盐酸安非他酮的合成工艺优化

由关键中间体3-氯-α-溴-苯基乙基酮合成盐酸安非他酮。研究了碱、相转移催化剂（PTC）、溶剂及反应时间对盐酸安非他酮产率的影响。得出优化反应条件为：在KOH碱性条件下,以PEG-400为相转移催化剂,乙腈作溶剂,室温反应6 h。优化反应条件下,盐酸安非他酮的产率为87.3%。     

Cyclic voltammetric study of zinc and zinc oxide electrodes in 5.3 M KOH

The behaviour of zinc and zinc oxide in 5.3 M KOH in the presence of alkaline earth oxides, SnO, Ni(OH)₂ and Co(OH)₂ was examined by cyclic voltammetry. The influence of the alkaline earth oxides was compared with additives of established effects (Bi₂O₃, LiOH, Na₂CO₃ and CdO). The alkaline earth oxide each exhibits a distinct behaviour towards zincate. Whereas, a single process of interaction with zincate was shown by CaO; two modes of reaction were obtained with SrO and BaO. Solid solution formation was noticed with BeO and MgO. The other additives forming solid solution with ZnO were CdO, SnO. The ionic sizes of Ni(OH)₂ and Co(OH)₂ allow solid solution formation with Zn(OH)₂. Both Bi₂O₃ and Na₂CO₃ enter into complexation with zincate. LiOH forms two distinct zincates, of which one is an oxo zincate leaching the `hydroxyl' functionality. Cyclic voltammetry revealed the deposition of the oxide/hydroxide additives as metal prior to the onset of zinc deposition and the potential range for this additive metal deposition is almost the same for different additives (SnO, CdO, Ni(OH)₂). The beneficial action of these additives to zinc alkaline cells is associated with a substrate effect. The implication of this electrocatalytic deposition of metals on a zinc oxide electrode is also discussed.     

Corrosion of stainless steel grades in H2O/KOH 50% at 120 °C: AISI304 austenitic and 2205 duplex

We report on the corrosion of austenitic (AISI304) and duplex (2205) stainless steels in H₂O/KOH 50% at 120 °C. The research is based on a combination of electrochemical, structural and compositional analyses, aimed at assessing the surface modifications resulting from anodic attack and their impact on corrosion resistance. Linear sweep voltammetry and electrochemical impedance spectrometry measurements were carried out in an air‐tight high‐temperature cell. In‐plane and cross‐sectional SEM micrography, X‐ray diffractometry and EDX profiling were used to characterise samples attacked under electrochemically controlled conditions. Electrochemical results have shown that AISI304 exhibits a complex passivating behaviour, while the anodic electrokinetics of the duplex is characterised by mixed kinetic control. AISI304 was found to fail by intergranular corrosion and to be covered: in passive conditions by acicular compounds and in transpassive conditions by a compact layer of corrosion products. Duplex samples, instead, exhibit an uniform form of corrosion morphology and bear a compact layer of corrosion products both in passive and in transpassive conditions.     

Cleaner Production of Wheat Straw Pulp

A pulping method using NH4OH with less amount of KOH as cooking liquor on wheat straw was developed. KOH could reduce consumption of NH3 and cooking time for its strong alkalinity. The effects of various pulping conditions such as composition of cooking liquor, liquid-to-solid ratio, maximum temperature, cooking time to the maximum temperature and cooking time at the maximum temperature were studied. Experimental results indicated that the rate of delignification was 85.12% and the pulp yield was 49.65% under suitable pulping conditions. It looks promising to use black liquor containing nitrogen, phosphorus, potassium and organic substance as fertilizer resources for agricultural production. A new pattern of ecological cycling may be set up between paper industry and farming.     

