邮票上的物理学史⑨--牛顿

"牛顿由于发现了万有引力定律而创立了科学的天文学,由于进行了光的分解而创立了科学的光学,由于建立了二项式定律和无穷理论而创立了科学的数学,由于认识了力的本性而创立了科学的力学."恩格斯的这段话很好地总结了牛顿的科学业绩.为了纪念牛顿在科学上的伟大建树,许多国家发行了多枚一套的邮票.     

自由落体实验的改进

针对教材中自由落体实验操作的不稳定性,改进了实验,增强了实验操作的稳定性,提高了实验的精确度,减少了实验次数,节省了时间,提高了课堂效率.     

地磁场测量实验教学设备的改造、替代及软件选取

介绍了周期幅值法测量地磁场的实验方法,指出了原实验设备存在的问题,同时提出了实验设备的改造方案,并详细介绍了如何软选取件模块.该工作降低了实验教学的维护成本,节约了因等待维护耗费的大量时间,保证了实验教学的顺利进行.     

控制环量设计涡轮的实验研究

采用控制环量方法设计了一单级涡轮。该方法打破了传统的设计规律,为验证该方法的可靠性进行了模型试验。在宽广的范围内测定了总特性;在设计点附近作了沿叶高效率分布及动叶进、出口速度三角形的测定。本文给出了主要试验结果并作了简要分析。结果表明基本上达到了设计要求,控制环量设计的主要特征得到了验证,该方法基本可行。     

双波段扫描辐射计的研制

介绍了一种新型小视场、高精度的双波段扫描辐射计。描述了系统的特点,分析了系统的总体方案。介绍了系统的工作原理,对系统的NETD进行了估算,对其探测器的选择、光学系统设计、调制系统设计、扫描机构设计、信号处理等方案进行了详细论述,对系统的标定和测量原理进行了分析,并给出了相应的计算公式。给出了系统的检测结果。     

大统一理论:回顾与展望

本文系统地讨论了大统一理论的来龙去脉。回顾了大统一理论的发展历史,讨论了其发展现状及存在问题,指出了进一步发展的方向。本文重点介绍了SU(5)和SO(10)两个模型,讨论了Higgs场、规范等级、渐近自由、重正化等问题。文章进而讨论了一些有趣问题,比如提供了对宇宙重子起源的解释、计算了质子衰变寿命、论述了B-L是否守恒以及讨论了中子和中微子可能有的振荡现象等。     

某空间望远镜相关跟踪系统摆镜随机振动分析

介绍了基础激励下机构随机振动响应的理论与分析方法.利用有限元分析软件ANSYS建立了某空间望远镜相关跟踪系统摆镜的有限元模型,并进行了随机振动响应分析.通过分析考察了其承受动力学环境的能力.对计算结果进行了分析.指出了现有结构中的薄弱环节,提出了改进方案,为摆镜的设计提供了重要参考依据.     

物理实验开放式教学初探

网上预约实验实现了各校区资源共享、教学内容有弹性满足了不同层次学生的需求，开放式教学增强了教师的责任心，激发了学生学习的主动性和积极性，提高了实验教学质量，充分利用了实验室的资源，取得了较好的效果。     

大统一理论:回顾与展望

本文系统地讨论了大统一理论的来龙去脉。回顾了大统一理论的发展历史,讨论了其发展现状及存在问题,指出了进一步发展的方向。本文重点介绍了SU(5)和SO(10)两个模型,讨论了Higgs场、规范等级、渐近自由、重正化等问题。文章进而讨论了一些有趣问题,比如提供了对宇宙重子起源的解释、计算了质子衰变寿命、论述了B-L是否守恒以及讨论了中子和中微子可能有的振荡现象等。     

La/酸化膨润土吸附剂的表征与除磷性能

以酸化改性膨润土为载体,采用浸泡法制备了稀土La掺杂的La/酸化膨润土吸附剂.通过XRD和FTIR对其结构进行了表征,探讨了膨润土的改性机理,研究了该吸附剂对废水的除磷性能.结果表明：酸化过程洗掉了膨润土中的杂质和氧化铝,稀土镧的掺杂在膨润土层间及表面引入了一定数量的羟基化合物,改善了膨润土的层间结构并生成了新的La-O-Si键,实现了La与膨润土的复合,提高了膨润土的吸附性能.     

