A New Aging Treatment Way for Near α High Temperature Titanium Alloys

Two near α titanium alloys,Ti-5.6Al-4.8Sn-2.0Zr-1Mo-0.35Si(1#) and Ti-6.0Al-4.8Sn-2.0Zr-1Mo-0.35Si(2#),were solution-treated in the upper α+β phase fields,and the duplex mixture microstructures consisting of the less volume fraction primary α phase(αp) and the transformed β phase(βt) were obtained.The aging treatments were carried out at 700℃ for 1# alloy and 760℃ for 2# alloy under varied terms,respectively.It guaranteed α2 ordered phase to precipitate only in αp but not in βt for the two alloys.The slower...     

BCC vs. HCP—The Effect of Crystal Symmetry on the High Temperature Mobility of Solid 4He

We report results of torsional oscillator (TO) experiments on solid ⁴He at temperatures above 1?K. We have previously found that single crystals, once disordered, show some mobility (decoupled mass) even at these rather high temperatures. The decoupled mass fraction with single crystals is typically 20–30%. In the present work we performed similar measurements on polycrystalline solid samples. The decoupled mass with polycrystals is much smaller, ～1%, similar to what is observed by other groups. In particular, we compared the properties of samples grown with the TO’s rotation axis at different orientations with respect to gravity. We found that the decoupled mass fraction of bcc samples is independent of the angle between the rotation axis and gravity. In contrast, hcp samples showed a significant difference in the fraction of decoupled mass as the angle between the rotation axis and gravity was varied between zero and 85 degrees. Dislocation dynamics in the solid offers one possible explanation of this anisotropy.     

Challenges for composites into the next millennium — a reinforcement perspective

This paper summarises the current level of technology within the manufacturing processes of filament winding, fibre placement, pultrusion and advanced textile preforming. It also examines the current problems within each of these manufacturing techniques and the areas of predicted future development.     

Quantitative Social Research — Belief Systems,the Way of Thinking and Sentiments of Five Nations —

The fundamental ideas of comparative quantitative social research from the international perspectives are mentioned in Introduction. Then a new method called cultural link analysis (abbreviated as CLA) is explained in section 2.

CLA includes the following three subjects.

• a. A spatial link inherent in the selection of the subject culture or society

• b. An item-structure link inherent in the commonalities and differences in item response patterns within and across different cultures

• c. A temporal link inherent in longitudinal analysis.

The design of data, based on this CLA, i.e. the method of cross-societal five nations’ surveys is described in the next section 3.

In the following sections, the analysis of data based on CLA are discussed. These topics are divided into two parts. In the first part, the formation of spatial link is depicted depending on the questions taken up in section 3. First, it emerges that Japanese-Americans in Hawaii make a linkage between Japanese and Americans. Then, it is shown that various links among the peoples in different cultures are found, depending on the questions used for analysis.

Section 4 (I) Japanese Americans in Hawaii as a linkage between Japanese and Americans

• (a) An Aesop’s fable

• (b) Interpersonal relations

• (c) Intermediate answers

Section 4(II) Relational graphic representation of each population based on simple tabulation. How chains are found …1.

Section 4(III) Relational graphic representation of each population based on the way of thinking and belief systems. How chains are found… 2.

In the second part, the results of analysis for the peoples in different cultures are discussed, based on the idea of “link of questions” in section 5.

Section 5(I) Analysis of various sets of questions

• (a) Trustfulness and work

• (b) Money, work and national goals

• (c) Aesop’s fable and related social attitudes

Section 5(II) Analysis on various scales

• (a) Analysis in every nation

• (b) Analysis by nation and concept-scale

• (c) Analysis by nation, scales and other questions

Section 6 Concluding remarks

The discussions of temporal link are not described here because, this problem has been already discussed in details in the book of “DAIGO NIHONJIN NO KOKUMINSEI” (The Fifth Volume of Japanese National Character), by Research Committee of Japanese National Character, The Institute of Statistical Mathematics; IDEMITSU SHOTEN, April, 1992.

