Preparation and Characterization of Phenolic Prepolymer Impregnated Chinese Fir by Cyclic Increasing-Pressure Method with Green and Efficient

The Chinese fir wood was impregnated using a cyclic increasingpressure method(CIPM)with phenolic prepolymers as the impregnating modifier.Unmodified Chinese fir and progressive increasing-pressure method(PIPM)impregnated Chinese fir were used as reference samples and were compared and analyzed.The product’s chemical structure,internal morphology,crystal structure,and heat resistance were characterized.The transversal and longitudinal sections showed better filling effects,so that it bore greater external loading and reduced the water storage space.CIPM infused more phenolic prepolymer into the Chinese fir.Not only producing more physical filling but also forming more hydrogen bond associations and chemical bond combinations.Compared with PIPM and unmodi-fied Chinese fir,the CIPM impregnated Chinese fir had better mechanical strength and water resistance.The cellulose chains in CIPM impregnated Chinese fir were more closely linked and their crystallinity were clearly improved.Changes in internal morphology and crystal structure explained the reason why the mechanical properties and water resistance of CIPM impregnated Chinese fir were improved significantly.This Chinese fir had lower thermal decomposition rates,higher decomposition residual rates,and smaller combustion flames,which confirmed that it possessed improved heat and fire resistance.

Increasing Pressure:Impacts of Migration on Cities:

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Maintaining Pressure on Sustainable Development

THE impression one gets after reading the 53-page resolution of the United Nations Summit on Sustainable Development, bet- ter known as Rio＋20, is that all those who compiled the document know what the so called ＂planet-in-peril＂ needs to cure its problems.

Intracranial pressure monitoring:Gold standard and recent innovations

Intracranial pressure monitoring (ICP) is based on the doctrine proposed by Monroe and Kellie centuries ago. With the advancement of technology and science, various invasive and non-invasive modalities of monitoring ICP continue to be developed. An ideal monitor to track ICP should be easy to use, accurate, reliable, reproducible, inexpensive and should not be associated with infection or haemorrhagic complications. Although the transducers connected to the extra ventricular drainage continue to be Gold Standard, its association with the likelihood of infection and haemorrhage have led to the search for alternate noninvasive methods of monitoring ICP. While Camino transducers, Strain gauge micro transducer based ICP monitoring devices and the Spiegelberg ICP monitor are the emerging technology in invasive ICP monitoring, optic nerve sheath diameter measurement, venous opthalmodynamometry, tympanic membrane displacement, tissue resonance analysis, tonometry, acoustoelasticity, distortionproduct oto-acoustic emissions, trans cranial doppler, electro encephalogram, near infra-red spectroscopy, pupillometry, anterior fontanelle pressure monitoring, skull elasticity, jugular bulb monitoring, visual evoked response and radiological based assessment of ICP are the non-invasive methods which are assessed against the gold standard.

Increased intracranial pressure and macular thickening:is there a link?

Dear Editor,I am Dr. Hamid Sajjadi, director of Neuro-Ophthalmology at San Jose Eye and Laser Medical Center in California USA and director of Department of Ophthalmology, Acacia Medical Center, Dubai, UAE. I write to present three cases of macular thickening (MT) and micro-papilledema associated with increased intracranial pressure (IICP).

Combined ab-interno trabeculectomy and cataract surgery induces comparable intraocular pressure reduction in supine and sitting positions

AIM:To analyze the therapeutic effect of combined abinterno trabeculectomy and cataract surgery on intraocular pressure(IOP)levels in supine and sitting postures during a 24-hour IOP profile.METHODS:Twenty-six eyes of twenty-six patients receiving ab-interno trabeculectomy using electroablation of the trabecular meshwork combined with cataract surgery or stand-alone were included in this retrospective analysis.IOP change during 24-hour IOP profiles within two years postoperatively were analyzed for eyes receiving surgery(“study eyes”)and compared to fellow eyes,which had not received surgery.Clinical data including mean sitting IOP(siIOP),mean supine IOP(su IOP)and the number of topical antiglaucomatous medications(TAM)were extracted from patients’files.RESULTS:Preoperatively,si IOP was 17.6±5.3 mm Hg in study and 17.1±4.7 mm Hg in fellow eyes(P=0.347).Patients were treated with an average of 2.8±1.0 TAM.Best corrected visual acuity(BCVA)was significantly worse in study eyes(P<0.001),visual field function was marginally not significantly dif ferent(P=0.057).Af ter surger y 9.6±6.8 mo,study eyes had a mean si IOP of 14.5±3.6 mm Hg(IOP reduction:-3.2 mm Hg,P=0.009),a mean su IOP of 18.0±3.5 mm Hg,and an average of 1.3±1.34 TAM(P<0.001),while in fellow eyes,mean si IOP was 16.2±3.4 mm Hg and mean su IOP was 20.5±5.1 mm Hg.Postoperatively,the relative IOP increase between sitting and supine postures was approximately 30%in both study and fellow eyes(P=0.99).CONCLUSION:IOP after ab-interno trabeculectomy shows a comparable relative reduction in both supine and sitting position.Classical trabeculectomy is known to lower su IOP overproportionally.

