硬膜外自控镇痛及关泵时机对产妇第二产程的影响

目的:探究硬膜外自控镇痛与关泵时机对产妇第二产程的影响。方法:选取分娩的198例产妇作为观察对象,随机分三组,各66例,其中A组关闭镇痛泵时间为宫口开至8~9 cm时,B组关闭镇痛泵时间为宫口开全时,C组未行硬膜外自控镇痛,对比3组患者的镇痛效果及对产程及分娩结局的影响。结果:A、B两组患者的镇痛效果优于C组(P<0.05),A、B两组患者第二产程长于C组(P<0.05),A、B组患者第二产程比较差异有统计学意义(P<0.05),其他指标比较差异无统计学意义(P>0.05);3组患者的产后2 h出血量、新生儿Apgar评分、剖宫产率及其他临床结局指标比较,差异无统计学意义(P>0.05)。结论:硬膜外自控镇痛能对产妇分娩疼痛有效缓解,并于宫口开至8~9 cm时将镇痛泵关闭可缩短第二产程,且未对母婴结局产生不利影响。

无负压供水系统中水泵水锤的瞬态分析

针对某大型无负压泵站,应用一维流体软件FLOWMASTER对开泵、关泵和水泵变频过程进行暂停分析,结果表明:无负压设备在关泵、开泵、升频和降频过程中,均产生水锤现象,而且水锤迅速在整个供水管网内传递;无负压泵站前端管网的水锤压力变化较小,压力变化不超过0.01MPa,泵站下游管网的水锤压力变化较大,超过0.03MPa,水锤最大压力低于0.337MPa,低于管道的承压值。

浅谈混凝土泵送与浇筑的施工技术

目前在珠江三角洲地区，随着高层建筑的大量涌现，泵送混凝土的施工越来越多地被采用，但在泵送和浇筑方面存在的质量问题也不少，期待着我们在实践中不断摸索规律去加以克服。本文根据泵送混凝土的性能与特点，对其施工技术作一些论述。

定向探管故障分析与解决方法实现

定向探管是随钻测量(MWD)系统的重要组成部分,采用三轴石英挠性加速度计和三轴磁通门传感器的组合设计,可测得高精度的井眼姿态、马达工具面和实钻井眼轨迹等参数。在马达定向时可提供连续井斜和工具面测量,为定向井工程师完成决策和调整井眼轨迹提供依据。中海油服自主研发的定向探管TMP,有两种测斜模式:开泵测斜和关泵测斜。关泵测斜,在停钻中测斜,测量数据精度高。近期在现场应用中,关泵测斜时会出现测斜数据的丢失,通过对TMP应用条件及电路设计展开研究,对其固件程序进行改进,保证TMP在关泵故障时,仍能获得正确的测斜数据,降低了现场的故障损失时间。

妇科患者术后尿管拔除最佳时机的选择

目的探讨妇科患者术后留置导尿管拔除的最佳时机。方法选择在我院妇科2009年7－10月手术后留置导尿管的260例患者,随机分为实验组和对照组,实验组患者有补液的在患者补液剩余500ml,即更换最后一袋补液时,同时患者有镇痛泵的给患者关镇痛泵,以后再拔除导尿管。对照组按照原来常规在补液结束后拔除导尿管,镇痛泵不关。结果实验组患者拔除导尿管后自然排尿率为99.23%,对照组为89.23%,两组比较差异显著,实验组优于对照组,P〈0.05。结论妇科患者术后留置导尿管拔除的最佳时机应由传统的补液结束后,不关镇痛泵时拔除改为在更换最后一袋补液即剩余500ml时并给患者关镇痛泵,同时拔除导尿管。

农用机井的科学使用

农用机井是一项重要的农田灌溉和人畜饮水设施,对抗御干旱,促进农业增产,解决人畜饮水起到了举足轻重的作用。但不少地方,由于机井使用不当,导致寿命缩短或水泵经常损坏。科学使用机井,不仅可保护机井和水泵,延长使用时间,而且可减少损失,不误农时灌溉和人畜饮水。

A Laser-Diode-Pumped Nd:YAG Laser Q-Switched with a YAG Color Center Chip

A laser-diode-pumped Nd: YAG laser Q-switched Passively with a YAG colorcenter chip has been deveolped. The Q-switched pulse output has a duration of 25-70ns,an energy of about 7.9 μJ and a repetition frequency of 1.25-5.0kHz when the laser cavityparameters and pump power are changed. The Q-switched dynamics is analyzed with therate equation theorry. The theoretical and experimental results agree well.

