Development of a Novel Parallel-spool Pilot Operated High-pressure Solenoid Valve with High Flow Rate and High Speed

High-pressure solenoid valve with high flow rate and high speed is a key component in an underwater driving system.However,traditional single spool pilot operated valve cannot meet the demands of both high flow rate and high speed simultaneously.A new structure for a high pressure solenoid valve is needed to meet the demand of the underwater driving system.A novel parallel-spool pilot operated high-pressure solenoid valve is proposed to overcome the drawback of the current single spool design.Mathematical models of the opening process and flow rate of the valve are established.Opening response time of the valve is subdivided into 4 parts to analyze the properties of the opening response.Corresponding formulas to solve 4 parts of the response time are derived.Key factors that influence the opening response time are analyzed.According to the mathematical model of the valve,a simulation of the opening process is carried out by MATLAB.Parameters are chosen based on theoretical analysis to design the test prototype of the new type of valve.Opening response time of the designed valve is tested by verifying response of the current in the coil and displacement of the main valve spool.The experimental results are in agreement with the simulated results,therefore the validity of the theoretical analysis is verified.Experimental opening response time of the valve is 48.3 ms at working pressure of 10 MPa.The flow capacity test shows that the largest effective area is 126 mm2 and the largest air flow rate is 2320 L/s.According to the result of the load driving test,the valve can meet the demands of the driving system.The proposed valve with parallel spools provides a new method for the design of a high-pressure valve with fast response and large flow rate.

Polymer-Based Micro Flow Sensor with Alternative Electronic Signal Interfaces for Low and High Flow Rates

The qualitative and quantitative assessment of gas flow has become increasingly relevant in the use of everyday systems. The micro flow sensor, developed by Innovative Sensor Technology AG （Switzerland）, is by principle a calorimetric flow sensor produced as a micro system on a glass substrate by means of photolithography and glass etching technology. These structures are arranged as a platinum micro heater and sensor in a Wheatstone bridge. The subsequent etching process produces an exposed area of polyimide membrane that is only a few microns thick and includes the resistive sensor structure as the active area. In addition, the RTD （resistance temperature detector） technology included on the sensor allows for the implementation of a variety of electronic biasing and signal processing modes. Since the sensor can be powered and the bridge can be measured in both CTA （constant temperature anemometer） and calorimetric mode, new possibilities are presented for both low and high flow rates with regard to temperature compensation, self-calibration and self-monitoring.

Electrical Resistivity Contrasts and High Flow Rates Discontinuous Aquifers Identification in a Sheared Crystallophyllian Basement Zone at Boniérédougou (North-Central Côte d’Ivoire)

This study proposes an alternative approach to the investigation of high flow hydrogeological fractures within the basement in the Dabakala region of north-central Côte d’Ivoire. The used approach consists of exploring the subsurface by measuring electrical resistivity contrasts along the main shear direction within crystallophyllian rocks. Electrical resistivity profiling and vertical electrical sounding techniques, coupled with boreholes monitoring, have identified fractured aquifers whose best flow rates are around 96 and 116 m3/h. These aquifers mostly hosted in granodiorite have an average strength of 10 meters and are located at depth of around 100 meters. They are associated with open fractures created by tangential shear stresses that have affected the Dabakala volcano-sedimentary trench formations. The search for fractured aquifers along the main shear direction offers great perspective for obtaining high flow rates.

A study of hydrate plug formation in a subsea natural gas pipeline using a novel high-pressure flow loop

The natural gas pipeline from Platform QKI8-1 in the southwest of Bohai Bay to the onshore processing facility is a subsea wet gas pipeline exposed to high pressure and low temperature for a long distance. Blockages in the pipeline occur occasionally. To maintain the natural gas flow in the pipeline, we proposed a method for analyzing blockages and ascribed them to the hydrate formation and agglomeration. A new high-pressure flow loop was developed to investigate hydrate plug formation and hydrate particle size, using a mixture of diesel oil, water, and natural gas as experimental fluids. The influences of pressure and initial flow rate were also studied. Experimental results indicated that when the flow rate was below 850 kg/h, gas hydrates would form and then plug the pipeline, even at a low water content （10%） of a water/oil emulsion. Furthermore, some practical suggestions were made for daily management of the subsea pipeline.

