Low Temperature Heat Capacities and Thermodynamic Properties of Zinc L-Threonate Zn(C_4H_7O_5)_2(s) by Adiabatic Calorimetry

Low-temperature heat capacities of the solid compound Zn（C4H7O5）2（s） were measured in a temperature range from 78 to 374 K, with an automated adiabatic calorimeter. A solid-to-solid phase transition occurred in the temperature range of 295？322 K. The peak temperature, the enthalpy, and entropy of the phase transition were determined to be （316.269±1.039） K, （11.194±0.335） kJ？mol-1, and （35.391±0.654） J？K-1？mol-1, respectively. The experimental values of the molar heat capacities in the temperature regions of 78？295 K and 322？374 K were fitted to two polynomial equations of heat capacities（Cp,m） with reduced temperatures（X） and [X = f（T）], with the help of the least squares method, respectively. The smoothed molar heat capacities and thermodynamic functions of the compound, relative to that of the standard reference temperature 293.15 K, were calculated on the basis of the fitted polynomials and tabulated with an interval of 5 K. In addition, the possible mechanism of thermal decomposition of the compound was inferred by the result of TG-DTG analysis.

低温液相法从脱硫废渣中制备不溶性硫磺

HPF脱硫废渣是煤气脱硫工序的副产物,含有焦油、铵盐、酚、萘等多种杂质,是煤化工企业难以处理的固体废弃物。通过萃取-结晶技术,得到了纯度高于99.97%的高纯度硫磺。在较低的温度条件下,用提纯的硫磺制备了不溶性硫磺,通过三因素三水平正交试验,得到了低温液相法的最佳工艺条件。采用化学分析、差热、热重分析和X射线衍射分析技术,对产品的结构和性质进行了分析定性。试验结果表明,不溶性硫磺晶体结构和普通硫磺存在显著差异,具有较好的热稳定性。

不同提取方法对井冈蜜柚皮精油组成与性质的影响

以井冈蜜柚皮精油(Jinggang pomelo peel essential oil,JPPEO)为研究对象,采用水蒸气蒸馏法、低温连续相变法两种方法进行提取,以精油得率为主要指标,研究了萃取温度、压力、时间等因素对井冈蜜柚皮精油得率的影响,并通过正交法进行低温连续相变法提取工艺优化,同时对精油的理化性质及化学组成进行分析。研究表明,低温连续相变提取井冈蜜柚皮精油(Low-temperature continuous phase transition extraction essential oil,L-JPPEO)的最佳工艺为:颗粒度30目,萃取温度55℃,萃取压力0.6 MPa,萃取时间60 min,解析温度70℃,此时精油得率为10.99‰,比水蒸气蒸馏法提取的精油(Hydro distillation essential oil,H-JPPEO)得率高出了2.88倍;理化性质实验结果表明,低温连续相变萃取的井冈蜜柚皮精油的不饱和脂肪酸含量较高,游离脂肪酸含量较低,酯类成分含量较低;傅里叶衰减全反射中红外光谱法(Fourier transform infrared spectroscopy,FTIR)鉴定出L-JPPEO和H-JPPEO含萜烯类化合物、醇类、酚类、醛类以及含羰基化合物。气相色谱-质谱联用法(Gas chromatography-mass spectrometry,GC-MS)从H-JPPEO、L-JPPEO样品中分别鉴定出23和32种化合物,其中两种精油都检测出的有15种物质,D-柠檬烯相对含量均最高,L-JPPEO中相对含量为4.75±0.16μg/mL,H-JPPEO中相对含量为640.93±44.47μg/mL;顶空气相色谱-离子迁移谱法(Headspace-gas chromatography-ion mobility spectrometry,HS-GC-IMS)从两种提取方法的精油均鉴定出71种化合物,与水蒸气蒸馏相比,低温连续相变萃取技术提取出较多的萜烯类(45.75%)、酮类(7.68%)及酯类(15.85%)、酸类(5.62%)成分。

