Evaluation of excavation damaged zones(EDZs)in Horonobe Underground Research Laboratory(URL)

Excavation of underground caverns,such as mountain tunnels and energy-storage caverns,may cause the damages to the surrounding rock as a result of the stress redistribution.In this influenced zone,new cracks and discontinuities are created or propagate in the rock mass.Therefore,it is effective to measure and evaluate the acoustic emission(AE)events generated by the rocks,which is a small elastic vibration,and permeability change.The authors have developed a long-term measurement device that incorporates an optical AE(O-AE)sensor,an optical pore pressure sensor,and an optical temperature sensor in a single multi-optical measurement probe(MOP).Japan Atomic Energy Agency has been conducting R&D activities to enhance the reliability of high-level radioactive waste(HLW)deep geological disposal technology.In a high-level radioactive disposal project,one of the challenges is the development of methods for long-term monitoring of rock mass behavior.Therefore,in January 2014,the long-term measurements of the hydro-mechanical behavior of the rock mass were launched using the developed MOP in the vicinity of 350 m below the surface at the Horonobe Underground Research Center.The measurement results show that AEs occur frequently up to 1.5 m from the wall during excavation.In addition,hydraulic conductivity increased by 2e4 orders of magnitude.Elastoplastic analysis revealed that the hydraulic behavior of the rock mass affected the pore pressure fluctuations and caused micro-fractures.Based on this,a conceptual model is developed to represent the excavation damaged zone(EDZ),which contributes to the safe geological disposal of radioactive waste.

Distribution of soil aggregates and organic carbon in deep soil under long-term conservation tillage with residual retention in dryland

To ascertain the effects of long-term conservation tillage and residue retention on soil organic carbon(SOC) content and aggregate distribution in a deep soil(>20-cm depth) in a dryland environment,this paper analyzed the SOC and aggregate distribution in soil, and the aggregate-associated organic carbon(OC) and SOC physical fractions. Conservation tillage(reduced tillage with residue incorporated(RT) and no-tillage with residue mulch(NT)) significantly increased SOC sequestration and soil aggregation in deep soil compared with conventional tillage with residue removal(CT). Compared with CT, RT significantly increased the proportion of small macroaggregates by 23%–81% in the 10–80 cm layer, and the OC content in small macroaggregates by 1%–58% in the 0–80 cm layer. RT significantly increased(by 24%–90%) the OC content in mineral-SOC within small macroaggregates in the 0–60 cm layer, while there was a 23%–80% increase in the 0–40 cm layer with NT. These results indicated that:(1) conservation tillage treatments are beneficial for soil aggregation and SOC sequestration in a deep soil in a dryland environment; and(2)the SOC in mineral-associated OC plays important roles in soil aggregation and SOC sequestration. In conclusion, RT with NT is recommended as an agricultural management tool in dryland soils because of its role in improving soil aggregation and SOC sequestration.

Removal of biofilm is essential for long-term ventilation tuberetention

BACKGROUND Although long-term retention of a ventilation tube is required in many ear diseases,spontaneous removal of conventional ventilation tube is observed in patients within 3 to 12 mo.To address this issue,we aimed to determine a new method for long-term retention of the ventilation tube.AIM To explore the value of removing the biofilm for long-term retention of tympanostomy ventilation tubes.METHODS A case-control study design was used to evaluate the safety and effectiveness of long-term tube retention by directly removing the biofilm(via surgical exfoliation)in patients who underwent myringotomy with ventilation tube placement.The patients were randomly divided into two groups:Control group and treatment group.Patients in the treatment group underwent regular biofilm exfoliation surgery in the clinic,whereas those in the control group did not have their biofilm removed.Only conventional ventilation tubes were placed in this study.Outcome measures were tube position and patency.Tube retention time and any complications were documented.RESULTS Eight patients with biofilm removal and eight patients without biofilm removal as a control group were enrolled in the study.The tympanostomy tube retention time was significantly longer in the treatment group(43.5±26.4 mo)than in the control group(9.5±6.9 mo)(P=0.003).More tympanostomy tubes were found to be patent and in correct position in the treatment group during the follow-up intervals than in the control group(P=0.01).CONCLUSION Despite the use of short-term ventilation tubes,direct biofilm removal can be a well-tolerated and effective treatment for long-term tube retention of tympanostomy ventilation tubes in patients who underwent myringotomy.