Influence of the total gas flow rate on high rate growth microcrystalline silicon films and solar cells

This paper reports that high-rate-deposition of microcrystalline silicon solar cells was performed by very-highfrequency plasma-enhanced chemical vapor deposition. These solar cells, whose intrinsic μc-Si：H layers were prepared by using a different total gas flow rate （Ftotal）, behave much differently in performance, although their intrinsic layers have similar crystalline volume fraction, opto-electronic properties and a deposition rate of - 1.0 nm/s. The influence of Ftotal on the micro-structural properties was analyzed by Raman and Fourier transformed infrared measurements. The results showed that the vertical uniformity and the compact degree of μc-Si：H thin films were improved with increasing Ftotal. The variation of the microstructure was regarded as the main reason for the difference of the J V parameters. Combined with optical emission spectroscopy, we found that the gas temperature plays an important role in determining the microstructure of thin films. With Ftotal of 300 sccm, a conversion efficiency of 8.11% has been obtained for the intrinsic layer deposited at 8.5 A/s （1 A=0.1 nm）.

Design and Experiment of Streamlined Piezoelectric Pump with Low Vortex and Large Flow Rate

Valveless piezoelectric pump is widely used in the medical,however,there is a general and difficult problem to be solved:Low vortex and large flow rate are not compatible,resulting in the blood prone to thrombosis during blood delivery.In this paper,a new valveless piezoelectric(PZT)pump with streamlined flow tubes(streamlined pump)is proposed.The design method and the working principle of the pump are analyzed.The velocity streamlines are simulated,and the results demonstrate that there are no obvious vortexes in the flow tube of the streamlined pump.Five prototype pumps(two cone pumps and three streamlined pumps)are designed and fabricated to perform flow rate and flow resistance experiments.The experimental results illustrate that the maximum flow rate of the streamlined pump is 142 mL/min,which is 179%higher than that of the cone piezoelectric pump,demonstrating that the streamlined pump has a large flow rate performance.This research provides an inspiration for future research on simple structure,low vortex and large flow rate volume-type pumps,and also provides a useful solution for thrombosis preventing.

华南陆缘火成岩区差异性地壳热结构及地热意义

高产热花岗岩是重要的壳内热源之一,我国华南陆缘花岗岩体分布广泛,为该区浅表热量的生成及聚集提供了可能。本文在简述区内花岗岩资源分布的基础上,系统分析了区内主要花岗岩体的放射性生热特征,并结合区内近些年施工的地热勘探深钻,对重点地热勘查区的深部地温场分布、地热通量、地壳热结构等进行了对比分析,提出了华南陆缘浅表地热资源的聚热模式。分析认为,华南陆缘地区具有“幔源供热-壳内生热-断裂传热-盖层保热”的四元聚热模式,其中,花岗岩体的放射性生热率是影响区内浅部地温场的主要因素之一,粤北—赣南岩体的生热率明显高于漳州地区的花岗岩体,其近似“热壳冷幔”型或“温壳温幔”型岩石圈热结构与漳州“热幔冷壳”型岩石圈热结构有一定的差异;断裂构造及盖层条件对于地下热量聚集及散失具有明显的控制作用。研究成果对于深入理解华南陆缘地热资源的成因、控热因素,以及今后该地区地热资源勘探开发实践具有一定的理论与指导意义。

Influence of total gas flow rate on microcrystalline silicon films prepared by VHF-PECVD

Hydrogenated microcrystalline silicon （μc-Si：H） films are fabricated by very high frequency plasma enhanced chemical vapour deposition （VHF-PECVD） at a silane concentration of 7% and a varying total gas flow rate （H2＋SiH4）. Relations between the total gas flow rate and the electrical and structural properties as well as deposition rate of the films are studied. The results indicate that with the total gas flow rate increasing the photosensitivity and deposition rate increase, but the crystalline volume fraction （Xc） and dark conductivity decrease. And the intensity of （220） peak first increases then decreases with the increase of the total gas flow rate. The cause for the changes in the structure and deposition rate of the films with the total gas flow rate is investigated using optical emission spectroscopy （OES）.