CaO和Na_(2)SO_(4)对α-锂辉石一步焙烧提锂过程的矿相调控

当前锂辉石提锂工艺主要采用高温转型—硫酸化焙烧法,通常需要1100℃左右转晶焙烧及硫酸化焙烧工序,存在能耗高、工艺流程长等问题。提出了一种以CaO和Na_(2)SO_(4)为混合助剂的一步低温焙烧法从α-锂辉石提取锂的工艺,进一步优化了助剂用量及焙烧温度。结果表明:在焙烧温度900℃、焙烧时间2 h,50%Na_(2)SO_(4)和6%CaO混合助剂作用下,锂浸出率达94.97%。借助XRD、FT-IR、SEM-EDS等分析方法明确了混合助剂对α-锂辉石一步焙烧提锂过程的矿相调控机理为:CaO在低温可与α-锂辉石反应生成钙长石及石英,破坏锂辉石的稳定结构,降低了α-锂辉石转型温度,Na_(2)SO_(4)与石英、锂辉石进一步反应生成钠长石和可溶性NaLiSO 4。该工艺显著降低了锂辉石的焙烧温度,实现了锂的短程高效提取,具有重要的应用价值。

超临界/密相CO_(2)管道泄漏压力响应及低温规律实验研究

为进一步了解超临界/密相CO_(2)在管道泄漏过程中的压力响应和温度变化,基于自行设计的高压CO_(2)管道泄漏实验装置,探讨压力响应、温降特性和相态变化的相互作用机理,以及低温分布规律。研究结果表明:19 mm口径纯CO_(2)的压降曲线有明显的2个阶段,且密相泄放存在明显的压力平台,N 2会明显提高泄放速率;相同截面上温度呈现“上热下冷”的分布特征,管道轴线方向,泄放端温降相对最严重;从相态变化角度看,超临界CO_(2)泄漏没有明显两相区,但对于密相而言,管道底部的CO_(2)会经历密相、液相、过热液相、气液两相、气相的相态转变过程。研究结果可为管道泄放安全运行以及规避断裂风险等方案设计提供参考。

连续相变萃取南瓜籽油的工艺优化及其成分分析

为了高效萃取南瓜籽油,充分发挥其应用价值,本研究采用连续相变萃取技术(continuous phase transition extraction,CPE)提取南瓜籽油,以提取率及活性成分含量为指标,研究萃取温度、萃取时间、萃取压力、解析温度对南瓜籽油提取效果的影响,通过响应面设计确定最佳提取工艺参数,并与超临界流体萃取技术(supercritical fluid extraction,SFE)和螺旋压榨法(screw pressing,SP)对比,对南瓜籽油的提取率、活性成分含量、理化性质和脂肪酸组成进行比较分析。结果表明,CPE萃取南瓜籽油的最佳工艺参数为:萃取温度46℃、萃取时间72 min、萃取压力0.51 MPa、解析温度65℃。此工艺参数下南瓜籽油的提取率高达96.75%,比SFE和SP法分别提高14.49%和35.24%;而总酚、类胡萝卜素、甾醇、锌含量分别为1333.80 mg/kg、8.41 mg/kg、2.59 mg/g和9.61 mg/100 g,分别是SFE法的1.56、2.29、1.17、1.40倍,分别是SP法的1.54、2.56、1.89、2.46倍。CPE所得南瓜籽油为澄清透明、粘稠性的液体,风味清香,其酸价、碘值和过氧化值的理化指标均符合LS/T 3250-2017标准的要求;气相色谱-质谱法(GC-MS)分析鉴定出7种脂肪酸,其中亚油酸和油酸占总脂肪酸含量的82.32%,比SFE和SP法分别提高5.66%和8.99%。该研究表明连续相变萃取技术在兼顾南瓜籽油提取率及活性成分含量的情况下,可以有效缓解油脂氧化酸败程度、提高不饱和脂肪酸含量,为高活性南瓜籽油的工业化连续性生产提供了参考。