     

The effect of adding Zn into the Sn–Ag–Cu solder on the intermetallic growth rate

Due to toxicity of lead in the commercial solder, lead-free solders were proposed. Among the potential lead-free solders, the Sn–Ag–Cu solders were considered as a potential replacement. To further improve the solder properties, a fourth element was added into the Sn–Ag–Cu solder. The present study investigates the effect of different weight percentage of Zn (up to 0.7 wt%) into the Sn-3.5Ag-1.0Cu solder on intermetallic and growth rate (k) after long time thermal aging. The solders were prepared using powder metallurgy method and X-ray diffraction analysis shows that there were Cu₆Sn₅, Cu₃Sn, CuZn and Ag₃Sn phases present after solder preparation. The solders were reacted with Cu substrate at 250 °C for 1 min and aged at 150 °C until 1,000 h. The morphology of the intermetallic was observed under scanning electron microscope and the elemental distribution was confirmed by energy dispersive X-ray. Intermetallic thickness and growth kinetic result show that the additions of 0.4 % zinc is sufficient in retarding the Cu₆Sn₅ and Cu₃Sn intermetallic growth.     

The magnicon — An advanced version of the gyrocon

A new VHF generator with circular deflection of a high power relativistic electron beam is described as an outgrowing of the gyrocon proposed by Budker in 1967.The output resonator of the device is placed in a static magnetic field providing synchronous interaction of electrons with the electromagnetic field. An accompanying magnetic field and prolonged time of interaction enable one to achieve higher power within the decimeter and centimeter wave range compared to that of the gyrocon and klystron due to the higher electrical strength of the output resonator, a decreased heat generation and an easier beam guidance. In order to get higher gain and efficiency the magnicon deflection resonator is also placed in a magnetic field (of double magnitude).Test results for a magnicon of 30 cm wave range built at the INP are given. The power obtained is 2.6 MW for a pulse duration of 30 μs with a repetition rate of 1 Hz and an electron efficiency of 85%.     

A Study of Diamond Growth Instability at High Temperature—High Pressure

In this paper, crystal growth instability of diamond was studied in a Fe-Ni-C system at high temperature-high pressure (HPHT). As any other crystal from solution, the flat or smooth growth interface of the diamond crystal is highly sensitive to growth conditions.The growth front interface should be of great importance to understand the diamond growth process.The presence of cellular growth interface by transmission electron microscopy indicated that there existed a narrow constitutional supercooling zone in front of the growth interface .Several parallel layers with cellular interface by TEM directly suggested that the diamond grows from the solution of carbon in the molten catalyst layer by layer, which is in accordance with the result obtained by scanning electron microscopy in this paper.Impurities are trapped by rapidly advancing growth layers during the diamond growth and they impose a great effect on the growth front stability.As the growth front interface approaches the impurity particle to a distance of about 10^-5-10^-7 cm, appreciable molecular forces begin to operate between them,and the impurity particle is trapped as the growth rate reaches a critical value.As a result,the driving force for crystallization under the impurity particles becomes smaller ,the front buckles under the particle.An impurity naturally reduces the growth rate to a different extent.     

Dislocation Mechanism of Diamond Crystal Growth from Fe—Ni—C System at High Temperature—High Pressure

Some dislocations,which are generated in the diamond single crystal during the diamond crystal growth from Fe-Ni-C system,may affect diamond crystal growth mode at high temperature-high pressure(HPHT). The concentric dislocation loops were successfully examined by Moire images.The surface morphologies of growing and as-grown diamond single crystals were observed by scanning electron microscopy(SEM).The concentric dislocation loops formation process and their effect on the diamond crystal growth mode were analyzed.It should be noted that whatever the nature of the dislocation is ,should the Burgers vector of dislocation has a component at the direction normal to the growth interface,the dislocation will make the face parallel to the growth interface grow into spiral face.The presence of consecutive spiral steps on the diamond crystal surface also provides a direct evidence of the dislocation mechanism of diamond crystal growth.     

The semi-elliptical surface crack—A solution by the alternating method

A numerical solution to the three-dimensional equations of elasticity is presented for the problem of a semi-elliptical surface crack in the surface of a finite thickness solid. The alternating method is used to develop the numerical results which incorporate the effects on the stress intensity factor due to the presence of both the front and the back surfaces. The stress intensity factor is presented as a function of position along the crack border for a variety of crack shapes and crack depths. A comparison of the results of this study is made with previous theoretical and experimental work.

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Résumé Une solution numérique à équations tridimensionnelles d'élasticité est présentée pour le problème de la fissure de surface semi-elliptique située en surface ou en solide d'épaisseurs finies.La méthode proposée est utilisée pour développer des résultats numériques qui incorporent les effets des facteurs d'intensité des contraintes associée à la fois des surfaces recto et verso du solide. Le facteur d'intensité des contraintes est décrit pour diverses positions de la fissure et ce dans divers cas de formes et de profondeurs de fissuration. Une comparaison est faite entre les résultats de cette étude et des travaux théoriques et expérimentaux antérieurs.

