Comparison of the interface reaction behaviors of CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) solid-state systems based on the diffusion couple method

The formation mechanism of calcium vanadate and manganese vanadate and the difference between calcium and manganese in the reaction with vanadium are basic issues in the calcification roasting and manganese roasting process with vanadium slag.In this work,CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples were prepared and roasted for different time periods to illustrate and compare the diffusion reaction mechanisms.Then,the changes in the diffusion product and diffusion coefficient were investigated and calculated based on scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) analysis.Results show that with the extension of the roasting time,the diffusion reaction gradually proceeds among the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples.The regional boundaries of calcium and vanadium are easily identifiable for the CaO–V_(2)O_(5) diffusion couple.Meanwhile,for the MnO_(2)–V_(2)O_(5) diffusion couple,MnO_(2) gradually decomposes to form Mn_(2)O_(3),and vanadium diffuses into the interior of Mn_(2)O_(3).Only a part of vanadium combines with manganese to form the diffusion production layer.CaV_(2)O_(6) and MnV_(2)O_(6) are the interfacial reaction products of the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples,respectively,whose thicknesses are 39.85 and 32.13μm when roasted for 16 h.After 16 h,both diffusion couples reach the reaction equilibrium due to the limitation of diffusion.The diffusion coefficient of the CaO–V_(2)O_(5) diffusion couple is higher than that of the MnO_(2)–V_(2)O_(5) diffusion couple for the same roasting time,and the diffusion reaction between vanadium and calcium is easier than that between vanadium and manganese.

Reaction behavior and non-isothermal kinetics of suspension magnetization roasting of limonite and siderite

In order to develop limonite and decrease CO_(2) emissions,siderite is proposed as a clean reductant for suspension magnetization roasting(SMR) of limonite.An iron concentrate(iron grade:65.92wt%,iron recovery:98.54wt%) was obtained by magnetic separation under the optimum SMR conditions:siderite dosage 40wt%,roasting temperature 700℃,roasting time 10 min.According to the magnetic analysis,SMR achieved the conversion of weak magnetic minerals to strong magnetic minerals,thus enabling the recovery of iron via magnetic separation.Based on the phase transformation analysis,during the SMR process,limonite was first dehydrated and converted to hematite,and then siderite decomposed to generate magnetite and CO,where CO reduced the freshly formed hematite to magnetite.The microstructure evolution analysis indicated that the magnetite particles were loose and porous with a destroyed structure,making them easier to be ground.The non-isothermal kinetic results show that the main reaction between limonite and siderite conformed to the two-dimension diffusion mechanism,suggesting that the diffusion of CO controlled the reaction.These results encourage the application of siderite as a reductant in SMR.

Shock-induced reaction behaviors of functionally graded reactive material

In this paper,the ballistic impact experiments,including impact test chamber and impact double-spaced plates,were conducted to study the reaction behaviors of a novel functionally graded reactive material(FGRM),which was composed of polytetrafluoroethylene/aluminum(PTFE/Al)and PTFE/Al/bismuth trioxide(Bi_(2)O_(3)).The experiments showed that the impact direction of the FGRM had a significant effect on the reaction.With the same impact velocity,when the first impact material was PTFE/Al/Bi_(2)O_(3),compared with first impact material PTFE/Al,the FGRM induced higher overpressure in the test chamber and larger damaged area of double-spaced plates.The theoretical model,which considered the shock wave generation and propagation,the effect of the shock wave on reaction efficiency,and penetration behaviors,was developed to analyze the reaction behaviors of the FGRM.The model predicted first impact material of the FGRM with a higher shock impedance was conducive to the reaction of reactive materials.The conclusion of this study provides significant information about the design and application of reactive materials.