Investigation on microscopic invasion characteristics and retention mechanism of fracturing fluid in fractured porous media

Reservoir damage caused by guar gum fracturing fluid and slick water seriously affects the subsequent oil and gas production. However, the invasion characteristics and retention mechanisms of fracturing fluids in the fracture-matrix zone are still unclear. In this work, a microscopic model reflecting the characteristics of the fracture-matrix zone was designed. Based on the microfluidic experimental method, the process of fracturing fluid invasion, flowback and retention in the fracture-matrix zone was investigated visually and characterized quantitatively. The factors and mechanisms affecting fracturing fluid retention in the fracture-matrix zone were analyzed and clarified. The results indicated that in the invasion process, the frontal swept range of slick water was larger than that of the guar gum fracturing fluid, and the oil displacement efficiency and damage rate were lower than those of the guar gum fracturing fluid under the same invasion pressure. With the increase in invasion pressure, the damage rate of slick water increased from 61.09% to 82.77%, and that of the guar gum fracturing fluid decreased from 93.45% to83.36%. Before subsequent oil production, the invaded fracturing fluid was mainly concentrated in the medium-high permeability area of the fracture-matrix zone. The main resistance of slick water was capillary force, while that of the guar fracturing fluid was mainly viscous resistance. The fracturing fluid retention was most serious in the low permeability region and the region near the end of the fracture.The experimental and numerical simulation results showed that increasing the production pressure difference could improve the velocity field distribution of the fracture-matrix zone, increase the flowback swept range and finally reduce the retention rate of the fracture fluid. The retention mechanisms of slick water in the fracture-matrix zone include emulsion retention and flow field retention, while those of the guar gum fracturing fluid include viscous retention and flow field retention. Emulsion retention is caused by capillary force and flow interception effect. Viscous retention is caused by the viscous resistance of polymer, while flow-field retention is caused by uneven distribution of flowback velocity.

Drilling Operation and Formation Damage

Transport of particle suspensions in oil reservoirs is an essential phenomenon in many oil industry processes. Solid and liquid particles dispersed in the drilling fluid (mud) are trapped by the rock (porous medium) and permeability decline takes place during drilling fluid invasion into reservoir resulting in formation damage. The formation damage due to mud filtration is explained by erosion of external filter cake. Nevertheless, the stabilization is observed in core floods, which demonstrates internal erosion. A new mathematical model for detachment of particles is based on mechanical equilibrium of a particle positioned on the internal cake or matrix surface in the pore space. In the current work the analytical solution obtained to mud filtration with one particle capture mechanism with damage stabilization. The particle torque equilibrium is determined by the dimensionless ratio between the drag and normal forces acting on the particle. The maximum retention function of the dimensionless ratio closes system of governing equations for colloid transport through porous medium.

Dynamic Characteristics of a Damaged Nine-story Building during the 2011 off the Pacific Coast Tohoku Earthquake

This paper describes the dynamic characteristics of a damaged nine story building in Sendal during the 2011 Tohoku Earthquake. Dynamic hysteresis characteristic is investigated. The system identification using the extended Kalman filter determined the amplitude dependency of natural frequency and damping factor, which are consistent with damage feature. Occurrence of partial uplifting in the transverse direction is suggested by the induced higher harmonics based on the wavelet analysis. Historical change of the amplitude dependent dynamic characteristics is also discussed based on the long-term monitoring data from microtremor level to strong motion level.

