Antennal sensilla of some forensically important flies in families Calliphoridae, Sarcophagidae and Muscidae

Antennal sensilla of some forensically important fly species in the families Calliphoridae (Chrysomya megacephala, Chrysomya rufifacies, Chrysomya nigripes and Lucilia cuprina), Sarcophagidae (Parasarcophaga dux) and Muscidae (Musca domestica) were studied using scanning electron microscopy. Five types of sensilla were observed: trichoid, basiconic, coeloconic, styloconic and sensory pit. Only trichoid sensilla are found on the scape of the antenna, while both trichoid and styloconic sensilla are located on the antennal pedicels of all species studied. Basiconic sensilla are the most numerous of the sensilla found on the antennae of both sexes of all fly species studied and are comprised of two subtypes: large and small basiconic sensilla. Coeloconic sensilla are characterized by short pegs, with either grooved or smooth surfaces, that are sunken into deep depressions. No marked difference was observed in the number, morphological structure or distributional pattern of any of the sensilla among the species studied, with the exception of there being more numerous sensory pits detected in female P. dux compared to the other species. The suggested function of each antennal sensillum was based on comparison with results of other investigations on similar sensilla.     

Sensory Equipment of the Antennal Flagellum of Several Species of Damalinia (Phthiraptera: Trichodectidae)

Sensilla comprising the sensory equipment of the antennal flagellum of eight species of Damalinia were studied using light and scanning electron microscopy. The sensillar complex consists of three pore organs and two sensilla coeloconica in both males and females. No relationship between their relative position in different genera and species has been found. The ‘pit organs' of the sensilla coeloconica have different shapes according to species. In the apex of the male flagellum, teeth are present in the species studied but the number and shapes are different. Adjacent to the teeth is a cluster of sensilla basiconica. At high magnification, no pores were found in the sensilla walls but their more or less blunt tips have small pores. The inner face of the male flagellum can be serrated or non-serrated.     

Larval ultrastructure of Parasarcophaga dux (Thomson) (Diptera: Sarcophagidae)

Ultrastructure of all larval instars of Parasarcophaga dux (Thomson), a common flesh fly species in Thailand, is presented using scanning electron microscopy. Special attention is given to the structure of anterior and posterior spiracles since these are important features used to differentiate between other sarcophagids. Each anterior spiracle in second and third instars has a single row of papillae varying in number from 14 to 17. The posterior spiracular discs have incomplete peritremes, with a prominent inner arc. Three long, narrow spiracular slits are oriented more or less vertically in each spiracular disc of third instar. Posterior spiracular hairs lack extensive branching and emanate approximately midway down the length of each slit. Microscopic morphology of the mouthhooks markedly differs between the first and second instars. The structure of these mouthhooks supports this fly species as being necrophagous or capable of producing myiasis.     

四种黑檀心材的红外光谱差异化与聚类分析

利用红外光谱结合模式识别和二维相关光谱对乌木、东非黑黄檀、风车木和成对古夷苏木四种黑檀硬木心材进行鉴别和聚类分析。红外光谱显示四种木材中的主体成分为纤维素（特征吸收峰位置在~1 370, ~1 158, ~1 034和~895 cm-1附近）、木质素（特征吸收峰位置~2 935, ~1 510, ~1 462和~1 426 cm-1附近）和草酸钙（特征吸收峰位置~1 615, ~1 318和~781 cm-1附近）。三种主体成分在四种木材红外光谱之间的相对峰强度H表明：乌木和东非黑黄檀中木质素含量较高,风车木中草酸钙含量较高,成对古夷苏木中含有一定量的脂类成分。根据红外光谱的差异性选取不同的波段,优选计算参数,分别对四种硬木心材进行相关系数判别分类和SIMCA聚类分析。相关系数判别分类模式识别中,成对古夷苏木中有一个样本未得到有效的验证,但是其余三个木材样品均得到了有效验证。SIMCA聚类模式识别中,四种木材心材之间的识别率、拒绝率和验证率都达到100%,说明不同木材之间没有重叠区域,可以完全的区分识别。二维相关红外光谱中,乌木与东非黑黄檀在升温过程中纤维素的C—O和C—C基团对温度敏感性较高,风车木中草酸钙热敏性较高,成对古夷苏木中木质素的热敏性高于纤维素。红外光谱结合聚类分析和二维相关红外光谱,不仅可以对木材主体成分进行的定性和相对含量的分析,在完善聚类模型基础上还可以对木材种类进行快速、有效的分类模式识别。     

