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1.
课程思政是目前高等学校教学改革的首要工作,我们开展了物理实验线上线下混合式课程思政的探索,在大学物理实验慕课构建立体多元的课程思政平台,在线上线下、课内课外开展课程思政建设.紧密结合物理实验教学内容和学生特点,挖掘工大元素、中国元素和物理学史元素.讲好工大故事,厚植爱校情怀,增强成才信心.讲好中国故事,厚植爱国情怀,坚...  相似文献   

2.
钱忠华  侯威  杨萍  封国林 《物理学报》2011,60(10):109204-109204
利用1961-2009年中国逐日最高温度资料,分成1961-1990年、1971-2000年和1981-2009年三个气候态(分别称为Ⅰ,Ⅱ,Ⅲ态),基于偏态概率密度函数定义极端温度事件,从频次、强度两个角度研究了不同气候态下中国夏季和冬季极端温度事件的时空变化特征. 空间分布上,夏季极端高温的频次、强度在Ⅰ态黄淮、江淮流域显著减小,在Ⅲ态,干旱半干旱以及经济发达的长江沿岸、长江三角洲以及东南沿海地区显著增加;冬季极端低温频次在Ⅱ态中的北方、长江三角洲以及Ⅲ态中的高原、东北东南部、长江三角洲显著降低. 冬季极端低温强度整体呈降低趋势,但区域特征不明显. 极端温度频次和强度在空间上一致性较好;时间演化上,夏季极端高温频次、强度均在Ⅱ,Ⅲ态显著增加,冬季极端低温频次、强度降低的趋势有所减缓. 在当前气候态(Ⅲ态)夏季极端高温在经济发达地区发生比较频繁且极端性在增强;冬季极端低温的发生维持在一个稳定状态且极端性也相对比较稳定. 极端温度事件的频次与强度在时间变化趋势上存在较好的一致性. 在Ⅰ,Ⅱ,Ⅲ态共同时段内,后一气候态检测出的极端高温频次均比前一气候态少,极端低温频次均比前一气候态多,这与背景温度随气候态逐渐升高是相一致的;后一气候态检测出的极端高温强度均比前一气候态小,极端低温强度均比前一气候态大. 在20世纪70年代末80年代初全球气候系统突变前,极端高温频次具有明显的下降趋势,突变后显著上升;极端低温频次在突变前后变化不明显. 极端高温强度突变前表现出轻微的下降趋势,在突变后上升趋势明显;极端低温强度在突变前后大致相当,突变后的整体强度稍低于突变前. 关键词: 极端高温 极端低温 气候态  相似文献   

3.
We study the interaction with bulk and surface modes of electrons emitted in the proximity of a solid surface. We analyze the modifications in the energy loss, and in bulk and surface plasmon excitations, taking into account the effects due to the sudden creation of the electron and residual atomic hole, and the finite distance to the surface. The process is described using the dielectric function formulation and the specular reflection model. We derive expressions for the electrostatic potential in the medium and in vacuum, which include all the terms due to bulk and surface modes. The effect of each term in the energy loss rate and in the average number of plasmon excitations is discussed. The results illustrate in detail the different spatial dependences of the electron and ion interactions with the bulk and surface perturbations, through the relevant range of distances for studies of electron emission in the proximity of solid surfaces.  相似文献   

4.
应用原子吸收光谱法测定了两份耐盐性不同的野生披碱草种质材料在不同盐浓度胁迫条件下根组织和叶组织中的大量元素(Na,K,Ca,Mg)和微量元素(Cu,Fe,Mn,Zn)含量,并对野生披碱草种质材料矿质元素吸收和积累的选择性与耐盐性的关系进行了分析,结果表明:随着盐胁迫浓度的升高,野生披碱草种质材料叶和根组织中Na含量不断增加,耐盐材料HS叶组织中的Na含量显著低于敏盐材料LS(P<0.05);而K和Ca含量呈下降的趋势,在高浓度盐胁迫下,耐盐材料HS中两种元素的含量显著高于敏盐材料LS(P<0.05);微量元素Fe和Zn在野生披碱草材料根、叶组织中的含量升高,Cu在根组织中的含量没有变化,但是在叶组织中升高,而Mn在根、叶组织中的含量都呈下降的趋势,耐盐材料HS叶组织和根组织中Zn和Fe含量低于敏盐材料LS,Mn含量显著高于敏盐材料LS(P<0.05)。  相似文献   