     

The focus of light—linear polarization breaks the rotational symmetry of the focal spot

Abstract

We experimentally demonstrate for the first time that a linearly polarized beam is focused to an asymmetric spot when using a high-numerical aperture focusing system. This asymmetry was predicted by Richards and Wolf in 1959 and can only be measured when a polarization-insensitive sensor is placed in the focal region. We used a specially modified photodiode in a knife-edge-type set-up to obtain highly resolved images of the total electric energy density distribution at the focus. The results are in good agreement with the predictions of a vectorial focusing theory.     

Lattice Distortion Analysis Directly from High Resolution Transmission Electron Microscopy Images—the LADIA Program Package

Direct strain mapping from high resolution transmission electron microscopy images is possible for coherent structures.At proper imaging conditions the intensity peaks in the image have a constant spatial relationship with the projected atom columns.This allows the determination of the geometry of the projected unit cell without comparison with image simulations.The fast procedure is particularly suited for the analysis of large areas.The software package LADIA is written in the PV-WAVE code and provides all necessary tools for image processing and analysis.Image iintensity peaks are determined by a cross-correlation technique,which avoids problems from noise in the low spatial frequency renage.The lower limit of strain that can be detected at a sampling rate of 44 pixels/nm is ≈2%.     

Integrating the customers’ perceived risks and benefits into the triple-channel retailing

Multiple channel retailing and channel selection strategy have become key issues for many corporations to place themselves at the heart of a new era of retailing. This paper studies a triple-channel system in which a manufacturer operates a conventional channel, a direct online channel, as well as increases its online presence with an online shopping platform. It also takes the heterogeneity of consumers’ price sensitivity and channel preferences into account. It highlights that the perceived risks and perceived benefits are aggregated into an inhibitor or activator entering the customers’ acceptance of triple channels and further affecting their purchasing decisions. Three cases are discussed to investigate the demand distributions, the profit behaviours, the optimal pricing strategies and the channel selection strategies. Theoretical analysis is further validated by a case study with the aid of agent-based modelling. Sensitivity analysis demonstrates that two acceptance indices – respectively, regarded as the consumers’ willingness to tolerate the perceived risks of the online channel and approve the perceived benefits from the third-party online platform – significantly govern the total profit in two stylised scenarios. This study schematically characterises the structure of demand distributions, helps the corporation to discern consumers’ channel choices and then focus its marketing efforts towards more profitable customers and strategic channel structures. Furthermore, some implications are outlined for the optimal supply chain designation decision.     

An Investigation into the Relationship Between Maintenance and Finance

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Investigation into The Yellowing on Aging of Sabril® Tablet Cores

Abstract

Uncoated Sabril® tablet cores under long term storage become slightly discolored from the initial white to a yellowish off-white color. In order to ensure the aesthetics of the product, Sabril tablet cores are film coated with an opaque white coating. The nature of this yellowing reaction was of interest even though discolored tablets showed no significant loss of potency on assay. Excipient compatibility studies showed that the vigabatrin active in Sabril mixed with Avicel (microcrystalline cellulose) in the presence of moisture also became off-colored when stressed at elevated temperatures.

The nature of the discoloration in aged Sabril core tablets was investigated. Chromatographic and spectroscopic data indicate that the source of this color comes from the Maillard Reaction between vigabatrin and Avicel which results in a multitude of products analogous to “browning reactions” of food products. A gravimetric determination of the leached colored products from 7 year old Sabril core tablets gave a residue of less than 0.1% relative to vigabatrin. Furthermore, based on spectroscopy, most of this residue was found to be povidone, an excipient in the tablets which was isolated along with the colored substances.

Therefore, the colored products identified in the core of Sabril tablets stored for an extended period of time represent only minor impurities. Their formation through aging arises via the Maillard Reaction and would only constitute a matter of aesthetics. The latter problem is avoided by the currently employed film coating process.

Similar reactions could be predicted for other drugs having amine functional groups if they are formulated with microcrystalline cellulose or reducing sugars.     

The determination of the permeability of concrete to oxygen by the Cembureau method—a recommendation

A committee was set up in 1981 by the Cembureau Working Party on the Quality of Concrete with the following aims and objectives:

The call of the intelligent MapIT G2——美国西蒙新一代智能布线解决方案

西蒙MapIT G2，由1U的MCP／DCP控制单元，智能铜缆配线架和光缆配线架，以及一套软件组成。整合了功能强大的创新智能配线架、用户友好主控制器以及MapIT软件，对整个网络的物理层活动实施实时追踪和报告。