Is there a universal scale of time?

The assumption that the same universal scale of time applies for different physical laws depends uponthe hypothesis that there is a unique universal scale of time in the universe. Intrinsic to that hypothesis is the assumption that if extraneous factors that affect physical clocks and processes that run on different physical principles could be removed, all clocks are synchronizable with one another. The consequences of that hypothesis not being true are considered. It was found thatclock asynchrony implies that: (1) a mass variation theory is probable; (2) there is a need for multiple clocks; and (3) t in the equations of physics is referring to clocks rather than time such that the properties of time are reduced to its direction (as characterized by thermodynamics and cosmology).     

工业用蒸发式和水冷式冷凝器的循环水量和能耗研究

通过计算与现场测试,分析比较了蒸发式与水冷式冷凝器的循环水量和能耗。参照美国的经验数据,蒸发式冷凝器的循环水量约为立式水冷式的19%、约为卧式水冷式38%。现场测试发现,三种典型品牌蒸发式冷凝器的实际平均循环水量约为立式水冷式的51%、约为卧式水冷式的76%。三种典型品牌蒸发式冷凝器的单位排热量水泵能耗差异近一倍。它们的水泵平均能耗约为立式水冷式的46%、约为卧式水冷式的42%。实际运行中,蒸发式冷凝器的风机能耗占主导。     

The new ethical trilemma: Security, privacy and transparency

Numerous ethical and societal issues are related to the development of nanotechnology. Among them, the risk for privacy has long been discussed. Some people say that technology is neutral and that it does not really change the nature of problems, which are mainly political, while others state that its contemporary developments considerably amplify them; there are even persons who assert that it will make privacy protection obsolete. This article discusses those different positions by making reference to the classical Panopticon that is an architecture for surveillance, which characterizes the total absence of privacy. It envisages the possible evolutions of the Panopticon due to the development of nanotechnologies. It shows that the influence of nanotechnology on privacy concerns cannot be dissociated from the influence of computers and biotechnologies, i.e. from what is currently called the NBIC convergence. Lastly, it concludes on the new ethical trade-off that has to be made between three contradictory requirements that are security, transparency and privacy.     

飞秒强激光对二氧化钛金红石晶体相变的影响

该文章报道了利用显微激光拉曼光谱仪研究近红外飞秒强激光脉冲诱导二氧化钛金红石单晶所引起的相变.实验辐照时间为60s,当激光辐照平均功率增加时,锐钛矿相的拉曼振动模式强度增强,金红石相的拉曼振动模式强度减弱.通过金红石相和锐钛矿相粉体等拉曼光谱的实验,肯定了随着辐照激光功率的增大,.可以通过拉曼光谱中锐钛矿A1g B1g(515 cm-1)振动模式标志峰和金红石相Eg(445 cm-1)振动标志峰分别对应面积的比判断其相变量.     

Full Quantum Theory of Transient-State Electromagnetically Induced Transparency

We develop a full quantum theory of transient-state electromagnetically induced transparency (EIT) in the vapor of three-level A-type atoms interacting with probe and coupling lasers. As applications of the full quantum theory, we show that transient-state EIT medium exhibits normal dispersion and find that group velocities of both coupling and probe lasers are greatly reduced. It is shown that the group velocity of the probe laser in the transient-state EIT case is equal to that in the adiabatic EIT case and that the coupling laser group velocity in the transient-state EIT is generally less than that in the adiabatic EIT.     

Quantum Measurement of Two-Qubit System in Damping Noise Environment

It is known that the inevitable interaction of the entangled qubits with their environments may result in the degradation of quantum correlation.We study the decoherence of two remote qubits under general local single-and two-sided amplitude-damping channel(ADC).By using concurrence,quantum discord and Clauser-Horne-ShimonyHolt(CHSH)inequality,we find that the relation between the residual quantum correlations and the initial ones are different.Recently,Wang et al.[Int.J.Theor.Phys.54(2015)5]showed that there exist a set of partially entangled states that are more robust than maximally entangled states in terms of the residual quantum correlation measured by concurrence,fully entangled fraction and quantum discord,respectively.Here we find that both in single-and two-sided ADC,only the evolution of CHSH inequality with the initial parameter is proportional to that of the initial nonlocality.That means the initial state with maximally nonlocality will retain its role in the evolution.It implies that the evolution of nonlocality may reveal the characteristics of quantum state better.Furthermore,we discuss the evolutions of the three different quantum measurements with the initial parameter under generalized amplitude damping channel(GADC)and find that they are all proportional to that of the initial state.     