Sintering characteristics, phase transitions, and microwave dielectric properties of low-firing [(Na_(0.5)Bi_(0.5))_(x)Bi_(1-x)](W_(x)V_(1-x))O_(4) solid solutionceramics

A series of high-k[(Na_(0.5)Bi_(0.5))_(x)Bi_(1-x)](W_(x)V_(1-x))O_(4)(abbreviated as NBWV(x value))solid solution ceramics with a scheelite-like structure are synthesized by a modified solid-state reaction method at the temperature range of 680-760 C.A monoclinic(0≤x<0.09)to tetragonal scheelite(0.09≤x≤1.0)structural phase transition is confirmed by X-ray difraction(XRD),Raman,and infrared(IR)analyses.The effect of structural deformation and order-disorder caused by Na^(+)/Bi^(3+)/W^(6+) complex substitution on microwave dielectric properties is investigated in deail.The compositional series possess a wide range of variable relative permittivity(er=24.8-80)and temperature coefficient of resonant frequency(TCF value,-271.9-188.9 ppm/℃).The maximum permittivity of 80 and a high Qxf value of~10,000 GHz are obtained near the phase boundary at x=0.09.Furthermore,the temperature-stable dielectric ceramics sintered at 680 C with excellent microwave dielectric properties of ε_(r)=80.7,Qxf=9400 GHz(at 4.1 GHz),and TCF value=-3.8 ppm/℃ are designed by mixing the components of x=0.07 and 0.08.In summary,similar sinterability and structural compatibility of scheelite-like solid solution systems make it potential for low-temperature co-fired ceramic(LTCC)applications.

基于气相色谱-离子迁移谱法结合感官评价对不同药食同源处理低温风干羊肉挥发性风味物质的表征及分析

为探究不同药食同源处理方式对低温风干羊肉品质的影响,以新鲜本地羊后腿肉为原料,经添加荷叶、葛根药食同源提取物及抗氧化剂特丁基对苯二酚进行腌制处理,采用低温风干[(8±1)℃,湿度50%~70%,风速2 m/s],通过感官评价与气相离子迁移色谱技术结合多元统计法对不同药食同源提取物处理的风干羊腿挥发性化合物特征进行分析。结果表明,4种不同处理的低温风干羊肉中共鉴定出52种挥发性有机组分(含单体及二聚体),其中醇类16种、醛类11种、酮类9种、酯类9种、酸类3种、烯烃类1种、吡嗪类1种、腈类2种。指纹图谱分析显示,4种不同处理的低温风干羊肉的特征挥发性有机物质存在明显差异。主成分分析显示,不同处理方式可显著改变低温风干羊肉的特征风味,该结果与感官评价结果基本吻合。聚类热图分析直观地验证了指纹图谱及主成分分析结果。研究结果为低温风干羊肉的口感和风味提升以及生产高质量风干羊肉提供了科学依据。

700kW生物质真空相变锅炉的设计与性能实验

秸秆高温燃烧时,大量钾(K)元素以气相形式释放,造成秸秆灰渣失去肥性。将燃烧温度降低至700℃以下,有限控制钾(K)的逸出,提高秸秆灰的肥性,减轻烟管受热面结渣腐蚀。文章设计了一种生物质真空相变锅炉,真空相变换热可以提高换热效率,燃烧室和烟管都设置于真空水室之中,利用热管传热原理,真空水室中的水相变过程中快速带走燃烧产生的热量,从而降低燃烧温度。实验结果表明燃烧室内温度可以降低到700℃左右。

