1-Butene isomerization and metathesis over Mo/mordenite-alumina: Factors influencing product distribution and induction period

Effects of space velocity, reaction temperature and support acidity on product distribution and induction period in 1-butene isomerization and metathesis over Mo/mordenite-alumina were investigated. As revealed by the catalytic performance results, induction period and objective product were closely related to the reaction conditions. Lower space velocity led to longer induction period and higher propene yield. The optimal reaction temperature for propene production is around 150 ~C and it shifted to 100 ~C for ethene production. 1-Butene auto-metathesis predominated in the reaction network if the support with lower degree of sodium exchanged. And propene gradually became the dominant product upon increasing the support sodium exchange degree. 6Mo/H100Na0M-30A1 catalyst with a support of full sodium exchange degree exhibited the highest propene yield.

The Induction Period of Hydrate Formation in a Flow System

The appearance of turbidity due to large numbers of critical size hydrate nuclei may significantly affect the outgoing light intensity and the flow resistance in the pipe loop. The induction period of hydrate formation was determined by analyzing the experimental data——either based on the shading ratio data of laser detector or based on the pressure drop data of the flow system. The induction period of CC12F2 (R12) in pure water and that of CH4 in (tetrahydrofuran ＋ water) systems were then measured with the above two methods. Experimental data show that the induction period depends on the driving force exponentially. Flow rate also has a significant influence on the hydrate nucleation. A new induction period model taking the driving force and liquid flow rate into account was proposed. And it is successfully applied to the calculation of the induction period, which is in good agreement with the experimental data obtained in this study.

Fouling Induction Period of CaCO_3 on Heated Surface

Fouling induction period of CaCO3 on heated surface was studied with the micro video technology. The rates of nucleating and nuclei growing were measured under various experimental conditions. The experimental results showed that both nucleating and nuclei growing rates of CaCO3 increased obviously with surface temperature and concentration of reagents. In addition, the experiment of fouling induction period on the surface material of chemical plated nickel-phosphorus-polytetrafluoroethylene indicated that not only the nucleate rate of CaCO3 decreased but also some fouling particles with certain size were easy to peel off from the heated surface under shearing stress, which means that the property of surface material is one of the most important factors influencing fouling induction periods.

Unseeded Induction Period and Primary Nucleation of Lithium Carbonate

A set of laser apparatus was used to study induction period and primary nucleation of lithium carbonate in reactive crystallization.The results show that induction period increases with the decrease of supersaturation degree and temperature.Magnetic field has nearly no impact on it,while the use of ultrasound reduces it obviously.The impacts of some impurities and additives on primary nucleation were investigated.It is found that the presence of Na2SO4,NH4Cl,(NH4)2SO4 and EDTA disodium prolongs induction period,whereas KCl,NaCl,NaBr and CH4N2O can decrease it.Many important parameters of primary nucleation are also obtained,as temperature goes up from 283 to 313 K,interfacial tension decreases from 44.8 to 41.5 mJ/m2,contact angle varies from 82.9o to 88.7o,nucleation order is between 5.0 and 5.4,surface entropy factors are all above 5,suggesting that the growth mechanism is a spiral growth.Besides,both the homogeneous and heterogeneous primary nucleations were monitored with on-line focused beam reflectance measurement.

Investigating the Effect of Methylcyclopentadienyl Manganese Tricarbonyl on the Properties of Unleaded Motor Gasoline (1): Induction Period

In this paper, the effect of MMT on the induction period of unleaded motor gasoline was studied, the manganese concentration, storage period of MMT-blended gasoline and environmental variables such as temperature and radiation intensity were considered to be main factors affecting the induction period of gasoline,when MMT-blended gasoline was exposed to light. It is found from experiments that the addition of MMT can improve the induction period of gasoline that is shielded from light, and reduce the induction period remarkably,when the gasoline is exposed to light. However, the radiation intensity is proved to be the leading influencing factor among all the environmental variables investigated.

