添加硼砂助熔剂煤灰熔融性的量子化学与实验研究

将硼砂按不同比例分别掺入四种高灰熔点煤灰中,对混合灰样熔融特性进行实验研究。 采用密度泛函理论对熔融过程中作为反应物的莫来石反应活性进行计算。莫来石属于正交晶系Pbam空间群。计算结果表明,莫来石很容易与电子接受体结合,不容易与电子给予体结合。当莫来石与电子给予体结合时,Si原子的活性高于Al。因此,向莫来石中加入助熔剂硼砂时,硼砂中的Na＋作为电子接受体,非常容易进入莫来石的晶格中,促使莫来石转变为霞石,降低了灰熔融温度。在还原性气氛下,煤灰熔融特性实验证实了理论计算结果。     

Effects of potassium feldspar on slagging and fluxing in phosphorus produced via electric furnace

In this study, thermodynamic calculations were conducted to investigate K-feldspar fluxing yellow phosphorus produced via an electric furnace. The results demonstrated that the reaction temperature of K-feldspar as a flux was lower than that during the traditional process. The characteristic temperatures of silica-CaO and potassium feldspar-CaO systems under different mass ratios of SiO₂/CaO were measured according to the CaO-substituting decomposition products of phosphorus; the results showed that the temperature of the silica-CaO system was higher, 96.2–114.3°C, compared to the potassium feldspar-CaO system under the same conditions. These results indicate that K-feldspar as a flux in a phosphorus furnace can save energy and reduce cost. X-ray diffraction (XRD) analysis further revealed that a complex transition phase of silicates and aluminosilicates was accompanied by a conversion reaction of the silica-CaO and potassium feldspar-CaO systems, and that K₂O capable of co-producing potash fertilizer escaped as a gas through the collection equipment.     

冷冻过程中胞内溶液均相成核温度的确定

为了研究冷冻过程中胞内溶液均相成核温度下降值与平衡凝固点下降值的关系, 提出了一种求解变组元系统成核温度的方法, 并联合细胞脱水方程, 进行了数值求解. 研究发现, 甘油-氯化钠-水三元系统的均相成核温度下降与平衡凝固点下降存在如下的线性关系: ⊿Th=1.17⊿Tm, 表明水溶液均相成核温度与溶质有关.     

利用旋风炉玻璃化处理垃圾焚烧飞灰实验研究

在自行设计的旋风炉实验台上对焚烧飞灰进行玻璃化熔融实验,系统研究了焚烧飞灰熔融前后微观形貌、灰渣中重金属特性和浸出特性。实验结果表明,焚烧飞灰旋风熔融后成黑色的脆硬玻璃态熔渣,表层呈浅黄色。在熔渣中N i、Cr的固溶率最高,均超过95%以上;低熔点重金属多数挥发至熔融烟气和熔融烟道飞灰颗粒中,Cd的固溶率仅有21%,Pb和Zn部分固溶于玻璃态熔渣中,两者固溶率可达42%以上。Cu和As的固溶率分别为37%和18%。熔融后的玻璃态熔渣重金属浸出率明显低于熔融前的焚烧飞灰,且均低于美国EPA的标准限值。     

Investigation of terminal olefine in the isothiocyanatotolane liquid crystals with alkoxy end group

Three series of liquid crystals based on isothiocyanatotolane core with terminal alkenoxy groups (4A-1?4C-2) have been synthesised via multi-step reactions. Their thermotropic mesophases and physical properties are evaluated by comparison with the alkoxyl analogues (4a-1?4c-2). The results show that the isothiocyanatotolane LCs with alkenoxyl terminals deliver higher birefringence (0.410~0.436), lower melting points, lower melting enthalpies and viscosity. The effects of the alkenoxy terminal groups and the lateral fluoro substituents on the mesomorphic behaviour and physical properties are discussed. The formulation of the mixture containing isothiocyanatotolane liquid crystals with alkenoxyl terminals provides evidence of an useful candidate for liquid crystal photonics.     

