Structures and Low Temperature Magnetic Anomalies of High Pressure RE_2CuO_4

A series of oxygen-doped RE_2CuO_4 (RE=Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm) was synthesized using high-pressure/oxygen-doped technique. The structures and low temperature magnetic properties were investigated. The XRD patterns indicate that the structures of high oxygen pressure RE_2CuO_4 (only for RE=Sm, Eu) samples are pure T′ phase, but when RE= Gd, Tb, Dy, Ho, Er, Tm, the structures turn to disorder. The magnetic anomalies that occurred at T^30 K are observed in high oxygen pressure RE_2CuO_4. It is found that the transition temperatures of weak ferromagnetic anomalies are nearly independent of the rare-earth components. Thus, the O-doping plays an important role in anomalous magnetic properties of RE_2CuO_(4+δ). The magnetic anomalies in RE_2CuO_4 are considered to be due to ferromagnetic clusters formed in the Cu-O plane after the oxygen doping.

Advanced high-pressure transport measurement system integrated with low temperature and magnetic field

We briefly introduce a new high-pressure transport measurement system integrated with low temperature and magnetic field that is being established as one of the user experimental stations of the Synergetic Extreme Condition User Facilities in the Huairou District of Beijing, China. To demonstrate the capabilities of the system for condensed matter research, the emergence of some pressure-induced phenomena and physics related to superconductivity found previously is also introduced, and then a perspective for such an advanced high-pressure system is presented.

Pressure-Induced Metallization and Electrical Phase Diagram for Polycrystalline CaB_6 under High Pressure and Low Temperature

The electrical properties of polycrystaltine CaB6 are revealed by in-situ resistance measurements under high pressure and low temperature. Due to the existence of grain boundaries, polycrystalline CaB6 behaves with semiconducting transport properties, which is different from the semimetallic CaB6 single crystals. The temperaturedependent resistance measurement results show that before the structural phase transition at 12.3 GPa the high pressure first induces the metallization at 6.5 GPa for CAB6. Moreover, the phase diagram for CaB6 is drawn based on the investigated electric conducting properties and at least three different conducting phases are found even at moderate high pressure and low temperature, indicating that the electric nature of CaB6 is very sensitive to the environment.

Research on the Low-carbon-high-value Agriculture Technology in the Comprehensive Improvement of Intra-county Environment Pollution——Taking the Development of Cultivation and Breeding Industry in the Ecological Cyclic Agricultural Garden in Shaoshan Irri

The comprehensive improvement strategy of intra-county environment pollution in the city and countryside was searched.By the research method which combined the microscopic view,the macroscopic view with the dynamic perspective,the seriousness of rural water quality,soil and atmospheric pollution in Xiangxiang,Xiangtan and the surrounding areas in Shaoshan irrigated area was revealed.The control measure which was 'four-dimensional pollution in the city and countryside'—— low-carbon-high-value agriculture and the technology innovation was proposed.The low-carbon-high-value technology innovation industrialization demonstration in three parts which included the pre-production,mid-production and post-production deep-processing of cultivation and breeding industry in the ecological cyclic agricultural garden in Shaoshan irrigated area was the driving force.We tried to propel the low-carbon ecological cultivation and breeding industry which included the paddy rice,grass,tree,medicinal herbs and pig,cow,chick,duck,fish.We wanted to relieve the structural unbalance of previous cultivation and breeding industry,'cheap grain hurting the farmers' and the short-leg problem of social-economic-ecological benefit.The results showed that the low-carbon-high-value agricultural system was a poly-generation technology system which promoted the multi-level and grading utilization,saved the energy,reduced the consumption and cleaned the production based on the ecology.

Practice and Cognition of Midway VSP in High Temperature and High Pressure Field of South China Sea

Ying-Qiong Basin is a typical high-temperature and overpressure basin, which is the main battlefield of oil and gas exploration in South China Sea and has made great breakthroughs in recent years. During drilling process in high pressure, the relationship between the deep and the pressure is directly related to the drilling safety and costs. In order to improve prediction accuracy, the VSP operation is carried out through the midway, and three points have been obtained: 1) The VSP has a higher accuracy of the interface depth in certain depth range of the drill bit. 2) When the low-frequency trend prediction is accurate before the drill bit, interval velocity of the VSP inversion is consistent with the formation velocity. 3) The VSP pressure forecast is based on the inversion layer velocity and under-compaction pressure. If the velocity prediction is not accurate, the pressure forecast must be erroneous. If the pressure has other sources, the formation pressure is not accurate even if the inversion velocity is accurate. The application scope and exploration effect of midway VSP operation are summarized and applied to Ledong 10-1 block in Yinggehai basin, which realize the breakthrough in the field of high temperature overpressure and provide the basis for other similar exploration areas to do VSP operation.