ICP-MS法分析不同种质荒漠肉苁蓉矿质元素分布特征

矿质元素是中药材品质评价的重要指标之一,与中药材功效物质合成及其功效的发挥密切相关,中药材矿质元素含量受其种质、采收时期、药用部位、产地等因素的影响。荒漠肉苁蓉是我国著名补益中药,也是药食同源类药材,其矿质元素含量越来越受到人们关注。应用ICP-AES法测定了黄花、白花、紫花三种类型荒漠肉苁蓉不同部位4种常量矿质元素和8种微量矿质元素含量。结果表明：（1）不同类型荒漠肉苁蓉均含有K、Ca、Mg、Na、Fe、Mn、Cu、Zn、Cr、As、Pb和Cd元素,但不同类型荒漠肉苁蓉矿质元素含量差异较大,黄花肉苁蓉矿质元素含量低于白花肉苁蓉和紫花肉苁蓉;白花肉苁蓉K、Ca、Mg、Na、和Cu含量高于紫花肉苁蓉,而Zn、Cr和Cd含量低于紫花肉苁蓉。（2）荒漠肉苁蓉中12种矿质元素分布特征差异明显,K、Ca、Mg、Na和Cu主要分布在上部。（3）荒漠肉苁蓉不同部位矿质元素比值差异显著,三种类型荒漠肉苁蓉K/Na值均为下部>中部>上部;Mg/Fe值紫花、白花类型中部最高,黄花类型上部最高;Zn/Mn比值紫花和黄花类型中部最高,而白花类型下部最高;Cu/Cr值白花和黄花类型上部最高,紫花类型中部最高。研究结果将为荒漠肉苁蓉的良种选育和质量控制与利用提供数据支撑。     

Cytochemical localization of calcium and X-ray microanalysis of Catharanthus roseus L. infected with phytoplasmas

The potassium pyroantimonate (KPA) Ca²⁺ precipitation technique, X-ray microanalysis and Electron Energy Loss Spectroscopy carried out by transmission electron microscopy were used to analyze the Ca²⁺ distribution in Catharanthus roseus L. leaves infected with phytoplasmas belonging to different taxonomic groups, and in phytoplasma cells. The analysis revealed that the distribution of Ca²⁺ was different in healthy and diseased plants (where the KPA deposits were numerous) and no differences were observed in the tissues of the three types of infected C. roseus L. Since no KPA precipitates were visible in the phloem and on phytoplasma cells, it is likely that Ca²⁺ ions are not directly involved in phytoplasma replication, but, in infected cells is a response to the pathogen indicative of a higher Ca²⁺ in the plasmalemma.     

Significant decrease in interfacial energy of grain boundary through serrated grain boundary transition

The mechanism of serrated grain boundary formation and its effect on liquation behaviour have been studied in a wrought nickel-based superalloy – Alloy 263. It was newly discovered that grain boundaries are considerably serrated in the absence of γ?′-phase or M₂₃C₆ at the grain boundaries. An electron energy-loss spectroscopy study suggests that serration is triggered by the discontinuous segregation of C and Cr atoms at grain boundaries for the purpose of relieving the excessive elastic strain energy. The grain boundaries serrate to have specific segments approaching one {111} low-index plane at a boundary so that the interfacial free energy of the grain boundary can be decreased, which may be responsible for the driving force of the serration. The serrated grain boundaries effectively suppress grain coarsening and are highly resistant to liquation due to their lower wettability resulting from a lower interfacial energy of the grain boundary.     

A guide on FIB preparation of samples containing stress corrosion crack tips for TEM and atom-probe analysis

The preparation of samples containing stress corrosion crack tips for 3D atom-probe tomography and transmission electron microscopy is of ultimate importance for understanding the mechanisms controlling crack propagation. In this paper, it will be shown that a focused ion beam machine equipped with an in situ micromanipulator is an ideal tool to systematically prepare such demanding samples. The methodology is described and discussed in detail, and several results are presented to demonstrate the potential of the technique.     

The effect of Magic Angle Spinning on proton spin–lattice relaxation times in some organic solids

Proton spectra of solids are usually broadened by strong proton homonuclear dipolar interactions. However, substantial line narrowing may be achieved by Magic Angle Spinning (MAS) in systems of low proton density or in systems in which rapid molecular motions occur. In such conditions, T₁(H) measurements are often used to characterise the dynamics of each resolved proton site. We show that T₁(H) values measured for solid organic compounds with high proton abundance, such as adamantane and glycine, may be strongly dependent on the spinning rate employed, so that care is required when values are compared. The effects of molecular motion and proton density on T₁(H) and its dependence on spinning rate were investigated. We found that an increase in molecular motion leads to an increase of T₁(H) at higher spinning rates. The opposite is found for systems with low proton densities which show relatively lower T₁(H), at higher spinning rates. A possible interpretation is suggested in terms of the reduced spin diffusion efficiency at higher spinning rates.     