Direct polyesterification by use of phosphorus oxychloride and LiCl in pyridine

The reaction of the N-phosphonium salt of pyridine derived from phosphorus oxychloride in pyridine was successfully used for the preparation of aromatic polyesters with high molecular weight when carried out in the presence of lithium chloride. In the copolycondensations of isophthalic and terephthalic acid with diphenols, the mode of reaction with the diacids was expected to produce several types of the diacid activated intermediates, which might control the sequences of the diacids in the copolymers. The possible variation of the sequences was studied in terms of the mode and copolymer properties such as glass transition temperatures and liquid crystalline transition temperatures. Competitive model reactions were carried out to discuss these relationships. © 1993 John Wiley & Sons, Inc.     

Experimental investigations for the location of reaction zones in a bagasse fired furnace

It is unfortunately not too rare to find that fire investigators estimate flame temperatures by looking up a handbook value, which turns out to be the adiabatic flame temperature. Generally, the measurement of temperature in an industrial furnace is difficult, time consuming and expensive. Combustion of bagasse has its own special set of problems which appear to be due largely to the high moisture content and varying particle sizes of the fuel. The present experimental investigation is carried out to estimate the location of reaction zones and temperature fields in a bagasse fired furnace. Furnace is modeled by three dimensional CFD codes. Both experimental and the computational results show a considerable delay to ignition due to the drying of fuel. Also the location of maximum temperature zones and the pattern of flame propagation inside the furnace are clearly indicated.     

润湿剂促进燃煤细颗粒声波团聚脱除的实验研究

在声波团聚室中研究了润湿剂液滴与细颗粒碰撞团聚脱除特性,提出了一种利用润湿剂促进细颗粒在声波场中捕集的新方法。结果表明,不同润湿剂溶液对细颗粒在声波场中的团聚脱除效果存在较大差异,采用JFC和FS-310润湿剂溶液时,细颗粒分级脱除效率与采用水时的分级脱除效率相近。而SDS和Silanol w22溶液,则可有效提高细颗粒在各粒径段的分级脱除效率。细颗粒在声波场中的脱除效率与润湿剂润湿性能具有很好的相关性,随润湿剂对细颗粒相对接触角增大而降低,在声压级为150 dB时,相对接触角由83°降低到0°,细颗粒脱除效率提高了18%,在无声场作用下,脱除效率仅提高了5%。细颗粒脱除效率随声压级的增大而提高,在低声压级条件下,添加润湿剂可有效提高细颗粒脱除效率,声压级在130 dB时,添加SDS溶液液滴后细颗粒脱除效率比声场单独作用时的脱除效率提高了25%。表明添加润湿剂可有效提高细颗粒在声波场中的团聚脱除效率,实现在低声压级条件下,获得高的细颗粒脱除效率。     

Key Experimental Results of the PYROSMANI Project

The presented key results were obtained in the course of experiments carried out within the PYROSMANI (PYROchemical processes Study for Minor ActiNIdes recycling in molten salt chlorides and fluorides) Project supported by Rosatom. The individual and joint solubility of UF₄, PuF₃ and CeF₃ in ternary LiF–NaF–KF and LiF- ThF₄-UF₄ melts was measured by method of isothermal saturation for the temperature range 550-800°C. The solubility measurement technique based on isothermal saturation was verified in LiF–NaF–KF eutectics for praseodymium trifluoride by the reflectance spectroscopy. The process under investigation was the extraction of lanthanum, neodymium, europium and samarium trifluorides from 73LiF-27BeF₂ melt (mole %) into liquid bismuth at 600-610°C. There were defined temperature dependences of kinematic viscosity and melting temperatures for molten 46.5LiF–11.5NaF–42KF; 73LiF-27BeF₂; 85LiF-15AlF₃ and 43.5LiF–24.3NaF–32.2UF₄ salt mixtures from liquidus temperature to 840°C.     

