速度算符和电子的颤动

指出了国外某些量子力学教材中关于速度算符的概念错误和相对论自由电子进行颤动的错误,分析了错误的原因.     

4道中考物理试题的商榷

通过查阅资料和严谨分析,指出了2020年徐州中考物理试卷中的4处错误,即医用口罩的防毒原理错误、风筝原理错误、实验题数据与事实违背,液体压强错误.指出了这些错误对广大师生的具体影响,以期提高促进各地中考命题的严谨性、科学性.     

泡利的错误

 几年前,在翻译美国物理学家温伯格(StevenWeinberg)的《爱因斯坦的错误》和撰写《玻尔的错误》(发表于本刊2013年第5期)时,我就萌生过一个念头,那就是继《爱因斯坦的错误》和《玻尔的错误》之后,若还有哪位现代物理学家的错误值得一写的话,就得说是泡利了。这也正是本文的主题--泡利的错误--之缘起。     

针对学生认识中的错误优化课堂教学

学生在学习中产生的错误是认知过程中必然出现的思维产物,它是学生思维状态的真实反映,学生的错误正好反映了他们思维上的各种缺陷,教师要善于区分错误答案的类型,在每种答案背后的误解或信息缺失中,挖掘出错误背后隐藏的问题,及时制定解决的措施和办法,促成新知识和能力的生成,从而把错误当作教学中宝贵的资源加以利用,并要善于利用学生的错误进行引导,使其"知其然,又知其所以然".     

基于增强GA-BP神经网络的软件错误定位方法

在软件开发和后期维护的过程中,进行软件调试来定位错误并修正错误是其中最复杂且成本最大的一部分;文章针对现有基于神经网络的软件错误定位方法中的权值和阈值设定不方便、鲁棒性差等问题,结合正交实验设计思想和遗传算法(Genetic Algorithm),提出了一种基于增强遗传BP神经网络的软件错误定位方法;并将其同基于GA-BP神经网络的和基于BP神经网络的定位方法都在MATLAB上进行了实验,实验数据来源西门子测试集,从结果上看,基于增强GA-BP神经网络的软件错误定位方法在定位错误的效率和精确度上都有一些进步。     

如何纠正学习物理的错误思维

教学实践表明,不少初中学生感觉物理不容易学会,甚至出现了部分学生认真学习物理,但成绩仍然不好的现象.究其原因,他们学习物理的思维出现了错误.本文从学生的思维错误,纠正思维错误的教学策略这两方面阐述培养学生物理思维能力的方法.     

几何光学中常见错误的研究

为了提高几何光学中解题的准确度,通过对几何光学中基本公式的归纳和常见的错误进行分析,得到了产生错误的原因．     

─道电动力学习题的讨论

本文指出了一道电动力学习题解法的错误之处和由此错误的解法却得到正确答案的原因，最后给出了正确的解答方法。     

运用物理实验转变学生有关摩擦力的错误前概念

针对物理教学中学生错误前概念难以转变的问题, 以摩擦力当中学生普遍存在的一些错误前概念为 例, 提出了运用物理实验转变学生有关摩擦力的错误前概念具体实施方案. 帮助学生纠正错误前概念, 建构科学概 念     

以错因为载体,努力提高教学效率

在学习过程中,学生不可避免地犯各种各样的错误,学习的过程始终伴随着对错误的发现、分析和纠正.实际上许多正确的观念和行为是在对错误的观念和行为的否定中得以形成的.钱学森先生曾说过:"正确的结果是从大量错误中得来的;没有大量的错误作阶梯,也就登不上最后正确结果的宝座."     

ICP-AES测定云南楚雄糖尿病患者发样微量元素的研究

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。     

Recent developments,challenges, and prospects of ultrasound-assisted oil technologies