5.
动力学阿尔文波是短波长的色散阿尔文波,其色散主要是由于垂直波长接近离子回旋半径或电子惯性长度等微观粒子动力学特征尺度而引起的。在频率远低于离子回旋频率的低频条件下,其平行波长通常仍然远大于离子惯性长度,这导致动力学阿尔文波在电磁偏振和传播方向上呈现显著各向异性的重要特性,并因此使其在磁等离子体的粒子能化现象和结构丝化现象中起重要作用。动力学阿尔文波早期于1970年代由Chen和Hasegawa研究聚变等离子体加热问题时首先提出。随后,在1980年代受到空间等离子体、特别是电离层-磁层耦合与极光现象研究的广泛关注。进入1990年代后,由于在空间卫星探测技术和地面等离子体实验技术的不断发展,特别是一些高分辨空间等离子体探测仪器和地面大型等离子体实验设备投入工作以来,在动力学阿尔文波的实验研究上取得了一系列突破性的重要进展。这不仅导致对动力学阿尔文波在磁等离子体动力学现象中重要作用的重新估价和正视,并再次激发了对动力学阿尔文波理论及其在实验室、空间和天体环境下各类等离子体活动现象中应用研究的广泛兴趣。自1990年代中期以来,我们在中国科学院紫金山天文台的研究小组一直致力于动力学阿尔文波及其在太阳和空间等离子体粒子能化现象中应用的研究。这篇综述性报告主要介绍了有关动力学阿尔文波非线性孤波理论及其在空间和太阳等离子体粒子能化现象中应用的研究进展,也是我们这十几年来在这一领域研究工作的一个总结。报告的第0章简要介绍动力学阿尔文波的一些主要特征及其在磁等离子体动力学现象中的重要作用。然后,在第1章中利用等离子体的双流体方程、结合有关的实验观测,系统介绍了动力学阿尔文波的色散、传播、偏振等基本特性和在一维孤波与二维涡旋等非线性结构理论方面的研究进展。接下来的第2、3、4章将聚焦在动力学阿尔文波的耗散机制及其在太阳和空间等离子体粒子能化现象中的应用研究上,分别包括:动力学阿尔文孤波的耗散结构及其在极光高能电子加速现象中的应用(第2章);动力学阿尔文孤波中重离子的各向异性能化机制及其在延伸日冕中少量重离子反常加热现象中的应用(第3章);以及动力学阿尔文波的反常耗散机制及其在日冕磁等离子体结构非均匀加热现象中的应用(第4章)。最后的第5章是一个简要的总结和几点进一步发展的展望。  相似文献   

6.
降雨对无线激光通信的影响   总被引:1,自引:0,他引:1  
朱耀麟  安然  柯熙政 《光学学报》2012,32(12):1206003
通过激光信号在雨介质中传输的实验发现,在大雨环境下,激光信号透射率要比在小雨或微雨的情况下大。这说明光信号在小雨时衰减较大,在大雨时衰减较小。这一现象与人们通常所认为的有所不同。针对降雨对激光信号的影响,根据Mie散射理论和Weibull雨滴尺寸分布模型,分析了不同尺寸的粒子对光的散射作用以及对衰减效率因子的影响,推导出单球粒子对光波的衰减公式,得到了衰减与降雨率的确定关系。通过数值计算发现,与小粒子相比大粒子的前向散射光强更大且更加集中;激光信号在雨介质中传输时,衰减系数在小雨时较大,中雨、大雨时较小,暴雨时不断增大。这一结果与实际情况较吻合,为激光在通信系统中的应用提供了一定的理论依据。  相似文献   

7.
B.B. He  W. Xu 《哲学杂志》2015,95(11):1150-1163
The effect of ausforming temperature and strain on the bainitic transformation kinetics was investigated in a low carbon boron steel. A new mechanism, which is based on the competition between the increase in nucleation rate and the decrease in average volume of bainite sheaf after deformation, is proposed. The increase in nucleation rate is due to the decrease in boron concentration at the grain boundaries after small deformation and the formation of sub-grain boundaries at the grain interior after large deformation. The decrease in average volume of bainite sheaf is ascribed to the frequent impingement of bainite sub-units after deformation. The increase in nucleation rate after deformation results in the decrease in incubation time, which is confirmed from the experiment. The increase in nucleation rate overcomes the decrease in average volume of bainite sheaf, resulting in the increase in transformation velocity and volume fraction after small deformation. On the contrary, the decrease in the average volume of bainite sheaf overcomes the increase in nucleation rate after large deformation, leading to the decrease in transformation velocity and volume fraction of bainite.  相似文献   