SIGMAPLUG—A NEW TEMPERATURE INDICATOR FOR REMAINING LIFE ASSESSMENT OF HIGH TEMPERATURE COMPONENTS

Improved life assessment techniques will enable engineering components to be replaced before failure, thereby reducing the risk of industrial accidents as well as minimizing financial loss due to unscheduled outages. For components operating at high temperatures, temperature measurement is very important. In many situations, the environmental conditions are too hostile for conventional techniques to be used. Researchers over the world have been looking for new techniques for temperature measurement and one such device, called Feroplug, has been developed previously by the and coworkers. The Feroplug has been patented in USA, UK and Europe by the British Technology Group. The underlying principle of the Feroplug is based on the transformation of ferrite in some specially designed duplex stainless steels. This paper describes a new invention called Sigmaplug which is a new development of the Feroplug but using an entirely different physical principle. It was discovered that the sigma phase in Fe

UranyI Phosphonates with Multiple UranyI Coordination Geometries and Low Temperature Phase Transition

Main observation and conclusion Two new uranium(VI)phosphonate compounds,namely K_(8)[N(C_(2)H_(5))_(4)]_(2)(UO_(2))_(17)(H_(2)O)_(4)[CH_(2)(PO_(3))_(2)]_(8)[CH_(2)(PO_(3))(PO_(3)H)]_(4)·16(H_(2)O)(1)and[N(C_(2)H_(5))_(4)]_(4)(H_(3)O)_(2)(UO_(2))_(10)[CH_(2)(PO_(3))_(2)]_(5)[CH_(2)(PO_(3))(PO_(3)H)]_(2)·10H_(2)O(2),have been synthesized under mild hydro/solvothermal condition.The structural analysis of the two compounds reveals that they both contain all three typical coordination geometries of the U(VI)ions,including UO;tetragonal,UO,pentagonal,and UOg hexagonal bipyramids.Moreover,compound 1 displays a tempera-ture-induced single crystal to single crystal phase transformation as confirmed by the Single-crystal X-ray diffraction data collected at different temperatures.Temperature-dependent fluorescence spectra presented herein illustrate the perturbation of the electronic structure of uranyl centers.

CALORIMETRY AT VERY LOW TEMPERATURES——MAGNETIC PHASE TRANSITION OF THE FIVE-COORDINATED COPPER(Ⅱ) COMPLEX, Cu(L-ISOLEUCINE)_2(H_2O)

I. INTRODUCTION Calorimetry at very low temperatures is one of the useful tools for the investigation of magnetic properties of materials. Paramagnetic substances often exhibit

Crystal structure and thermochemical properties of bis(1-octylammonium) tetrachlorochromate phase change materials

A new crystalline complex （C8H17NH3）2CdCI4（s） （abbreviated as CsCd（s）） is synthesized by liquid phase reaction. The crystal structure and composition of the complex are determined by single crystal X-ray diffraction, chemical analysis, and elementary analysis. It is triclinic, the space group is P-1 and Z = 2. The lattice potential energy of the title complex is calculated to be UpoT （CsCd（s））=978.83 kJ.mol^-1 from crystallographic data. Low-temperature heat capacities of the complex are measured by using a precision automatic adiabatic calorimeter over a temperature range from 78 K to 384 K. The temperature, molar enthalpy, and entropy of the phase transition for the complex are determined to be 307.3±0.15 K, 10.15±0.23 kJ.mol^-1, and 33.054-0.78 J.K^-1.mol^-1 respectively for the endothermic peak. Two polynomial equations of the heat capacities each as a function of temperature are fitted by using the leastsquare method. Smoothed heat capacity and thermodynamic functions of the complex are calculated based on the fitted polynomials.

