展开更多
关键词 光子发射 海洋 甲藻 细胞信息传递
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Superior labral anterior posterior lesions of the shoulder:Current diagnostic and therapeutic standards 被引量:4
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作者 Dominik popp Volker Sch?ffl 《World Journal of Orthopedics》 2015年第9期660-671,共12页
Surgical treatment of superior labral anterior posterior(SLAP) lesion becomes more and more frequent which is the consequence of evolving progress in both,imaging and surgical technique as well as implants.The first c... Surgical treatment of superior labral anterior posterior(SLAP) lesion becomes more and more frequent which is the consequence of evolving progress in both,imaging and surgical technique as well as implants.The first classification of SLAP lesions was described in 1990, a subdivision in four types existed. The rising comprehension of pathology and pathophysiology in SLAP lesions contributed to increase the types in SLAP classification to ten. Concerning the causative mechanism of SLAP lesions, acute trauma has to be differed from chronic degeneration. Overhead athletes tend to develop a glenohumeral internal rotation deficit which forms the basis for two controversial discussed potential mechanisms of pathophysiology in SLAP lesions: Internal impingement and peel-back mechanism. Clinical examination often remains unspecific whereas soft tissue imaging such as direct or indirect magnetic resonance arthrography has technically improved and is regarded to be indispensable in detection of SLAP lesions. Concomitant pathologies as Bankart lesions, rotator cuff tears or perilabral cysts should be taken into consideration when planning a personalized therapeutic strategy. In addition, normal variants such as sublabral recess, sublabral hole, Buford complex and other less common variants have to be distinguished. The most frequent SLAP type Ⅱ needs a sophisticated approach when surgical teatment comes into consideration. While SLAP repair is considered to be the standard operative option, overhead athletes benefit from a biceps tenodesis because improved patient-reported satisfaction and higher rate of return to pre-injury level of sports has been reported. 展开更多
关键词 SUPERIOR labral ANTERIOR POSTERIOR lesion TENODESIS SUPERIOR labral ANTERIOR POSTERIOR repair SHOULDER arthroscopy BICEPS tendon
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Mechanism of interaction between electromagnetic fields and living organisms 被引量:4
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作者 Fritz-Albert popp 张锦珠 《Science China(Life Sciences)》 SCIE CAS 2000年第5期507-518,共12页
Based on nonlinear phenomena of biophoton emission observed in the past, an interference model concerning with the mechanism of interaction between living organisms and electromagnetic fields was raised. Caused by bio... Based on nonlinear phenomena of biophoton emission observed in the past, an interference model concerning with the mechanism of interaction between living organisms and electromagnetic fields was raised. Caused by biological nonlinearly polarizable double layer, destructive interference of incoming and reflected waves establishes in the outside. As a consequence, in the inside constructive interference takes place at the same time. The interference patterns may play an important role in biological self organization and in biological functions. We investigate the boundary conditions necessary for explaining these non-linear optical effects in terms of the phase conjugation. It turns out that there are solutions of the Maxwell equations which satisfy destructive interference of biophotons in agreement with the experimental results. Necessary provisions are nonlinearly polarizable optically active double layers of distances which are small compared to the wavelength of light. In addition, they have to be able to move into the nodal planes of the impinging waves within a small time interval compared to the coherence time. These conditions are likely fulfilled in the optically dense, but ordered and optically excited, highly polarizable living matter. 展开更多
关键词 ELECTROMAGNETIC FIELDS INTERACTION MECHANISM biophotons COHERENCE interference.
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Emerging role of the gut microbiome in post-infectious irritable bowel syndrome:A literature review
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作者 Vasile Valeriu Lupu Cristina Mihaela Ghiciuc +7 位作者 Gabriela Stefanescu Cristina Maria Mihai Alina popp Maria Oana Sasaran Laura Bozomitu Iuliana Magdalena Starcea Anca Adam Raileanu Ancuta Lupu 《World Journal of Gastroenterology》 SCIE CAS 2023年第21期3241-3256,共16页
Post-infectious irritable bowel syndrome(PI-IBS)is a particular type of IBS,with symptom onset after an acute episode of infectious gastroenteritis.Despite infectious disease resolution and clearance of the inciting p... Post-infectious irritable bowel syndrome(PI-IBS)is a particular type of IBS,with symptom onset after an acute episode of infectious gastroenteritis.Despite infectious disease resolution and clearance of the inciting pathogen agent,10%of patients will develop PI-IBS.In susceptible individuals,the exposure to pathogenic organisms leads to a marked shift in the gut microbiota with prolonged changes in host-microbiota interactions.These changes can affect the gut-brain axis and the visceral sensitivity,disrupting the intestinal barrier,altering neuromuscular function,triggering persistent low inflammation,and sustaining the onset of IBS symptoms.There is no specific treatment strategy for PI-IBS.Different drug classes can be used to treat PI-IBS similar to patients with IBS in general,guided by their clinical symptoms.This review summarizes the current evidence for microbial dysbiosis in PI-IBS and analyzes the available data regarding the role of the microbiome in mediating the central and peripheral dysfunctions that lead to IBS symptoms.It also discusses the current state of evidence on therapies targeting the microbiome in the management of PI-IBS.The results of microbial modulation strategies used in relieving IBS symptomatology are encouraging.Several studies on PI-IBS animal models reported promising results.However,published data that describe the efficacy and safety of microbial targeted therapy in PI-IBS patients are scarce.Future research is required. 展开更多
关键词 Gut microbiome Infectious gastroenteritis Irritable bowel syndrome Post infection syndrome PATHOPHYSIOLOGY Inflammation
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