Analysis of Factors Influencing Shut in Pressure Cone in Offshore Strong Bottom Water Reservoir

X oilfield is an offshore strong bottom water reservoir with water cut up to 96% at present, and liquid extraction has become one of the main ways to increase oil production. However, the current liquid production of the oilfield reaches 60,000 m3/d due to the limitation of offshore platform, well trough and equipment, the oilfield is unable to continue liquid extraction. In order to maximize the oil production of the oilfield, it is necessary to study the strategy of shut in and cone pressure. Through numerical simulation, this paper analyzes the influence of different factors, such as crude oil density, viscosity, reservoir thickness, interlayer, permeability and so on, on the drop height of water cone and the effect of precipitation and oil increase after well shut in. At the same time, the weight of each factor is analyzed by combining the actual dynamic data with the fuzzy mathematics method, and the strategy of well shut in and cone pressure is formulated for the offshore strong bottom water reservoir. It provides the basis and guidance for the reasonable use of shut in pressure cone when the reservoir with strong bottom water meets the bottleneck of liquid volume.

Clinical significance of large decompressive craniectomy to control intractable increased intracranial pressure in patients with traumatic brain injury

Objective To investigate the role of decompressive craniectomy (DC) to decrease intractable intracranial hypertension(ICH) due to diffuse brain swelling and / or cerebral edema after severe traumatic brain injury and the time window of DC to affect on prognosis. Methods The clinical record of 132 patients who underwent DC for posttraumatic intractable ICH in our hospital from July 2003 to

灯泡贯流式水轮机增减负荷动态特性分析

水轮机频繁经历变负荷工况转换过程,使得机组在较短时间内工作参数急剧变化,严重影响电站稳定运行。该研究以某贯流式水轮机为研究对象,在考虑自由液面和水体重力的情况下,采用动网格技术对贯流式水轮机相同出力范围下的减、增负荷过渡过程的动态特性进行分析。研究结果表明:由于增负荷和减负荷过渡过程的起始工况导致起始流动状态不同,因此在相同出力时,机组内的流动分布不同,减负荷过程尾水管内的涡流面积及强度明显小于增负荷工况,且尾水管涡带尺度也明显小于增负荷过程;相比于增负荷过程,减负荷过程中转轮叶片大范围的低压区极易引发空化;机组内的水压力脉动主要以尾水管涡带引起的0.1f_n(f_n为转频)低频压力脉动和转轮的旋转引起3f_n的高频压力脉动为主,增负荷过程的压力脉动幅值明显大于减负荷过程,两种压力脉动共同作用,使得贯流式水轮机主要振动区域集中于转轮。研究结果对贯流式水轮机的设计与运行具有一定的指导意义。

冲击速度及骨料率对混凝土动强度的影响研究

混凝土结构抗爆炸冲击能力研究具有很重要的军事防护意义.国内外学者已对混凝土动强度的提高机理进行了大量研究,但大多探讨单个因素对混凝土动强度的影响,缺乏对多因素耦合作用下混凝土动强度规律的研究,并且对混凝土抗压动强度和抗拉动强度间的关系研究也较少.通过霍普金森压杆试验仪的单轴压缩试验和巴西圆盘劈裂试验,测定了不同骨料率和冲击速度下混凝土的抗压动强度和抗拉动强度,再对试验结果进行研究分析,得到混凝土动强度的理论表达式,并将混凝土抗拉抗压动强度进行了对比分析.结果表明:混凝土抗压动强度与混凝土骨料率和冲击速度呈正相关,且随着混凝土骨料率的增大,冲击速度越小,混凝土抗压动强度增加幅度越大,受动载时,混凝土抗压动强度提高幅值大于抗拉动强度提高幅值.