Ho(0.5)Yb(5)氟氧化物玻璃的直接上转换增敏发光

本文研究了HoYb共掺氟氧化物玻璃的直接上转换增敏发光现象。发现了位于 (5 4 4 5nm ,1836 5cm- 1 )和 (6 5 8 5nm ,15 186cm- 1 )的两条很强的上转换发光 ,它们是 5S2 → 5I8和5F5→ 5I8的荧光跃迁。还有其他的一些上转换发光5F3→ 5I8,5S2 → 5I7和5I4 → 5I8的跃迁。还发现存在一种特征的饱和现象 ,即所有上转换发光随激光功率变化的F P双对数关系曲线都是一条相当好的直线 ,其斜率会随着光斑的增大而增大 ,由分析得知这是由能量扩能散造成的。     

Tm3+在二苯甲酰基甲基亚砜配合物体系中对Dy3+的荧光增强效应

合成了六种高氯酸掺杂稀土(Dy³⁺,Tm³⁺)与二苯甲酰基甲基亚砜的配合物。经元素分析、稀土络合滴 定、摩尔电导率及差热-热重分析,表明配合物组成为 (Dy_x,Tm_y)L₅(ClO₄)₃·3H₂O(x : y=1.000 : 0.000,0.995 : 0.005,0.990 : 0.010,0.950 : 0.050,0.900 : 0.100,0.800 : 0.200;L=C₆H₅COCH₂SOCH₂COC₆H₅)。并详细讨论了六种稀土配合物的荧光光谱。从配合物的荧光光谱图可以看出,Tm³⁺对Dy³⁺的荧光有增强效应。这可能 是因为在惰性稀土离子Tm³⁺与活性稀土离子Dy³⁺之间有能量的传递。而且当Dy³⁺与Tm³⁺的量比为0.950 : 0.050时,掺杂配合物表现出最佳的发光性质。另外,Tm³⁺对577.4 nm处⁴F_9/2→⁶H_13/2 峰的荧光敏化作用的程度高于对487 nm处⁴F_9/2→⁶H_15/2 峰的荧光敏化作用。⁴F_9/2→⁶H_15/2 峰的荧光强度增强了212％,而⁴F_9/2→⁶H_13/2峰的荧光强度增强了264％。所以,Dy³⁺离子的两个特征峰的发射强度比趋近于1,为1.078,使得配合物在紫外灯下发白色荧光。有可能成为一类发白色荧光的发光材料。     

SU(6)破缺效应对核子形状因子的贡献

最近杰斐逊实验室测量了中子的两个弹性电磁形状因子之比GEn/GMn,它反映了中子内部的电磁分布并能帮助理解中子的内部结构.传统的相对论组分夸克模型在解释质子的两种电磁形状因子之比GEp/GMp是很成功的,但在解释中子的该比值时计算值比实验值要低.为了解释这种现象,我们在相对论组分夸克模型框架下计算考察了SU(6)破缺效应的贡献.发现考虑该破缺效应后的计算结果同实验符合有明显改善.     

Surface modification of poly(styrene-b-(ethylene-co-butylene)-b-styrene) elastomer via photo-initiated graft polymerization of poly(ethylene glycol)

Poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) copolymer biomedical elastomer was covalently grafted with poly(ethylene glycol) methyl ether methacrylate (PEGMA) via a photo-initiated graft polymerization technique. The surface graft polymerization of SEBS with PEGMA was verified by ATR-FTIR and XPS. Effect of graft polymerization parameters, i.e., monomer concentration, UV irradiation time and initiator concentration on the grafting density was investigated. Comparing with the virgin SEBS film, the PEGMA-modified SEBS film presented an enhanced wettability and a larger surface energy. Besides, the surface grafting of PEGMA imparted excellent anti-platelet adhesion and anti-protein adsorption to the SEBS surface.     

三螺旋DNA分子poly(dT)·poly(dA)·poly(dT)的构型和振动谱

我们计算了ｐｏｌｙ（ｄＴ）·ｐｏｌｙ（ｄＡ）·ｐｏｌｙ（ｄＴ）的Ｈｏｗａｒｄ模型的原子笛卡尔坐标，并利用晶格动力学方法对模型进行了简正分析。结果发现其０ Ｐ ０对称振动模式位于８０４ｃｍ－１，这和８１０ｃｍ－１附近没有拉曼和红外谱线的实验结果不符。在８００～１０００ｃｍ－１的范围内只有四个振动模式，明显少于拉曼和红外光谱在该范围内的谱线数目。所以我们认为Ｈｏｗａｒｄ模型需要进一步地完善和修正，ｐｏｌｙ（ｄＴ）·ｐｏｌｙ（ｄＡ）·ｐｏｌｙ（ｄＴ）必须具有三条不完全一致的脊骨     

