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 inductinn period of CaCO3 on heated surface was studied with the micro video technology. The rates of nucleating and nuclei growlng were measured under various experlmen-tal conditions. The experimental results showed that both nucleating and nudel 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-indicated thnt 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 streas, which means that the property of surface material is one of the rnont 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.

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.

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。

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。

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。

聚羧酸减水剂对粉煤灰基浆料水化进程调控机制

粉煤灰基喷浆材料的流动性对实际工程应用有重要作用,为探究减水剂对粉煤灰基浆料流动性的调控机制,通过减水率、流动度、凝结时间、浆体黏度和剪切应力等表征,比较了不同减水剂掺量对浆体流动性能的影响,并筛选出最佳减水剂及用量。采用水化热测定仪、X射线衍射和扫描电子显微镜,探究了聚羧酸减水剂(PCE)对粉煤灰基浆料水化进程与时间的变化规律,提出了PCE对喷浆材料的水化机理。结果表明,PCE对粉煤灰基浆料流动性能改善最明显,饱和掺量为0.6%时,减水率可达29.3%;流动度由113 mm延伸至351 mm;初凝时间由32 min延长至149 min,终凝时间由42 min延长至182 min,出现明显缓凝现象。在早期水化进程中,PCE吸附作用会抑制C3A溶解,阻碍钙矾石(AFt)生长并改变其晶型。同时PCE络合作用会与Ca^(2+)结合成络合物,影响Ca(OH)2生成,延缓Ca^(2+)富集过程,延长诱导期。C3S的水化也受到抑制,使C-S-H成核数量减少,降低了第二水化放热峰。到水化进程中后期PCE的抑制作用失效,材料力学强度逐渐提升。PCE仅能延缓材料早期的水化进程,但对中后期的水化进程无影响。

全身麻醉诱导后无通气期间不同氧浓度对肥胖患者氧合指数的影响

目的探究全身麻醉诱导后无通气期间不同氧浓度对肥胖患者氧合指数的影响。方法选择ASA分级Ⅱ~Ⅲ级的年龄18~65岁的肥胖患者(30 kg/m^(2)<BMI<40 kg/m^(2))75例,根据麻醉诱导期吸入氧浓度将其分为H组、M组、L组,按照理想体重给予诱导药物,待患者睫毛反射消失、自主呼吸停止后,放置口咽通气道,双手托下颌扣紧面罩机械通气预给氧(H组采用100%氧浓度,M组采用80%氧浓度,L组采用60%氧浓度),在可视光棒引导下行气管插管,暂不连接氧气,待氧饱和度降至92%时连接呼吸机。主要结局指标包括无通气期间患者麻醉诱导前(T_(0))、预给氧后(T_(1))、入麻醉复苏室前(T_(2))的氧合指数。次要结局指标包括T_(0)、T_(1)、T_(2)各时间点肺不张的发生例数;经皮血氧饱和度(SpO_(2))下降至92%的时间(开始插管至SpO_(2)降至92%的时间)、连接呼吸机后SpO_(2)恢复至100%的时间、插管时间及手术时间;患者术后肺部并发症发生率及住院时间。结果与H组相比,M组及L组T_(1)时间点氧合指数降低(P<0.05);与H组患者相比,T_(1)、T_(2)时间点M组及L组肺不张的发生率降低(P<0.05);3组患者中H组SpO_(2)下降至92%的时间为(197±57)s,M组为(157±31)s,L组为(131±23)s,与H组相比,M组及L组患者SpO_(2)下降至92%的时间均更短(P均<0.05)。H组SpO_(2)恢复至97%的时间短于M组与L组(P均<0.05)。3组患者的术后肺部并发症发生率及住院时间比较差异均无统计意义(P均<0.05)。结论肥胖患者全身麻醉诱导期间给予100%氧浓度时的氧合指数高于80%与60%氧浓度,有利于给氧后SpO_(2)的恢复,且3种给氧浓度术后肺部并发症发生率及住院时间无差异。

基于脑电非线性特征和AdaBoost算法的诱导期麻醉深度检测

提出一种结合自适应增强学习AdaBoost算法和脑电非线性特征的麻醉深度评估方法,通过提取脑电信号中的4种非线性特征(KC复杂度、小波熵、排序熵、模糊熵)作为输入,以双谱指数作为参考输出,将诱导期麻醉深度分为清醒、轻度麻醉、中度麻醉。使用9例全麻患者的诱导期脑电信号对该方法进行评估,3种不同麻醉状态分类准确度为86.69%,Kappa系数为0.837,表明该方法可以较好地区分诱导期3种不同麻醉水平,为麻醉深度监测提供新思路。