There has been consistent drive towards research and innovation in oil production technologies in order to achieve improved effectiveness and efficiency in their operation. This drive has resulted in breakthrough in technologies such as the application of ultrasound (US) in demulsification and enhanced oil recovery (EOR), and usage of high-volume hydraulic fracturing and special horizontal well for shale oil and gas extraction. These can be observed in the increment in the number of commercial oil technologies such as EOR projects that rose from 237 in 1996 to 375 in 2017. This sustained expansion in EOR resulted in their total oil production rising from 1.5 million barrels per day in 2005 to 2.3 million barrels per day in 2020. And this is predicted to increase to about 4.7 million barrels per day in 2040, which represent about 4% of total production. Consequently, in this review, the developments in the utilization of US either as standalone or integrated with other technologies in EOR and dehydration of water in oil emulsions were analyzed. The studies include the optimization of fluid and US properties in EOR and demulsification. Reports on the treatment of formation damage resulting from inorganic salts, organic scales, drilling fluid plugs, condensate, paraffin wax and colloidal particle with US-assisted EOR were also highlighted. Moreover, the mechanisms were examined in order to gain insightful understanding and to aid research investigations in these areas. Technologies such as US assisted green demulsification, high intensity focused ultrasound, and potential pathways in field studies were assessed for their feasibilities. It is essential to evaluate these technologies due to the significant accrued benefits in them. The usage of green demulsifiers such as deep eutectic solvents, ionic liquids and bio-demulsifiers has promising future outlook and US could enhance their technical advancement. HiFU has been applied successfully in clinical research and developments in this area can potentiality improve demulsification and interfacial studies (fluid–fluid and solid–fluid interactions). As regards field studies, there is need to increase actual well investigations because present reports have few on-site measurements with most studies being in laboratory scale. Furthermore, there is need for more detailed modeling of these technologies as it would assist in conserving resources, saving research time and fast-tracking oil production. Additional evaluative studies of conditions such as the usage of Raschig rings, crude oil salinity and high temperature which have improved demulsification of crude oil emulsions should be pursued.     

Seasonal- and age-dependent changes of the structure and chemical composition of the spherites in the midgut gland of the harvestmen Gyas annulatus (Opiliones)

Spherites—round laminated membrane bound structures—are located in the cytoplasm of all cell types of the midgut gland in the harvestmen Gyas annulatus. The spherites consist of an organic matrix composed of glycoproteins and proteoglycans whose sugar portion are carboxylated glycosaminoglycans. Different elements are embedded in this matrix, and their presence varies during the life cycle. All spherites in juveniles are composed of alternating concentrically arranged electron dense and electron lucent layers of organic matrix material before overwintering (December). At that time, spherites contain calcium, phosphorus and silicon. Calcium and phosphorus are located in their electron dense layers, and silicon spotwise, mainly peripheral. Material seems to be lost during overwintering of Gyas as electron lucent ‘empty’ layers appear in spherites in March. The ‘lost’ material could be used as energy supply and/or to provide molecules for synthesis processes during non-nourishing overwintering. Spherites do not contain calcium and phosphorus in July and October. These elements seem to have important biological relevance in the formation and hardening of the cuticle during the moultings in spring. In contrast to calcium and phosphorus, silicon is still stored in spherites in July and October but in decreasing concentration, therefore it could be involved in metabolic processes in adult Gyas. In the period from July to the end of their adult life in late autumn, an increasing number of spherites disintegrate and their remnant organic matrix material progressively aggregates with other cellular waste material in one or more huge vacuoles of glandular cells.     

Spectral Properties of Single BODIPY Dyes in Polystyrene Microspheres and in Solutions

The absorption, fluorescence, fluorescence quantum yield, and photostability of five BODIPY dyes are characterized and compared as single dyes in two environments, in 40-nm polystyrene spheres and in solution. The absorption and fluorescence spectra of the dyes in spheres are similar in profile but shifted to lower energies compared to those in solution. All the dyes are highly fluorescent, with three having fluorescence quantum yields of 1.0. For three of the five dyes, the yields were the same in spheres as in solution (1.00, 1.00, and 0.73). The high concentration of these dyes in spheres does not quench their fluorescence. For two other dyes the yields dropped, from 1.00 to 0.55 in one case and 0.83 to 0.50 in another, comparing the dyes in solution versus in spheres. The photodegradation of the dyes decreases in spheres compared to in solution in all but one case. For one dye, it decreases as much as 800-fold. Dyes overlooked because of low fluorescence or stability in solution could become useful fluorescent materials in the microsphere environment.     

夏秋两季洱海、太湖表层混合层的深度变化特征及其机理分析

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.     