Synthesis and reaction behavior of calcium silicate hydrate in basic system

At the molar ratio of CaO to SiO2 of 1, with calcium hydroxide and sodium silicate, calcium silicate hydrate was synthesized at 50, 100, 170 ℃, respectively. The results show that temperature favors the formation of calcium silicate hydrate with perfect structure. When calcium silicate hydrate reacts with caustic solution, the decomposition rate of calcium silicate hydrate increases with the increasing caustic concentration and decreases with the raising synthesis temperature and the prolongation of reaction time. The decomposition rate is all less than 1.2% in caustic solution, and XRD pattern of the residue after reaction with caustic solution is found as the same as that of original calcium silicate hydrate, which indicates the stable existence of calcium silicate hydrate in caustic solution. When reacted with soda solution, the decomposition rate increases with the increasing soda concentration and reaction time, while decreases with the synthesis temperature. The decomposition rate is more than 2% because （CaO·SiO2·H2O（CSH（Ⅰ））,） except (Ca5（OH）2Si6O16·4H2O) and (Ca6Si6O17（OH）2,) is decomposed. So the synthesis temperature and soda concentration should be controlled in the process of transformation of sodium aluminosilicate hydrate into calcium silicate hydrate.

Reaction behavior of MgO refractory with high-Mn and high-Al steel

To understand the mechanism of the interfacial reaction between high-Mn and high-Al steel and MgO refractory,a series of laboratory experiments as well as thermodynamic calculations were performed.The effects of Mn and Al contents in the steel and the reaction time on the interfacial reaction were investigated.It was observed that the erosion of the MgO refractory is caused by the reaction of Al and Mn in the steel with MgO in the refractory,which would lead to the formation of(Mn,Mg)O·Al_(2)O_(3) spinel and(Mn,Mg)O solid solution.The formation mechanism of the spinel and solid solution is as follows.The Al in the steel firstly reacts with MgO in the refractory to generate MgO·Al_(2)O_(3) spinel,and then,the spinel reacts with Mn in the steel to form(Mn,Mg)O·Al_(2)O_(3) spinel.Finally,the MnO in the spinel reacts with the MgO in the inner refractory to form(Mn,Mg)O solid solution.In addition,only(Mn,Mg)O·Al_(2)O_(3) spinel is present in the interfacial reaction layer of the refractory when the Al content in the steel is sufficient.

Reaction behaviors occurring in Ti/Al foil metallurgy

Reaction behaviors occurring in Ti/Al foil metallurgy were systematically investigated.Particular emphasis was focused on the reaction between solid Al and Ti as well as subsequent reaction between TiAland Ti layer.In the solid reaction between Al and Ti,the presence of residual Al is mainly caused by inhomogeneous growth of TiAllayer and micro-voids existing at the interface.However,through reaction between molten Al and Ti,TiAl/Ti multilayer can be achieved with complete consumption of Al.During subsequent high-temperature heat treatment,TiAl/Ti multilayer will eventually turn into TiAl/TiAl multilayer accompanying with simultaneous formation and successive disappearance of intermediate phases,such as TiAland TiAl.Moreover,it is found that the growth direction of TiAl layer changes as a function of annealing time between different couples in multi-intermetallics system.

Reaction behavior of associated rare earth minerals during coal-based reduction

In order to ascertain the reaction behavior of rare earth minerals in coal-based reduction, X-ray diffraction（XRD）, scanning electron microscopy（SEM）, and energy dispersive spectroscopy（EDS） analyses were applied to investigate the rare earth minerals in Bayan Obo.The occurrence state and regularity of rare earth elements were analyzed under different reduction time. The results reveal that rare earth elements in rare earth minerals exist in RE（CO3）F（bastnaesite） and REPO4（monazite）. In this research, at 1,498 K with a C/O molar ratio（i.e., molar ratio of fixed carbon in the coal to reducible oxygen in the ore） of2.5, rare earth minerals primarily decompose into RE2O3at5 min. When the time is extended to 10 min, solid-phase reactions occur among RE2O3, CaO, and SiO2, and the resultant is cerium wollastonite（CaO·2RE2O3·3SiO2）. At reaction time 〉20 min, rare earth elements mainly exist in cerium wollastonite（CaO·2RE2O3·3SiO2）, and the grain size varies in the range of 10–30 μm. The results show that coal-based reduction is efficient to recover rare earth minerals in reduced materials.