超稠油老区氮气辅助VHSD开发数值模拟

转直井辅助水平井重力泄油(VHSD)开发方式已成为超稠油老区进一步提高区块采油速度、油藏采收率的重要调整手段。氮气辅助VHSD的增能提压、顶部隔热效应可有效解决超稠油老区吞吐后压力保持程度低、驱泄操作压力低、蒸汽腔温度低的问题,进而实现节约蒸汽用量、提高产油水平、提升油汽比和减耗降碳的目的。以克拉玛依油田九区某VHSD开发单元为例,采用数值模拟方法分析了在氮气辅助VHSD开发过程中注氮时机、注氮方式、注氮量等参数对提压增能、建立隔热层的影响,以及采出速度和累计注采的变化特点。研究表明,转驱泄初期采用段塞方式注入氮气可有效建立隔热层;矿场试验表明,井组油汽比提升0.025,日产油提升0.7 t,取得了较好的应用效果。研究成果为同类型超稠油老区氮气辅助VHSD效益开发提供了技术借鉴。

不同粗骨料粒径混凝土动态压缩强度的离散性研究

为了研究粗骨料粒径差异引起的动态压缩试验离散性问题,制备了最大粒径分别为8 mm、14 mm和26 mm的混凝土与砂浆试件,通过动静态压缩试验,得到不同应变率下各试样的应力-应变曲线和应变率-动态增长因子曲线。为了更直观地分析由粗骨料粒径差异引起的试验离散性问题,定义粒径系数λ为粗骨料最大粒径d与试件直径D之比,引入变异系数CV,运用数理统计方法量化离散性,得到λ与CV关系图,直观反映试验离散性与粗骨料粒径关系。分析表明:λ=0.34为混凝土材料异质性临界点;当粒径系数λ<0.34时,混凝土材料异质性影响不明显;当λ>0.34时,粗骨料的粒径过大已经影响到了混凝土的动态响应,材料异质性明显增强。该结论的得出对今后工程与试验中粗骨料粒径的选取有指导意义。

大型养殖工船氧锥设计与运行效果试验

保证养殖水体适宜的溶氧浓度对养殖鱼类的健康生长至关重要。为满足养殖工船超大封闭水体及高密度养殖的需氧要求,以氧锥作为研究对象,建立氧锥尺寸模型,根据双膜理论与菲克定律以及增氧机增氧能力试验标准,开展氧锥增氧性能试验。结果显示:氧锥出口的溶氧质量浓度能达到40 mg/L,超饱溶氧接近400%,实现超高溶氧饱和度;在氧气进气量为7.6 m^(3)/h,氧锥操作压力为0.07~0.25 MPa条件下,增氧能力受操作压力影响不明显,但是最佳进气量范围受操作压力影响显著。操作压力越大,当氧气进气量增大时,越不容易形成大气泡析出水面,从而保持较高的氧气利用率;在氧气进气量大于6.5 m^(3)/h,操作压力为0.07~0.25 MPa,每个养殖舱配置1个氧锥能满足养殖舱氧量需求。该研究为大型养殖工船增氧设备的工程设计及稳定高效运行提供了基础数据。

高黏土陆相页岩实验技术及其应用

页岩储层“四性”实验评价是页岩油勘探开发的重要基础及核心。现有实验技术存在页岩含油量检测不准、微纳米孔隙测量视域小及代表性差、流动性直接测量参数缺乏等难题,不适应古龙页岩油生产需求。通过研发实验装备、确定实验条件,建立基于保压密闭岩心“四性”实验技术及流程。结果表明:古龙高成熟和成熟页岩含油量测定较国标法可减少损失71%和50%,应用新建不同成熟度页岩含油量恢复模型,恢复了国标法现场录井页岩含油量数据;高成熟与低成熟阶段页岩中干酪根有机质、不同赋存状态油和水定量特征差别明显,受干酪根有机质向页岩油转化及演化程度的控制;页岩孔缝组合构成规模储集空间及流动网络通道,储集空间分为2大类7亚类12种类型,总孔隙度高于粉砂质岩、灰质岩、云质岩;确定页岩油上部、中部、下部油层组含油性与流动性特征,圆柱状页岩样品驱替油率为16%~43%,同一地层温度(100℃)不同驱替压力(10~50 MPa)下的超临界CO_(2)驱替使孔隙度增加4.51百分点、渗透率增加0.53×10^(-3)μm^(2)。研究成果为页岩油规模增储和效益上产提供了实验依据。