The Geometric and Thermodynamic Properties of Grain Boundary Junctions

We provide an overview of the properties of triple junctions and quadruple points. It is shown that these junctions may exhibit distinct behaviors that imply that they have and thermodynamically distinct properties in the same way that grain boundaries can be considered as thermodynamically distinct phases, separate from the material that they inhabit. It is shown that the treatment of triple junctions as thermodynamically distinct defects is a natural extension of the treatment of grain boundaries, and that it can be further extended to other junctions such as quadruple nodes. Equilibrium dihedral angles under conditions of anisotropic interfacial energy are explored, and it is found that the dihedral angles may be variable under a range of different conditions.     

Entanglement and Non-Locality in Quantum Protocols with Identical Particles

We study the role of entanglement and non-locality in quantum protocols that make use of systems of identical particles. Unlike in the case of distinguishable particles, the notions of entanglement and non-locality for systems whose constituents cannot be distinguished and singly addressed are still debated. We clarify why the only approach that avoids incongruities and paradoxes is the one based on the second quantization formalism, whereby it is the entanglement of the modes that can be populated by the particles that really matters and not the particles themselves. Indeed, by means of a metrological and of a teleportation protocol, we show that inconsistencies arise in formulations that force entanglement and non-locality to be properties of the identical particles rather than of the modes they can occupy. The reason resides in the fact that orthogonal modes can always be addressed while identical particles cannot.     

非离子型O／W微乳液导数分光光度法测定铝的增敏作用

本文研究了Ｔｒｉｔｏｎ－Ｘ－１００正戊醇／正壬烷／水组成的非离子型Ｏ／Ｗ微乳液对铬天菁Ｓ为显色剂，二阶导数分光光度法测定铝的增敏作用。结果表明，此法简便，快速，与相应的胶束体系比较，测定灵敏度有所提高，某些试验条件更为宽容，可不经分离直接测试试样中的微量铝。通过测定显色剂ＣＡＳ在胶束，微乳液中的分配系数和平均有效介电常数，探讨了微乳液增敏作用的机理。     

航天器变速热泵回路的技术优势分析

在保证航天器废热排放量的基础上,通过计算对比分析了固定转速热泵回路热控系统和变速热泵回路热控系统的耗电量,结果证明后者比前者节能20％左右。综合分析还表明:变速热泵可以实现软启动,对航天器上的电网无冲击,对其它用电设备无干扰;可以实现快速制冷和供热;控温精度高,回舱流体温度波动小;可靠性高,寿命长;脉动噪声小;可以实现无级调速,具有热负荷调节范围宽等技术优势。变速热泵技术已经发展成熟,具备了在航天器上应用的条件。     

Does the Realistic Interpretation of a Mathematical Superposition of States Imply a Mixture?

Contrary to conventional view, it is shown that, for an ensemble of either single-particle systems or multi-particle systems, the realistic interpretation of a mathematical superposition of states that mathematically describes the ensemble does not imply that the ensemble is a mixture. Therefore it cannot be argued, as is conventionally done, that the realistic interpretation is wrong on the basis that some predictions derived from the mixture are different from the corresponding predictions derived from the mathematical superposition of states.     

癌细胞对血清光谱的影响

研究了在血清中加入不同剂量的癌细胞对血清光谱的影响。比较了两种癌细胞的光谱 ,并与正常血清的谱线做了比较。实验结果表明 :随着癌细胞个数的降低 ,吸收谱和荧光谱强度均呈增加趋势 ,但增加到一定程度时又开始下降 ;正常血清的谱线强度明显较强。结论 :荧光光谱表明癌细胞抑制了正常血清中某种基团的振动 ,吸收光谱则表明癌细胞抑制了酪氨酸对光的吸收。     

Energetics of molecular motor proteins: could it pay to take a free ride?

ABSTRACT

Molecular motor proteins are used in biological systems to generate directed motion. They consist of one end that can bind to and then move along a filament. The other end can then bind to a cargo that needs transporting and the motor then pulls it along. Here, we consider the energetics of this process allowing for the friction force exerted by the surrounding fluid, given that the process takes place in a confined geometry. In nature, not all motor/cargo complexes are bound to the filament, many are in solution. Here, we address the question of whether this can be energetically favourable given that the unbound complexes will be transported by the flow generated by those that are bound. A simple theory suggests that this is the case and that there exists an optimal coverage of bound complexes. Simulations of a model of this system that includes all the relevant hydrodynamic effects confirm that the assumptions in the theory are valid so long as the coverage of bound complexes is not too low. Using realistic values for the parameters involved yields an optimal coverage that is plausible for the biological systems involved.     