非结构化高维大数据异常流量时间点挖掘算法

非结构化数据的维度较高,每个样本数据包含的特征非常多,导致了维度灾难问题,使得降低维度并保持有效特征提取难度较大,影响大数据流量异常时间点挖掘的精度。为此,提出新的基于空间映射的非结构化高维大数据流量异常时间点挖掘方法。通过近似解集的几何特征建立稀疏回归模型,求解高维目标空间映射到低维目标子空间的稀疏投影矩阵。根据密度分布选择出一个高密度集合作为聚类中心的候选集,确定聚类的初始聚类中心。同时对聚类形成的各个簇采用剪枝算法,选择时间点候选集,对候选集展开二次判断,挖掘高维大数据流量异常时间点。实验结果表明,数据的降维能有效提高流量异常挖掘精度。相比之下,所提方法的高维大数据流量异常时间点挖掘更加精准,耗时更短。

化疗患者行个体化低流率腹部增强CT:双源CT低管电压高管电流的可行性分析

目的 探讨在癌症患者中使用双源CT结合低流速和低管电压方案的可行性。方法 共纳入90名进行上腹部增强CT扫描的患者,并随机分为A组、B组和C组(每组30人)。在A组中,患者使用120kVp和448mgl/kg对比剂量进行扫描。B组患者以100kVp和336 mgl/kg对比剂量进行扫描。C组患者以70kVp和224mgI/kg对比剂量进行扫描。对CT值、标准差、信噪比、对比噪声比、主观评分、对比剂剂量和流速进行测量。结果 在三组中,除了肾脏外,主观图像评分无统计学差异(均P>0.05)。与其他组相比,C组在大多数感兴趣区域(ROIs)中显示出显著更高的CT值、更低的噪声水平以及更高的SNR和CNR值(P<0.05)。与A组相比,C组所用对比剂剂量减少了47.3%(79.2±13.7 vs.41.7±8.9,P<0.01),对比剂注射速率降低了19.2%(2.6±0.5 vs.2.1±0.4,P<0.01)。结论 在化疗后血管受损的患者中使用70kVp管电压结合高管电流的方法,在保证图像质量和诊断信心的同时降低流速是可行的。

低MFR双峰HDPE标准试样的研制及应用

以低熔体流动速率(MFR)、相对分子质量分布呈双峰(简称双峰)的高密度聚乙烯(HDPE)100N粉料为原料,先用筛网除去大颗粒和微小粉末,再加入0.2%(w)抗氧剂1010和0.2%(w)抗氧剂168混匀造粒,并除去大、小粒子及异形粒子制备标准试样。对标准试样进行均匀性、稳定性检验,并进行了氧化诱导时间、熔点、结晶点、白度的稳定性实验,以及对标准试样进行了定值及统计允许区间值的确定。结果表明:低MFR双峰HDPE标准试样的MFR标称值为(0.226±0.007)g/10 min,标准试样MFR均匀、稳定。

高速飞行器边界层质量引射降热减阻技术流量分区优化研究

边界层质量引射被认为是解决临近空间高超声速飞行器关键部位热防护问题和减小其飞行阻力的有效途径之一.然而,已有研究主要关注边界层质量引射对热流或阻力的单独影响,少有研究对边界层质量引射能够带来的降热减阻效果进行综合评估.针对高空高超声速层流条件下钝楔与钝锥外形的边界层质量引射降热减阻问题开展数值模拟研究,并采用多目标优化方法开展了边界层质量引射的分区流量优化设计,在满足减阻性能的同时,提高了整体的热防护效果,实现了给定冷却剂流量条件下的降热减阻综合性能优化.研究结果表明,层流条件下,边界层质量引射通过改变速度边界层和温度边界层能够显著降低壁面摩阻和热流.在单位面积引射质量流量为28.028 g/(m^(2)·s)时,对于钝楔外形,采用均匀引射方案能够减阻3.60%,同时峰值热流下降12.06%,而采用分区优化方案能够将减阻效果提高到4.30%,同时峰值热流下降91.01%;对于钝锥外形,采用均匀引射方案会造成阻力增大2.60%,同时峰值热流仅下降8.57%,而采用分区优化方案能够在减阻19.75%的情况下同时将峰值热流降低99.95%.

高压差大流量工况下套筒式减压阀的减压过程研究

随着工业技术的进步,许多行业面临高压差和大流量的工作条件,这对减压阀的设计提出了新的挑战。本文研究了一种套筒式减压阀在高压差大流量工况下的减压过程,通过数值模拟方法分析了不同开度与工况下套筒式减压阀内部的流场特性。研究发现,为了在保持氮气流量为2.5 kg/s的情况下实现从35 MPa至6 MPa的减压比,需要采用4级减压方案。此外,仿真结果还揭示了不同行程下套筒阀内部的压力和速度分布特征,特别是在节流孔处的压力急剧下降及流速增加的现象。本研究可为高压差大流量工况下套筒式减压阀的设计提供参考。