Steam reforming of acetic acid over Ni-Ba/Al2O3 catalysts:Impacts of barium addition on coking behaviors and formation of reaction intermediates

The influence of barium addition to a Ni/Al2O3 catalyst on the reaction intermediates formed,the activity,resistance of the catalyst to coking,and properties of the coke formed after acetic acid steam reforming were investigated in this study.The results showed the drastic effects of barium addition on the physicochemical properties and performances of the catalyst.The solid-phase reaction between alumina and BaO formed BaAl2O4,which re-constructed the alumina structure,resulting in a decrease in the specific surface area and an increase in the resistance of metallic Ni to sintering.The addition of barium was also beneficial for enhancing the catalytic activity,resulting from the changed catalytic reaction network.The in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) study of the acetic acid steam reforming indicated that barium could effectively suppress the accumulation of the reaction intermediates of carbonyl,formate,and C=C functional groups on the catalyst surface,attributed to its relatively high ability to cause the gasification of these species.In addition,coking was considerably more significant over the Ba-Ni/Al2O3 catalyst.Moreover,the Ba-Ni/Al2O3 catalyst was more stable than the Ni/Al2O3catalyst,owing to the distinct forms of coke formed (carbon nanotube form over the Ba-Ni/Al2O3 catalyst,and the amorphous form over the Ni/Al2O3 catalyst).

Influence of Bi Addition on Pure Sn Solder Joints: Interfacial Reaction, Growth Behavior and Thermal Behavior

The effects of different Bi contents on the properties of Sn solders were studied. The interfacial reaction and growth behavior of intermetallic compounds（IMCs） layer（η-Cu6 Sn5 + e-Cu3 Sn） for various soldering time and the influence of Bi addition on the thermal behavior of Sn-x Bi solder alloys were investigated. The Cu6 Sn5 IMC could be observed as long as the molten solder contacted with the Cu substrate. However, with the longer welding time such as 60 and 300 s, the Cu3 Sn IMC was formed at the interface between Cu6 Sn5 and Cu substrate. With the increase of soldering time, the thickness of total IMCs increased, meanwhile, the grain size of Cu6 Sn5 also increased. An appropriate amount of Bi element was beneficial for the growth of total IMCs,but excessive Bi（≥ 5 wt%） inhibited the growth of Cu6 Sn5 and Cu3 Sn IMC in Sn-x Bi/Cu microelectronic interconnects. Furthermore, with the Bi contents increasing（Sn-10 Bi solder in this present investigation）, some Bi particles accumulated at the interface between Cu6 Sn5 layer and the solder.

Thermal Behavior,Nonisothermal Decomposition Reaction Kinetics of Mixed Ester Double-base Gun Propellants

The thermal decomposition behavior and nonisothermal reaction kinetics of the double-base gun propellants containing the mixed ester of triethyleneglycol dinitrate（TEGDN） and nitroglycerin（NG） were investigated by thermogravimetry（TG） and differential thermogravimetry（DTG）, and differential scanning calorimetry（DSC） under the high-pressure dynamic ambience. The results show that the thermal decomposition processes of the mixed nitric ester gun propellants have two mass-loss stages. Nitric ester evaporates and decomposes in the first stage, and nitrocellulose and centralite II（C2） decompose in the second stage. The mass loss, the DTG peak points, and the terminated temperatures of the two stages are changeable with the difference of the mass ratio of TEGDN to NG. There is only one obvious exothermic peak in the DSC curves under the different pressures. With the increase in the furnace pressure, the peak temperature decreases, and the decomposition heat increases. With the increase in the content of TEGDN, the decomposition heat decreases at 0.1 MPa and rises at high pressure. The variety of mass ratio of TEGDN to NG makes few effect on the exothermic peak temperatures in the DSC curves at different pressures. The kinetic equation of the main exothermal decomposition reaction of the gun propellant TG0601 was determined as： dα/dt=1021.59（1-α）3e-2.60×104/T. The reaction mechanism of the process can be classified as chemical reaction. The critical temperatures of the thermal explosion（Tbe and Tbp） obtained from the onset temperature（Te） and the peak temperature（Tp） are 456.46 and 473.40 K, respectively. ΔS≠, ΔH≠, and ΔG≠ of the decomposition reaction are 163.57 J·mol^-1·K^-1, 209.54 kJ·mol^-1, and 133.55 kJ·mol^-1, respectively.

