The pore arrangement in the emu (Dromaius novæhollandiæ) eggshell as shown by plastic models

Pores arising in the cone layer merge with a plexus of tubules running just under and parallel to the outer surface of the emu eggshell. The outer surface of the shell is irregular due to dark green crystalline material arranged as flat domes. The plexus of tubules vent to the ambient environment via short pores opening in the valleys between these domes.     

Gasbench-IRMS水平衡氢同位素分析方法研究及应用

采用Gasbench-IRMS对水平衡氢同位素质谱分析影响因素进行了研究，确立了分析方法。通过实验室和标准水样GBW04403的分析，验证了该方法具有良好精度和准确度。在此基础上进行了本地饮用水的分析，并结合H_2^-H₂O(l)体系氢同位素分馏平衡方程，实现实验室氢气工作标准气的标定，结果与铬还原法标定值相一致。     

Assessment of Sliding Friction of a Nanostructured Solid Lubricant Film by Numerical Simulation with the Method of Movable Cellular Automata (MCA)

Tribofilms formed during dry sliding usually exhibit a nanocrystalline structure and complicated composition. In the present study, tribofilms consisting mainly of a solid lubricant, namely graphite nanoparticles, are considered. Systems providing such tribofilms are candidates for anti-friction applications. Since sliding action always leads to mixing of the materials at both sides of the tribological interface, it was of major interest to study the impact of different amounts of a hard constituent, SiC in the considered case, within the soft matrix systematically. Furthermore, the impact of normal pressure was considered. A mechanically mixed layer was observed for the whole range of normal pressures and SiC volume fractions. The calculated coefficient of friction decreased significantly with increasing thickness of this layer but was only marginally affected by SiC volume fraction, which is good news for anti-friction applications.     

Retraction of ‘Basu,S., Dahl,K.N. & Rohde,G.K. (2013) Localizing and extracting filament distributions from microscopy images. Journal of Microscopy, 250, 57–67. doi:10.1111/jmi.12018’

The above article, published online on 4 March 2013 in Wiley Online Library ( wileyonlinelibrary.com ), has been retracted by agreement between the authors, the journal Editor in Chief, Tony Wilson, the Royal Microscopical Society and John Wiley & Sons Ltd.  The retraction has been agreed following an investigation by an ad hoc advisory committee of senior faculty members assembled by the College of Engineering, Carnegie Mellon University. The committee concluded that all the parties involved acted honourably, but implicit misunderstandings and unintended miscommunications led to the unfortunate inclusion of several images used in the study without proper approval from the copyright owner.     

Cellular architecture of the testis of Egyptian wild boar (Sus scrofa) in young and adult age

Testicular parenchyma is split into lobules, each lobule contains convoluted seminiferous tubules surrounded by myoid cells and the interstitial tissue contains groups of Leydig cells. The seminiferous tubules are lined by two groups of cells the first one is the spermatogenic cells and the second one is Sertoli cells.     

Determination of protein with Thioguanine (6-TG) as a probe by synchronous fluorescence technique

The synchronous fluorescence technique was developed for the determination of human serum albumin (HSA) in human body fluids with Thioguanine (6-TG) as a molecular probe. Under the optimal experimental conditions, the synchronous fluorescence peak of HSA–6-TG system is located at about 301 nm and the enhancement synchronous intensity was proportion to the concentration of HSA. The calibration graphs are linear over the range of 0.69–552.0 μg mL⁻¹ with a correlation coefficient (R) of 0.9994. The detection limit was 0.133 μg mL⁻¹. It was successfully applied to determine the protein in human body fluids including serum, urine and saliva samples with 6-TG as probe with a satisfying result. In the analysis of human body liquids samples, the relative standard deviations (RSDs) were 0.55–3.31%, which obtained from 6 replicate determinations and recoveries were in the range of 97.0–104.1%.     