果园作业平台车架耐久性研究

针对农用机械作业工况复杂、受多种外力、对结构件寿命影响较大等问题,以果园作业平台车架为研究对象,编制车架加速载荷谱,分析车架耐久性。采用有限元分析方法,对车架进行力学分析并选取关键载荷测点,建立果园作业平台多体动力学模型采集相应测点载荷谱,利用伪损伤保留编辑法获取不同伪损伤保留量的加速载荷谱,从压缩时间效率、伪损伤域、功率谱密度、穿级/雨流计数和统计值参数等方面对比,分析伪损伤保留量对加速载荷谱质量的影响。通过车架耐久性仿真对比不同编辑方案对耐久性分析精度和效率的影响。对比结果表明,伪损伤保留量不低于90%才能保证加速载荷谱的质量。仿真结果表明,车架最小寿命历程大约为65000 km,根据果园作业平台使用条件和用户使用情况调查,了解果园作业平台每年大约行驶8100 km,使用年限为8年,该车架满足要求。且伪损伤保留量为95%时为最佳编制方案,加速载荷谱时间压缩量为55%,车架耐久性仿真分析误差能控制在5%内且仿真效率提高391%,本文为提高农用机械部件耐久性载荷的编辑质量提供参考。

基于外寒内饮探讨咳嗽发热性外感疾病传变诊治规律

咳嗽发热是疾病过程,其症状、病机并非一成不变,而是逐步发展变化,初期邪气进犯太阳,外寒里饮偏重,用药干预后疾病痊愈或转归传变,入里化热与饮相结或者转入少阴,阳虚水泛冲逆。针对由外寒内饮病机引起的咳嗽发热性外感病,其治疗及转归在于寒之多少,饮之多寡以及是否化热损及正气。风寒侵袭太阳,表寒束表则予麻黄汤或甘草麻黄汤;寒束饮停则用小青龙汤;若寒饮冲逆较重则用射干麻黄汤;风寒束表、郁久化热,其证轻者用越婢汤或麻杏石甘汤,其证重者则以小青龙加石膏汤或厚朴麻黄汤治疗;若水饮郁热伤及正气则以《古今录验》续命汤及泽漆汤治疗。若风寒邪气侵犯太阳与少阴,两感相传,则以大青龙汤加附子、小青龙汤加附子治疗;若阳气虚损,表寒不重,里饮弥散则以麻黄附子细辛汤、麻黄附子甘草汤、桂枝去芍药加麻黄附子细辛汤加减治疗;外感病末期,阳气虚损,水湿泛滥,冲逆射肺则予桂苓五味甘草汤、苓甘五味姜辛汤、苓甘五味姜辛夏杏汤等方治疗,若阳虚水饮上泛严重,则用真武汤加干姜、细辛、五味子等治疗。

A review of surface damage/microstructures and their effects on hydrogen/helium retention in tungsten

The change in surface damage/microstructures and its effects on the hydrogen(H)isotope/helium(He)dynamic behavior are the key factors for investigating issues of tungsten(W)-based plasma-facing materials(PFMs)in fusion such as surface erosion,H/He retention and tritium(T)inventory.Complex surface damage/microstructures are introduced in W by high-temperature plasma irradiation and new material design,typically including pre-damage and multi-ion co-deposition induced structures,solute elements and related composites,native defects like dislocations and interfaces,and nanostructures.Systematic experimental and theoretical researches were performed on H isotope/He retention in complex W-based materials in the past decades.In this review,we aim to provide an overview of typical surface damage/microstructures and their effects on H/He retention in W,both in the experiment and multiscale modeling.The distribution/state,dynamics evolution,and interaction with defects/microstructures of H/He are generally summarized at different scales.Finally,the current difficulties,challenges and future directions are also discussed about H/He retention in complex W-based PFMs.

热解法回收T300J碳纤维强度保留率影响因素研究

以T300J碳纤维为增强体,E44环氧树脂为基体,三乙烯四胺为固化剂,制得T300J/E44碳纤维复合材料,并采用高温热解法回收T300J/E44复合材料中的T300J碳纤维,探索了不同的热解温度、热解保温时间、热解气氛,以及复合材料的损伤程度对回收的碳纤维的力学性能的影响。结果表明:在氮气保护(50 mL/min),热解温度为450℃,热解保温时间为30 min的高温解热工艺条件下,回收的碳纤维的表面良好,强度保留率可以达到96%;T300J/E44复合材料经预拉伸处理,纤维未拉断时,再热解回收获得的碳纤维的强度保留率仍可达到89%。

Long-Term Cumulative Damage Model of Historical Timber Member under Varying Hygrothermal Environment

A long-term damage cumulative model for the duration of load effect of structural timber is proposed in this paper, which is economical in analysis as well as involving long-term hygrothermal effect. Based on the Miner linear damage cumulative theory, the cumulative damage model is applied to analyze the annual hygrothermal, daily cyclic thermal and daily cyclic relative humidity＇s effect on load-duration behavior and to calculate the sum of damage in one year. The results indicate that the annual and daily hygrothermal effect should be taken into consideration when calculating the damage accumulation, in which the influence levels from large to small are annual hygrothermal, daily relative humidity and daily thermal effect, Considering both annual and daily hygrothermal variations as external loads the long-term model is determined. Its application to service-life prediction of a historic timber structure verifies the feasibility and high-efficiency of the proposed approach.

