容量法快速测定钾

测定钾时,多数情况下有钠存在。故多采用重量法,如铂氯酸法、过氯酸法、四苯硼化钠法和钴亚硝酸钠法等。前三种方法,虽很准确,但手续麻烦,尚需要贵重和难得的试剂H_2PtCl_3、HClO_4和Na[B(C_6H_5)_4],     

K2SiF6容量法快速测定水泥中SiO2

Ｋ_２ＳｉＦ_６容量法快速测定水泥中ＳｉＯ_２王士龙，郑礼胜，张虹山东建材学院（２５００２２）１引言Ｋ２ＳｉＦ６容量法测定水泥中ＳｉＯ２是现行的标准方法［１］之一，由于其分析速度较快而被普遍采用。但此方法操作过程中仍需将Ｋ２ＳｉＦ６沉淀、过滤、分离，操?..     

复混肥料中硼含量的测定

采用电位滴定法测定复混肥料中硼的含量，该法较分光光度计法简便、快速、准确度和精密度较高，便于推广应用。     

磷钼酸喹啉容量法快速测定化肥中五氧化二磷

江西贵溪化肥有限责任公司建厂初期一直采用721分光光度法测定化肥中P2O5,仪器产生的误差导致分析结果的准确度低,影响工艺生产调控,产品质量波动较大。     

离子交换容量法快速测煤中全硫

在化工生产中,尤其是以煤为原料生产氮肥、甲醇的工厂,准确快速测硫,对指导生产的意义很大。特别是氮肥生产测硫不准,会给精炼系统适成困难,铜液中CuS沉淀增多,除增加铜耗外,还会使铜液粘度增大,以致引起铜洗塔出口气体带液事故。     

高氯酸氧化容量法快速测定合金钢中铬

建立了适用于合金钢中的高、中、低铬含量（含铬量范围为1．0％-40％）的分析方法。合金钢屑分解后，铬元素被高氯酸氧化为六价铬，在一定的酸性条件和磷酸的作用下，用硫酸亚铁铵溶液作滴定液，N-苯代邻位氨基苯甲酸作指示剂，将六价铬还原为三价铬。该方法简单快速，准确度高，结果满意，适于合金钢中铬的测定。     

三氟化硼三乙醇胺中硼的测定

三氟化硼三乙醇胺中的氟和ＴＥＡ干扰硼的测定。用蒸馏法将硼从样品中分离出来，然后用甘露醇法进行测定。操作简便，测得结果满意。     

硼酸锌中硼的测定

介绍了测定硼酸锌中硼的沉淀分离法、离子交换法、EDTA络合掩蔽法、8—羟基喹啉络合掩蔽法。     

容量法测定腐植酸复肥中腐植酸含量

现行标准GB11957-1989对腐植酸复肥中腐植酸测定方法操作步骤繁,手续多,耗时长。本文以容量法测定腐植酸复肥中腐植酸。总体方差0.087%,实验方法与标准方法不存在显著性差异;本方法操作手续简便,具有较好的准确度和精密度。结果满意。     

298.15K时浓磷酸水溶液的体积性质

在２９８．１５ｋ的浓磷酸水溶液中，认为存在Ｈ３ＰＯ４＝Ｈ＾＋Ｈ２ＰＯ４＾和Ｈ２ＰＯ＾１＋Ｈ３ＰＯ４＝Ｈ５Ｐ２Ｏ８两个化学平衡。用修正的Ｐｉｔｚｅｒ离子相互作用模有达磷酸水溶液的过剩Ｇｉｂｂｓ自由能，推导出能精确描述浓度高达１８．０ｍｏｌ．ｋｇ＾－１的磷酸水溶液体积性质的数学模型。     

气相色谱法测定混合制剂中乙草胺与2，4—D丁酯的含量

本文以气相色谱法测定乙草胺与 ２,４－Ｄ丁酯混合制剂中各组分含量。采用 Φ３ｍｍ ｘ２ｍ的不锈钢柱,内填充物为５％ＯＶ－１０１／１０１白色硅烷化担体,邻苯二甲酸二正丁酯为内标物。变异系数小于１％,乙草胺平均回收率为９９．３％,２,４－Ｄ丁酯平均回收率９９．０％。方法用于实际测定,结果令人满意。     