5-Br-PADAP-OP显色体系分光光度法测定水中镉(Ⅱ)

以2-(5-溴-2-吡啶偶氮)-5-二乙氨基苯酚(5-Br-PADAP)为显色剂,采用分光光度法直接测定了水中的微量镉。镉(Ⅱ)与5-Br-PADAP形成1：2的红色稳定络合物,最大吸收波长位于560nm处。镉含量在0～15μg/25mL范围内符合比尔定律,表观摩尔吸光系数为ε_(560)=1．35×10~5L·moL~(-1)·cm~(-1)。人工合成样的平均回收率为104．25％,相对标准偏差为3．55％。使用该方法测定浑河水、地下水、自来水、海新河水中镉的含量,相对标准偏差分别为0．60％、0．72％、0．51％、0．31％。加标平均回收率分别为97．93％,101．69％、99．46％、99．36％。该方法准确性、选择性良好,操作简便、快捷,有一定的实用性。     

包覆聚丙烯酸正丁酯硅胶键合固定相RP-HPLC法测定多环芳烃

以3-巯丙基三甲氧基硅烷为偶联剂,将聚丙烯酸正丁酯(BAn)键合到硅胶上,制成反相高效液相色谱法(RP-HPLC)用包覆聚丙烯酸正丁酯硅胶键合固定相(Sil-BAn)。采用Sil-BA16固定相,以甲醇-水混合液为流动相,对多环芳烃、硝基取代甲苯、二氯苯结构异构体进行了液相色谱法分析,考察了该键合固定相的适用pH范围及水解稳定性。结果表明,Sil-BA16能迅速分离多环芳香族化合物;Sil-BA16对硝基取代甲苯的保留性能小于二氯取代苯。该固定相基于多重羰基π-苯环π间的相互作用对芳香族化合物可以达到迅速良好的分离,并且在pH=2.5～7.5范围内水解稳定性良好。     

反相高效液相色谱法测定喹吖啶酮类颜料中间体2，5-二对氯苯氨基-1，4-苯二甲酸的纯度

建立了利用反相高效液相色谱法(RP-HPLC)测定喹吖啶酮类有机颜料中间体2,5-二对氯苯氨基-1,4-苯二甲酸(DpCTA)纯度的方法.所用色谱柱为C18EcIipse XDB(150mm×4.6mm,5μm),流动相为乙腈--乙酸铵缓冲溶液(体积比为63:37,Ph为4.0),流速为1.0 Ml/min,检测波长为330nm,柱温20℃.在该色谱条件下进行样品测定,DpCTA含量在20～120 mg/L范围内线性关系良好,相关系数为0.9995.实验表明,该法可用于DpCTA的纯度分析.     

Mono- and multiatomic steps with constant periodicity as observed by STM in vicinal Au(111) surfaces

Scanning tunnelling microscopy images of a vicinal Au(111) surface obtained in UHV are presented. Arrays of mono- and multiatomic steps along the [011] direction are seen with a peculiarly constant periodicity. The steps, exposing (100) facets, have a height ranging from one to seven atoms while the terrace width of eight atoms remains constant.     

Boundary Lubrication of Oxide Surfaces by Poly(L-lysine)-g-poly(ethylene glycol) (PLL-g-PEG) in Aqueous Media

In this work, we have explored the application of poly(L-lysine)-g-poly(ethylene glycol) (PLL-g-PEG) as an additive to improve the lubricating properties of water for metal-oxide-based tribo-systems. The adsorption behavior of the polymer onto both silicon oxide and iron oxide has been characterized by optical waveguide lightmode spectroscopy (OWLS). Several tribological approaches, including ultra-thin-film interferometry, the mini traction machine (MTM), and pin-on-disk tribometry, have been employed to characterize the frictional properties of the oxide tribo-systems in various contact regimes. The polymer appears to form a protective layer on the tribological interface in aqueous buffer solution and improves both the load-carrying and boundary-layer-lubrication properties of water.     

The Influence of location of balls and ball diameter difference in rolling bearings on the nonrepetitive runout (NRRO) of retainer revolution

The nonrepetitive runout (NRRO) value of retainer revolution is caused mainly by the diameter differences of balls mounted in a bearing. Additionally, when more than one ball has diameter difference, the NRRO value of retainer revolution is believed to vary with the location of balls. In this study, the authors theoretically analyzed the NRRO value of retainer revolution considering the diameter differences and location of balls mounted in a bearing. Consequently, it is clarified that the mean value of the retainer revolution component calculated in all locations of balls decreased with increasing number of balls in a rolling bearing.     