KED碰撞模式-电感耦合等离子体质谱（ICP-MS）法测定多种煤中磷

煤是重要的工业生产和生活能源燃料,磷元素又是煤中主要的有害微量元素之一,磷元素极易进入大气、水体和土壤,对环境和生态造成严重污染,为快速准确测定不同煤质样品中磷元素的含量,建立了混合酸消解-KED碰撞模式-电感耦合等离子体质谱法（ICP-MS）测定多种煤中磷的方法。讨论了样品灰化温度、灰化时间、消解试剂等对磷元素测定结果的影响,试样经箱式电阻炉在815 ℃,灼烧1.5 h灰化后,采用盐酸-硝酸-氢氟酸-高氯酸体系进行酸解,王水提取,以磷元素特定质量数31 (质荷比,m/z )定性,以磷元素和103Rh内标元素质谱信号的强度比值与磷元素的浓度成正比进行定量分析,向碰撞反应池中通入碰撞混合气,与相同质量数的多原子离子物质的发生有效碰撞使其质荷比发生变化,从而降低氧化物产率、消除双电荷产生的质谱干扰,准确测定试样中磷的含量。磷标准溶液浓度在0.5～50 μg/mL范围内呈现良好的线性关系,磷校准曲线方程为y=3985x-226.23,相关系数(R2) =0.9998。方法检出限为0.96 μg/g。选用17种不同种类国家一级标准物质进行验证,测定值与认定基本一致,相对标准偏差(RSD)均≤9.6%,(n=12),相对误差(RE) 均≤4.6%,各种标准物质磷元素测定t值均小于2.20（t 0.05,11值）,该方法测定结果与标准物质认定值具有较好的一致性,且无显著性差异,该方法可用于不同煤质样品中磷元素的测定。     

Determination of available phosphorus in soils by using a new extraction procedure and a flow injection amperometric system

A new extraction procedure based on an off-line extraction column was proposed for extracting of available phosphorus from soils. The column was fabricated from a plastic syringe fitted at the bottom with a cotton wool and a piece of filter paper to support a soil sample. An aliquot (50 mL) of extracting solution (0.05 M HCl + 0.0125 M H₂SO₄) was used to extract the sample under gravity flow and the eluate was collected in a polyethylene bottle. The extract was then analyzed for phosphorus contents by a simple flow injection amperometric system, employing a set of three-way solenoid valves as an injection valve. The method is based on the electrochemical reduction of 12-molybdophosphate which is produced on-line by the reaction of orthophosphate with acidic molybdate and the electrical current produced was directly proportional to the concentration of phosphate in range of 0.1-10.0 mg L⁻¹ PO₄-P, with a detection limit of 0.02 mg L⁻¹. Relative standard for 11 replicate injections of 5 mg L⁻¹ PO₄-P was 0.5%. A sample through put of 35 h⁻¹ was achieved, with consumption of 14 mg KCl, 10 mg ammonium molybdate and 0.05 mL H₂SO₄ per analysis. The detection system does not suffer from the interferences that are encountered in the photometric method such as colored substances, colloids, metal ions, silicate and refractive index effect (Schlieren effect). The results obtained by the column extraction procedure were well correlated with those obtained by the steady-state extraction procedure, but showed slightly higher extraction efficiency.     

Synthesis of a diverse set of phosphorus ligands on solid support and their screening in the Heck reaction

Representative members from five different families of supported phosphine and phosphinite ligands have been prepared from common templates—polymer-bound aminoalcohols. These include β-aminophosphines, N,β-diphosphinoamines, α,β-diphosphinoamines, β-aminophosphinites and N-phosphino-β-aminophosphinites. Representatives of each family of ligands were complexed with Pd(OAc)₂ and screened in the Heck reaction of iodo- and bromobenzene. While the reaction of iodoarenes is ligand-independent, the reaction of bromoarenes is ligand-sensitive. The rationale for this behavior is suggested. Lead ligands for the reaction of bromoarenes were determined.     

Viscosity-Temperature Behavior of Hydroxypropyl Cellulose Solution in Presence of an Electrolyte or a Surfactant: A Convenient Method to Determine the Cloud Point of Polymer Solutions

The viscosity of hydroxypropyl cellulose (HPC) solution with or without an additive has been measured continuously as a function of temperature with the help of a vibro-viscometer. The viscosity of the polymer solution showed a gradual decrease initially with increase in temperature until a particular point beyond which there was a sharp decrease in the viscosity, which coincided with the clouding of the solution. The cloud point temperature (CP) of the polymer solution was determined from the first derivative plot of viscosity vs. temperature. Effect of addition of an electrolyte or a surfactant on the CP of HPC solution has also been studied. While a decrease in CP of HPC solution in presence of fluoride, chloride, or bromide ions was observed, presence of iodide or thiocyanide ions led to an increase in the CP. However, presence of an ionic surfactant initially lowered the CP but beyond a particular surfactant concentration a sharp increase in cloud point was observed due to interaction of the surfactant with the polymer. The results suggest that surfactants with longer hydrophobic tail or more hydrophobic groups have more affinity for HPC.     

