IMAGING SCIENCE AND PHOTOCHEMISTRY

Review and Prospect of Imaging Technology

YAN Lei, JING Xin, YANG Bin

2012, 30(4): 241-250. DOI: 10.7517/j.issn.1674-0475.2012.04.241

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This paper expounds the three stages ofimaging technology history: electronic machinery, automation and digital stage,including the transition from film type to magnetic recording one, the compatibility between film type and digital type, and the frontier technology of spatial resolution, radiometric resolution, spectral resolution and temporal resolution of digital imaging. We also put forward an automatic control theory for image processing from parts to system, and expound future tendency of imaging technology.

Celluloses Grafted with Fluorene-Benzene and Carbazole-Benzene Copolymer and Its Application to the Detection of Nitro-Aromatic

LENG Hong-fei, WU Wen-hui

2012, 30(4): 251-259. DOI: 10.7517/j.issn.1674-0475.2012.04.251

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Sensing celluloses were prepared from fluorene-benzene and carbazole-benzene copolymer grafted to chemical modification of cellulose paper by Suzuki coupling reaction for the detection of nitro-aromatic explosives. Fluorescence quenching studies have shown that, the two kinds of sensor have higher fluorescence quenching efficiency than the thin film state, due to the modified cellulose have a high specific surface area and porosity structure, which are beneficial for the rapid diffusion of DNT vapor molecules. In addition, the two sensing cellulose have shown good fluorescence quenching efficiency after four quenching-recovery circles, which indicates that the sensing cellulose has a good fluorescence quenching reversibility and stability.

Construction of Nanostructured Silica Surfaces by Spray-Coating and Their Optical and Wetting Properties

GAO Liang-juan, HE Pu, LI Xiao-yu, HE Jun-hui

2012, 30(4): 260-268. DOI: 10.7517/j.issn.1674-0475.2012.04.260

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Silica nanoparticles with different sizes were fabricated via the Stöber method by adjusting the reaction temperature and the volumes of ethanol and water. Simple and convenient spraying-coating method was used to construct coatings on slide glasses with synthesized silica nanoparticles of 20 nm in size. Adhesion of silica nanoparticles to slide glasses was enhanced by calcination of the silica nanoparticle coatings at 550 ℃. After surface modification with 1H, 1H, 2H, 2H-perflurooctyltriethoxysilane, the wetting properties of these coatings changed from hydrophilicity to hydrophobicity. The silica nanoparticle coatings constructed by spray-coating are anti-reflective. When the mass percentage of silica nanoparticles was 0.48% and the number of spray-coating cycles was 3, the transmittance of coating reached as high as 95.5% in the visible range. It was found by scanning electron microscopy observations that the coatings obtained by spray-coating are uniform and controllable. The spray-coating approach to the construction of nanoparticle coatings are a simple and fast fabrication process, and is suitable for large area applications.

Synthesis of Pure β-Ca₃(PO₄)₂ Bioceramics with Gelatin by Precipitation Method

MA Ming, WANG Xue-song, ZHANG Bing, GUO Yan-chuan

2012, 30(4): 269-279. DOI: 10.7517/j.issn.1674-0475.2012.04.269

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Pure β-tricalcium phosphate (β-TCP) was synthesized using the precipitation method, starting from the gelatin, Ca (NO₃)₂ and (NH₄)₂HPO₄ precursors by adopting the initial Ca/P ratio of 1.5. FT-IR spectroscopy and X-ray diffractometry indicated the solution derived precipitate was calcium deficient phosphate (Ca-dHAP) and it would thermally transform into pure β-TCP as the amount of gelatin exceeds 0.22% (mass concentration). The Ca-dHAP crystal dimensions decreased with increasing gelatin amount as shown by crystallite calculation and SSA measurement. TEM results showed that the as prepared Ca-dHAP powders were needle-like and formed a botryoidal shape characteristic of β-TCP when being calcined at high temperatures. The DTA/TG results showed that gelatin chemically bonded with the Ca-dHAP crystals which could be beneficial for the absorption of water molecules and the absorbed water molecules, then subsequently reacted with Ca-dHAP to form HA which would react with a second phase calcium pyrophosphate (Ca₂P₂O₇) (CPP) to prepare pure β-TCP. In this paper, we also studied the mechanism of gelatin on the formation of β-TCP.