Methanol-to-olefin induction reaction over SAPO-34

The methanol-to-olefin induction reaction over the SAPO-34 was performed using a fluidized-bed system.We found that the whole induction period could be divided into three reaction stages.Further investigation of the reaction kinetics revealed that this induction reaction behavior was different from that over H-ZSM-5 catalyst.Compared with the H-ZSM-5,the generation of initial active centers is easier over SAPO-34 because of its limited diffusivity and the spatial confinement effect of the cages.However,the autocatalysis reaction stage is difficult over SAPO-34 because of the continuous formation of inactive methyladamantanes.

Relationship between Bishop Score and Success of Induction of Labour in Federal Teaching Hospital, Abakaliki, Ebonyi State

Background: The ripeness of the cervix is of critical importance to the probability of successful labour induction. Aim: To determine the relationship between successful induction of labour and Bishop score. Materials and Methods: A retrospective study of all obstetric patients who had induction of labour between January 1st 2012 and December 31st 2015 was done in Federal Teaching Hospital Abakaliki. The information obtained from patients’ case notes was analyzed using descriptive and inferential statistics at an alpha level of 0.05 for all statistical tests. Results: During the study period, there were 9548 deliveries;2.76% (264) was by induction of labour with success rate of 75.4%. The mean age of the women was 28.4 ± 5.8 years;majority where nulliparous (45.45%). The most common indication for induction of labour was postdatism (43.94%). Success of induction of labour was most likely at Bishop score of 8 to 10 (OR = 0.79, 95% CI 0.72 - 0.84). Induction delivery interval was shortest with use of Foley catheter and misoprostol. Conclusion: Our study has shown that success of induction of labour was most likely at Bishop Score of 8 - 10. We advocate the use of Foley catheter and misoprostol for cervical ripening especially when there is need to expedite delivery.

Effects of dexmedetomidine + propofol intervention during general anesthesia induction on endotracheal intubation

Objective:To investigate the effects of dexmedetomidine + propofol intervention during general anesthesia induction on endotracheal intubation.Methods: A total of 218 patients receiving tracheal intubation general anesthesia in the hospital between January 2017 and December 2017 were divided into the control group (n=109) and the dexmedetomidine group (n=109) by random number table method. Control group underwent routine propofol anesthesia induction and dexmedetomidine group underwent dexmedetomidine anesthesia induction on the basis of propofol. The differences in the severity of inflammatory response and stress response were compared between the two groups of patients after general anesthesia induction (T0), 1 min after endotracheal intubation (T1), 5 min after endotracheal intubation (T2) and 10 min after endotracheal intubation (T3).Results:At T0, there was no statistically significant difference in serum levels of inflammatory factors and stress hormones between the two groups. At T1, T2 and T3, serum inflammatory factors CRP, IL-1, IL-6, IL-8 and TNF-α levels of dexmedetomidine group were lower than those of control group;serum stress hormones ACTH, Cor, NE, AngⅠ and AngⅡ levels were lower than those of control group. Conclusion: Dexmedetomidine + propofol general anesthesia induction can effectively reduce the inflammatory stress response caused by endotracheal intubation.

五相感应电机变采样周期模型预测控制策略

针对无调制模块的模型预测控制器MPC(model predictive controller)存在的谐波含量高问题,提出1种新型基于模型的变采样周期MPC策略,并将其应用于五相感应电机驱动系统。分析了MPC对时间固定离散化所带来的问题,而引入调制或调制替代来解决此问题将使控制系统复杂度增加,故遵循更简单、自然的思路,基于追击算法来改变采样间隔,结合MPC确定最优控制动作和实施时间,实现变采样周期MPC方案。利用五相感应电机驱动系统开展实验,实验结果验证了新型变采样周期MPC优良的参考跟踪和电流谐波性能。