经鼻高流量湿化氧疗在有创通气撤机中的应用研究

目的:经鼻高流量湿化氧疗在有创通气撤机中的应用研究。方法:选取2021年7月至2023年12月收治的60例有创通气撤机患者为研究对象,分为常规组30例、研究组30例(随机数字表法),常规组采用传统气泡式湿化鼻导管吸氧方式,研究组采用经鼻高流量湿化氧疗,对比两组24~48h再插管率、有创通气撤机成功率、ICU住院时间等指标。结果:研究组临床指标水平优于常规组(P<0.05);研究组24h重插管率、48h重插管率均较常规组低,有创通气撤机成功率较常规组高(P<0.05);两组pH比较无差异(P>0.05),研究组干预后PaO_(2)水平较常规组表达高,PaCO_(2)水平较常规组表达低(P<0.05);研究组干预后心率、呼吸频率均低于常规组(P<0.05)。结论:经鼻高流量湿化氧疗,可有效改善患者临床指标,降低重插管率,提高有创通气撤机成功率,进而改善患者气道状态,心率与呼吸频率,值得推广。

高速来流作用下带孔隙容腔建压过程及特性

高速来流作用下带孔隙的容腔内部压强演变过程对弹体头罩分离、整流罩脱落、舱门开启等有着重要影响。围绕带进气口和卸流孔隙的容腔结构,建立了预估容腔压强变化的理论模型和数值模型,并结合实验验证探讨了开孔位置、进出口面积以及容积大小对容腔建压过程的影响。结果表明排气孔位置和大小对容腔建压效果具有显著影响。当进排气口面积比为0.75时,容腔迎风区域孔隙在初始建压阶段能够提升建压速率,但稳定状态下孔隙由进气转变为排气,容腔压强相对无排气孔隙状态降低约39%;容腔表面斜率过渡区域孔隙受流动形态演化影响,相应容腔压强变化较为复杂,在稳定阶段容腔压强相对无排气状态降至50%;孔隙位于容腔后部时,稳定阶段压强最低,约为无排气状态的44%。同时,进口面积增加会显著增加容腔压强,排气孔隙面积增加会降低容腔压强并减少建压时间。容腔体积对建压速度具有一定影响,但对最终建压结果影响较小。

高流速复杂水域下的海底输水管道施工技术

以舟山市大陆引水三期工程(金塘岛引水工程)为例,对浅水铺管船增配的锚泊系统定位能力进行了理论分析和计算,同时介绍了高流速复杂水域环境下的长距离海底输水管道铺设总体施工工艺和关键施工技术,以期为类似工程提供借鉴。

改良动态ROX指数对急性呼吸衰竭患者HFNC治疗失败的预测价值

目的 分析改良动态ROX指数对急性呼吸衰竭患者高流量鼻导管(HFNC)治疗失败的预测价值。方法 选取2021年3月至2023年3月的急性呼吸衰竭患者102例,HFNC成功66例,失败36例,改良ROX指数为PaO_(2)/FIO_(2)与RR×HR的比值×100,动态指数定义为HFNC前与HFNC 2 h指数的差值,分析不同指数对HFNC失败的预测效能及相关因素。结果 HFNC失败组年龄、APACHE II评分高于HFNC成功组。HFNC 2 h时,HFNC成功组HR、RR和FiO_(2)低于HFNC失败组,SpO_(2)、PaO_(2)、PaCO_(2)、SpO_(2)/FIO_(2)和PaO_(2)/FIO_(2)高于HFNC失败组。HFNC成功组HFNC持续时间、HFNC 2 h ROX,动态ROX,HFNC 2 h改良ROX和改良动态ROX指数均高于HFNC失败组。动态ROX、HFNC 2 h改良ROX和改良动态ROX的AUC(95%CI)分别为0.703(0.590~0.790)、0.726(0.622~0.829)和0.811(0.717~0.902),临界值分别为0.97、6.78和0.12。对混杂因素进行调整后,动态ROX>0.97、HFNC 2 h改良ROX>6.78和改良动态ROX>0.12是HFNC失败风险降低的影响因素。结论 改良动态ROX指数可早期预测HFNC预后,改良动态ROX>0.12和HFNC 2 h改良ROX>6.78在预测急性呼吸衰竭患者HFNC失败风险方面表现良好。