Preparation Hydrophobic Graphene Aqueous Dispersion and Electrochemical Properties

KIM Song-hun, LI Dan-dan, LI Jiu-ming, YU Yuan, LI Yu-zhen, ZHI Jin-fang

2012, 30(4): 280-288. DOI: 10.7517/j.issn.1674-0475.2012.04.280

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The direct dispersion of hydrophobic graphene sheets in water without the assistant of surfactant stabilizers has recently been recognized as an important task for production of individual graphene sheets. We developed a facial method to disperse hydrophobic graphene sheets in aqueous medium through enlarging the amount of hydrazine-hydrate in the absence of surfactant or any other foreign electrostatic stabilization agents. Homogeneous aqueous graphene dispersion had produced lower zeta potential of more negative than -32.5 mV at solution pH of 5.89 and was stable for six months without any precipitate. The folded individual single-layer graphene sheets with 0.38 nm layer thick and the formation of a hexagonal crystalline graphene structure were observed from AFM and TEM images, respectively. XPS analysis showed the efficient reduction of graphene oxide. As-prepared graphene-glassy carbon electrode (GE-GCE) showed a relatively sensitive electrochemical response toward the detection of AA and UA than glassy carbon electrode (GCE).

A Hybrid Reduction Procedure for Preparing Flexible Transparent Graphene Films with Improved Electrical Properties

KIM Song-hun, LI Dan-dan, YU Yuan, XU Tao, QIAN Jun, ZHI Jin-fang

2012, 30(4): 289-298. DOI: 10.7517/j.issn.1674-0475.2012.04.289

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A novel procedure for producing flexible transparent conductive Graphene films was reported. The synthetic procedure includes a solution-processed chemical reduction and an anodized aluminum oxide (AAO) membrane filter-assisted for thermal reduction. Final flexible transparent graphene films produced by this method exhibited the sheet resistance less than 850 Ω/square with 80% transmittance under visible-light irradiation (wavelengths: 540-840 nm). This sheet resistance value is close to that of the graphene films obtained from CVD method (280-770 Ω/square), and is much lower than that of the graphene films obtained from solution process (usually, in 10³-10⁴Ω/square).

Photopolymerization Kinetics of 2,2',5-tris(2-fluorophenyl)- 4-(3,4-dimethoxypheny)- 4',5'-diphenyl-1,1'-biimdazole Combination Photoinitiator Systems

PENG Cheng, WANG Ke-min, LU Jian, QIAN Xiao-chun, JIANG Shan, NIE Jun, MA Gui-ping

2012, 30(4): 299-307. DOI: 10.7517/j.issn.1674-0475.2012.04.299

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The photopolymerization kinetics of combination photoinitiator systems which were composed by 2,2',5-tris(2-fluorophenyl)-4-(3,4-dimethoxypheny)- 4',5'-diphenyl-1,1'-biimdazole(WJ-HABI), photosensitizer N, N-bis(diethylamino) benzophenone (EMK) and hydrogen donors N-pheylglycine(NPG) were investigated by Real-time Infrared(RT-IR) spectroscopy. The different initiator concentrations, the different compositions of photoinitiator systems, light intensity and different functional monomers on the polymerization were studied. The results indicated that with the increase of initiator concentration and light intensity, the double bond conversion and the polymerization rate increased.

Progress in Improving Photographic Properties of PTG Materials

LIANG Hai-yan, LI Qiu-yan, LI Shu-jing, WANG Xin-rui, YE Hong, LI Jin-pei

2012, 30(4): 308-317. DOI: 10.7517/j.issn.1674-0475.2012.04.308

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In this paper,the methods and the results in the researches for improving photographic properties were reviewed based on both the formation of latent image and the process of heat development. In the former, improving photographic properties by increasing efficiency of light absorbance, improving efficiency of forming latent image and reducing atoms of center of smallest latent image were summarized, and in the latter, the influence of developer, organic silver salt, development advancers, pH, and pAg on the photographic properties were analyzed. Some other possible factors were proposed.

Design and Mechanism of Photo-Controlled Metal Ion (Zn²⁺ and Cd²⁺) Release System

ZHANG Xu, CHEN Yi

2012, 30(4): 318-318. DOI: 10.7517/j.issn.1674-0475.2012.04.318

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