Knowledge arising from long-term research of variable retention harvesting in Tierra del Fuego: where do we go from here?

Nothofagus pumilio forests in Tierra del Fuego are the southernmost forests in the world,where extreme climate conditions represent a challenge to attain sustainable forest management.Retention forestry was proposed as an alternative to increase the species conservation in managed stands.Here,we synthetized results related to the implementation of a variable retention harvesting based on a combination of aggregate patches and dispersed retention during the last 18 years comparing with other silviculture proposals(e.g.,shelterwood cuts)and control treatments(primary unmanaged forests).We summarized the results for(i)sawmill operations,(ii)timber yield,(iii)overstory stability,(iv)forest structure,(v)microclimate and natural cycles,(vi)natural regeneration dynamics(flowering,seeding,foraging,recruitment,growth,and mortality),and(vii)biodiversity(mammals,understory plants,mistletoes,birds,arthropods,mosses,lichens,and fungi).In general,aggregate patches maintained forest structure and micro-environmental variables,and slightly increased biodiversity and forest reproduction variables compared to unmanaged primary forests.On the contrary,dispersed retention decreased forest structure variables and greatly increased biodiversity(richness and abundance)when it was compared to unmanaged primary forests.Ecological conditions are influenced by variable retention harvesting,but direction and magnitude of the effect depend and differ according to retention types.Besides this,biodiversity taxa greatly differed among groups depending on retention types.In general,the species assemblages in aggregate patches were similar to those found in primary unmanaged forests,while they were significantly modified in the dispersed retention.This occurred due to(i)local extinction of some original species,(ii)the introduction of native species from the surrounding environments,or(iii)the invasion of exotic species.This silvicultural method has been a useful tool to conserve biodiversity and ecosystem functions,approaching to the balance between economy,ecology,and social requirements in the managed areas.

《伤寒杂病论》心下诸症浅析

心下是人体的运化中枢,脾胃为后天之本,百病之源,全身各脏腑经络之气的升降沉浮均围绕中土脾胃运转,机体任何一部位产生的病理变化均可能影响到心下。心下诸症变化多端,主要包括悸、满、濡、坚、硬、痞、闷、急、痛、呕、结等,病证本质是水停心下、胃家实、水结于胸腹、胃有邪热、邪留半表半里、胃中虚、气机失调冲逆、邪气结在胸中、妇人产后外感等,治疗上以利尿祛水解表、攻下祛实、攻实散水结、祛热下火除烦、补中和胃祛邪为原则,采用小青龙等解表散饮、承气汤等攻实泄下、陷胸汤等泄热逐水、泻心汤等清泄邪热、柴胡汤等和解少阳、五苓散等健脾利水。但处方用药不可单一而概括之,需要因时因人因地制宜,也需抓主症明病机,辨证施治。

低渗透天然气气层损害机理及其预防

低渗气藏通常具有束缚水饱和度高、毛细管压力高、地表面积大等特点 ,使得低渗透气层在钻井、完井和开发过程中引起的损害更具特殊性。文章研究了低渗透气藏在气层打开后主要产生的损害特点和损害机理 ,并对预防各种损害的方法进行了探讨。研究结果表明 ,液相滞留、应力敏感性、水敏性和反向自吸效应损害是气层损害的主要特点。在预防和治理气层损害问题时 ,应综合考虑 ,系统运筹。