农用机井的科学使用

农用机井是一项重要的农田灌溉和人畜饮水设施,对抗御干旱,促进农业增产,解决人畜饮水起到了举足轻重的作用.但不少地方,由于机井使用不当,导致寿命缩短或水泵经常损坏.科学使用机井.不仅可保护机井和水泵,延长使用时间,而且可减少损失,不误农时灌溉和人畜饮水.

Endoscopic findings in patients with Schatzki rings:Evidence for an association with eosinophilic esophagitis

AIM:To investigate endoscopic findings in patients with Schatzki rings(SRs) with a focus on evidence for eosinophilic esophagitis(EoE).METHODS:We consecutively approached all adult patients scheduled for elective outpatient upper endoscopy for a variety of indications at the German Diagnostic Clinic,Wiesbaden,Germany between July 2007 and July 2010.All patients with endoscopically diagnosed SRs,defined as thin,symmetrical,mucosal structures located at the esophagogastric junction,were prospectively registered.Additional endoscopic findings,clinical information and histopathological findings with a focus on esophageal eosinophilia(≥ 20 eosinophils/high power field) were recorded.The criteria for active EoE were defined as:(1) eosinophilic tissue infiltration ≥ 20 eosinophils/hpf;(2) symptoms of esophageal dysfunction;and(3) exclusion of other causes of esophageal eosinophilia.Gastroesophageal reflux disease was excluded by proton pump inhibitor treatment prior to endoscopy.The presence of ≥ 20 eosinophils/hpf in esophageal biopsies in patients that did not fulfil the criteria of EoE was defined as esophageal hypereosinophilia.RESULTS:A SR was diagnosed in 171(3.3%;128 males,43 females,mean age 66 ± 12.9 years) of the 5163 patients that underwent upper gastrointestinalendoscopy.Twenty of the 116 patients(17%) from whom esophageal biopsies were obtained showed histological hypereosinophilia(≥ 20 eosinophils/hpf).Nine of these patients(8 males,1 female,mean age 49 ± 10 years) did not fulfill all diagnostic criteria of EoE,whereas in 11(9%) patients with ≥ 20 eosinophils/hpf,a definite diagnosis of EoE was made.Three of the 11 patients(27%) with definite EoE had no suspicious endoscopic features of EoE.In contrast,in the 25 patients in whom EoE was suspected by endoscopic features,EoE was only confirmed in 7(28%) patients.Patients with EoE were younger(mean age 41.5 ± 6.5 vs 50.5 ± 11.5 years,P = 0.012),were more likely to have a history of allergies(73% vs 29%,P = 0.007) and complained more often of dysphagia(91% vs 34%,P = 0.004) and food impaction(36% vs 6%,P = 0.007) than patients without EoE.Endoscopically,additional webs were found significantly more often in patients with EoE than in patients without EoE(36% vs 11%,P = 0.04).Furthermore,the SR had a tendency to be narrower in patients with EoE than in those without EoE(36% vs 18%,P = 0.22).The percentage of males(73% vs 72%,P = 1.0) and frequency of heartburn(27% vs 27%,P = 1.0) were not significantly different in both groups.The 9 patients with esophageal hypereosinophilia that did not fulfil the diagnostic criteria of EoE were younger(mean age 49 ± 10 years vs 58 ± 6 years,P = 0.0008) and were more likely to have a history of allergies(78% vs 24%,P = 0.003) than patients with < 20 eosinophils/hpf.Predictors of EoE were younger age,presence of dysphagia or food impaction and a history of allergies.CONCLUSION:A significant proportion of patients with SRs also have EoE,which may not always be suspected according to other endoscopic features.

Spin Transport in a Rashba Ring-Quantum Dot System Pumped by Microwave Fields

We report a theoretical study on producing electrically spin-polarized current in the Rashba ring with parallel double dots embedded, which are subject to two time-dependent microwave fields. By means of the Keldysh Green＇s function method, we present an analytic result of the pumped current at adiabatic limit and demonstrate that the interplay between the quantum pumping effect and spin-dependent quantum interference can lead to an arbitrarily controllable spin-polarized current in the device. The magnitude and direction of the charge and spin current can be effectively modulated by system parameters such as the pumping phase difference, Rashba precession phase, and the dynamic phase difference of electron traveling in two arms of ring; moreover, the spin-polarization degree of the charge current can also be tuned in the range [-∞, ＋∞]. Our findings may shed light on the all-electric way to produce the controllable spin-polarized charge current in the field of spintronics.

