Chinese Journal of Nature

Heat transfer enhancement techniques for single-phase fluid tubular heat exchangers

LIN Zong-Hu

2013, 35(5): 313-319.

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As the fast development of industries, on account of large capacity apparatus may reduce the capital and operation cost, different industries endeavor to develope large capacity apparatus. Thus, the volumes and weights of heat exchangers belong to these industries may increase accordingly. How to decrease the volumes and weights of these large heat exchangers by scientific creative methods became key techniques for industries development. Besides, in the case of developing new energy, desalination of sea water, waste heat utilization and energy saving apparatus, on account of the low temperature difference between the cold and hot medium, heat exchanger of these regions are quite large. Therefore developing small and high efficient new heat exchangers are also urgently
needed. This problem can be sloved using heat transfer enhancement techniques. In this paper, the important meanings of heat transfer enhancement techniques are described. Besides, developing ways, methods for reviewing its efficiency, and heat transfer enhancement techniques for single-phase tubular heat exchangers are also mentioned.

Barlike structure in the inner Galaxy

ZHAO Jun-Liang

2013, 35(5): 320-325.

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The presence of a large scale bar in the inner Galaxy has been well established by various tracers since 1990, such as near infrared radiation (NIR) light, red clump giants, AGB stars and IRAS sources, and by different methods, such as bulge surface brightness, NIR star counts and kinematics of stars. It has been confirmed from various kinds of researches that our Milky Way should be morphologically catalogued as a barred spiral galaxy instead of a normal spiral one.

Ten years after the Human Genome Project: from genome biology to precision medicine

YU Jun

2013, 35(5): 326-331.

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Ten years after the Human Genome Project, genomics has now heading toward biology and medicine, making both more detailed down to individual genes and more precise at single cell levels. In the new paradigm, knowledge of biology and medicine has to be acquired in a divide-and-conquer approach and managed in different tracks but synthesized and networked together ultimately. Large organized scientific projects are needed to bring together research forces from both basic and clinical research fields to solve key scientific issues, and to bring in new technology and security for future healthcare.

The formation mechanism of fog pollution

CHEN Jian-Min;LI Xiang

2013, 35(5): 332-336.

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Fog pollution is one of the hazardous weather phenomena. The occurrence, damage, observation methods, and the present situation of fog were discussed and analyzed in this paper. On this basis, the formation mechanism of fog pollution and chemical behaviors of pollutants during the fog process were focused. In addition, the difficulties and future direction of current fog research were also proposed.

Haze and hygroscopic growth

YIE Xin-Na;CHEN Jian-Min

2013, 35(5): 334-341.

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China is facing the critical situation of the high occurrence of haze. The enhancement in secondary inorganic species in PM2.5 is largely responsible for the haze formation, reflecting the complex pollution with coal-burning and traffic emissions. Both particle size distribution and refractive indices are remarkably changed after deliquescence and hygroscopic growth of secondary aerosols in atmospheric environment. Aerosol hygroscopicity is largely dependent on chemical composition as well as size effect. The aerosols may exist as liquid droplet under rather lower relative humidity due to the drag hysteresis. The urban aerosols contain in China nearly-hydrophobic, less-hygroscopic and more-hygroscopic mode particles, varying content of each mode among cities. Hygroscopic growth may contribute 60% to the visibility decrease during haze episode, exceeding extinction effect of dry aerosols themselves. Hygroscopic growth can also provide a carrier for heterogeneous reaction with gas pollutants. This process favors the formation of sulfate and nitrate, which further deteriorate the visibility.

Haze/Fog and human health: a literature review

CHEN Ren-Jie;GAN Hai-Dong

2013, 35(5): 342-344.

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In recent years, heavy and persistent haze/fog events in China have aroused serious public concerns. These events were mainly caused by high levels of air pollutants (typically particulate matter with an aerodynamic diameter less than 2.5 μm, PM2.5). The authors reviewed the recent scientific developments about the health effects of PM2.5 and its chemical compositions on the respiratory, cardiovascular, reproductive and neurological system and cancers. Then, the potential susceptible subpopulations were summarized. Several suggestions were provided to allievate and avoid the hazardous health effects of haze/fog events.

Network science and engineering faced with a new challenge and developing opportunity under the wave impact of big data

FANG Jin-Qing

2013, 35(5): 345-354.

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In recent years, under the wave impact of big data, like many areas，network science and engineering are facing with a new challenge of leading edge topics——network of networks (NON) and are being a development opportunity at home and abroad. Baed on introduction to big dada science, different kinds, main features and some progresses in a part of theories for NON are reviewed briefly. Several challenging topics and rare opportunity are offered breifly.

New advance on study of animal behavior (Ⅷ) : sperm competition

SHANG Yu-Chang

2013, 35(5): 355-358.

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In this paper, we will introduce the effect of sperm competition—that is, the direct competition between the sperm of different males to fertilize a female’s eggs—on mating success and the evolution of mating systems. In some promiscuous and some polyandrous mating systems, males compete not only for access to mating opportunities with females, but directly for access to eggs. In these systems, competition occurs after a female has mated with numerous males. If females store sperm from numerous matings, sperm from different males may compete with one another over access to fertilizable eggs. When sperm competition exists, selection can operate directly on various attributes of sperm, such as sperm size and shape. If a male wins a physical fight with the opponents, this may provide him access to an estrous female that may lead to a mating opportunity, which may result to fertilization.

Research and exploiture on bioenergy of new energy plant duckweed

ZHU Ye-Rong;LI Ya-Hui;LIU Miao-Miao;LIU Fei;BAI Yan-Ling;WANG Yong

2013, 35(5): 359-364.

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Duckweed is an aquatic plant that has the sole advantage for producing high levels of starch. It is focused on the field of bioenergy research. Here we review the current understanding of the research and exploiture on the starch of duckweed simply.

Terahertz spectroscopy of magnetically ordered structure：spin wave excitation, dispersion, and coherent control

YUE Zhong-Yue;JIN Zuan-Ming;ZHOU Run-Ze;MA Guo-Hong

2013, 35(5): 365-371.

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In this paper, we reviewed the research progress about terahertz wave interacting with the magnetically ordered structure; and terahertz time domain spectroscopy is presented to be an effective method to study the spin wave excitation and dynamics. Based on the recent research work at laboratory of ultrafast photonic of Shanghai University, we demonstrate that the spin wave can be excited and coherently controlled with the magnetic component of terahertz pulses.

The history of elastica model on the slender rod

LIU Jian-Lin

2013, 35(5): 372-377.

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The elastica model of slender rods exists widely in nature and engineering applications, such as submarine cables, high voltage transmission lines, compliant ropes, springs, drilling rods and oil suction rods in petroleum engineering, nano-fibers and nano-tubes, DNA and high polymers, stems in climbing plants. It is more challenging to analyze the deformation of the elastica of slender rods, which are normally accompanied by strong geometry nonlinearity. The history of elastica proves really dramatic. It has lasted almost 8 centuries up to date, and there were a lot of distinguished scientists involving in this problem, from the viewpoints of mathematics, mechanics and experiments, etc. In this paper, the history of elastica is introduced spanning from planar elastica, spatial elastica to the analogies between elastica and some other physical phenomena. The history of elastica can help us understand how mathematics and mechanics are closely combined with engineering technologies in face of engineering applications.

Open a new chapter in science

GUAN Yi

2013, 35(5): 378.

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A founder of turbulence modeling theory: Zhou Pei-yuan

MENG Qiang-Xun

2013, 35(5): 387-390.

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Zhou Pei-yuan, hydrodynamic, turbulence, modeling theory, history of mechanics

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