KOH对低阶煤在超临界水中制取富氢气体的影响

以超临界水介质中低阶煤制取富氢气体为目的,利用120 ml小型间歇反应装置,在KOH/煤为0.7％～10％(质量)、温度400～650℃、压力12～30 MPa、停留时间0～30 min的范围内,考察了KOH催化下操作参数对小龙潭褐煤反应特性的影响。结果表明,随着KOH/煤质量比的增加,煤转化率和气体产率升高。KOH/煤质量比为10％时,气相产物中H_2百分含量增加一倍,H_2产率提高1.7倍。升高反应温度可以使KOH的催化作用更显著。对比氮气气氛和超临界水中煤催化热解反应发现,反应温度为600℃时,添加相同量的KOH催化剂,氮气气氛下煤转化率升高4.4％(质量),SCW条件下煤转化率升高7.8％(质量),说明超临界水反应环境下KOH的催化作用更加明显。提高反应压力可以促使煤转化率和气体产率升高。与KOH添加量和温度相比,停留时间对H_2产率的影响较小,随着停留时间的延长,CH_4产率略有增加。     

玉米秸秆木质素脱除动力学研究

采用KOH在不同温度下蒸煮稀酸预水解后的玉米秸秆。确定了不同蒸煮温度下木质素脱除速率常数,木质素脱除动力学方程表达为:WL=0.0137exp(-∞t)+0.8433exp(-k2t)+0.1430exp(-k3t)。利用Arrhenius方程确定木质素在大量脱除段以及残余脱除段的活化能分别达到54.46kJ/mol和27.62kJ/mol。确定在该体系中最佳蒸煮温度为100℃,蒸煮时间为100min,木质素脱除率可达到90%以上。     

Electrochemical capacitors based on highly porous carbons prepared by KOH activation

Various coal and pitch-derived carbonaceous materials were activated for 5 h at 800 °C using potassium hydroxide and 1:4 component ratio. Porosity development of the resultant activated carbons (ACs) was assessed by N₂ sorption at 77 K and their capability of the charge accumulation in electric double layer was determined using galvanostatic, voltammetric and impedance spectroscopy techniques. ACs produced from different precursors are all microporous in character but differ in terms of the total pore volume (from 1.05 to 1.61 cm³ g⁻¹), BET surface area (from 1900 to 3200 m² g⁻¹) and pore size distribution. Very promising capacitance values, ranging from 200 to 320 F g⁻¹, have been found for these materials operating in acidic 1 mol l⁻¹ H₂SO₄ electrolytic solution. The variations in the electrochemical behavior (charge propagation, self-discharge, frequency response) are considered in relation to the porous texture characteristics, elemental composition but also possible effect of structural ordering due to various precursor materials used. Cycling investigation of all the capacitors has been also performed to compare ability of the charge accumulation for different carbon materials during subsequent cycles.     

微波辐射-KOH活化兰炭粉制备活性炭

研究了以兰炭粉为原料,KOH为活化剂,采用微波辐射法制备活性炭的可行性。探讨了微波功率、碱炭质量比和活化时间对活性炭吸附性能的影响。同时采用美国ASAP-2020吸附仪测定了所制备活性炭的N2吸附脱附等温线和孔径分布,采用红外光谱分析了样品的表面官能团。结果表明:微波功率为700 W,碱炭质量比为3,活化时间为15 min工艺条件下制得的活性炭碘吸附值为694.5 mg/g,比表面积为513.62 m2/g,总孔容为0.510 3 cm3/g,平均孔径为3.973 8 nm,该活性炭为中孔型。以兰炭粉为原料,传统加热和微波加热制备的活性炭红外光谱图其峰形基本一致,只是峰强不同。     

一种基于MEMS工艺的新型THz喇叭天线的设计与仿真

提出了一种太赫兹(THz)天线结构:基于MEMS 工工艺的THz角锥喇叭天线.采用电磁场仿真软件Ansoft HFSS 11对所设计的天线进行仿真,结果表明该天线在2.5 THz ～3.5 THz范围以内具有回波损耗优于-25 dB,增益大于15 dB的良好特性.天线可以通过MEMS工艺(硅基KOH刻蚀)制造,具有加工...     

A comparative study of micropipe decoration and counting in conductive and semi-insulating silicon carbide wafers

Micropipes are considered to be one of the most serious defects in silicon carbide (SiC) wafers affecting device yield. Developing a method to count and map micropipes accurately has been a challenging task. In this study, the different etching behavior of conductive and semi-insulating wafers in molten potassium oxide (KOH) is compared. Micropipes and closed-core screw dislocations exhibit different morphology after etching and can be easily distinguished with a polishing process. Based on a new sample preparation procedure and a digital imaging technique, a novel method of efficiently and reliably mapping and counting micropipes in both conductive and semi-insulating SiC wafers is developed.