Development and application of multi-field coupled high-pressure triaxial apparatus for soil

The increasing severity of ground subsidence,ground fissure and other disasters caused by the excessive exploitation of deep underground resources has highlighted the pressing need for effective management.A significant contributing factor to the challenges faced is the inadequacy of existing soil mechanics experimental instruments in providing effective indicators,creating a bottleneck in comprehensively understanding the mechanisms of land subsidence.It is urgent to develop a multi-field and multi-functional soil mechanics experimental system to address this issue.Based soil mechanics theories,the existing manufacturing capabilities of triaxial apparatus and the practical demands of the test system,a set of multi-field coupled high-pressure triaxial system is developed tailored for testing deep soils(at depths of approximately 3000 m)and soft rock.This system incorporates specialized design elements such as high-pressure chamber and horizontal deformation testing devices.In addition to the conventional triaxial tester functions,its distinctive feature encompass a horizontal deformation tracking measuring device,a water release testing device and temperature control device for the sample.This ensemble facilitates testing of horizontal and vertical deformation water release and other parameters of samples under a specified stress conditions,at constant or varying temperature ranging from-40℃–90℃.The accuracy of the tested parameters meets the requirements of relevant current specifications.The test system not only provides scientifically robust data for revealing the deformation and failure mechanism of soil subjected to extreme temperature,but also offers critical data support for major engineering projects,deep exploration and mitigation efforts related to soil deformation-induced disaster.

Interannual and Interdecadal Variability of East Asian Acas and Their Impact on Temperature of China in Winter Season for the Last Century

The interannual and interdecadal varinbility of the Siberian High (SH) and the Aleutian Low (AL) from aspects of strength and location for the past one hundred years as well as their possible relations with temperature changes over China's Mainland are investigated. The data sets used are the historical sea level pressure for 1871-1995 and surface air temperature (SAT) over China in the last 100 years. The results show that the SAT in different regions over China, central strength of the SH and the AL, the south-reaching latitude of the 1030 hPa contour of the SH and the pressure gradient between the SH and the AL experienced two obvious changes during this period. One occurred in the 1920s, with a more prominent one in the 1980s. These variations are closely linked with the change of winter temperature over China in the interdecadal timescale. In the last 50 years, there is a remarkable interannual correlation between the strength of Active Centers of Atmosphere (Acas) and the winter temperature of northern and eastern regions in China. The abrupt change of Acas in the 1980s is consistent with the rising of the SAT in China. Since the late 1980s, the atmospheric circulation is experiencing a remarkable modulation, which may cause the interdecadal transition of warming trend.

Corrosion Rate of Hydrogenation to C110 Casing in High H_2S Environment

The corrosion behavior of C110 bushing at high temperature and high pressure with a high H2S / CO2 was studied, and a basis for the materials selection of sour gas well bushing was provided in H2S, CO2 and saline coexisting environment. Under acidic condiction, hydrogen atoms greatly entered into the material and caused the material properties changed. Weight loss method was used to study the corrosion rate of hydrogen charging samples and original untreated samples in simulated oil field environment. PAR2273 electrochemical workstation was used to examine the electrochemical performance of samples untreated, hydrogen charging after reacting in autoclave. The corrosion product film was observed through SEM. The experimental results show that sample with hydrogen charging has a much more obvious partial corrosion and pitting corrosion than the untreated blank sample even the downhole corrosion speed of bushing is increased after being used for a period of time. Polarization curve shows the corrosion tendency is the same between sample with or without hydrogen charging and corrosion tendency is reduced by corrosion product film. A layer of dense product film formed on the surface of samples provides a certain protective effect to the matrix, but cracked holes which will accelerate partial corrosion of the sample were also observed.

Resistivity response to the porosity and permeability of low rank coal

Laojunmiao coal samples from the eastern Junggar basin were studied to understand the relationship between coal resistivity and the physical parameters of coal reservoirs under high temperatures and pressures.Specifically,we analysed the relationship of coal resistivity to porosity and permeability via heating and pressurization experiments.The results indicated that coal resistivity decreases exponentially with increasing pressure.Increasing the temperature decreases the resistivity.The sensitivity of coal resistivity to the confining pressure is worse when the temperature is higher.The resistivity of dry coal samples was linearly related to φ~m.Increasing the temperature decreased the cementation exponent(m).Increasing the confining pressure exponentially decreases the porosity.Decreasing the pressure increases the resistivity and porosity for a constant temperature.Increasing the temperature yields a quadratic relationship between the resistivity and permeability for a constant confining pressure.Based on the Archie formula,we obtained the coupling relationship between coal resistivity and permeability for Laojunmiao coal samples at different temperatures and confining pressures.