转小鼠金属硫蛋白(MT)基因烟草不同器官中金属离子铅和锌的分布

转金属硫蛋白(MT)基因植物具有清除重金属污染的能力,但是金属离子在植物体内的分布研究较少。文章以多代培育纯合的转MT烟草为材料,研究了转MT基因烟草积累铅和锌以及铅和锌在不同器官的分布情况。结果表明转基因植株的老叶、茎部和根部铅和锌积累量显著高于普通烟草植株,整株的铅和锌含量分别提高了21.8%和27.2%。铅和锌在植物体内的分布也发生了变化,转基因植株老叶和根中的铅含量分别高出普通烟草同位置的30.2%和47.8%,锌在转基因植株老叶、茎和根中的含量分别高出普通烟草同位置的44.7%,29.2%和21.6%,说明铅更容易在转基因植株老叶和根中积累,而锌更容易在转基因植株的老叶和茎中积累。     

Nanoscale Science and Engineering in Romania

In spite of difficult working conditions and with very low financial support, many groups from Romania are involved in emerging fields, such as the nanoscale science and technology. Until the last years, this activity was developed without a central coordination and without many interactions between these research groups. In the year 2000, some of the institutes and universities active in the nanotechnology field in Romania founded the MICRONANOTECH network. The aim of this paper is to emphasize the main activities and results of the Romanian groups working in this novel domain. Most of the groups are deal with the nanomaterial technology and only few of them have activities in nanostructure science and engineering, in new concepts and device modeling and technology. This paper describes the nanotechnology research development in two of the most significant institutes from Romania: Centre for Nanotechnologies from National Institute for Research and Development in Microtehnologies (IMT-Bucharest) and from National Institute for Research and Development in Materials Physics (INCD-FM), Magurele. The Romanian research results in nanotechnology field were presented in numerous papers presented in international conferences or published in national and international journals. They are also presented in patents, international awards and fellowships. The research effort and financial support are outlined. Some future trends of the Romanian nanoscale science and technology research are also described.     

Staining methods applied to glycol methacrylate embedded tissue sections

The use of glycol methacrylate (GMA) avoids some technical artifacts, which are usually observed in paraffin-embedded sections, providing good morphological resolution. On the other hand, weak staining have been mentioned during the use of different methods in plastic sections. In the present study, changes in the histological staining procedures have been assayed during the use of staining and histochemical methods in different GMA-embedded tissues.

Samples of tongue, submandibular and sublingual glands, cartilage, portions of respiratory tract and nervous ganglion were fixed in 4% formaldehyde and embedded in glycol methacrylate. The sections of tongue and nervous ganglion were stained by H&E. Picrosirius, Toluidine Blue and Sudan Black B methods were applied, respectively, for identification of collagen fibers in submandibular gland, sulfated glycosaminoglycans in cartilage (metachromasia) and myelin lipids in nervous ganglion. Periodic Acid-Schiff (PAS) method was used for detection of glycoconjugates in submandibular gland and cartilage while AB/PAS combined methods were applied for detection of mucins in the respiratory tract. In addition, a combination of Alcian Blue (AB) and Picrosirius methods was also assayed in the sublingual gland sections.

The GMA-embedded tissue sections showed an optimal morphological integrity and were favorable to the staining methods employed in the present study. In the sections of tongue and nervous ganglion, a good contrast of basophilic and acidophilic structures was obtained by H&E. An intense eosinophilia was observed either in the striated muscle fibers or in the myelin sheaths in which the lipids were preserved and revealed by Sudan Black B. In the cartilage matrix, a strong metachromasia was revealed by Toluidine Blue in the negatively-charged glycosaminoglycans. In the chondrocytes, glycogen granules were intensely positive to PAS method. Extracellular glycoproteins were also PAS positive in the basal membrane and in the region occupied by the lamina externa and reticular fibers surrounding each smooth muscle cells of the blood vessels. In the epithelial cells of the respiratory tract, acid and neutral mucins were histochemically detected by AB and PAS methods, respectively. Moreover, granules containing acid and neutral mucins were revealed in purple by AB and PAS concomitantly. In the sublingual gland sections, a distinct affinity of acid mucins by AB (in turquoise-blue) and collagen fibers by Picrosirius (in red) was obtained when these methods were combined. Although some routine dyes used in paraffin sections have showed a weak stain in historesin sections, our results showed that different dyes could be applied in GMA sections if modified staining procedures were assayed. Therefore, appropriate staining contrast and, thus, detection of one or different substances in a same section can be acquired in association to the good morphological resolution provided by GMA.     

动力学阿尔文波及其在太阳和空间等离子体中的应用

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。     

近五年我国近红外光谱分析技术研究与应用进展

评述了我国近五年来(2009年—2013年)近红外光谱分析技术的研究与应用进展,内容涉及软硬件研发、方法研究、以及诸多领域的应用开发等方面,并对今后我国近红外光谱技术的发展方向提出了建议。引用文献209篇。