流动注射分光光度法测定溶液中镍（Ⅱ）和钻（Ⅱ）含量

本文研究了流动注射分光光度法测定溶液中镍和钴含量的新方法。以三乙烯四胺溶液作载流，分别在210nm和220nm处建立了镍和钴的标准曲线，并通过控制pH值实现了混合液中两种离子含量的测定。镍和钴离子的定量线性范围分别为0．2～1×10^-4mol／L和0．2～1×10^-5mol／L，最低检出限为0．1×10^-4mol／LNi和0．1×10^-5mol／LCo，相对标准偏差（RSD）分别为1．1％和2．7％，方法简便易行，测定结果令人满意。     

Reduction of erosion rate by particle size distribution (PSD) modification of hematite as weighting agent for oil based drilling fluids

Natural hematite (Fe₂O₃) and barite (Ba₂SO₄) are usually employed as weighting agents for oil based drilling fluids in several venezuelan fields. Hematite has shown some physico-chemical advantages with respect to barite: a greater specific gravity and solubility in acid media and lower attrition rate. However, the most challenging issue related to hematite field applications has been to reduce its high erosive potential. Effects of particle size distribution (PSD) have been evaluated with four different samples of hematite (48, 38, 30 and 18 μm based on the statistical parameter D_(v,0.9)) respect to commercial barite. These samples were used to prepare fluids with a density of 1977 kg/m³. An erosion test loop was used to expose different samples of AISI 1020 flat steel to the erosive action of jet fluid. Wear of metallic samples was measured by weight lost and wear mechanisms were identified by laser profilometry, SEM and EDS. The investigation showed that the erosion rate (E) produced by hematite decreases potentially with size grain reduction (D_(v,0.9)) and depends on the morphology and angularity of the particle in comparison with barite. Laboratory results were validated on field tests with drilling fluids formulated with hematite of different PSD.     

Nanofinishing of freeform surfaces (knee joint implant) by rotational-magnetorheological abrasive flow finishing (R-MRAFF) process

Freeform complex surfaces have become an inevitable part of many devices to perform specific functions. Some of these components require nanolevel surface roughness value to meet the desired requirements in their applications. Finishing of freeform surfaces to nanometer surface roughness value is always difficult for any process. Rotational-magnetorheological abrasive flow finishing (R-MRAFF) process has been applied so far for finishing internal surfaces of relatively simple geometry. In this work, an attempt has been made to improve external topography of freeform surfaces using this process. Large hydrodynamic pressure coupled with magnetic fluid is the principal idea behind these experiments. A smooth mirror like finished surface is achieved with improved finishing rate (nanometer/min) by controlling two motions (axial and rotational) simultaneously on stainless steel workpiece similar to knee joint implant. Magnetorheological polishing fluid with different mesh sizes of abrasive particles and at different extrusion pressures is used to reduce final surface roughness value, to increase uniformity of surface finish on the freeform surface and to enhance finishing rate. Surface roughness ranging from 35 to 78 nm is achieved at various locations as compared to larger variation in Ra value obtained in the earlier research work.     

Leaf epidermal characters of Solanum sect. polytrichum (Solanaceae) as taxonomic evidence

The morphological similarities among the species of Solanum are remarkable, and are often very difficult one clear distinction between them. This paper presents a comparative anatomical study of the leaf epidermis of five Brazilian species of Solanum sect. Polytrichum, carried out using light and scanning electron microscopy. The leaf epidermis surfaces were investigated to evaluate their taxonomic significance to be used for separation and delimitation of the species of the section. As results, some micro-morphological characters of the leaf epidermis, such as density, distribution and type of stellate trichomes, and the anticlinal walls of epidermal cells, and also the type and distribution of stomata proved to be the most useful and distinctive characters for the separation and delimitation of the species, and also may contribute as an additional support to the interspecific taxonomy and systematic of Solanum sect. Polytrichum.     

用仿真工具优化车辆动力系统(一)

在本文的第一部分，介绍了一种理想的车辆动力系统的计算机辅助开发过程。它显示了现代仿真技术在产品持续发展过程中的作用，该技术采用硬件回路作非在线的仿真，并通过现代化的试验手段对车辆进行匹配。特别重要的是提供了将电控变速器和发动机控制单元综合的可能性。接着是在线仿真在诸如发动机和变速器模式方面的应用和发展，它是上述开发过程的基础。根据上述的方法论，本文论述了仿真技术已取得的成绩和将来的应用可能性。     

用仿真工具优化车辆动力系统(二)

在本文的第一部分，介绍了一种理想的车辆动力系统的计算机辅助开发过程。它显示了现代仿真技术在产品持续发展过程中的作用，该技术采用硬件回路作非在线的仿真，并通过现代化的试验手段对车辆进行匹配。特别重要的是提供了将电控变速器和发动机控制单元综合的可能性。