中药周期疗法联合促排卵方案治疗多囊卵巢综合征不孕症Meta分析

目的:系统评价中药周期疗法联合促排卵方案治疗多囊卵巢综合征(PCOS)不孕症的临床疗效及安全性。方法:计算机检索PubMed、EMbase、Web of Science、the Cochrane Library、中国生物医学文献数据库(CBM)、中国知网(CNKI)、万方数据库、维普数据库,检索时限为建库至2024年2月,纳入中药周期疗法治疗PCOS不孕症的随机对照试验。由2位研究人员独立按照纳入、排除标准进行文献筛选和数据收集。采用RevMan5.4软件进行Meta分析。结果:最终纳入15项研究,涉及患者1171例,其中治疗组594例,对照组577例。Meta分析结果显示,与对照组比较,治疗组妊娠率[RR=1.80,95%CI(1.58,2.04),P<0.00001]、排卵率[RR=1.10,95%CI(1.06,1.14),P<0.00001]和总有效率[RR=1.25,95%CI=(1.15,1.37),P<0.00001]升高,子宫内膜厚度增厚[MD=1.12,95%CI(0.94,1.29),P<0.00001],雄激素[MD=-0.39,95%CI(-0.52,-0.26),P<0.00001]、促黄体生成激素[MD=-1.49,95%CI(-1.93,-1.05),P<0.00001]水平及卵巢过度刺激征发生率[RR=0.25,95%CI(0.08,0.79),P=0.02]与不良反应发生率[RR=0.36,95%CI(0.19,0.67),P=0.001]降低。结论:中药周期疗法联合促排卵方案治疗PCOS不孕症疗效优于单纯促排卵方案治疗,能够促进生育,调节性激素水平,安全性较高。

改变诱导药物顺序对全麻诱导期呛咳、体动的影响

目的研究改变诱导顺序对全麻诱导期出现呛咳、躯体颤动的作用。方法对100例择期手术女性患者进行随机分组,分别采用诱导顺序A(咪达唑仑-舒芬太尼-依托咪酯-顺式阿曲库铵)和诱导顺序B(舒芬太尼-顺式阿曲库铵-咪达唑仑-依托咪酯-舒芬太尼)。比较2组血压、心率及血氧饱和度;比较2组不良事件发生情况;比较2组麻醉诱导期的呛咳、躯体颤动发生率以及呛咳、躯体颤动程度。结果诱导顺序B组比A组出现呛咳、体动的次数更少,呛咳发生率分别为18%和56%(P<0.05);体动发生率分别为14%和46%(P<0.05)。结论改变诱导药物顺序可以减少诱导期的呛咳和躯体颤动,建议在临床实践中开展相关策略。

差示扫描量热法测定压缩机油-引发剂混合体系半衰期

采用差示扫描量热法(DSC)和Kinetics Neo专业软件建立了相应的化学动力学模型,对超高压乙烯压缩机油-引发剂混合体系的半衰期进行了研究。建立的3步连串模型适用于压缩机油-引发剂混合体系半衰期的测定。测定结果表明,国产压缩机油+DTBP引发剂混合体系和进口压缩机油+DTBP引发剂混合体系对DTBP引发剂半衰期的影响均较小,国产压缩机油和进口压缩机油与乙烯反应介质的相容性相当。(图11表2参考文献9)

水性抗氧剂组成以及含量对ASA树脂性能的影响

采用乳液聚合法制备了核壳比为6/4的ASA核壳接枝共聚物胶乳,系统地研究了水性抗氧剂的组成以及含量对ASA接枝共聚物热氧老化性能的影响,并采用熔融共混法制备ASA树脂,探究了水性抗氧剂的组成以及含量对ASA树脂力学性能、表观性能的影响。结果表明,水性抗氧剂的组成CPL/DLTP为2/3时,其ASA接枝共聚物的热氧老化性能最优;随着水性抗氧剂含量的增加,ASA接枝共聚物的氧化诱导期显著增长;水性抗氧剂的加入量超过1%以后,ASA接枝共聚物的氧化诱导期增长不显著;在230℃空气条件下,添加1%水性抗氧剂的ASA接枝共聚物的氧化诱导期可达73.1 min,其抗热氧老化能力是相同条件下不添加水性抗氧剂ASA接枝共聚物的80倍以上;水性抗氧剂的组成及含量对ASA树脂的力学性能无明显影响,对其表观性能如白度影响明显。