Wetting behavior and reaction mechanism of non-corrosive flux on aluminum

The energy-dispersive spectroscopy （ EDS ） , X-ray diffraction analysis （ XRD ） and differential thermal analysis （DTA） were used to analyze the melting, spreading process, and reaction mechanism of non-corrosive flux on the surface of aluminum. The result indicates that the whole process can be divided into three stages. In the first stage, flux is heated from room temperature to its melting point, which is called the endothermic stage, mainly absorbs heat and generates a small amount of liquid flux. When the temperature exceeds the melting point of flux, a large amount of liquid flux is generated and reacts with oxide films on the surface of aluminum. This stage is called the reaction stage. The third stage is a spreading and cleaning process, in which residues and reaction products quickly flow out from the center with liquid flux. The different compositions of flux perform different functions in brazing. K3AlF6 can remove oxide film us a cleaner. Only in liquid or molten state can flux remove oxide film on the substrate.

ASYMPTOTIC BEHAVIOR OF SOLUTION FOR A CLASS OF REACTION DIFFUSION EQUATIONS

A class of initial boundary value problems for the reaction diffusion equations are considered.The asymptotic behavior of solution for the problem is obtained using the theory of differential inequality.

肿瘤科护士铂类药物过敏反应知信行现状及影响因素分析

目的:探讨肿瘤科护士铂类药物过敏反应知信行现状及影响因素,为开展相关教学培训提供依据。方法:便利选取武汉市5所医院227名肿瘤科护士作为研究对象,自行设计肿瘤科护士铂类药物过敏反应知信行调查问卷进行调查。结果:共回收有效问卷227份,肿瘤科护士铂类药物过敏反应知信行总分(140.77±23.50)分,知识维度得分(51.28±14.21)分,态度维度(43.17±6.86)分,行为维度(46.32±6.07)分;专科护士、参加过铂类药物过敏反应相关培训、处理过铂类药物过敏反应的病人是肿瘤科护士对铂类药物过敏反应知信行评分的影响因素(均P<0.01)。结论:肿瘤科护士对铂类药物过敏反应有着积极的态度和行为,但是知识储备不足。根据影响因素开展铂类药物过敏反应针对性培训十分必要。

长林小蠹对非寄主植物精油的电生理和行为反应

长林小蠹(Hylurgus ligniperda)为鞘翅目象虫科小蠹亚科树皮类小蠹,是国际重大林业检疫性害虫。其体型较小,生活隐蔽,繁殖迅速,防治困难。为筛选对长林小蠹有生物活性的行为调控剂,共选取10种非寄主植物精油,对长林小蠹雌、雄成虫进行电生理及行为反应测定。结果表明:与对照相比,质量浓度为100及500 mg·L^(-1)的生姜油、质量浓度为20及500 mg·L^(-1)的薄荷油、质量浓度为500 mg·L^(-1)的桉叶油均能引起雌、雄成虫较为强烈的触角电位反应(P<0.05);质量浓度为500 mg·L^(-1)的甜罗勒油、丁香油、柠檬草油能引起雌虫较为强烈的触角电位反应(P<0.05);质量浓度为20 mg·L^(-1)的丁香油及甜罗勒油、质量浓度为500 mg·L^(-1)的肉桂皮油及红橘油能引起雄虫较为强烈的触角电位反应(P<0.05)。“Y”型嗅觉仪行为测定中,质量浓度为500 mg·L^(-1)的生姜油及桉叶油对长林小蠹雌虫具有引诱作用,质量浓度为100 mg·L^(-1)的生姜油及质量浓度为500 mg·L^(-1)的桉叶油对雄虫具有引诱作用。质量浓度为20 mg·L^(-1)的薄荷油、质量浓度为100 mg·L^(-1)的肉桂皮油及甜罗勒油、质量浓度为500 mg·L^(-1)的丁香油对雌虫具有驱避作用;质量浓度为20 mg·L^(-1)的甜罗勒油、丁香油、薄荷油及质量浓度为500 mg·L^(-1)的肉桂皮油对雄虫具有驱避作用。风洞行为测定可以看出,质量浓度为100及500 mg·L^(-1)的生姜油、质量浓度为20 mg·L^(-1)的桉叶油对长林小蠹雌、雄成虫均具有引诱作用。质量浓度为100及500 mg·L^(-1)的甜罗勒油、质量浓度为20 mg·L^(-1)的薄荷油对雌、雄成虫均具有驱避作用。生姜油、桉叶油对长林小蠹雌、雄成虫均具有引诱作用,甜罗勒油、薄荷油对其均具有驱避作用。

