铬铁矿硫酸酸解过程强化

针对铬铁矿硫酸酸解条件苛刻的难题,提出机械活化和氧化剂相结合强化铬铁矿硫酸酸解过程的新方法.以南非铬铁矿为原料,考察了液固比、硫酸浓度、机械活化、氧化剂加入量、温度等参数对铬浸出过程的影响,对铬铁矿硫酸酸解过程铬的浸出动力学进行了研究.结果表明,最佳浸出条件为:液固比2.4 m L/g,硫酸浓度80%(?),机械活化时间20 min,氧化剂加入量13%(?),温度120℃,浸出时间5 h,该条件下铬浸出率达92.36%.浸出过程符合未反应收缩核模型.</p

3-MCPD and Glycidyl Esters in Potato Chips Sold in Turkey

3-Kloropropan 1,2-diol (3-MCPD) maddesi gıda kaynaklı bulaşanlardandır. 3-MCPD, Avrupa Komisyonu'nun Gıda Bilimsel Komitesi tarafından genotoksik karsinojen olarak belirlenmiş ve İngiltere Gıda Danışma Komitesi tarafından gıda ve gıda maddelerinde minimum düzeylere indirilmesi önerilen proses tabanlı bulaşan olarak tanımlanmıştır. Bu çalışmanın amacı, piyasadan elde edilen ve farklı markalardan alınan patates cipslerinin 3-MCPD esterleri ve glisidil esterlerinin miktarlarının belirlenmesidir. Patates cipslerinde bulunan 3-MCPD esterleri ve glisidil esterleri miktarları üzerine üretim yönteminin (markanın) ve kızartma amacıyla kullanılan yağ tipinin etkisi istatistiksel olarak incelenmiştir. Ayrıca ortalama vücut ağırlığına sahip bir bireyin, saptanan miktarlarda 3-MCPD esteri içeren patates cipsi tüketim sınırları ve tolere edilebilir günlük alım miktarları üzerinden hesaplanmıştır. Patates cipslerinin toplam 3MCPD esterleri ve glisidil esterleri miktarlarının belirlenmesi için DGF C VI 18(10) standart yöntemi kullanılmıştır. En yüksek 3-MCPD esterleri miktarı 2.97 mg/kg olarak B2 markasında (Örnekleme 1) bulunmuştur. Ayrıca en yüksek glisidil esterleri miktarı B2 markasında (Örnekleme 2) 6.01 mg/kg olarak tespit edilmiştir.3-Chloropropane 1,2-diol (3-MCPD) is a food-based contaminant. 3-MCPD is declared as a genotoxic carcinogen formed in foods by the Scientific Committee on Food of the European Commission and the UK Food Advisory Committee has recommended reducing its level to minimum in foods. The objective of this study is to determine 3MCPD esters and glycidyl esters contents of commercially available potato chips sold in Turkey. For this purpose, various brands of potato chips were obtained from local markets. The effects of production method (brands) and frying oil were investigated statistically based on the formation of 3-MCPD esters and glycidyl esters in various brands of potato chips. Moreover, maximum consumption for potato chips was calculated based on tolerable daily intake of 3MCPD esters for individuals of average body weight. DGF C V 18 (10) standard method was used for determination of 3-MCPD esters and glycidyl esters in potato chips. Maximum value for 3-MCPD esters was 2.97 mg/kg in B2 brand (Sample Block 2). Also, the highest amount of glycidyl esters was determined as 6.01 mg/kg in B2 brand (Sample Block 2)

Research on high-speed optical receiver with integrated large photosensitive surface photodetector based on standard CMOS process

为提高大纤芯(1 MM)塑料(POf)光纤通信用的单片集成光接收机(OEIC)的速率并降低成本,对SI基大光敏面光电探测器(Pd)的结构、性能以及后续放大电路进行了研究。首先,基于标准CMOS工艺流程对n+/n-WEll/P-Sub Pd结构进行建模和优化设计,对其光谱响应曲线和频率特性曲线进行了仿真;其次,建立Pd等效电路模型,结合设计的后续放大电路进行协同设计与仿真;最后,采用0.5μM CMOS工艺对单个面积为200μMx200μM的Pd以及后续放大电路单片集成电路进行了流片、封装和测试。实验结果表明,在-2.5V偏压下和650nM波长入射光,n+/nWEll/P-Sub Pd的响应度约有0.12 A/W,暗电流约为-9PA;单片光接收机在小于10-9的误码率bEr条件下,灵敏度为-23dbM,并得到250 MbIT/S速率的清晰眼图。In order to improve the speed and lower the cost of the monolithic integrated optical receiver for large core(1mm)plastic optical fiber(Pof)communication,the structure and performance of large photosensitive surface photodetector(PD)and subsequent amplifying circuit based on silicon are investigated.Firstly,based on the standard CMOS process,the model of N+/N-well/P-sub PDs structure is established and optimized.The PD′s characteristics of optical spectral responsivity and frequency response are simulated.Then,the collaborative design and simulation are accomplished through combining the established PD′s equivalent circuit model with the designed subsequent amplifying circuit.Finally,by using the 0.5μm CMOS process,the single PD with size of 200μm×200μm,and the monolithic integrated circuit of PD and post amplifiers are packaged and tested,respectively.The tested results indicate that at the wavelength of 650 nm,the responsivity of N+/N-well/p-sub PD is 0.12A/W,the dark current is about 9pA,under the bias voltage of-2.5V.The sensitivity of the monolithic integrated opticalreceiver is-23 dBm under the bit-error-rate(BER)of 10-9.And a clear eye-diagram with the speed of250Mbit/s is achieved.The designed monolithic integrated optical receiver can be applied to 250Mbit/s optical fiber communication systems very well.国家自然科学基金(61205060);国家自然科学基金青年基金(61401101); 东南大学毫米波国家重点实验室开放基金(K201401); 安徽省自然科学基金(1408085QF122); 安徽高校省级自然科学研究(2014KJ022); 福建省科技计划重点(2013H0047); 阜阳师范学院博士科研启动基金(FSB201501002); 阜阳师范学院科技成果孵化基金(2013KJFH05)和资助项