8.
Summary The purpose of this study was to investigate the sex particularities in human cardiovascular responses to different external influences using the traditional physiological approach and non-traditional methods of dynamical systems theory. Measurements were taken in 21 healthy women and 15 men exposed to noise stress, passive coping, and in 35 women and 25 men exposed to double mental arithmetic stress, active coping. Results showed that, firstly, cardiovascular reactivity in men and women was determined by the type of stress. Thus, in a majority of humans heart rate did not change during noise but increased during mental stress, blood pressure decreased during noise but increased during mental stress. Secondly, results demonstrated the significant sex differences in the basal and stress cardiovascular activity. So, the women showing the greater basal and stress heart rate displayed the hypotensive responses to passive coping more often and the hypertensive responses to active coping less often than men. Thirdly, the changes in normalized entropy of the electrocardiogram signal, reflecting the changes in heart physiological variability, also depended on the sex of subjects and the nature of stress. During noise normalized entropy increased in a majority of women but decreased in a majority of men. Mental stress caused both decreases and increases in normalized entropy in men and women. But the increases in normalized entropy during stress and especially during recovery were greater in women than in men. Normalized entropy was demonstrated to be a more sensitive marker of sex and individual differences in cardiovascular responses to stress than heart rate and blood pressure. Results suggest that the lower blood pressure reactions and the greater increases in normalized entropy,i.e. in physiological heart variability, may partly result in higher cardiovascular stress resistance in women relative to men. Paper presented at the International Workshop ?Fluctuations in Physics and Biology: Stochastic Resonance, Signal Processing and Related Phenomena?, Elba, 5–10 June 1994.  相似文献   

9.
Phase transitions are common in inanimate systems and have been studied extensively in natural sciences. Less explored are the rich transitions that take place at the micro- and nano-scales in biological systems. In conventional phase transitions, large-scale properties of the media change discontinuously in response to continuous changes in external conditions. Such changes play a significant role in the dynamic behaviours of organisms. In this review, we focus on some transitions in both free-living and biofilms of bacteria. Particular attention is paid to the transitions in the flagellar motors and filaments of free-living bacteria, in cellular gene expression during the biofilm growth, in the biofilm morphology transitions during biofilm expansion, and in the cell motion pattern transitions during the biofilm formation. We analyse the dynamic characteristics and biophysical mechanisms of these phase transition phenomena and point out the parallels between these transitions and conventional phase transitions. We also discuss the applications of some theoretical and numerical methods, established for conventional phase transitions in inanimate systems, in bacterial biofilms.  相似文献   

10.
I trace the origins of teaching and research in physics and astronomy during the 17th and 18th centuries at the Academy of Turku (Åbo), which was relocated to Helsinki in 1827 and renamed as the Imperial Alexander University of Finland, and which in turn in 1917 became the University of Helsinki. I discuss the growth of physics in Helsinki during the 19th century, which culminated in the opening of a large new Physical Institute in 1911, pointing out the individuals responsible for these developments and the sites associated with them. I also discuss related events, such as the founding of a new astronomical observatory and a new magnetic observatory and the development of technical education in Helsinki. I conclude by discussing the construction of an accelerator laboratory and other important developments in physics in Helsinki after 1945.  相似文献   

11.
Photon correlation spectroscopy and rheological measurements are performed to investigate the microscopic dynamics and mechanical responses of aqueous solutions of triblock copolymers and aqueous mixtures of triblock copolymers and anionic surfactants. Increasing the concentration of triblock copolymers results in a sharp increase in the magnitude of the complex moduli characterising the samples. This is understood in terms of the changes in the aggregation and packing behaviours of the copolymers and the constraints imposed upon their dynamics due to increased close packing. The addition of suitable quantities of an anionic surfactant to a strongly elastic copolymer solution results in a decrease in the complex moduli of the samples by several decades. It is argued that the shape anisotropy and size polydispersity of the micelles comprising mixtures cause dramatic changes in the packing behaviour, resulting in sample unjamming and the observed decrease in complex moduli. Finally, a phase diagram is constructed in the temperature-surfactant concentration plane to summarise the jamming-unjamming behaviour of aggregates constituting triblock copolymer-anionic surfactant mixtures.  相似文献   