改进型BCM-100H丙烯聚合催化剂在Horizone装置应用及高性能产品开发

原BCM-100H催化剂生产较高MFR(熔体流动速率)产品时聚合物细粉较多,不利于装置运行。本文考察了改进型BCM-100H催化剂在Horizone装置的工业应用,并与原催化剂及进口催化剂进行对比;使用该催化剂首次在该装置上开发3个高MFR高刚性高抗冲共聚产品K8740H、KH39M和KH75M。结果表明:改进后BCM-100H催化剂活性,氢调敏感性,共聚能力等性能基本不变;聚合物粉料中≤0.15 mm细粉减少约80%,聚合物等规指数(绝对值)提高0.5%,优于进口催化剂;K8740H弯曲模量和常温冲击强度分别是1.36 GPa和8.51 kJ·m^(-2),优于进口同类产品;KH39M和KH75M弯曲模量和冲击强度分别是1.57 GPa,6.00 kJ·m^(-2)和1.59 GPa,5.84 kJ·m^(-2),优于国产同类产品;对助剂进行了筛选优化,可将产品弯曲模量提高5%~10%。产品弯曲模量和冲击强度分别达到1.72 GPa和5.72 kJ·m^(-2),超过进口同类牌号水平。

临河坳陷北部古近系临河组超深层油气藏形成条件与勘探前景

近年来,通过加大深层—超深层碎屑岩晚期油气成藏地质认识研究,在河套盆地临河坳陷实现了超深层碎屑岩油气勘探的重大发现。基于对临河坳陷古近系烃源岩热模拟、钻录试井资料及成储成藏演化分析,主要形成3点地质认识:(1)临河坳陷北部古近系发育富含树脂体(陆源)和藻类体(水生)的优质烃源岩,该烃源岩在低演化阶段开始大量生排烃,具有生烃强度大、生烃窗口宽的特点,淖西洼槽带超深层热演化程度相对较高,油气资源潜力大;(2)发育远源水浅坡缓大型辫状河三角洲沉积,砂体广覆式分布,受低地温、晚深埋、高石英含量、弱压实、弱胶结等弱成岩因素影响,形成了以弱成岩保孔主导、叠加后生超高压改造扩缝的成储新机制,储层物性好,极大拓展了超深层油气勘探空间;(3)生烃期早充注、持续沉降深埋热演化、加速生排烃和持续充注形成过饱和与超高压油气藏,而超高压一旦超过储源交互体破裂压力,形成缝孔连通、源储同聚、连续型大面积展布的常规油气成藏新认识,有力提高了超深层常规油气藏勘探潜力。临河坳陷北部古近系临河组超深层油气成藏条件优越,有利勘探区规模大,展现了良好的勘探前景,同时进一步丰富了超深层碎屑岩晚期油气成藏理论认识,对类似盆地尤其是万米超深层的源内勘探具有重要指导意义。

煤油流量对HVOF喷涂FeCrMoSi-Ti_(3)SiC_(2)涂层高温摩擦磨损性能的影响

目的提高燃煤锅炉四管的耐磨性能。方法使用喷雾造粒技术制备FeCrMoSi/Ti_(3)SiC_(2)复合粉末,并利用超音速火焰喷涂技术(HVOF)在12CrMoV基体上制备煤油流量分别为26、28、30、32 L/h的复合涂层。使用X射线衍射仪(XRD)、扫描电镜(SEM)及其自带的能谱仪(EDS)、Raman、维氏显微硬度计和摩擦磨损试验机研究FeCrMoSi/Ti_(3)SiC_(2)粉末及其涂层相组成、组织结构,检测涂层的力学性能,并对涂层在800℃下的摩擦学性能和磨损机理进行系统分析。结果粉末物相主要由Ti_(3)SiC_(2)、Fe-Cr和TiC组成,涂层的物相与粉末类似,但是新产生了SiC相,且随着煤油流量的升高,Ti_(3)SiC_(2)物相逐渐分解。当煤油流量为30、32 L/h时,涂层内Ti_(3)SiC_(2)物相大量分解。涂层的硬度和断裂韧性随着煤油流量的升高表现出先升高、后降低的趋势,孔隙率和磨损率呈现先减小、后增大的趋势。当煤油流量为28 L/h时,涂层磨损率最低,约为5.44×10^(-15)m^(3)/(N·m)。结论煤油流量为28 L/h时,涂层表面生成的SiO_(2)、TiO_(2)和Fe_(2)O_(3)等氧化物均匀分布在磨痕和对偶球表面,有效阻挡了对偶球和涂层的直接接触,使得涂层显示出最优异的摩擦学性能。涂层的主要磨损机制为氧化磨损和黏着磨损。