汽车零部件疲劳分析载荷谱加速编辑法研究

以某试验场实车采集的轮心六分力信号和关键点监测信号为基础数据,分别采用伪损伤保留法、损伤保留法和峰谷值抽取法对实测信号加速编辑;从时间压缩比例、功率谱密度、统计参数、穿级计数和雨流计数等5个方面对加速谱进行了讨论分析;从疲劳仿真角度进一步探讨了不同加速编辑法分析零部件疲劳问题求解结果精度的差别,并对加速谱效率进行了评估。研究结果表明,3种加速编辑法分析得出的转向节疲劳寿命的相对误差差距较小,均在3.72%以内,但疲劳仿真效率较原始载荷谱有大幅提高。综合考虑多方面分析角度,损伤保留法可准确删除原始信号中的无损伤段,获取时间最短加速谱的同时功率谱密度吻合程度最好,分析零部件疲劳问题效率及分析结果的精度最高,损伤保留法相对伪损伤保留法和峰谷值抽取法更具优势。

中药保留灌肠预防宫颈癌患者放射性直肠损伤的效果

目的探讨中药保留灌肠预防宫颈癌患者放射治疗所致放射性直肠损伤的效果。方法按随机数字表法将2009年11月至2011年6月在南通市肿瘤医院行放射治疗的100例宫颈癌患者分为对照组及中药预防组各50例,对照组采用放射治疗常规护理,中药预防组除常规护理外,在后装放射治疗后用自制中药80～100ml行保留灌肠,1次/d,连续3d,直至后装治疗结束。观察后装放射治疗5次3d内、治疗结束后3个月、6个月两组患者发生放射性直肠损伤的情况。结果中药预防组后装放射治疗5次3d内1、2级直肠损伤发生率均低于对照组(均P<0.05);放射治疗结束后3个月、6个月,中药预防组保留灌肠直肠损伤的发生率均低于对照组,差异均有统计学意义(均P<0.05)。结论宫颈癌患者放射治疗时给予中药保留灌肠可预防放射性直肠损伤。

河141区块注入水水质对储层的伤害

河141区块属于低孔低渗油藏,因地层能量低,须采用注水方式开发。该文研究了不同注入水水质对该块沙一段储层的损害规律及损害程度,并确定了适合其储层注入水水质推荐指标,提出了水质处理建议。

页岩储层压裂裂缝表面软化规律实验研究

针对中国典型的页岩储层开展自发渗吸对比实验,并结合页岩表面硬度测试,分析了页岩自发渗吸能力与裂缝表面软化程度的关系,研究不同水化阶段页岩裂缝表面力学性质变化规律。实验结果表明:吸水最初的1 d是裂缝表面发生硬度伤害的主要阶段,占总伤害的50%~75%,随后硬度伤害持续、缓慢增加;渗吸速率和单位体积岩石吸水量与页岩裂缝表面软化程度并没有直接关系,但吸水孔隙体积倍数、有效驱动力系数与页岩裂缝面软化程度有明显的正相关性,其值越高水岩作用越剧烈。

低渗天然气气层损害机理探究

结合低渗气藏的地质特征 ,并通过气层潜在性损害因素的分析对比 ,深入调查研究了低渗气藏在气层打开后产生损害的特点和损害机理 ,并对损害程度定量化进行了探讨 .研究结果表明 :低渗气藏除具有油层相类似的损害特征外 ,液相滞留、压力敏感性和含水饱和度程度是气层损害的突出特点 .这些损害特征的综合作用 。

中药保留灌肠联合艾灸治疗放射性肠炎63例临床观察

目的观察中药保留灌肠联合艾灸治疗放射性肠炎(RE)的临床疗效。方法将123例RE患者随机分为2组。治疗组63例予中药保留灌肠联合艾灸治疗,对照组60例予常规西药治疗。2组治疗1个月后观察疗效,比较治疗前后中医症状积分变化。结果治疗组总有效率92.1%,对照组总有效率76.7%,2组总有效率比较差异有统计学意义(P<0.05),治疗组疗效优于对照组。治疗组治疗后黏液脓血便、腹泻、腹痛、里急后重积分均低于本组治疗前及对照组治疗后(P<0.01);对照组治疗后腹泻、腹痛积分均低于本组治疗前(P<0.01,P<0.05)。结论中药保留灌肠联合艾灸治疗RE,疗效较好,安全、副作用少,患者依从性较好,为RE的有效治疗方案之一。