12.
吴德金 《物理学进展》2011,30(2):101-172
动力学阿尔文波是短波长的色散阿尔文波,其色散主要是由于垂直波长接近离子回旋半径或电子惯性长度等微观粒子动力学特征尺度而引起的。在频率远低于离子回旋频率的低频条件下,其平行波长通常仍然远大于离子惯性长度,这导致动力学阿尔文波在电磁偏振和传播方向上呈现显著各向异性的重要特性,并因此使其在磁等离子体的粒子能化现象和结构丝化现象中起重要作用。动力学阿尔文波早期于1970年代由Chen和Hasegawa研究聚变等离子体加热问题时首先提出。随后,在1980年代受到空间等离子体、特别是电离层-磁层耦合与极光现象研究的广泛关注。进入1990年代后,由于在空间卫星探测技术和地面等离子体实验技术的不断发展,特别是一些高分辨空间等离子体探测仪器和地面大型等离子体实验设备投入工作以来,在动力学阿尔文波的实验研究上取得了一系列突破性的重要进展。这不仅导致对动力学阿尔文波在磁等离子体动力学现象中重要作用的重新估价和正视,并再次激发了对动力学阿尔文波理论及其在实验室、空间和天体环境下各类等离子体活动现象中应用研究的广泛兴趣。自1990年代中期以来,我们在中国科学院紫金山天文台的研究小组一直致力于动力学阿尔文波及其在太阳和空间等离子体粒子能化现象中应用的研究。这篇综述性报告主要介绍了有关动力学阿尔文波非线性孤波理论及其在空间和太阳等离子体粒子能化现象中应用的研究进展,也是我们这十几年来在这一领域研究工作的一个总结。报告的第一章简要介绍动力学阿尔文波的一些主要特征及其在磁等离子体动力学现象中的重要作用。然后,在第二章中利用等离子体的双流体方程、结合有关的实验观测,系统介绍了动力学阿尔文波的色散、传播、偏振等基本特性和在一维孤波与二维涡旋等非线性结构理论方面的研究进展。接下来的第三、四、五章将聚焦在动力学阿尔文波的耗散机制及其在太阳和空间等离子体粒子能化现象中的应用研究上,分别包括:动力学阿尔文孤波的耗散结构及其在极光高能电子加速现象中的应用(第三章);动力学阿尔文孤波中重离子的各向异性能化机制及其在延伸日冕中少量重离子反常加热现象中的应用(第四章);以及动力学阿尔文波的反常耗散机制及其在日冕磁等离子体结构非均匀加热现象中的应用(第五章)。最后的第六章是一个简要的总结和几点进一步发展的展望。  相似文献   

13.
This article comprises the results of comprehensive study of the structure and distribution in the high temperature fracture area of rapidly quenched heat-resistant superalloy of grade EP741NP after tensile tests. The structure and boron distribution in the fracture area are studied in detail by means of direct track autoradiography in combination with metallography of macro- and microstructure. A rather extensive region of microcracks generation and intensive boron redistribution is detected in the high temperature fracture area of rapidly quenched nickel superalloy of grade EP741NP. A significant decrease in boron content in the fracture area and formation of elliptically arranged boride precipitates are revealed. The mechanism of intense boron migration and stability violation of the structural and phase state in the fracture area of rapidly quenched heat-resistant nickel superalloy of grade EP741NP is proposed on the basis of accounting for deformation occurring in the fracture area and analysis of the stressed state near a crack.  相似文献   

14.
赵巧华  孙绩华 《物理学报》2013,62(3):39203-039203
湖泊表层混合层深度的变化不仅影响湖泊水生生态系统的演变, 而且影响流域的局地气候、降水量的时空格局等. 基于2008年夏秋两季洱海(高原湖泊)和太湖(平原湖泊)的气象与水温廓线观测资料, 分析探讨了两湖表层混合层深度的变化特征及其机制. 结果表明: 夏季洱海能维持持续的分层现象, 秋季有明显的日分层现象, 而在相应的两季中, 太湖仅可能存在日分层现象; 洱海表层混合层深度较同期太湖更浅; 太湖两季的表层混合层深度变化较洱海频繁, 即太湖水体混合与分层的交替过程对气象条件的响应较洱海更为迅速. 太湖这类浅水湖泊, 水深是抑制其存在稳定、持续分层的关键因素, 在合适的辐射条件下, 可形成日分层现象; 而洱海这类深度的湖泊, 净热量通量是影响其是否存在持续、稳定分层的主要因子. 该研究为进一步探讨湖泊与大气两种湍流运动的耦合机制及水生生态环境演替规律等提供了有力的参考.  相似文献   