复合硫酸盐焙烧—水浸法提取中低品位锂瓷石中的锂

以硫酸钠-硫酸钾混合硫酸盐为焙烧助剂,采用焙烧—水浸法提取中低品位锂瓷石(Li_(2)O含量1.86%)中的锂,探讨了硫酸盐种类、矿料比、焙烧温度、焙烧时间等因素对锂浸出率的影响,研究了焙烧过程的热力学,物料的微观形貌和物相变化。结果表明,与单个硫酸盐焙烧法相比,混合硫酸盐法可以明显提高锂离子浸出率,在850℃焙烧1h,锂瓷石∶硫酸钾∶硫酸钠配比为1∶0.35∶0.15时,锂浸出率可达到95.2%。硫酸盐焙烧过程中,先出现钾长石(KAlSi_(3)O_(8)),之后钾长石转变成白榴石(KAlSi_(2)O_(6))及石英(SiO_(2))。

Low-melting mixture solvents:extension of deep eutectic solvents and ionic liquids for broadening green solvents and green chemistry

Green solvents such as water and ionic liquids(ILs)are pillars of the great mansion of green chemistry and green processing.Initially proposed as a new family of ILs,deep eutectic solvents(DESs)have received fast development in the past two decades.In this contribution,DESs are reviewed critically and the concept is extended to lowmelting mixture solvents(Lo MMSs),which cover all kinds of materials including ionic compounds,molecular compounds,and metals.Six classes of Lo MMSs are proposed as the new classification system and examples are given.Finally,several thermodynamic issues concerning Lo MMSs are discussed.Two new concepts,robustness of Lo MMSs and high-entropy Lo MMSs,are proposed.

46MnVS5钢奥氏体连续冷却转变研究

为支撑46MnVS5非调质钢轧后控冷工艺的优化,及合理制定钢后热处理工艺,利用Gleeble3800热模拟机热膨胀法,结合组织及硬度检测分析,研究46MnVS5非调质钢过冷奥氏体连续冷却转变规律。试验测定了46MnVS5钢Ac1、Ac3、Ar1、Ar3平衡临界相变点温度,并测定了该钢种奥氏体连续冷却转变CCT曲线。结果表明,当冷速小于2℃/s时,组织转变为铁素体+珠光体;冷速≥2℃/s时,开始出现少量贝氏体和少量马氏体,组织转变为铁素体+珠光体+贝氏体+马氏体;冷速≥7℃/s时,主要转变为马氏体和贝氏体;冷速≥20℃/s时,组织转变为马氏体。通过研究,得到了不同冷速下46MnVS5钢奥氏体连续冷却转变规律,绘制了CCT曲线,为轧后控冷工艺优化提供试验数据支撑,同时支撑下游用户合理制定后续热加工冷却工艺。

Exciting News from Indentations onto Silicon, Copper, and Tungsten

Indentations onto crystalline silicon and copper with various indenter geometries, loading forces at room temperature belong to the widest interests in the field, because of the physical detection of structural phase transitions. By using the mathematically deduced FNh3/2 relation for conical and pyramidal indentations we have a toolbox for deciding between faked and experimental loading curves. Four printed silicon indentation loading curves (labelled with 292 K, 260 K, 240 K and 210 K) proved to be faked and not experimental. This is problematic for the AI (artificial intelligence) that will probably not be able to sort faked data out by itself but must be told to do so. High risks arise, when published faked indentation reports remain unidentified and unreported for the mechanics engineers by reading, or via AI. For example, when AI recommends a faked quality such as “no phase changes” of a technical material that is therefore used, it might break down due to an actually present low force, low transition energy phase-change. This paper thus installed a tool box for the distinction of experimental and faked loading curves of indentations. We found experimental and faked loading curves of the same research group with overall 14 authoring co-workers in three publications where valid and faked ones were next to each other and I can thus only report on the experimental ones. The comparison of Si and Cu with W at 20-fold higher physical hardness shows its enormous influence to the energies of phase transition and of their transition energies. Thus, the commonly preferred ISO14577-ASTM hardness values HISO (these violate the energy law and are simulated!) leads to almost blind characterization and use of mechanically stressed technical materials (e.g. airplanes, windmills, bridges, etc). The reasons are carefully detected and reported to disprove that the coincidence or very close coincidence of all of the published loading curves from 150 K to 298 K are constructed but not experimental. A tool-box for distinction of experimental from faked indentation loading curves (simulations must be indicated) is established in view of protecting the AI from faked data, which it might not be able by itself to sort them out, so that technical materials with wrongly attributed mechanical properties might lead to catastrophic accidents such as all of us know of. There is also the risk that false theories might lead to discourage the design of important research projects or for not getting them granted. This might for example hamper or ill-fame new low temperature indentation projects. The various hints for identifying faked claims are thus presented in great detail. The low-temperature instrumental indentations onto silicon have been faked in two consecutive publications and their reporting in the third one, so that these are not available for the calculation of activation energies. Conversely, the same research group published an indentation loading curve of copper as taken at 150 K that could be tested for its validity with the therefore created tools of validity tests. The physical algebraic calculations provided the epochal detection of two highly exothermic phase transitions of copper that created two polymorphs with negative standard energy content. This is world-wide the second case and the first one far above the 77 K of liquid nitrogen. Its existence poses completely new thoughts for physics chemistry and perhaps techniques but all of them are open and unprepared for our comprehension. The first chemical reactions might be in-situ photolysis and the phase transitions can be calculated from experimental curves. But several further reported low temperature indentation loading curves of silicon were tested for their experimental reality. And the results are compared to new analyses with genuine room temperature results. A lot is to be learned from the differences at room and low temperature.