凝析气井合理产量确定方法研究

气井合理产量标定是气田开发的一项基础工作,是提高凝析气田经济效益的关键性问题。本文通过参阅当前国内外气田开发方面一些相关文献,结合五区南气田的实际情况,分别采用经验法、采气曲线法、节点分析方法、携液计算法、最优化方法、试采法以及数值模拟方法等方法对气井产能进行评价,探讨凝析气井合理产量的各种确定方法。     

容量法测定微量元素预混合饲料中锌、铜含量

探讨了用容量法测定微量元素预混合饲料中锌、铜含量的分析条件;样品用盐酸和硝酸处理后,用EDTA滴定法测定锌、铜合量,再用硫脲掩蔽铜,用EDTA滴定法测定锌含量,总量减去锌含量即可得到铜含量。     

Volumetric Heat Transfer Coefficient in Fluidized‐Bed Dryers

In literature, there are several Nu=f(Re) equations to specify the heat transfer coefficient between solids and the drying gas, but these equations differ significantly because of the inaccuracy of determining the contact surface between the two phases. A pilot‐plant fluidized‐bed dryer is developed to study the heat and mass transfer phenomena during the drying process. A volumetric heat transfer coefficient is applied for modeling fluidized‐bed dryers. A modified Nusselt number is defined to compare the experimental results and those of the literature. The modified Nu'=f(Re) equation exhibits a proper correlation between the results of the experiments in the literature and those of our experiments.     

Effect of Chemical Structure of Solid Lipid Matrix on Its Melting Behavior and Volumetric Expansion in Pressurized Carbon Dioxide

Supercritical carbon dioxide (SC-CO₂) technology offers new opportunities for green processing of lipids; however, there is little information of the melting behavior and volumetric expansion of solid lipids in pressurized CO₂. In this study, melting behavior and volumetric expansion of two different solid lipid classes and the effect of the structural differences within the same lipid class on the melting behavior in pressurized CO₂ were investigated. The melting point of the solid lipids decreased linearly with increasing pressures up to a certain level; then, it stayed constant. The highest melting point depression was observed for soybean oil monoacylglycerol (SO-MAG) at 51.5 °C/110 bar, whereas the lowest was for fully hydrogenated soybean oil (FHSO) containing 30% SO-MAG at 55.0 °C/79 bar. Melting point depression depended on lipid class. SO-MAG exhibited a higher melting point depression than FHSO (triacylglycerol form), and its blends with SO-MAG. There was no difference in melting point depression between glyceryl 1,2-distearate and glyceryl 1,3-distearate up to 200 bar (P > 0.05). A positive correlation between the melting point depression and volumetric expansion of solid lipids was observed. The highest volumetric expansion was for SO-MAG in the linear region of the melting point depression curve, achieving 14.4% expansion compared to 9.3% for FHSO (P < 0.05). The highest dT/dP value (0.17 °C bar⁻¹) was obtained for SO-MAG, whereas the FHSO (0.09 °C bar⁻¹) had the lowest one. Findings of this study will help optimize solid lipid-involving SC-CO₂ processes for better protection of heat-sensitive compounds while improving energy efficiency.     

高效液相色谱法分析青荚叶中豆甾醇的含量

采用反相高效液相色谱法(RP-HPLC)测定青荚叶中豆甾醇的含量,色谱柱为Thermo C18柱(250 mm×4.6 mm,5μm),流动相为甲醇∶水(97∶3),流速1.0 m L/min,进样量20μL,检测波长210 nm。结果表明,豆甾醇进样量在0.216~2.16μg,其峰面积与浓度呈良好的线性关系(R2=0.999 5),回收率为97.79%。方法专属性强,准确可靠,可用于青荚叶中豆甾醇的含量测定。     

Volumetric properties at high pressure of waste oil methyl ester compared with diesel oil

In this paper, the isothermal compressibility coefficient, the cubic expansion coefficient and the propagation speed of pressure waves of waste oil methyl ester (WOME) and diesel oil (DO) are presented. These properties can be derived mathematically from the specific volume, the only property measured in this work (from 288.15 to 328.15 K and from atmospheric pressure to 350 MPa). The modified Tait–Tammann Equation has been adjusted to the experimental data with a high correlation coefficient and confidence level. Because of their different physical properties, the use of WOME instead of DO can affect the behaviour of some diesel equipments and, for instance, the economic efficiency and the behaviour of heat engines.