15.
Molecular mobility in sorbitol and maltitol is studied with spectroscopic techniques and molecular dynamics simulations in order to evaluate the relative contributions of the intermolecular and intramolecular interactions involved in the relaxation processes. The results of the molecular dynamics simulations performed on the polyols in the bulk or in vacuum compares well with the results of the analysis of the relaxation diagrams in the framework of the Perez et al. model. They both imply that the difference in the relative contributions of the intermolecular and intramolecular interactions associated with the different chemical architectures of the two polyols must be taken into account. The intermolecular interactions cannot be neglected and they are stronger in sorbitol than in maltitol in relation with the linear structure of this polyol. The intramolecular barrier, higher in the maltitol molecule with a more complex structure, could be at the origin of the higher junction temperature between the α and β relaxation processes.  相似文献   

16.
利用高光谱反演、监测植被生长状况的基础是光谱特征识别。以半干旱采煤塌陷区为样地,利用Field Spec 3地物光谱仪与SPAD-502叶绿素仪同步采集采煤地表塌陷形成的不同应力区(非采区、中性区、拉伸区、压缩区)典型植物叶片光谱反射率与叶绿素含量(SPAD值),分析典型植物相同应力区SPAD值升高其光谱特征的变化,对比不同应力区典型植物SPAD值较高与较低时光谱特征的差异,并借助Matlab软件深入研究不同应力区典型植物SPAD值与差值指数、归一化指数的相关关系。结果表明:(1)不同应力区同种植物光谱曲线随着SPAD值不同变化规律相异,可见光波段区分明显,其余波段受应力影响的区域样本SPAD值不同,反射率比非采区波动更为剧烈与无序。可见光波段,糙隐子草、柠条、杨树、油蒿SPAD值低的样本光谱曲线绿峰缺失,SPAD值升高,绿峰出现但位置红移,SPAD值高于30时,为典型植被光谱曲线,油松样本SPAD值越高反射峰值越小;受应力影响的区域SPAD值低的样本谷、峰、边特征参数缺失更多,光谱变化规律不强。(2)400~700 nm波段,不同应力区糙隐子草、油蒿、油松、柠条样本SPAD值较低组反射率显著高于较高组,杨树样本相反;780~1 350 nm波段,拉伸区的糙隐子草、非采区的油蒿和柠条、压缩区的油松和杨树样本SPAD值较高组与较低组的反射率差异小;相较于非采区,受应力影响的糙隐子草、油蒿、柠条样本在所测波段SPAD值较高组与较低组的同波段反射率差值显著减小。(3)受应力影响的区域样本SPAD值与光谱指数相关性较之非采区在某些波段大面积增强。与非采区相比,中性区的油蒿、油松、柠条、杨树样本SPAD值与光谱指数的最大相关系数值均增大,糙隐子草相反;非采区植物SPAD值与NDVI最大相关系数均高于DI,波段组合多位于近红外,受应力影响区域的样本最大相关系数多数位于可见光波段。本研究为矿区不同应力区典型植物高光谱波段识别与植物健康状态监测、矿区生态环境精准治理提供了理论支撑。  相似文献   

17.
The activity of cytosolic antioxidative defence enzymes in the liver and white muscle of thinlip gray mullet (Liza ramada Risso) were compared in winter and spring in the Adriatic Sea. Activity of antioxidative enzymes is functionally organized due to metabolic demands: analyses of variance and correlation analysis revealed tissue- and seasonal- specific organization of antioxidative enzymes. In winter GST activity increased in both tissues compared with spring. At the same time decreased GSH-Px and GR activities were observed and this effect was more pronounced in liver then in white muscle. From correlation analyses it is concluded that the antioxidative components correlate, but the composition of the antioxidative defence system is different in respect to season and tissue. This means that the antioxidative defence system reorganizes its structure due to oxidative demands and to protect the tissues against reactive oxygen species and to establish homeostasis. Discriminant analyses separated groups according to the complete organization of individual components of the system very well and identified individual components (CAT, GST and GR) which contribute most to the differences. Statistical differences were observed between enzyme activities in tissues (liver and muscle) in both winter and spring, and between seasons (winter and spring) for liver tissue only. Since environmental parameters, such as temperature and oxygen concentration in the sea differ with season, we conclude that in this species the tissues examined expressed their antioxidative defence systems in different ways in respect of external/environmental conditions. We propose that tissue- and seasonal- specific levels of antioxidant enzyme activities should be considered in the interpretation of data from future biomonitoring field studies, especially in relation to low temperature.  相似文献   

