A complete VARMA modelling methodology based on scalar components

Abstract. This article proposes an extension to scalar component methodology for the identification and estimation of VARMA models. The complete methodology determines the exact positions of all free parameters in any VARMA model with a predetermined embedded scalar component structure. This leads to an exactly identified system of equations that is estimated using full information maximum likelihood.     

基于HMS87C1408B的籽棉、菜籽和粮食水分综合测试仪

介绍了使用HMS87C1408B作为主控芯片的籽棉、菜籽和粮食水分综合测试仪的实现方法,重点说明了阻抗变换、软件驱动LCD和语音播报技术的实施.     

静止同步串联补偿电源的控制与驱动电路的设计

介绍了一种新型的串联补偿电源(SSSG)，提出了基于80C196MC的波形发生器来设计SSSG的控制器与驱动电路，能够准确、灵活地产生所需电压，连续、平滑地补偿容性、感性无功功率等系统参数，并设计组成单相SSSG系统，进行实验系统试验与调试达到了预期的目的。     

汽车空调制冷系统中应用R407C的分析

本文对混合工质R407C与R12的物理和热力性质进行了比较分析，并针对汽车空调制冷系统的特点，对两种工质在变工况下进行了制冷系统的理论循环分析，阐明了在汽车空调制冷系统中使用R407C的可行性。     

The oxidation of two ternary Ni-Cu-10 at.% Al alloys in 1 atm of pure O2 at 800-900 °C

The oxidation of the ternary alloys Ni-45Cu-10Al and Ni-30Cu-10Al has been studied at 800-900 °C under 1 atm O₂. The presence of 10 at.% Al reduces significantly the oxidation rate of the corresponding Cu-Ni alloys during the initial oxidation stages, even before the establishment of a complete Al₂O₃ layer. The weight of individual sample of the two ternary Ni-Cu-10Al alloys at 800 °C increases more rapidly than at 900 °C during the initial oxidation stage. As oxidation proceeds, the weight gain at 800 °C slows down to a degree that the total weight gain after 24 h oxidation at 800 °C is less than that at 900 °C. Due to a faster formation of the Al₂O₃ layer, which suppresses earlier the further oxidation of Cu and Ni, the external region of the scales grown on Ni-45Cu-10Al contain much less Cu and Ni oxides than those grown on Ni-30Cu-10Al. The transition from the internal oxidation to the selective external oxidation of the most reactive component Al in Ni-Cu-Al alloys is favored by higher values of the Al content, of temperature and of the Cu/Ni ratio.     

Formation Kinetics of Unsaturated (Ti, W)C Solid Solution

ＦｏｒｍａｔｉｏｎＫｉｎｅｔｉｃｓｏｆＵｎｓａｔｕｒａｔｅｄ（Ｔｉ，Ｗ）ＣＳｏｌｉｄＳｏｌｕｔｉｏｎＬｉｎＣｈｅｎ’ｇｕａｎｇ，ＤｅｎｇＦｅｎｇｘｉａｎｇ，ＨｅＣｏｎｇｘｕｎａｎｄＧａｏＺｈａｏｚｕ（林晨光）（邓凤翔）（贺从训）（高兆祖）（Ｇｅｎｅｒ...     

Influence of Drying Conditions on Ascorbic Acid during Convective Drying of Whole Persimmons

Degradation kinetics of food constituents may be related to the matrix molecular mobility by glass transition temperature. Our objective was to test this approach to describe ascorbic acid degradation during drying of persimmons in an automatically controlled tray dryer with temperatures (40 to 70°C) and air velocities (0.8 to 2.0 m/s) varying according a second order central composite design. The Williams-Landel-Ferry model was satisfactorily adjusted to degradation curves for both control strategies adopted—constant air temperature and temperature fixed inside the fruit. Degradation rates were higher at higher drying temperatures, independent of the necessary time to attain the desired moisture content.     

离子液体催化C_5馏分中二烯烃的聚合反应

合成了多种基于1-丁基-3-甲基咪唑阳离子的离子液体,并作为裂解C5馏分中混合二烯烃聚合反应的介质。考察了离子液体种类、反应温度、反应时间和添加Lew is酸对混合二烯烃聚合反应的影响。实验结果表明,以硝酸根为阴离子的离子液体对混合二烯烃的聚合反应具有一定的阻聚作用;以六氟磷酸根为阴离子的离子液体能明显促进混合二烯烃的聚合反应,提高二聚物的含量;添加Lew is酸(质量分数为1%的ZnCl2)的离子液体对混合二烯烃的聚合反应具有更明显的促进作用,其效果仅次于酸性氯铝酸类离子液体,反应温度以30℃以下为宜,温度过高将促使二聚物进一步聚合,形成三聚物乃至多聚物,降低二聚物的含量。     

Passivation and corrosion behaviours of cobalt and cobalt-chromium-molybdenum alloy

Passivation and corrosion behaviour of the cobalt and cobalt-base alloy Co30Cr6Mo was studied in a simulated physiological solution containing chloride and bicarbonate ions and with pH of 6.8. The oxido-reduction processes included solid state transformations occurring at the cobalt/electrolyte interface are interpreted using theories of surface electrochemistry. The dissolution of cobalt is significantly suppressed by alloying it with chromium and molybdenum, since the alloy exhibited “chromium like” passivity. The structural and protective properties of passive oxide films formed spontaneously at the open circuit potential or during the anodic polarization were studied using electrochemical impedance spectroscopy in the wide frequency range.