Domestic and International Present Status and Utilization of Hafnium Resource

2013 ◽  
Vol 423-426 ◽  
pp. 679-684
Author(s):  
Yu Bo ◽  
Xiao Liu ◽  
Yun Gang Li ◽  
Zong Ying Cai
Keyword(s):  
Present Status ◽  
Rare Metal ◽  
Processing Method ◽  
Development Prospect ◽  
Metal Metal ◽  
Comprehensive Performance ◽  
Hafnium Alloy ◽  
At Home

Metal hafnium has research significance as a rare metal. Metal hafnium, hafnium alloy and hafnium compounds are made a simple introduction, the distribution of hafnium resource is summarized at home and abroad, and the processing method of hafnium resource and the development prospect of comprehensive performance of hafnium resource are discussed.

The Development of Modern Rural House at Home and Abroad Present Situation and Prospect Analysis

2013 ◽  
Vol 869-870 ◽  
pp. 84-87
Author(s):  
Dong Ping Cui ◽  
Da Peng Zhao
Keyword(s):  
Present Situation ◽  
Current Situation ◽  
Development Prospect ◽  
Residential Construction ◽  
Rural Housing ◽  
Advanced Experience ◽  
Development Direction ◽  
At Home

In this article, through analyzing the current situation of the development of the rural house at home and abroad, summarizes domestic and foreign advanced experience of the construction of the development of rural housing and the main problems and puts forward the development direction of rural residential construction and development prospect at home and abroad, in order to further strengthen the construction of rural house provides a good reference and reference.

Research on Nanomaterials and its Latest Application

2014 ◽  
Vol 912-914 ◽  
pp. 305-308 ◽  
Author(s):  
Guo Min Lin ◽  
Miao Shang ◽  
Wen Guang Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Present Status ◽  
Development Prospect ◽  
Atoms And Molecules ◽  
New Material

Nanotechnology decides the ability of human manipulation of the atoms and molecules, the goal is to master the ability to create new material and design to create the desired application products, and nanomaterials is the basis of the integration of a variety of nanotechnology. The connotation and development prospect of nanotechnology are introduced. The present status and the research emphasis in every stage of the nanomaterials are pointed out and nanomaterials are classified according to the different way. The characteristics of all kinds of nanomaterials and applications in all fields are analyzed.Key words: Nanomaterials; Nanotechnology; Fullerenes; Graphene; Carbon nanotubes

scholarly journals Analysis of heat and mass transfer mechanism of vacuum freeze-drying in the primary drying

2007 ◽  
Vol 3 (2) ◽  
pp. 183-191
Author(s):  
Hua Li ◽  
Lihua Li ◽  
Xingli Jiao ◽  
Xueli Qin
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Transfer Process ◽  
Present Status ◽  
Freeze Drying ◽  
Mass Transfer Process ◽  
Transfer Mechanism ◽  
Drying Process ◽  
Mass Transfer Mechanism ◽  
At Home

The freeze-drying process is a complex heat and mass transfer process virtually. The drying process of freeze-drying is not only the key stage which decides the success of freeze-drying, but also the most difficult stage to control. There are lots of papers about heat and mass transfer in vacuum freeze drying at home and abroad. The present status of research on heat and mass transfer during vacuum freeze drying in the primary drying is summed up and analyzed, the trend of research in this field is discussed in this paper.

scholarly journals Mathematical model of vacuum freeze-drying in the secondary drying

2007 ◽  
Vol 3 (2) ◽  
pp. 192-196
Author(s):  
Hua Li ◽  
Lihua Li ◽  
Xingli Jiao ◽  
Xueli Qin
Keyword(s):  
Mathematical Model ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Transfer Process ◽  
Present Status ◽  
Freeze Drying ◽  
Mass Transfer Process ◽  
Drying Process ◽  
Secondary Drying ◽  
At Home

The freeze-drying process is a complex heat and mass transfer process virtually. The drying process of freeze-drying is not only the key stage which decides the success of freeze-drying, but also the most difficult stage to control. There are lots of papers about heat and mass transfer in vacuum freeze drying at home and abroad. The present status of research on heat and mass transfer during vacuum freeze drying in the secondary drying is summed up and analyzed, and the trend of research in this field is discussed in this paper.