Mouthparts of Megaselia scalaris (Loew) (Diptera: Phoridae)

Mouthparts of adult Megaselia scalaris (Loew), a fly species of medical importance, were examined using scanning electron microscopy. Sexual dimorphism of the labellum was observed in the mouthpart structures of this species. The labella of males were clothed with a dense covering of microtrichia, but these were found to be entirely absent from the labella of females. Aside from this difference, trichoid and conical sensilla that are most likely used as taste or contact chemoreceptors appear on the labellum and labrum of both sexes. In addition, five pairs of sharply pointed teeth at the ventral surface of the labellum is another feature that is shared by the two sexes. A plausible feeding mechanism for this fly is also advanced.     

Spectator fermion binding of bosons

We consider a two-component mixture of charged fermions on neutralizing background with all sign combinations and arbitrarily small mass ratios. In the two-impurity limit for the heavier component we show that the pair forms a bound state for all charge combinations. In the lowest order approximation we derive a closed-form expression for V_eff(r), the binding potential which has short-range repulsion followed by attraction. In the classical limit, when the mass of embedded particles is large, m₂ å m, we can calculate from V_eff(r) also the cohesive energy E and the bond length R of a metallic crystal such as lithium. For lithium metal the lowest-order result is R = 3.1 Å, E = −1.8 eV, while the corresponding experimental values are 3.4 Å and −1.6 eV. The same interaction for two holes on a parabolic band with m₂ > m gives the quantum mechanical bound state which one may interpret as a boson or local pair in the case of high-T_c and heavy-fermion superconductors.     

Incommensurability in an exactly-soluble quantal and classical model for a kicked rotator

The Hamiltonian H = 2πp + V(θ) Σ^∞_−∞ δ(t − n)(0 θ < 2π) is solved exactly, classically and quantally; the so lutions depend strongly on . There is no classical chaos and the phase cylinder p, θ is filled with invariant curves, which are finite loops around the cylinder if is sufficiently irrational and are translates of the infinitely long p axis if is rational. Quantal quasi-energy states correspond exactly to these invariant curves: localized in p and extended in θ if is sufficiently irrational, and extended in p and localized in θ if is rational. For a classical or quantal initial pure-momentum state, the energy at time t = n grows as n² if is rational (resonance) and remains bounded if is sufficiently irrational (non-resonance). If is very nearly rational (marginal resonance), the energy may grow as n^λ where λ is expressed in terms of exponents describing the irrationality of and the continuity class of V(θ). If the value of is uncertain, ensemble-averaging over shows that the energy grows ultimately as n, i.e. diffusively, as though under random impulses.     

Antibunching and sub-poissonian photon statistics in the Jaynes-Cummings model

Sub-poissonian photon statistics and antibunching by the definition based on the positive derivative of g⁽²⁾ (t, t+τ) as a function of the delay time τ at τ=0 are treated in a single-mode single-two-level-atom model. It is shown, in particular, that sub-poissonian behaviour may be accompanied by bunching or antibunching and photon-antibunching may be accompanied by sub-poissonian or super-poissonian field statistics. It is also shown that the photon-antibunching persists with increasing mean photon number of an initial chaotic state while the sub-Poisson behaviour disappears.     

3004铝合金“反常”锯齿屈服现象的研究

在应变速率为5.56×10^-5s^-1—5.56×10^-3s^-1的范围内，在不同温度下(从223K至773K)，对3004铝合金进行系列拉伸试验，探索其锯齿屈服规律；通过激活能的计算、内耗研究、微观组织观察和能谱分析，探讨锯齿屈服的机理与物理本质.结果表明，3004铝合金在形变过程中会出现动态应变时效现象；发现了一种“反常”的锯齿屈服现象：在出现锯齿屈服的温区内，存在锯齿屈服临界应变量转变温度T_t， 关键词： 动态应变时效 锯齿屈服 铝合金 内耗     

Frequency of voice problems among teachers and other occupations

This study describes the frequency of reporting vocal problems among a random sample of elementary and high school teachers (n = 554) compared to individuals working in other occupations (n = 220). Teachers were more likely to define themselves as ever having a voice problem (32% versus. 1 %, p < .05); having a tired, weak, or effortful voice (p < .05 each); and having a higher frequency of symptoms of physical discomfort with speaking (p < .05). They also were more likely to perceive that their voice problem negatively affected current job performance (p < .05) and limited options regarding change in work (p < .05). About 20% of teachers but only 4% of nonteachers had missed work due to their voice. These findings suggest that teachers are at highrisk for disability from voice disorders and that this health problem may have significant work-related and economic effects.     