甘麦大枣汤联合失眠认知行为疗法治疗抑郁共病失眠的疗效观察

目的:探讨甘麦大枣汤联合失眠认知行为疗法(CBT-I)治疗抑郁共病失眠的疗效,为抑郁共病失眠的临床治疗提供新方法。方法:选取某精神卫生中心收治的110例抑郁共病失眠患者,随机分为观察组和对照组各55例,对照组给予常规西医治疗,观察组给予为期6周的甘麦大枣汤联合CBT-I治疗,比较两组患者HAMD-17、PSQI和SERS评分差异。结果:观察组干预结束时和随访时PSQI、SERS得分低于对照组(P<0.01),PSQI得分、HAMD得分、SERS得分均低于干预前(P<0.01);对照组干预结束时PSQI总分、HAMD总分均下降(P<0.01或P<0.05),SERS得分上升(P<0.01)。结论:甘麦大枣汤联合CBT-I对抑郁共病失眠的临床效果显著,可持续缓解抑郁症状,提升睡眠质量,且安全性高,在临床中具有推广价值。

不同条件下焦炭的高温反应行为及热态性能评价

针对某钢铁企业四种捣固焦,研究了不同条件下焦炭高温气化反应行为,从不同角度评价焦炭热态性能。结果表明,在国标条件下,四种焦炭的CRI和CSR分别在21%~31%和54%~68%范围内。随着焦炭反应性的升高,气化溶损反应开始温度和激烈温度均降低,且两者分别在887~948℃和1315~1423℃范围内。随着溶损率的增加,焦炭C和D的固定溶损率反应后强度均降低,且前者大于后者,但两者差值明显低于国标条件下的差值。高炉实际运行结果显示,在其他条件不变的情况下,使用焦炭C和D时高炉技术经济指标相差不大。采用高温下固定溶损率反应后强度和平均反应速率评价焦炭的热态性能更符合炉内情况,推荐的检测条件为温度1200~1400℃、固定溶损率为20%~30%。

基于微信平台的公众药品不良反应认知度和行为意向调查研究

目的为探索提升公众对药品不良反应(ADR)的认知和应对能力提供参考。方法采用自行设计的调查问卷以问卷星的形式通过互联网微信平台进行发放填写问卷并统计分析。结果共回收有效问卷2117份。90.84%的被调查者比较重视ADR,70.15%的被调查者认为ADR是由药品本身的属性引起的,仅13.18%的被调查者上报过ADR;77.94%的被调查者是通过说明书来了解所服用药品的ADR,发生ADR后42.51%的被调查者处置方法是不妥当的;70.24%的被调查者是有意愿得ADR相关知识的,公众最希望了解的ADR相关知识第一位和第二位分别是“如何减少或避免发生ADR”和“发生ADR后应该怎么办”,公众希望获取ADR相关知识的途径前两位是“网络平台科普文章”和“网络平台科普视频”。结论公众对用药安全重视度普遍较高,对于获取ADR知识的意愿也是比较强烈的,但对ADR的理解和认知有待进一步提高。应继续建立健全完善的公众上报机制,充分利用互联网,加大科普宣教力度,提高公众对ADR的理解、识别和处理能力以及主动上报意识。

