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51.
Epicuticle, isolated from wool via the Allwörden reaction, was examined by electron microscopy and analysed chemically. It is proteinaceous; lipids and carbohydrates could not be detected. The component amino acids are: cystine, glycine, glutamic acid, serine, valine, alanine, lysine, α-amino-adipic acid, and threonine. A tentative model for the epicuticle is proposed.  相似文献   
52.
A brief summary of the structure of keratin fibres is followed by a review of their mechanical and allied properties. Among these properties are tensile stress–strain properties, stress relaxation, and creep, and torsional stress–strain properties and stress relaxation. The mechanism of supercontraction, properties of set fibres and disulphide-reduced fibres, and thermal transitions in keratin are also discussed. Finally, the various theoretical attempts that have been made to explain these properties are critically reviewed.  相似文献   
53.
《应用陶瓷进展》2013,112(2):111-117
Abstract

Due to fast hydrolysis of AlN when in contact with water, AlN based ceramics are processed in organic solvents, which are volatile, expensive, harmful to the health and environment. The present work intends to protect AlN powder against hydrolysis in order to enable aqueous processing of AlN based ceramics. A commercial AlN powder was treated in an ethanol solution of H3PO4 and Al(H2PO4)3 kept at 80°C for 24 h to protect it from hydrolysis. The dispersing behaviour of the treated AlN powder in water and the ability to consolidate defect free parts of AlN and β-Si4Al2O2N6 ceramics from aqueous suspensions by slip casting and gelcasting techniques were studied. The consolidated parts were then sintered in a graphite furnace and the sintered bodies exhibited properties [bulk density (BD), apparent porosity (AP), crystalline phase composition and microstructural features] similar to those reported in literature for the same materials processed from organic media.  相似文献   
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An account is given of the setting behaviour of wool fabrics after treatment with a variety of anhydrides of carboxylic acids. The incorporation of relatively large numbers of small acyl groups had little effect on the settability, but bulky acyl groups caused a large enhancement. Unlike untreated wool, wool containing large numbers of bulky acyl, e.g., benzoyl, groups can be steam-set extremely readily without any need for prior wetting.

From a detailed study of the setting behaviour and set stability of benzoylated fabric, it was concluded that two main types of interaction were involved, namely, electrostatic and hydrophobic interactions. Electrostatic interactions were believed to predominate at low levels of acylation, the result being inhibition of set. These were outweighed by hydrophobic interactions at higher levels of acylation with bulky anhydrides, which resulted in set stabilization. Disulphide-bond rearrangements appear to play little part in the setting of wools with high contents of bulky acyl groups.  相似文献   
57.
《金属精饰学会汇刊》2013,91(5):243-247
Abstract

This paper describes how copper plating is influenced by modulated current. By unipolar pulse plating smooth, compact and fine grained structures can be obtained, but the macro throwing power is worse than by direct current plating. The best throwing power is obtained by pulse reverse plating. In additive containing solutions, excellent throwing power has been obtained at the following parameters: T c/T a=20, i a/i c=1–3·5 and Q a/Q c<0·2. Without additives the surface becomes less smooth. Finally, superimposed pulse reverse plating has the possibility to combine the advantages of uni- and bipolar pulse plating in an additive free process.  相似文献   
58.
NoSQL databases are designed to address performance and scalability requirements of web based application which cannot be addressed by traditional relational databases. Due to their contrast in priorities and architecture to conventional relational databases using SQL, these databases are referred as “NoSQL” databases since they ​incorporate lots of additional features in addition to the features of conventional databases. The relational databases strongly follow the ACID (Atomicity, Consistency, Isolation, and Durability) properties while the NoSQL databases follow BASE (Basically Available, Soft State, Eventual consistency) principles. This survey paper is an analytical study on BASE features of some of NoSQL databases.  相似文献   
59.
none 《粉末冶金学》2013,56(1):61-67
Abstract

Dimensional change during solvent debinding is linked to defects such as cracking and slumping in powder injection moulded components. Owing to the delicate condition of the compact during debinding, considerable difficulty exists in determining the magnitude and cause of swelling or shrinkage. Previous studies of this dimensional change have used measurement techniques involving contact or force on the sample, which may alter the behaviour. This study observes in situ dimensional change during solvent debinding using a non-contact laser dilatometer. Dimensional change was investigated for iron and stainless steel powder injection moulded bars with wax-polymer binders. The effects of solvent temperature, paraffin wax content, paraffin wax density, particle size and solids loading were analysed. Comparisons between the dimensional change and mass loss observations during solvent debinding suggest a relationship between the two phenomena based on soluble polymer swelling.  相似文献   
60.
《粉末冶金学》2013,56(3):208-212
Abstract

The Fe–48 at.-%Al powder used for powder injection moulding (PIM) was prepared by mechanical alloying in a high energy planetary ball mill and subsequent vacuum annealing. The effects of stearic acid (SA) as the process control agent on powder characteristics were investigated using X-ray diffractometer, laser particle size analysis and scanning electron microscopy. The dependence of solvent debinding efficiency of PIM feedstock on the powder characteristics was also studied. The results indicate that a low SA content for ball milling helps to prepare near spherical, coarse powder particles that exhibit good solvent debinding efficiency. On the contrary, a high SA content leads to thin layered, small particles with poor PIM solvent debinding efficiency. An intermediate SA content such as 1 wt-% makes the ball milled powder combine the advantageous characteristics for PIM process.  相似文献   
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