Extended kalman filter‐based nonlinear model predictive control of a continuous KCl‐NaCl crystallizer

An extended Kalman filter (EKF)‐based nonlinear quadratic dynamic matrix control (EQDMC) for an evaporative cooling draft‐tube baffled (DTB) KCl crystallizer is developed. The controller is used to maintain the productivity, crystal mean size and impurity of crystals. Since these controlled variables are not directly measurable, the EKF is used to estimate them. The nonlinear controller is a combination of an extended linear dynamic matrix control (EDMC) and the quadratic dynamic matrix control (QDMC). This combination provided good control of the system despite the process nonlinearity, constraints, and inadequate reliable online measurement of the controlled variables. The performance of the controller in the presence of plant/model mismatch, disturbance, wrong estimation and simultaneous step changes in the controller setpoints is discussed.     

KCl含量对乳化炸药压力减敏的影响

在相同的乳胶基质中分别添加0%、2%、4%、6%和8%的KCl,再分别用膨胀珍珠岩和化学发泡剂敏化制备2组乳化炸药。测试各乳化炸药水中爆炸冲击波,得出它们未受压和受压后的爆炸冲击波压力峰值,利用波峰值计算乳化炸药的压力减敏度。依据压力减敏度数值,分析KCl含量对乳化炸药压力减敏作用的影响,并测试不同KCl含量下分散相的析晶点,分析不同KCl含量造成压力减敏变化的原因。结果表明:KCl含量在0%～2%之间时,乳化炸药的压力减敏度无明显变化,KCl含量在2%～8%之间时,KCl含量对乳化炸药的压力减敏度有较大影响,而且呈现出正线形相关性。     

三辛胺-异戊醇有机溶剂萃取制备磷酸二氢钾

以工业湿法磷酸和氯化钾为原料,开展溶剂萃取法制备磷酸二氢钾的研究。通过筛选确定采用三辛胺-异戊醇作有机萃取剂,考察了有机相与水相比、反应时间、反应温度及循环次数等因素对萃取法制备磷酸二氢钾的影响。实验结果表明,在三辛胺-异戊醇按体积比为1∶1制成混合萃取剂、反应温度为20 ℃、萃取时间为60 min的最优条件下,磷酸二氢钾产品的回收率≥95%,产品纯度≥98%。该方法具有产品纯度高,萃取温度低、操作简单等优点。     

Thermal conductivity of aqueous solutions of NaCl and KCI at high pressures

This paper presents new experimental measurements of the thermal conductivity of aqueous solutions of NaCl and KCl at high pressures. The measurements were made with a parallel-plate apparatus. The temperatures covered the range from 293 to 473 K at pressures up to 100 MPa and concentrations from 0.025 to 0.25 mass fraction of NaCl and KCl. The measurements included 6 isobars at pressures from 0.1 to 100 MPa at intervals of 20 MPa, 10 isotherms at temperatures from 293 to 473 K at intervals of 20 K, and 6 isopleths at concentrations from 0.025 to 0.25 mass fraction of NaCl and KCl at intervals of 0.05. The precision of the measurements was ±1.6%. The thermal conductivity obtained for NaCl + H₂O and KCl + H₂O was compared with data of other authors, with satisfactory agreement. The viability of the technique was confirmed and the essential features of a high-precision instrument were established.     

Friction force microscopy investigations of potassium halide surfaces in ultrahigh vacuum: structure,friction and surface modification

Friction force microscopy measurements on the vacuum‐cleaved (001) surfaces of KF, KCl and KBr have been carried out. All surfaces exhibit atomically flat terraces with monatomic steps aligned preferentially along low‐index lattice directions. Stick‐slip lateral forces with the lattice periodicity are observed on all surfaces. Tip‐sample contact creates higher friction domains on the terraces of all three materials. The structure, topography and degree of friction force contrast of these domains is material dependent. The dependence of friction upon load generally does not coincide with the behavior expected for an elastic contact. We propose that the observed domains result from surface structural changes created by low load tip‐sample contact on these relatively soft materials. This revised version was published online in June 2006 with corrections to the Cover Date.     