浸入式喷吹铁水包内多相流行为与反应动力学

为提高喷吹式铁水预脱硫过程的脱硫效率,以某厂180 t铁水包为基础,建立了铁水包内CFD-DSM(计算流体力学-脱硫反应模型)耦合模型,系统研究了铁水预脱硫过程的气-固-液多相流行为及反应动力学,揭示了溶解镁脱硫、镁气泡脱硫、氧化钙脱硫与渣层脱硫对脱硫反应的贡献,阐明了载气及镁粉流量对脱硫反应的影响规律。结果表明:气泡流股的穿透深度较小,但其并未依附着喷枪壁面上浮。随氧化钙粉剂的连续喷吹,粉剂沿喷枪壁面上浮。脱硫过程中溶解镁脱硫为主要的脱硫机制,其次为镁气泡脱硫、氧化钙脱硫和渣层脱硫。各反应机制的脱硫速率均随时间先增大后减小。载气流量对脱硫反应影响较小,而镁粉流量对脱硫反应影响最大。当初始硫质量分数为470×10^(-6),铁水中硫质量分数脱至100×10^(-6)时,镁粉流量每增加1 kg/min,喷吹时间平均缩短约43 s。

Finemet型非晶合金的复杂晶化动力学行为

Finemet型铁基多元合金是目前应用极广泛的纳米晶软磁材料之一。深入认识其形成过程的晶化动力学特性,对更好地调控制备工艺以获得稳定且软磁性能更优的目标纳米晶具有重要意义。为此,通过差示扫描量热仪(Differential scanning calorimeter,DSC)在不同升温速率的条件下研究了Fe_(74)Si_(14.5)B_(7.5)Nb-(3)Cu_(1)(原子分数,%)非晶的非等温晶化行为,首先利用Kissinger-Akahira-Sinose(KAS)、Flyn-Wall-Ozawa(FWO)、Starik和Boswell这几种典型的等转化率法求得Fe_(74)Si_(14.5)B_(7.5)Nb-(3)Cu_(1)合金的晶化过程激活能Eα,之后采用补偿效应法得出指前因子A,从而实现了反应模型f(α)的数值重建和Avrami指数n(α)的求解。结果表明,Fe_(74)Si_(14.5)B_(7.5)Nb-(3)Cu_(1)非晶合金的晶化仅较接近维度扩散的反应机理模型,但不完全符合现有任何理论模型,是一个涉及多个反应模型的复杂反应。晶体形核速率在晶化初期(α<0.2)由增长阶段快速达到降低阶段(n(α)=2.3),而在0.2<α<0.5时缓慢降至零(n(α)=1.5),之后在晶化末期(α>0.5),晶体在已有晶粒的基础上继续长大(n(α)<1.5),整个晶化过程为形核速率持续降低的三维生长。Fe_(74)Si_(14.5)B_(7.5)Nb-(3)Cu_(1)非晶合金的晶化是一个由三维扩散主导的多个晶化机制共同控制、多个反应模型协同参与的复杂过程。

托莫西汀与阿立哌唑对注意缺陷多动障碍儿童冲动行为及认知功能的影响

目的:比较托莫西汀与阿立哌唑对注意缺陷多动障碍儿童冲动行为及认知功能的影响。方法:选取2020年7月—2022年12月宜春市第三人民医院收治的102例注意缺陷多动障碍患儿,采用随机数字表法分为研究组(给予托莫西汀治疗)和对照组(给予阿立哌唑治疗),每组51例。两组连续治疗1个月后评价治疗效果。对比两组联合型瑞文测验(CRT)评分、蒙特利尔认知功能评估量表(MoCA)评分、临床效果、不良反应。结果:治疗后,两组比较推理能力、类同比较能力、知觉辨别能力、系列关系能力、抽象推理能力、智商数评分较治疗前均升高,差异均有统计学意义(P<0.05),且研究组均高于对照组(P<0.05)。治疗前,两组MoCA评分对比,差异无统计学意义(P>0.05);治疗后,两组MoCA评分较治疗前均升高,差异均有统计学意义(P<0.05),且研究组高于对照组,差异有统计学意义(P<0.05)。研究组临床疗效优于对照组(P<0.05)。研究组不良反应发生率低于对照组,差异有统计学意义(P<0.05)。结论:与阿立哌唑相比,托莫西汀治疗注意缺陷多动障碍患儿可有效提升综合能力,减少冲动行为,提高认知功能及临床疗效,降低不良反应发生率。