准噶尔盆地南缘中段深层—超深层超压成因机制及其与成藏的关系——以HT1气藏为例

近年来,准噶尔盆地南缘深层—超深层油气勘探不断取得突破,该地区深层—超深层普遍发育超压,明确超压成因机制及其与油气富集关系,对深层—超深层的油气勘探具有指导意义。利用DST实测压力资料分析了南缘深层—超深层压力分布特征,通过综合泥岩压实曲线、VES-VP交会图版、DEN-VP交会图版综合判识了HT1气藏复杂超压成因,并结合声发射实验及应力场模拟等技术方法,分析讨论了HT1气藏超压与油气成藏的关系。分析认为:(1)南缘深层—超深层除山前第一排冲断带外,普遍发育压力系数达2.0以上的极强超压。垂向上超压分布在吐谷鲁群厚层泥岩及其之下地层中,平面上强超压主要发育在南缘中段山前第二、三排构造带及西段四棵树凹陷内;(2)综合识别出HT1气藏发育欠压实成因及构造挤压成因超压,其中区域性厚层泥岩快速沉积造成欠压实超压产生,而喜马拉雅运动晚期天山隆起对南缘形成的N-S向强挤压应力是深层—超深层构造挤压超压形成的原因;(3)深层流体超压的形成,一方面促进了HT1气藏清水河组背斜圈闭的褶皱变形,形成油气优势汇聚部位,另一方面改变了呼西背斜周缘的流体动力场格局,使得气势梯度增加,增强了天然气运移动力,为油气在呼西背斜的富集提供了良好的动力条件。

粉煤灰高性能混凝土动态压缩性能试验研究

为研究冲击荷载下高性能混凝土抗压性能,利用分离式霍普金森压杆对C30、C40、C50强度等级的普通混凝土(NC)和高性能混凝土(HPC)进行了5种应变率下的动态压缩性能试验,并与各类试件的静态抗压强度、弹性模量进行对比分析,还采用LS-DYNA有限元软件对冲击压缩试验进行了模拟。结果表明HPC的静态抗压强度和弹性模量均明显优于NC,HPC更加密实,抵抗变形能力更强。随应变率增加,混凝土动态抗压强度提高,提高幅度越大其破坏程度更严重。NC和HPC的动态抗压强度、动态弹性模量均有明显的应变率效应。受粉煤灰和硅灰的影响,HPC的弹性模量增长因子随应变率的变化不大。模拟结果反映了HPC-50抵抗动态冲击压缩的能力优于NC-50,模拟的破坏规律与实际试验中的破坏规律具有一致性。

甲醇装置脱硫槽压差升高的原因分析及应对措施

甲醇装置采用乙烯装置裂解单元的低压甲烷为原料,原料中烯烃含量偏高的情况时有发生,影响甲醇装置的安全平稳运行。甲醇装置在脱硫槽更换了具有加氢能力的B脱硫剂后,出现了压差逐渐升高的情况,通过现场验证和实操摸索,并采用低温加氢工艺技措,有效解决了脱硫槽压差升高的瓶颈问题。

疏松砂岩稠油油田钻井液提速技术研究

渤海绥中36-1、旅大5-2油田属于特高孔、特高渗储层,经过二次调整开发地层压力体系复杂,钻井过程中要钻遇到多种复杂地层,存在地层压力、地层状态、岩性和地层分层深度等不确定等因素,制约了钻井时效。为了加快勘探开发进程,研究和开发了钻井液提速剂,降低了钻屑对钻具的吸附,改变岩石表面润湿性,提高钻井液润滑性能,从而提高钻井速度。提速剂在渤海油田A6井、A9井、A12井、A18、A22井得到了应用,从应用的效果来看,试用的5口井平均倒划眼率比原来降低了21.6%。

某区块注水井稳砂解堵技术研究应用

针对X油田某区块注水压力高、注水量达不到配注的问题,文章从油藏特征、地层油水性质、注水水质等因素出发,分析欠注原因。在此基础上,采取“解除堵塞、黏土防膨、稳砂固砂、降压增能”治理思路,开展疏松砂岩稳砂解堵工艺技术应用,为平衡注采关系提供了新的途径。

人造结石的静动态巴西劈裂试验研究

为探讨人造结石在不同条件下的力学性能,制备了不同配比(硬度、孔隙率、粉水比、蛋白含量)的牙科石膏试样(人造结石),对其开展准静态巴西劈裂试验,并利用φ40 mm分离式霍普金森压杆进行动态加载,结合高速相机、数字图像相关等测试方法观察试样在劈裂过程中的破坏过程以及应变场演化规律,获得应变时程曲线。试验结果表明:人造结石的准静态拉伸强度与硬度、粉水比成正比,与孔隙率成反比,而蛋白质含量对拉伸强度的影响不大,但会影响其韧脆性。在动态加载下,人造结石试样具有明显的应变率强化效应,拉伸强度动态增强因子与应变率对数之间呈线性增长关系。研究方法为人造结石的力学特性研究提供了一种有效的实验方法和分析手段。