定喘颗粒对OVA诱导豚鼠急性哮喘的作用研究

目的探讨定喘颗粒对于卵清蛋白(Ovalbumin,OVA)诱导的豚鼠急性哮喘模型的影响。方法通过腹腔注射OVA溶液并进行行为学评分后,随机分为模型组、硫酸特布他林组、喘嗽宁片组、定喘颗粒低剂量组、定喘颗粒中剂量组、定喘颗粒高剂量组,并从未处理豚鼠中随机选取8只作为空白组。在给药2周后通过OVA喷雾进行刺激,检测模型组及各给药组中豚鼠的引喘潜伏期,利用酶联免疫吸附测定(Enzyme linked immunosorbent assay,ELISA)检测豚鼠血清和支气管肺泡灌洗液(Bronchoalveolar lavage fluid,BALF)中白细胞介素-4(Interleukin-4,IL-4)和白细胞介素-10(Interleukin-10,IL-10)的水平,并借助嗜酸粒细胞直接计数液检测全血和BALF中嗜酸性粒细胞(Eosinophil,EOS)的数量,苏木素-伊红(Hematoxylin-eosin,HE)染色检测豚鼠肺部组织的病理变化情况并评估。结果与空白组相比,模型组炎症相关指标出现明显异常,指示造模成功。与模型组相比,阳性药组尤其是硫酸特布他林片组,以及定喘颗粒高剂量组给药均可延长OVA诱发急性支气管哮喘豚鼠的引喘潜伏期,降低血液及BALF中IL-4和IL-10的水平和EOS的数量,并缓解肺部组织的病理变化。结论定喘颗粒可以有效缓解急性哮喘时出现的炎症情况,并减少哮喘相关炎症导致的肺部病理损伤。

儿童急性淋巴细胞白血病诱导缓解期并发严重感染的临床分析

目的:探讨儿童急性淋巴细胞白血病(acute lymphoblastic leukemia,ALL)诱导缓解期感染的临床特点,分析发生严重感染的危险因素,为临床干预提供理论依据。方法:回顾性分析2020年6月—2022年6月于南京医科大学附属儿童医院诊治的ALL患儿188例,均采用CCCG-ALL-2020方案化疗,重点采集患儿诱导缓解期并发感染的临床资料,对感染部位、致病菌和严重感染危险因素进行分析。结果:180例(95.7%)ALL患儿诱导缓解期发生感染,感染部位/原因前3位分别为不明原因感染(28.4%)、上呼吸道感染(23.6%)、下呼吸道感染(16.9%)。48例(26.7%)患儿发生严重感染,23.8%(43/180)的患儿经历了微生物学记录的感染,G-菌与G+菌的比例相当。严重感染组住院时长、住院费用、单位体表面积抗生素费用均显著高于非严重感染组(P<0.05)。中高危(OR=2.804,95%CI:1.234~6.375,P=0.014)、血清白蛋白<35 g/L(OR=4.708,95%CI:2.067~10.726,P=0.001)、中性粒细胞缺乏持续时间>7 d(OR=3.697,95%CI:1.393~9.816,P=0.009)是诱导缓解期发生严重感染的独立危险因素。结论:感染在ALL诱导缓解期高发,中高危、血清白蛋白<35 g/L、中性粒细胞缺乏持续时间>7 d是诱导缓解期发生严重感染的独立危险因素,应针对性采取有效的预防措施。

基于GAM的感应电动机比例预测方法研究

华中四省电网稳定计算负荷模型由一定比例的感应电动机并联恒阻抗组成,但电网稳定计算使用固定不变的感应电动机比例参数不能适应负荷的发展。提出一种基于GAM(Generalized Additive Model)的感应电动机比例预测方法,命名为TP-GAM(Trend and Periodicity Generalized Additive Model)。先利用纵横结合的异常检测对缺失的电力时序数据进行检测和填充修正;再根据变电站、城市、省份三个级别进行逐级聚合计算感应电动机比例;最后对感应电动机比例的时序历史数据进行周期性和趋势性的特征分析和预测。以某地区真实的感应电动机比例数据进行实验,结果表明提出的TP-GAM框架对感应电动机比例进行预测方法所得结果与传统的时间序列模型对比具有更高的预测精度。