18.
对光纤中磁流体在梯度磁场作用下的光透射特性进行了研究,提出光纤中磁流体的光透射率变化主要来源于梯度磁场引起的磁流体密度分布变化。根据郎之万函数和流体理论,推导了光纤中磁流体在梯度磁场作用下的密度分布,并根据Beer-Lambert定律,得到磁流体光功率透射衰减和纳米粒子局部密度的关系,从而建立光纤中磁流体在梯度磁场作用下光透射特性的理论模型。进而对光纤中磁流体在不同梯度磁场作用下的光透射功率进行数值分析,得到不同磁场强度和磁场梯度下光纤中磁流体透射功率的变化规律。最后将数值分析的结果和实验数据进行对比,验证了模型的合理性, 同时也验证了梯度磁场作用下磁流体光透射功率的变化主要来源于磁流体密度分布变化的推论。  相似文献   

19.
我国中低品位胶磷矿量大、分布广,磷矿中杂质种类及含量对于磷石膏结晶及磷酸品质均有较大影响。以湖北某地区的典型低品位胶磷矿为原料,采用X射线光电子能谱仪、扫描电镜、能谱等方法,分析了磷矿及反应后磷石膏中的主要杂质种类及含量变化,并以此推测湿法磷酸过程中杂质的主要变化。结果表明磷矿中的主要成分是氟磷灰石和石英,杂质组分占比最高的分别是硅、铝、氟、镁,其中硅主要以石英和硅酸钙存在,氟主要存在于氟磷酸钙中,铝是以不同形式的铝硅酸盐存在的,而镁则是以MgF2和部分硅酸盐存在。通过酸解反应,钙与硫酸根生成磷石膏,硅元素主要存在于固相石膏中,而铝、氟、镁则大部分进入到液相磷酸中,其中存在于固相中的硅则基本以石英形式存在,硅酸钙溶解于酸液中,铝主要以铝硅磷的化合物存在,氟则以氟硅化物形式存在,大部分的MgF2溶解进入液相,磷石膏中镁主要以镁硅酸盐形式存在。通过磷矿中杂质存在形式及反应过程的变化研究,可以更好的明晰酸解过程中的体系变化,从而为磷石膏结晶过程的考察和控制提供理论基础。  相似文献   

20.
韦薇  杨怡  黄凡  王中良 《光谱实验室》2010,27(3):977-982
探讨微量元素与糖尿病间的关联性及临床意义。采用ICP-AES等离子体发射光谱仪测定了楚雄地区糖尿病患者人发中11种元素,采用2,3-二氨基萘荧光法测定发样中的硒元素。选取糖尿病患者120例,对照组35例。糖尿病组发样中常量元素Ca、Mg低于对照组,P高于对照组;除Cd、Cr、Fe外,微量元素Zn、Se、Ni、Mn、Cu等5种元素低于对照组,并有显著差异(P0.01)。糖尿病组间性别比较数据显示男性除发Ni、Mn、P外,其余元素含量均低于女性,其中发锌远低于女性。3个不同年龄段糖尿病人群的微量元素含量变化显示Fe、P2种元素随年龄增加含量增高;Mg、Cd2种元素随年龄增加含量减少;其余各元素变化情况为Fe、P元素在老年组中较高,Cu、Cd、Mg较低;Mn、Cr、Cu元素含量在中年组中较高,而Zn、Se略低;Zn、Se在青年组较高,而Mn、Cr低。城市人群发中Zn、Cd、Cu、Mg、Ca含量比农村人群高;Se元素含量二者间差别也不大,其余元素含量均低于农村人群。楚雄地区糖尿病患者发中Zn、Se、Mg、Mn4种元素水平低,楚雄地区糖尿病患者致病原因可能与地区属低Se水平和患者体内硒水平低有关。  相似文献   

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