尼索地平对离体人子宫动脉收缩的影响

目的: 研究尼索地平对氯化钾（KCl）和去氧肾上腺素(phenylephrine, PHE)所致离体人子宫动脉收缩的影响。方法: 采用离体血管实验法,以KCl、PHE在含钙离子和不含钙离子的K-H液中预收缩离体人子宫动脉环,观察尼索地平对血管收缩的影响。 结果: 在含钙离子的K-H液中,尼索地平抑制KCl（50 mmol/L、80 mmol/L）所致血管收缩的IC50分别为（7.52±1.33）×10^-9 mol/L和（2.75±0.53）×10^-7 mol/L,尼索地平抑制PHE［（1×10^-6）mol/L和（5×10^-6）mol/L）］所致血管收缩的IC₅₀分别为（6.17±1.21）×10^-8 mol/L和（1.51±0.49）×10^-6 mol/L。在无钙离子K-H液中,尼索地平无抑制离体血管收缩的作用。结论: 尼索地平对离体人子宫动脉的收缩有抑制作用。     

KCl复配5’-肌苷酸二钠替代钠盐对鱼糜凝胶特性的影响

为研制低盐鱼糜,探究食盐替代物KCl和5’-肌苷酸二钠（inosine 5’-monophosphate disodium salt,IMP）对鱼糜凝胶品质的影响,以鲢鱼鱼糜为研究对象,设计3 组实验,A组添加2.0% NaCl,B组添加0.8% KCl和1.2% NaCl,C组添加0.7% KCl、0.1% IMP和1.2% NaCl,通过测定鱼糜凝胶的白度、持水性、强度、质构、水分分布与组成以及微观结构变化,探究NaCl的最佳替代方案。结果表明：相比于A组,B组鱼糜凝胶白度、持水性、强度变低,硬度、胶着性、咀嚼性、内聚性显著降低,弹性无显著变化,不易流动水含量减小、自由水含量升高,凝胶网络空间结构形成不完全;C组鱼糜凝胶除咀嚼性显著下降外,其余指标未发生显著劣变,说明KCl和IMP复配是一种理想的NaCl替代方案。     

钠、镁离子对氯化钾结晶影响的研究

文章通过MSMPR结晶系统对纯氯化钾及加入2%的氯化镁后的溶液与加入光卤石母液后的溶液进行了氯化钾结晶动力学的研究,计算出了三种情况下氯化钾结晶的基本动力学关系式,分析钠、镁离子对氯化钾结晶过程中成核与生长速率的影响程度,为用光卤石生产氯化钾产品,提高其取得率及增大晶体粒度提供了理论依据.     

提高氯化钾产品质量的工艺研究

通过对氯化钾生产过程中光卤石及氯化钾的成核、结晶理论进行分析探讨,并结合生产实际,提出了利用TDB结晶技术生产光卤石和利用控速结晶技术生产优质氯化钾的理论并进行了工艺研究.实验证明,采用本工艺技术生产的氯化钾产品,其粒径达0.45mm以上、干基氯化钾含量达98%以上.     

激光全息干涉法测量液相质扩散系数数字图像处理的研究

用He-Ne激光器、CCD和图像采集系统等仪器设备,搭建了数字激光全息干涉法测量液相质扩散系数的实验系统,并测试获得了浓度为0.33 mol/l KCl水溶液在298.15 K温度下的全息干涉图像,采用了图像增强、全息干涉条纹图再现及相位展开等数字图像处理过程的关键技术对全息干涉图进行处理,得到了相位展开后物光相位差,经换算后获得了该溶液的质扩散系数.为化工工程上研究替代制冷荆急需的质扩散系数测量提供了有效的方法.