Shape-controlled crystallisation pathways in dense fluids of ccp-forming hard polyhedra

Emergent directional entropic forces that favour facet-to-facet alignment of neighbouring colloidal particles – arising from multi-body interactions upon crowding – should cause the process by which colloidal crystals form from fluids of hard polyhedra to be different than that from fluids of hard spheres. We compute nucleation-free energy barriers for a family of shapes that all self-assemble the same cubic close-packed (ccp) crystal structure formed by hard spheres and find that changing rhombicuboctahedra into rhombic dodecahedra by successively removing facets that compete with the ccp structure cause a systematic decrease in barrier heights. We show that this decrease arises from the increased prominence of facets aligned with neighbouring shapes in the target crystal, which produce local environments in the fluid that facilitate crystallisation.     

Valence electronic structure of tantalum carbide and nitride

The valence electronic structures of tantalum carbide (TaC) and tantalum nitride (TaN) are studied by using the empirical electronic theory (EET). The results reveal that the bonds of these compounds have covalent, metallic and ionic characters. For a quantitative analysis of the relative strength of these components, their ionicities have been calculated by implanting the results of EET to the PVL model. It has been found that the ionicity of tantalum carbide is smaller than that of tantalum nitride. The EET results also reveal that the covalent electronic number of the strongest bond in the former is larger than that of the latter. All these suggest that the covalent bond of TaC is stronger than that of TaN, which coincides to that deduced from the first-principles method.     

电荷转移对纳米金属吸附分子拉曼光谱影响

在金,银纳米粒子表面修饰对巯基苯胺(PATP)分子,对其进行紫外及拉曼光谱性质表征。紫外吸收光谱显示修饰了单分子层的纳米粒子表面等离子体共振发生较大的红移,银粒子位移程度大于金粒子的。其拉曼散射增强效应研究表明,对巯基苯胺b2振动模式的极大增强是由电磁增强和化学增强效应共同决定的。金、银粒子上对巯基苯胺单分子层拉曼散射增强效应的差异主要来自金属与对巯基苯胺之间电荷转移能力的不同。     

293～563 K下甲醇结构的研究

利用金刚石压腔和拉曼光谱,研究了甲醇从室温到563 K下的结构特征。结果表明：随着温度的升高,体系压力也在不断增大;ν_CH区伸缩振动和ν_OH区伸缩振动同时受到温度和压力的影响,但两种作用相反。由于压力效应大于温度效应,随温度压力的增大,ν_CH区伸缩振动的拉曼位移向高频方向移动,说明C—H键键能在增大;而O—H伸缩振动峰的相对面积随温度压力的增大而增大,说明对C—H键而言,O—H键总强度是增加的,由此推测在地质条件下,压力可能阻碍或延长了干酪根的降解生烃过程。     

Tiling solutions for optimal biological sensing

Biological systems, from cells to organisms, must respond to the ever-changing environment in order to survive and function. This is not a simple task given the often random nature of the signals they receive, as well as the intrinsically stochastic, many-body and often self-organized nature of the processes that control their sensing and response and limited resources. Despite a wide range of scales and functions that can be observed in the living world, some common principles that govern the behavior of biological systems emerge. Here I review two examples of very different biological problems: information transmission in gene regulatory networks and diversity of adaptive immune receptor repertoires that protect us from pathogens. I discuss the trade-offs that physical laws impose on these systems and show that the optimal designs of both immune repertoires and gene regulatory networks display similar discrete tiling structures. These solutions rely on locally non-overlapping placements of the responding elements (genes and receptors) that, overall, cover space nearly uniformly.     

Can an Attractive Potential Increase the Pressure of an Ideal Electron Gas?

We examine the intuitive, classical idea that an interactive system involving commonly used attractive potentials should always have a pressure which is less than that of an ideal Fermi gas. We find that quantum effects are of crucial importance and that, while this idea is normally correct, under certain circumstances, the pressure can exceed that of the ideal Fermi gas.     

Robust wide zero-average-index gap in photonic heterostructures that incorporate left-handed materials

In this article, we theoretically study electromagnetic waves that propagate in a one-dimensional photonic heterostructure that contains left-handed materials. We suggest a type of heterostructure that is composed of two photonic crystals (PCs) that consist of different materials, rather than the previously studied heterostructures that are based on changing the thicknesses of alternating layers, to target zero-average-index gap enlargement. Numerical calculations of the transmittance show that the suggested structure possesses an ultra-wide zero-average-index gap that is robust for both transverse electric and magnetic polarizations. The demonstrated wide gap is independent of the incidence angle. The proposed structure works as a perfect stop-band filter, which completely blocks both polarizations, and may have many other potential applications.