交联聚乙烯电缆绝缘试验样品热处理后热效应研究

基于差示扫描量热法(DSC)在电缆热历史分析中的应用,进一步研究具有不同热历史的交联聚乙烯(XLPE)电缆绝缘的热效应及其变化规律,可帮助分析电缆绝缘实际运行中的受热情况。将电缆绝缘试验样品置于不同温度和时间条件下热处理,以模拟电缆绝缘的不同受热过程,然后采用DSC测量热处理后的绝缘试验样品在升温过程中产生的热效应,对比分析得出热处理温度和时间与DSC一次加热曲线的关系,试验结果表明,DSC一次加热曲线中吸热峰的数量、大小、峰值温度,及氧化诱导期等与试验样品的热处理温度、时间和氧气环境密切相关,尤其依赖热处理温度,可为初步分析电缆运行中是否发生过载或短路故障提供依据。

基于补偿饱和电感的开关磁阻电机位置估计方法

为了解决开关磁阻电机(SRM)的全周期电感交点因磁路饱和而产生偏移的问题,该文提出了一种基于补偿饱和电感的SRM无位置传感器控制方法。首先,通过脉冲注入获取SRM的全周期电感;其次,离线测量在不同负载工况下的相电感交点偏移角度,并且采用余弦和函数来拟合负载转矩与偏移角度的关系;最后,实时检测当前负载转矩值,进而计算出需要补偿的偏移角度。当电机进入电感饱和工作状态后,通过拟合补偿相电感位置交点的方法来提高转子位置角的估算精度。采用1台四相8/6极SRM为样机进行仿真和实验分析。该文方法没有新增加硬件,1个电角度周期内仍然可以更新8次转子位置角信息,消除了累计误差。

心理弹性、社会支持对维持性血液透析诱导期病人恐惧疾病进展的影响

目的:探讨心理弹性、社会支持对维持性血液透析(MHD)诱导期病人恐惧疾病进展的影响。方法:选取MHD诱导期病人152例,采用一般资料量表、心理弹性量表、社会支持量表和恐惧疾病进展量表进行问卷调查。结果:143例病人最终纳入调查。心理弹性问卷总得分(58.73±10.37)分、社会支持总分(38.15±5.59)分、恐惧疾病进展总得分为(46.53±7.02)分。不同年龄、婚姻、学历、家庭月收入、并发症、血液透析知识的MHD诱导期病人的心理弹性得分差异有统计学意义(P<0.01);不同年龄、婚姻、学历、家庭月收入的病人社会支持差异有统计学意义(P<0.01);不同年龄、婚姻、家庭月收入、并发症、血液透析知识的病人恐惧疾病进展差异有统计学意义(P<0.01)。心理弹性及其维度与恐惧疾病进展呈负相关性(P<0.05~P<0.01);社会支持维度中,除支持的利用度(P>0.05)外,其余各维度均与恐惧疾病进展呈负相关性(P<0.05~P<0.01)。经多重线性回归分析显示,年龄大和并发症≥3个的MHD诱导期病人恐惧疾病进展评分高(P<0.05和P<0.01)),已婚、家庭月收入>10 000元、血液透析知识较多、心理弹性和社会支持得分高的病人恐惧疾病进展评分低(P<0.05~P<0.01),7个变量对病人恐惧疾病进展评分的影响为79.3%(P<0.05)。结论:MHD病人的恐惧疾病是一个复杂的、受多种因素影响的心理感受。临床上医护人员应采取针对性的干预措施,帮助病人建立正确的应对方式,从而缓解疾病进展恐惧心理。

六氟丙烯气相环氧化反应诱导期及CuO/SiO_(2)催化剂失活机理

铜基催化剂在催化烯烃环氧化反应上具有优异的催化性能和广阔的应用前景。目前,已有专利将负载型铜基催化剂应用于六氟丙烯(HFP)气相环氧化反应,并且表现出优异的催化性能,但是反应存在诱导期及催化剂在后期活性明显降低等问题,限制了其进一步的应用发展。通过等体积浸渍法制备CuO/SiO_(2)催化剂,并通过FT-IR、XRD、TEM和TG等对CuO/SiO_(2)催化剂的物理-化学性质进行分析,系统研究其在HFP气相环氧化反应中存在诱导期及失活的原因。结果表明,Cu-F物种是反应的活性中心,而该物种由原料气(空气与HFP)和CuO反应才能产生,这是反应过程中产生诱导期的原因所在;而反应后Cu颗粒的聚集长大是催化剂活性降低的主要原因。