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Dongfang, China

Chen Z.,University of Sichuan | Zhou T.,University of Sichuan | Hui J.,University of Sichuan | Li L.,University of Sichuan | And 4 more authors.
Vibrational Spectroscopy | Year: 2012

A new perturbation-correlation moving-window two-dimensional correlation (PCMW2D) infrared spectroscopy was employed to study the complex crystallization of the polyoxymethylene/poly(ethylene oxide) (POM/PEO) crystalline/crystalline blends for the first time. The online polarizing microscope measurement found POM/PEO forms the crystalline/crystalline blends with a typical island structure. The PCMW2D IR spectra determined three processes of the POM/PEO crystallization. The first is the maximum crystallization temperature of POM (138 °C). The second is the POM recrystallization process (72 °C). The thickening speed of the lamellae (FCC), as well as the crystallization of the macrocyclic POM, is faster than the improvement of POM ECC. The existence of the PEO melts significantly decelerates the improvement speed of ECC in interface. The third is the maximum crystallization temperature of PEO (35 °C). According to the results of the generalized 2D correlation analysis, it can be found the POM ECC plays a leading role during the POM/PEO crystallization. © 2012 Elsevier B.V.

Li Y.,University of Sichuan | Li Y.,China BlueChemical Ltd. | Zhou T.,University of Sichuan | Chen Z.,University of Sichuan | And 3 more authors.
Polymer | Year: 2011

Non-isothermal crystallization process of polyoxymethylene (POM) from the melts was studied by two-dimensional correlation infrared spectroscopy. A hybrid structure of FCC (1135 cm-1) and ECC (904 cm-1) during the crystallization from the molten state was found. Non-isothermal kinetics of POM crystallization was also investigated using DSC curves. A newly perturbation-correlation moving-window two-dimensional (PCMW2D) technique was used to explore the complex crystallization process. We determined three processes in crystallization. The first is the initial stage of the crystal nucleus growing or the formation of certain local ordered structures in the melts. It can be inferred the formation of the crystal nucleus of FCC is earlier than that of the ECC. The second is the maximum crystallization temperature of POM. The last is the further improvements of crystals (especially in ECC) and the crystallization of the cyclic POM of low molecular weight. However, this process of FCC is slower than ECC. The temperature-dependent IR spectra at reheating were also analyzed using PCMW2D. © 2011 Elsevier Ltd. All rights reserved.

Chen K.-Y.,China BlueChemical Ltd.
Xiandai Huagong/Modern Chemical Industry | Year: 2014

In order to overcome difficulties encountered in condensing and washing processes for 3 000 t/a polypropylene carbonate (PPC) plant, some new processes are studied. The efficiency of condensing and washing of PPC can be improved by removing volatile matters from PPC through flashing, spray condensing and washing with multiple kettles, which is helpful to upgrade the production technology of PPC.

Liu C.-Z.,China BlueChemical Ltd.
Huaxue Gongcheng/Chemical Engineering (China) | Year: 2012

Hainan Fu Dao Chemical Co., Ltd. is an enterprise introducing the Norsk Hydro fluidized bed granulation technology to produce urea in China. A very serious caking problem happened when the granular urea device was put into production. For this problem, the device process design, production and operating conditions, product storage conditions, packaging and transport and so on were analyzed, but the problem was still not solved. In this case, the factors leading to caking of granular urea and the mechanism of chemical reactions leading to agglomeration were further analyzed, finding out the key factors, and proposing the solutions to program through practice. Ultimately a fundamental solution to the problem was found out, and the effect was significant. This project was successfully applied in Hainan 2 700 t/d granular urea granulation plant.

Che S.-G.,Chinese Academy of Agricultural Sciences | Zhao B.-Q.,Chinese Academy of Agricultural Sciences | Li Y.-T.,Chinese Academy of Agricultural Sciences | Yuan L.,Chinese Academy of Agricultural Sciences | And 4 more authors.
Journal of Integrative Agriculture | Year: 2015

As one of the staple food crops, rice (Oryza sativa L.) is widely cultivated across China, which plays a critical role in guaranteeing national food security. Most previous studies on grain yield or/and nitrogen use efficiency (NUE) of rice in China often involved site-specific field experiments, or small regions with insufficient data, which limited the representation for the current rice production regions. In this study, a database covering a wide range of climate conditions, soil types and field managements across China, was developed to estimate rice grain yield and NUE in various rice production regions in China and to evaluate the relationships between N rates and grain yield, NUE. According to the database for rice, the values of grain yield, plant N accumulation, N harvest index (HIN), indigenous N supply (INS), internal N efficiency (IEN), reciprocal internal N efficiency (RIEN), agronomic N use efficiency (AEN), partial N factor productivity (PEPN), physiological N efficiency (PEN), and recover efficiency of applied N (REN) averaged 7.69 t ha-1, 152 kg ha-1, 0.64 kg kg-1, 94.1 kg kg-1, 53.9 kg kg-1, 1.98 kg kg-1, 12.6 kg kg-1, 48.6 kg kg-1, 33.8 kg kg-1, and 39.3%, respectively. However, the corresponding values all varied tremendously with large variation. Rice planting regions and N rates had significant influence on grain yield, N uptake and NUE values. Considering all observations, N rates of 200 to 250 kg ha-1 commonly achieved higher rice grain yield compared to less than 200 kg N ha-1 and more than 250 kg N ha-1 at most rice planting regions. At N rates of 200 to 250 kg ha-1, significant positive linear relationships were observed between rice grain yield and AEN, PEN, REN, IEN, and PFPN, and 46.49, 24.64, 7.94, 17.84, and 88.24% of the variation in AEN, PEN, REN, IEN, and PFPN could be explained by grain yield, respectively. In conclusion, in a reasonable range of N application, an increase in grain yield can be achieved accompanying by an acceptable NUE. © 2015 Chinese Academy of Agricultural Sciences.

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