Characterisation and quantification of organic phosphorus and organic nitrogen components in aquatic systems: a review

This review provides a critical assessment of knowledge regarding the determination of organic phosphorus (OP) and organic nitrogen (ON) in aquatic systems, with an emphasis on biogeochemical considerations and analytical challenges. A general background on organic phosphorus and organic nitrogen precedes a discussion of sample collection, extraction, treatment/conditioning and preconcentration of organic phosphorus/nitrogen from sediments, including suspended particulate matter, and waters, including sediment porewaters. This is followed by sections on the determination of organic phosphorus/nitrogen components. Key techniques covered for organic phosphorus components are molecular spectrometry, atomic spectrometry and enzymatic methods. For nitrogen the focus is on the measurement of total organic nitrogen concentrations by carbon hydrogen nitrogen analysis and high temperature combustion, and organic nitrogen components by gas chromatography, high-performance liquid chromatography, gel electrophoresis, mass spectrometry, nuclear magnetic resonance spectrometry, X-ray techniques and enzymatic methods. Finally future trends and needs are discussed and recommendations made.     

Reactivity of chlorinating agents/PPh3 for the chlorination of alcohols and carboxylic acids: a comparative study

The reactivity of chlorinating agents was examined with the aid of ¹H NMR using competitive reactions between selected chlorinating agents and CBr₄ towards alcohols and carboxylic acids. The reactivity was greatly dependent on the type of substituent on the chlorinating agents. COCCl₃ and CN substituted trichloromethyl groups enhanced the reactivity of the chlorinating agent with PPh₃ for the chlorination of alcohols and carboxylic acids.     

An assessment of analytical performance of dissolved organic nitrogen and dissolved organic phosphorus analyses in marine environments: a review

To better understand the cycling of marine dissolved organic matter, analytical methods are required allowing for data on dissolved organic nitrogen and phosphorus (DON and DOP) to be acquired with high analytical performance. The coverage of documented DON and DOP analytical performance is very limited; instead analytical data are mostly available for total dissolved N and P (TDN and TDP) analyses. This substitution overestimates analytical performance for DON and DOP measurements due to the cumulative effect of Standard Deviation applied for detection limit and precision evaluations. The little available data obtained by photolytic, chemical, a combination of both, and high temperature combustion methods indicate that current detection limit is 0.30 µM for DON and 0.010 µM for DOP. Precision for both analytes, in general, is ≤4.5%. The data on accuracy is scarce despite availability of Reference Materials for TDN and NO₃^? + NO₂^? analyses, and for the TDN measurement is <5%; even fewer data exist for TDP due to a lack of reference material for this analysis. The Beer–Lambert law is linear up to 200 µM for TDN and 5–6 µM for TDP. Current analytical abilities for DON/DOP measurements are not ready yet to set the level of dissolved organic carbon analysis. The advance in the analytical performance for DON and DOP measurements depends upon the possibility to improve the analytical performance for dissolved inorganic N and P measurements involved in DON and DOP estimations. For the DOP analysis, an international standard method becomes necessary to develop and evaluate collaboratively. The chemical oceanographers’ community should reconsider requirements needed for the coverage of analytical performance for DON and DOP measurements to make this data more shareable and transparent. The lack of these data protracts marine analysts from attaining further methods improvement and development.     

Development of a series of cross-linking agents that effectively stabilize alpha-helical structures in various short peptides

A series of cross-linking agents of varying rigidity and length were designed to stabilize helical structures in short peptides and were then synthesized. The sequences of the short peptides employed in this study each include two X residues (X=Dap, Dab, Orn, and Lys) at the i/i+4, i/i+7, or i/i+11 positions to provide the sites for cross-linking. These peptides were subjected to reaction with the synthesized cross-linking agents, and the helical content of the resulting cross-linked peptides were analyzed in detail by circular dichroism. For each of the peptide classes we found combinations with the cross-linking agents suitable for the construction of stable helical structures up to >95 % helicity at 5 degrees C. Our method could also be applied to biologically related sequences seen in native proteins such as Rev.