An LD-pumped dual-wavelength actively Q-switched Nd:Sc_(0.2)Y_(0.8)SiO_5 laser

We demonstrate a laser-diode （LD） pumped actively Q-switched laser with Nd：Sc0.2Y0.5SiO5 （Nd：SYSO） crystal for the first time. A stable actively Q-switched laser is obtained at dual wavelengths of 1 075.2 nm and 1 078.2 nm. The maximum average output power of 720 mW is obtained at the repetition rate of 15 kHz under the pump power of 8.7 W. The minimum pulse width of 58 ns is obtained at the repetition rate of 5 kHz under the pump power of 8.7 W, corresponding to the peak power of 1.9 kW and the pulse energy of 112 μJ.

Early effects of oral administration of omeprazole and roxatidine on intragastric pH

Objective： The ideal medication for the treatment of acid-related diseases, e.g., peptic ulcers, stress- related gastric bleeding, functional dyspepsia, and gastroesophageal reflux disease, should have a rapid onset of action to promote hemostasis and relieve the symptoms. The aim of our study was to investigate the inhibitory effects on gastric acid secretion of a single oral administration of a proton pump inhibitor, omeprazole 20 mg, and an H2-receptor antagonist, roxatidine 75 mg. Methods： Ten Heficobacterpylori-negative male subjects participated in this randomized, two-way crossover study. Intragastric pH was monitored continuously for 6 h after single oral admini- stration of omeprazole 20 mg and roxatidine 75 mg. Each administration was separated by a 7-d washout period. Results： During the 6-h study period, the average pH after administration of roxatidine was higher than that after administration of omeprazole （median： 4.45 vs. 2.65; P=0.0367）. Also during the 6-h study period, a longer duration of maintenance at pH above 2, 5, and 6 was observed after administration of roxatidine 75 mg than after administration of omeprazole 20 mg （median： 90.6% vs. 55.2%, P=-0.0284; 43.7% vs. 10.6%, P=0.0125; 40.3% vs. 3.3%, P=0.0125; respectively）. Conclusions： In Helicobacter pylori-negative healthy male subjects, oral administration of roxatidine 75 mg increased the intragastric pH more rapidly than that of omeprazole 20 mg.

Performance analysis of air-water dual source heat pump water heater with heat recovery

A new air-water dual source heat pump water heater with heat recovery is proposed.The heat pump system can heat water by using a single air source,a single water source,or air-water dual sources.The water is first pre-heated by waste hot water,then heated by the heat pump.Waste heat is recovered by first preheating the cold water and as water source of the heat pump.According to the correlated formulas of the coefficient of performance of air-source heat pump and water-source heat pump,and the gain coefficient of heat recovery-preheater,the formulas for the coefficient of performance of heat pump in six operating modes are obtained by using the dimensionless correspondence analysis method.The system characteristics of heat absorption and release associated with the heat recovery-preheater are analyzed at different working conditions.The developed approaches can provide reference for the optimization of the operating modes and parameters.The results of analysis and experiments show that the coefficient of performance of the device can reach 4-5.5 in winter,twice as much as air source heat pump water heater.The utilization of waste heat in the proposed system is higher than that in the system which only uses waste water to preheating or as heat source.Thus,the effect of energy saving of the new system is obvious.On the other hand,the dimensionless correspondence analysis method is introduced to performance analysis of the heat pump,which also has theoretical significance and practical value.

Continuous wave and passively Q-switched Nd:Lu_(0.15)^- Y_(0.85)VO_4 laser with 885nm direct pumping

The 885 nm direct pumping directly into the^4F_(3/2)emitting level of Nd^(3+)is applied on an Nd:Lu_(0.15)Y_(0.85)VO_4 crystal.The maximum output power of 2.8 W for continuous wave(CW)operation is obtained.For Q-switched operation,the maximum average output power is 1.2 W with pulse repetition of 23.69 kHz and pulse width of 35 ns at the pump power of 27.9 W.The high-quality fundamental transverse mode can be observed owing to the reduction of thermal effect for Nd:Lu_(0.15)Y_(0.85)VO_4 crystal by 885 nm direct pumping.

The polarization-dependent supercontinuum generation in photonic crystal fibers with high birefringence and two-zero dispersion

A polarization-dependent supercontinuum spectrum source of light from the UV to infrared region has been generated in our photonic crystal fiber with birefringence B=2.23×10 3.By tuning the polarization direction of the input pulse,it is found that the width of the supercontinuum spectrum changes dramatically with the input polarization directions.At the same time,we qualitatively explain the blue-shift peak and the red-shift peak in the experimental spectrum using phase matching conditions on dispersive waves,stoke waves and the pump wave.In addition,we also found that supercontinuum spectrum generation,to some extent,is dependent on the pump wavelength and average power of the pump.The spectrum is broadened with the increase of average power,but unchanged after average power reaches a certain value;when the pump wavelength is located in the anomalous dispersion and further away from the zero-dispersion wavelength,the spectrum of the supercontinuum is wider.