Present status of radio astrometry with baselines ≤ 35 km

1978 ◽  
Vol 48 ◽  
pp. 175-178 ◽  
Author(s):  
K. J. Johnston
Keyword(s):  
Present Status ◽  
Future Work

A summary of results for radio astrometry with baselines ≤ 35 km and priorities for future work are given.

Quasiperiodic interfaces: HREM observations of grain and phase boundaries

1990 ◽  
Vol 48 (4) ◽  
pp. 332-333
Author(s):  
K. L. Merkle
Keyword(s):  
Atomic Structure ◽  
Direct Determination ◽  
Lattice Parameter ◽  
Atomic Scale ◽  
Misfit Dislocations ◽  
Oxide Systems ◽  
Atomic Structures ◽  
Periodic Arrays ◽  
Parameter Ratio ◽  
Metal Metal

The atomic structures of internal interfaces have recently received considerable attention, not only because of their importance in determining many materials properties, but also because the atomic structure of many interfaces has become accessible to direct atomic-scale observation by modem HREM instruments. In this communication, several interface structures are examined by HREM in terms of their structural periodicities along the interface.It is well known that heterophase boundaries are generally formed by two low-index planes. Often, as is the case in many fcc metal/metal and metal/metal-oxide systems, low energy boundaries form in the cube-on-cube orientation on (111). Since the lattice parameter ratio between the two materials generally is not a rational number, such boundaries are incommensurate. Therefore, even though periodic arrays of misfit dislocations have been observed by TEM techniques for numerous heterophase systems, such interfaces are quasiperiodic on an atomic scale. Interfaces with misfit dislocations are semicoherent, where atomically well-matched regions alternate with regions of misfit. When the misfit is large, misfit localization is often difficult to detect, and direct determination of the atomic structure of the interface from HREM alone, may not be possible.

Low-temperature Mo-catalyzed growth of crystalline Si3N4 by CVD

1993 ◽  
Vol 51 ◽  
pp. 918-919
Author(s):  
K.L. More ◽  
R.A. Lowden ◽  
T.M. Besmann
Keyword(s):  
Vapor Deposition ◽  
Hot Isostatic Pressing ◽  
Chemical Vapor ◽  
Processing Method ◽  
Crystalline Material ◽  
Structural Ceramic ◽  
Alternative Processing ◽  
Strong Candidate ◽  
Hot Pressing Sintering ◽  
Processing Techniques

Silicon nitride possesses an attractive combination of thermo-mechanical properties which makes it a strong candidate material for many structural ceramic applications. Unfortunately, many of the conventional processing techniques used to produce Si3N4, such as hot-pressing, sintering, and hot-isostatic pressing, utilize significant amounts of densification aids (Y2O3, Al2O3, MgO, etc.) which ultimately lowers the utilization temperature to well below that of pure Si3N4 and also decreases the oxidation resistance. Chemical vapor deposition (CVD) is an alternative processing method for producing pure Si3N4. However, deposits made at temperatures less than ~1200°C are usually amorphous and at slightly higher temperatures, the deposition of crystalline material requires extremely low deposition rates (~5 μm/h). Niihara and Hirai deposited crystalline α-Si3N4 at 1400°C at a deposition rate of ~730 μm/h. Hirai and Hayashi successfully lowered the CVD temperature for the growth of crystalline Si3N4 by adding TiCl4 vapor to the SiCl4, NH3, and H2 reactants. This resulted in the growth of α-Si3N4 with small amounts of TiN at temperatures as low as 1250°C.

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