Molecular dynamics simulation of surface melting behaviours of the V（110） plane

The modified analytic embedded-atom method and molecular dynamics simulations are applied to the investigation of the surface premelting and melting behaviours of the V（110） plane by calculating the interlayer relaxation, the layer structure factor and atomic snapshots in this paper. The results obtained indicate that the premelting phenomenon occurs on the V（110） surface at about 1800K and then a liquid-like layer, which approximately keeps the same thickness up to 2020K, emerges on it. We discover that the temperature 2020K the V（110） surface starts to melt and is in a completely disordered state at the temperature of 2140K under the melting point for the bulk vanadium.     

利用SU（2）_（q，s）量子代数的两参数变形振子实现讨论SU（2）_（q，s）相干态

利用ＳＵ（２）ｑ，ｓ量子代数的两参数变形振子实现构造出与Ｐｅｒｅｌｏｍｏｖ相干态形式不同的ＳＵ（２）ｑ，ｓ相干态．证明了ＳＵ（２）ｑ，ｓ，量子代数的表示基是正交的，并讨论了它的相干态的归一性和完备性．指出ＳＵ（２）ｑ，ｓ相干态的相干性受参数ｑ，ｓ的影响，它比单参数变形ＳＵ（２）ｑ相干态更具一般性．     

Tip-surface interactions at redox responsive poly(ferrocenylsilane) (PFS) interface by AFM-based force spectroscopy

Poly(ferrocenylsilanes) (PFS) belong to the class of redox responsive organometallic polymers. Atomic force microscopy (AFM)-based single molecule force spectroscopy (SMFS) was used earlier to study single chain PFS response and redox energy driven single chain PFS molecular motors. Here we present further AFM investigations of force interactions between tip and a grafted PFS surface under potential control in electrochemical redox cycles. Typical tip-Au interaction is considered as reference in the force measurements. First the electrostatic component in the diffused double layer (DL) in NaClO₄ electrolyte environment was considered for a “grafted to” PFS, which dominated the interplay between the tip and sample surface. The DL forces can also hinder the physisorption of PFS chain onto the tip when the voltage was applied at −0.1 V. On the other hand, if the tip contacted the PFS surface prior to the electrochemical process, physisorption of PFS chains governed the overall interaction regardless of subsequently applied surface potential. In addition, prolonged contact time, t_c, may also contribute to the stability of tip-PFS bridging and detection of electrostatic forces between the tip-PFS interface. The results showed that tip-substrate interaction forces without PFS grafts have negligibly small force contributions under similar, electrochemically controlled, conditions used in single PFS chain based molecular motors.     

Sorption of Organic Solvents in Poly(Dimethyl Siloxane) Membrane. II. Effect of Sorption on the Polymer Crystals upon Cooling

Polymer crystalline properties in poly(dimethyl siloxane) (PDMS) film after solvation by various solvents was determined using low temperature differential scanning calorimetry (DSC). At various solvent uptake levels, the crystalline thermal properties of the solvated polymer were modified to different extents as revealed by the shifts in crystalline melting point (T_m) and its enthalpy (ΔH_m). Water uptake in PDMS was very limited (<0.01 g/g) and T_m did not significantly change during the sorption process. For toluene and cyclohexane penetrants, T_m moved toward a much lower temperature depending on the sorption levels. At low solvent uptakes, the T_m values decreased linearly with solvent uptakes due to formation of a miscible phase. Beyond a threshold, the T_m remained stable and an additional penetrant fusion peak appeared, implying the onset of a microphase separation phenomenon. The ΔH_m values for the swollen membranes were decreased, with the exception of the water penetrant. This indicates that a lower percentage of polymer chains were involved in the crystalline domain for swollen PDMS.     

Solvatochromism of Ternary Iron (II) Diimine Cyanide Complexes in 2-Ethyl-2-(hydroxymethyl) 1,3-Propanediol (Trimethylol Propane)

The solvatochromic behaviour of bis-(2,2′-bipyridyl)-biscyanoiron (II) and 2,2′- bipyridyltetracyanoiron (II) in 2-ethyl-2-(hydroxymethyl)-1,3-propanediol has been established. The significance and sensitivities of the solvatochromic shifts of these charge-transfer bands are outlined for the two iron complexes above.