陈皮挥发油的低温连续相变萃取及特性分析

陈皮作为传统中药材,其所含挥发油具有祛痰、平喘等多种药理作用。本研究采用低温连续相变萃取技术从陈皮中提取挥发油,探讨了原料颗粒度、萃取时间、萃取压力、萃取温度和和解析温度对提取率的影响,并通过L9(34)正交试验优化萃取工艺对挥发油提取率的影响。同时对陈皮挥发油理化性质和脂肪酸组成进行了分析。结果表明,低温连续相变萃取陈皮挥发油的最佳工艺条件为:原料颗粒度40目,萃取时间60 min,萃取压力0.6 MPa,萃取温度30℃,解析温度70℃,在此条件下陈皮挥发油的提取率为3.31%。低温连续相变萃取陈皮挥发油呈黄色至红棕色半固体膏状物,内含10.6%多甲氧基黄酮类物质,碘值为122.4 g I/100 g,酸价为73.8 mg KOH/g,过氧化值为0.1 g/100 g。经GC-MS分析发现,陈皮挥发油主要脂肪酸组成为亚油酸(30.01%),十八碳-9-烯酸(25.43%),亚麻酸(16.32%)和硬脂酸(4.56%)。

纳米铁酸盐的制备研究 低温催化相转化法合成纳米级铁酸锌及表征

以ＺｎＳＯ４·７Ｈ２Ｏ和ＦｅＣｌ３·６Ｈ２Ｏ为原料，在微量相转化催化剂存在下，利用沸腾回流的液相法制备了纳米铁酸锌微晶．当反应物总浓度高达１．２ｍｏｌ·Ｌ－１时，仍可获得粒径＜２０ｎｍ均匀粒子．研究了初始ｐＨ值对产物组成的影响．使用ＸＲＤ、ＴＥＭ、ＩＲ及磁强仪对产物进行了表征，并测定了所得产物的密度及比表面．

低温连续相变萃取广佛手精油及其组成分析

采用低温连续相变萃取技术提取广佛手精油,以精油得率为主要指标,研究了萃取温度、压力、时间等因素对广佛手精油得率的影响,并通过正交实验确定最佳提取工艺条件,同时对精油的质量及化学组成进行分析。研究表明,低温连续相变提取广佛手精油的最佳工艺为:原料堆密度0.4 kg/L,萃取温度60℃,萃取压力0.6 MPa,萃取时间75 min,颗粒度30目,此时精油得率为9.25‰。所得广佛手精油为黄色至深棕色半固体膏状物,具有佛手挥发油特有的浓郁香味,无异味,其主要化学组成为酸类、烯烃类、酯类,分别达到了广佛手精油相对百分含量的44.3%、26.67%、7.89%。