A molecular insight into coke formation process of vacuum residue in thermal cracking reaction

Understanding the coking behaviors has been considered to be really essential for developing better vacuum residue processing technologies.A battery of thermal cracking tests of typical vacuum residue at 410℃ with various reaction time were performed to evaluate the coke formation process.The total yields of ideal components including naphtha,atmospheric gas oil(AGO)and vacuum gas oil(VGO)of thermal cracking reactions increased from 10.89%to 40.81%,and the conversion ratios increased from8.05%to 43.33%with increasing the reaction time from 10 to 70 min.The asphaltene content increased from 12.14%to a maximum of 22.39%and then decreased,and this maximum of asphaltene content occurred at the end of the coking induction period.The asphaltenes during the coking induction period,at the end and after coking induction period of those tested thermal cracking reactions were characterized to disclose the structure changing rules for coke formation process,and the coke formation pathways were discussed to reveal the coke formation process at molecular level.

放松训练结合音乐疗法对诱导期血液透析患者的影响

目的探讨放松训练结合音乐疗法对诱导期血液透析患者心理及生活质量的影响。方法选取2022年7月—2023年2月福建省泉州市第一医院收治的90例血液透析患者为研究对象。按照护理方法不同分为对照组与观察组,各45例。对照组进行常规护理,观察组在常规护理的基础上进行放松训练结合音乐疗法。比较2组护理前后心理状况及生活质量评分。结果护理后,2组患者的抑郁自评量表(self-rating depression scale,SDS)和焦虑自评量表(self-rating anxiety scale,SAS)评分低于护理前,差异有统计学意义(P<0.05);且观察组患者SDS和SAS评分低于对照组,差异有统计学意义(P<0.05)。观察组SDS、SAS护理前后差值分别为(14.11±5.39)分、(15.61±4.42)分,对照组SDS、SAS护理前后差值分别为(8.71±2.23)分、(8.82±2.72)分,差异有统计学意义(P<0.05)。2组患者生活质量评分高于护理前,差异有统计学意义(P<0.05);且观察组患者生活质量评分高于对照组,差异有统计学意义(P<0.05)。2组躯体功能、心理功能、社会功能护理前后差值比较,差异有统计学意义(P<0.05)。结论将放松训练结合音乐疗法用于诱导期血液透析患者中能够安抚患者焦虑抑郁情绪,使其生活质量得到提高,可以在诱导期血液透析患者临床护理中推广应用。

降低汽油氧化安定性测定仪诱导期故障率的方法探讨

诱导期是在加速氧化条件下评定汽油安定性的指标之一,表示车用汽油在贮存时氧化并生成胶质的倾向。汽油的诱导期越长,生成胶质的倾向越小,抗氧化安定性越好。故诱导期可反映油品的贮存安定性。汽油氧化安定性测定仪使用周期达20年以上,由于元器件老化,在使用过程中受高温、高压的影响,故障频繁,故障率高。在使用过程中也会直接影响准确度,安定性不好的汽油,在储存和输送过程中容易发生氧化反应,生成胶质,使汽油的颜色变深,甚至会产生沉淀。因此测定结果的准确性直接影响产品的效益。因此,本文通过试验找出影响准确度的根本原因,并采取措施消除故障点,延长备件寿命,以此提高分析结果的准确性。