Cavitation occurrence around ultrasonic dental scalers

Ultrasonic scalers are used in dentistry to remove calculus and other contaminants from teeth. One mechanism which may assist in the cleaning is cavitation generated in cooling water around the scaler. The vibratory motion of three designs of scaler tip in a water bath has been characterised by laser vibrometry, and compared with the spatial distribution of cavitation around the scaler tips observed using sonochemiluminescence from a luminol solution. The type of cavitation was confirmed by acoustic emission analysed by a ‘Cavimeter’ supplied by NPL. A node/antinode vibration pattern was observed, with the maximum displacement of each type of tip occurring at the free end. High levels of cavitation activity occurred in areas surrounding the vibration antinodes, although minimal levels were observed at the free end of the tip. There was also good correlation between vibration amplitude and sonochemiluminescence at other points along the scaler tip. ‘Cavimeter’ analysis correlated well with luminol observations, suggesting the presence of primarily transient cavitation.     

Integrability,multi-soliton and rational solutions,and dynamical analysis for a relativistic Toda lattice system with one perturbation parameter

Under investigation in this paper is a relativistic Toda lattice system with one perturbation parameter α abbreviated as RTL_(α) system by Suris, which may describe the motions of particles in lattices interacting through an exponential interaction force. First of all, an integrable lattice hierarchy associated with an RTL_(α) system is constructed, from which some relevant integrable properties such as Hamiltonian structures, Liouville integrability and conservation laws are investigated. Secondly, the discrete generalized(m, 2 N-m)-fold Darboux transformation is constructed to derive multi-soliton solutions, higher-order rational and semirational solutions, and their mixed solutions of an RTL_(α) system. The soliton elastic interactions and details of rational solutions are analyzed via the graphics and asymptotic analysis. Finally, soliton dynamical evolutions are investigated via numerical simulations,showing that a small noise has very little effect on the soliton propagation. These results may provide new insight into nonlinear lattice dynamics described by RTL_(α) system.     

Ge-Sb-Se硫系玻璃的折射率和热光系数

Ge-Sb-Se硫系玻璃被认为是极佳的红外传输材料和有潜力的非线性光学材料.在光学设计中,玻璃的线性折射率(n)及其热光系数(ζ)是关键技术参数.以预测和调控Ge-Sb-Se玻璃的n和ζ为目的,考察了玻璃的n,ζ,密度(d)和体积膨胀系数(β)与化学参数dSe和拓扑网络结构参数r的内在联系.研究发现,玻璃的n随d的增加而增大;ζ随β的增大而近似线性减小;β随dSe的减小或r的增大而减小;当Ge含量固定时, d随dSe的减小或r的增大而增大,当Sb含量固定时, d在dSe=0时具有最小值.基于实测d和n,拟合获得了Ge, Sb和Se元素在2—12μm波段的摩尔折射度(R_i),分别为R_(Ge)=10.16—10.50 cm~3/mol,RSb=16.71—17.08 cm~3/mol和RSe=11.15—11.21 cm~3/mol,根据d和R_i计算得到的n与实测值的偏差小于1%.基于实测ζ和β,拟合得到了Ge, Sb和Se元素在2—12μm波段的摩尔折射度温度系数(φ_i),分别为φ_(Ge)=21.1—22.6 ppm/K,φ_(Sb)=7.2—8.4 ppm/K和φ_(Se)=90.2—94.2 ppm/K,根据β和φ_i计算得到的ζ与实测值的偏差小于6 ppm/K.     

Branched polymers from a double-scaling limit of matrix models

Multicritical potentials and correlation functions are given for models of rectangular M × N matrices, in the limit that N goes to infinity. These models are soluble without using orthogonal polynomials, and describe filamentary random surfaces, or, equivalently, a phase of branched polymers. It is shown that the equations describing multicritical behaviour are obtained from the hierarchy of flows that preserve Burgers' equation. Instanton solutions are studied - they imply that only the k = 2 model is unitary, and that the coefficients (for arbitrary k) of g_st^l is the perturbative expansion of the specific heat grow as l!.     

The Thomas-Fermi atom in a strong magnetic field: The weak ionization limit

It is proved that the binding energy, radius and chemical potential of the N-electron Thomas-Fermi atom with the nuclear charge Z in a strong magnetic field at q = 1 − N/Z 1 may be expressed as a power series in q^1/3 and In q. The exact values of the first expansion coefficients are found. A comparison with numerical data shows these expansions to be applicable up to q = 0.2.