Chinese Journal of Nature

XU Mi

2013, 35(2): 79-84.

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The sodium cooled fast reactor possesses a number of inherently safe properties: high thermo-conductivity, low pressurized sodium system, tiny corrosion on materials used in SFR by sodium, no any acute molten fuel-sodium interaction, no long-lived nuclides produced after irradiation, enough dynamic viscosity and heat volume expansion to design possibly an passive accident decay heat removal system, etc. The CEFR is a sodium cooled pool type fast reactor with thermal power 65 MW and electric power 20 MW. Besides above-mentioned properties, the CEFR is designed with negative reactivity effect of temperature,
power and sodium void, independent passive accident decay heat removal systems, passive leaked sodium receivers, passive over-pressure protection system and passive cooled reactor core molten receiver, etc. And the CEFR is also equipped by reliable active maturity safety systems. The safety of CEFR is reached to the safety aims of Generation Ⅳof nuclear systems.

Phase selection rules for complex multi-component alloys with equiatomic or close-to-equiatomic compositions

GUO Sheng; LIU Chain T.

2013, 35(2): 85-96.

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Abstract Alloying greatly expands the amount of available materials beyond the naturally existing ones, and more importantly offers the material scientists opportunities to initiatively control the composition-structure-property relationship in materials. Since commonly used metallic materials are mostly multi-component alloys, the know-how of alloying through compositional control, certainly plays a critical role in designing materials with desired structure and properties. However, alloying in multi-component alloys is an extremely complicated issue, as the alloyed products could be the amorphous phase, various solid solutions and intermetallic compounds containing two or more alloy components. By narrowing down the scope of the multi-component alloys to those with equiatomic or close-to-equiatomic compositions only, and also aiming at framing out the rules that govern the phase selection upon alloying in multi-component alloys in a broad sense, we have identified here a simple and easily executable two-parameter scheme that can effectively predict the formation of the amorphous phase, solid solutions and intermetallic compounds, in multi-component alloys, simply from the given alloy compositions. We believe this scheme reveals a clear physical scenario governing the phase selection in multi-component alloys, helps to simplify the alloy design, and benefits the future
development of advanced metallic alloys like bulk metallic glasses and high entropy alloys.

Prospect and retrospect of molten salt electrolysis process for producing refractory metals and alloys

LU Xiong-Gang;ZOU Xing-Li

2013, 35(2): 97-104.

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The production of refractory metals and alloys has always been a high energy costs, complex and difficult metallurgical and materials processing process. How to extract the high-value metals and alloys direct from complex refractory metal oxides compounds is a very important and difficult research focus in the fields of modern metallurgy and materials preparation. However, the new electro-deoxidation technology developed in recent years may bring a route to this unsolved problem. In this paper, we review the conventional molten salt electrolysis process for production of refractory metals and analyze its shortages. Moreover, the
new electro-deoxidation process, i.e., the Fray-Farthing-Chen (FFC) Cambridge process is introduced in detail. In particular, the research progress and prospect of the solid oxide membrane (SOM) process modified by our group are presented and highlighted in this paper.

Research progress of maize opaque endosperm mutants

YAO Dong-Sheng;SONG Ren-Tao

2013, 35(2): 105-111.

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Maize (Zea mays) is one of the world's most important food crop and also an important model of plant genetics. The long history of maize studies was accumulated plenty of genetic mutants. A group of seed mutants with opaque or floury endosperm were called opaque mutants, which usually reduced grain hardness and transparency. Mutants like opaque2 were found to be able to significantly improve the nutritional quality of maize seeds, hence attracted lots of attentions on the study of opaque endosperm mutants. In early years, only few opaque endosperm mutant genes, such as opaque2 and floury2 etc., were cloned and studied, and their functions were found to be related with the transcription and translation of major storage proteins in maize. In recent years, with
the advancement of science and technology, more opaque mutant genes, such as opaque1, opaque5 and opaque7, were cloned and studied, which revealed further mechanisms for storage component synthesis and deposition in maize seeds. These studies expanded our knowledge for the development and metabolism of maize endosperm.

The research progress of pollen wall development

ZHU Jun;YANG Zhong-Nan

2013, 35(2): 112-117.

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In angiosperm, the pollen wall is a layer of dense material on the microgametocyte surface, which plays important roles in protecting pollen from various environmental stresses and microorganism attacks, and in cell-cell recognition during pollination. The pollen wall is constituted of the outer layer exine and the inner layer intine. The exine is further divided into sexine and nexine. The material for exine is directly from the tapetum cells, and the deposition pattern of exine is decided by the primexine. Intine is synthesized by microspore itself. Recently, multiple genes were reported to be involved in the pollen wall formation in Arabidopsis theliana. The mutations of the majority of these genes lead to male sterility in plants. The functions of these genes are related to tapetal development, sporopollenin biosynthesis and transport, callose wall and primexine formation. The functions of these genes in the pollen wall development are introduced in this paper.

The circadian clock in plants

XU Xiao-Dong;XIE Qi-Guang

2013, 35(2): 118-126.

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Circadian clock generates endogenous rhythms to confer the fitness advantages for most organisms. Plants with the evolved self-sustaining rhythms could anticipate the changes of environment, synchronize own growth and development with oscillated outer signals. This review summarizes the emerging of research work on the various circadian rhythms, introduces the concepts of chronobiology and related theory, etc, and describes in detail on the current basic network architecture of circadian systems of higher plants, including the prominent transcriptional and posttranslational mechanism.

Photo-induced deformation of liquid crystalline elastomers

LIU Yu-Yun;YU Yan-Lei

2013, 35(2): 127-134.

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Photoresponsive polymeric materials have attracted increasing attention due to the unique advantages of light energy such as clean, safe, remote controllable and transient. Photoresponsive polymeric materials are a kind of functional polymers that can absorb energy and undergo intra- or inter-molecular physical or chemical transformations. Through the rational design, photoresponsive polymeric materials undergo macroscopic shape changes and complicated movements such as contraction, bending, creeping, rotation, and so on. Therefore, they can be fabricated to a variety of intelligent soft actuators with a wide range of
applications in many fields. This review describes photodeformable liquid crystalline elastomers as well as their research development in the field of light-driven soft actuators.

Exploring progress on brain networks (II)：progress, thinking and challenges

FANG Jin-Qing

2013, 35(2): 135-143.

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The author presents the advances including topology frequent mapping for brain network, long distance network of monkey brain, brain function of human and monkey, senile dementia, similarity for brain growing, internet evolving and cosmic expansion，worthy of consideration problems and challenging topics.

Spring of megascience

GUAN Yi

2013, 35(2): 145-152.

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Founder of gene synthesis:Har Gobind Khorana

GUO Xiao-Qiang

2013, 35(2): 153-156.

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Lecturer，Department of Biochemistry，Bethune Military Medical College，Shijiazhuang 050081，China

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