多发性骨髓瘤患者诱导化疗期营养波动及影响因素

目的:前瞻性纵向观察多发性骨髓瘤(MM)患者诱导化疗期营养状况波动情况,分析其变化规律,并探讨化疗期间营养不良的影响因素。方法:选取2019年1月至2022年12月空军军医大学第二附属医院140例新发MM患者,分别于化疗前、化疗第1~第4疗程5个时间点使用患者主观整体营养状况评价(PG-SGA)量表、BMI和血清白蛋白(ALB)评估患者营养状况。使用重复测量方差分析MM患者诱导化疗期营养状况的波动趋势,采用广义估计方程分析营养不良的潜在影响因素。结果:完成5次调查的患者有136例,诱导化疗期间营养不良发生率为37.50%~56.62%。患者的PG-SGA得分呈先降后升趋势(P<0.001)、BMI及ALB呈先升后降趋势(P<0.001),但亚组分析显示诱导化疗后期疗效≥部分缓解(PR)的患者群体ALB呈上升趋势(P<0.001)。整个诱导化疗期MM患者PG-SGA标准下的营养不良受年龄、有无初始营养不良、医院焦虑抑郁量表(HADS)评分、是否给予营养支持、化疗后感染及疗效的影响(P<0.05);BMI标准下的营养不良则受年龄、匹兹堡睡眠质量指数、HADS评分、疾病分期、是否给予营养支持及有无初始营养不良的影响(P<0.05);ALB标准下的营养不良受年龄、疾病分期、是否给予营养支持、疗效及化后感染的影响(P<0.05)。结论:诱导化疗期MM患者营养状况呈先好转后恶化趋势。疾病分期为III期、有睡眠障碍、有焦虑抑郁、有初始营养不良、化疗后有感染、疗效未达到PR及没有给予营养支持的老年MM患者更容易发生营养不良,诱导化疗期应更加关注。

Catalytic performance of biological method seeds on jarosite process

The catalytic performance on jarosite process of jarosite seeds via biosynthesis and chemical processes were studied, respectively. The SEM and XRD results showed that biosynthetic jarosite seeds （BIO seeds） had smooth surface and mainly consisted of potassium jarosite. The chemical synthesis jarosite seeds （CHM seeds） had a loose cauliflower-like surface and mainly consisted of hydronium jarosite. The catalytic performance of BIO seeds was better than that of CHM seeds on the formation of final jarosite product. The induction time can be shortened to 20 min, the reaction temperature can be reduced to only 75 ℃, and the initial reaction speed was enhanced obviously, up to 3.933%/min. The crystallinity of final jarosite product using BIO seeds can achieve 97.22%, while it was only 12.89% without seeds. This indicates that the precipitation process of jarosite is more complete with BIO seeds.

水垢成垢诱导期机理研究

为了研究水垢成垢诱导期间发生的物理化学过程 ,基于溶液中离子活度的平衡关系、质子平衡条件及质量守衡等关系建立了计算CaCO3水溶液中 9种成分的计算程序 .导出了用单一电导测定精确确定溶液中全部 9种成分随时间变化的技术 .实验中采用计算机数据采集及数据处理的综合技术 .同时使用摄像显微镜和原子力显微镜监测悬挂在溶液中金属板表面垢的沉积过程 .研究清晰地表明 ,诱导期的起因是由于溶液中的成核机制 ;诱导期的存在又反映了晶粒与器壁之间非常微弱的键合 .

基于电导滴定法的碳酸钙成垢诱导期实验研究

基于碳酸钙成垢过程动力学与电导滴定过程电导率随滴定时间变化特征的对比分析,本文拟议了一个碳酸钙成垢诱导期的定义;基于自主研制的模拟实验检测装置进行的实验表明:可在线、实时准确测定碳酸钙成垢诱导期及其定义中的各时间段,可同期检测滴定过程中溶液钙、碳酸根等离子浓度、碳酸钙成核速率、生长速率、反应级数等参数,其中测得的分数反应级数证实了非线性化学的一个理论推断。实验检测结果还表明:所拟定的碳酸钙成垢诱导期定义既可确切反映碳酸钙成垢过程又易于被准确检测。