Partial Melting and Its Implications for Understanding the Seismic Velocity Structure within the Southern Tibetan Crust

In order to constrain the crustal wave velocity structure in the southernTibetan crust and provide insight into the contribution of crustal composition, geothermal gradientand partial melting to the velocity structure, which is characterized by low average crustalvelocities and widespread presence of low-velocity zone(s), the authors model the crustal velocityand density as functions of depth corresponding to various heat flow values in light of velocitymeasurements at high temperature and high pressure. The modeled velocity and density are regarded ascomparison standards. The comparison of the standards with seismic observations in southern Tibetimplies that the predominantly felsic composition at high heat flow cannot explain the observedvelocity structure there. Hence, the authors are in favor of attributing low average crustalvelocities and low-velocity zone(s) observed in southern Tibet mainly to partial melting. Modelingbased on the experimental results suggests that a melting percentage of 7-12 could account for thelow-velocity zone(s).

基于压力衰减法的低渗透储层高温敏感性评价实验

低渗透油气藏在钻完井过程中易受到损害且难以解除,而利用传统的稳态驱替法评价低渗透储层损害存在适用性差及实验效率低等技术局限。为此,基于压力脉冲衰减法基本原理,分析了上游压力衰减规律及其与岩心渗透率的关系,以岩心损害前后压力脉冲衰减时间为评价指标,建立了适用于低渗透储层损害评价的实验设备与方法,并利用渤海湾盆地渤中凹陷深部低渗透砂岩岩心,开展了室温和150℃高温条件下的敏感性实验。研究结果表明:(1)当实验条件一定时,压力衰减时间仅与岩心的渗透率有关,压力脉冲衰减法可在无需计算渗透率的情况下对低渗透岩心的损害程度进行评价;(2)实验设备组成简单且操作便捷,避免了复杂的渗透率计算及其带来的误差,实验所需时间远低于常规的稳态法且可重复性良好,在低渗透气藏、特低渗透及超低渗透油藏具有很好的适用性;(3)高温环境明显加剧了储层的敏感性损害,深部高温储层损害特征及技术对策研究需要充分考虑高温的影响。结论认为,该认识解决了传统低渗透储层敏感性评价方法适用性差的难题,为高温低渗透储层保护技术对策研究提供了实验方法支撑和理论依据。

高海拔地区铁路隧道施工期围岩热流密度数值模拟

冷负荷预测是隧道施工的重要任务,目前传统隧道冷负荷预测方法无法满足高海拔铁路隧道施工环境。为高海拔铁路隧道的冷负荷预测提供准确方法,建立一个热湿耦合多孔介质模型,考虑围岩孔隙率和低压环境对隧道围岩热流密度的影响。建立高海拔铁路隧道围岩热流密度预测模型,分析渗流水和衬砌的存在对围岩热流密度的影响,对比不同环境参数对围岩热流密度的影响。结果表明,隧道的冷负荷取决于围岩的热流密度。预测模型可以准确计算隧道围岩热流密度,其均方根误差为0.573 W/m^(2)。围岩渗流水和衬砌对隧道热湿环境产生显著影响。压力对围岩热流密度的影响最小。围岩温度每升高10℃时,围岩初始热流密度增加了58.74 W/m^(2)。此外,每当隧道目标温度增加4℃或孔隙率增加0.1,分别导致围岩初始热流密度减少了23.5、0.14 W/m^(2)。研究结果可以为实际高海拔铁路隧道工程的冷负荷预测提供新的理论方法和参考依据。

高低温对碳纤维/环氧树脂复合材料高压气瓶的性能影响

为了获得T1000碳纤维/环氧树脂复合材料高压气瓶环境适应能力,有效地掌握气瓶高低温适应性固有规律,以容积50 L、工作压力30 MPa的复合材料气瓶(钛为内衬、碳纤维/环氧树脂为复合层)为研究对象,首先介绍了高低温循环下带压气瓶(在-40~80℃范围内成功通过热真空、热循环验证,具备高压承载能力)的热真空、热循环试验数据,然后采用与气瓶相同复合材料的拉伸试样(缠绕角分别为0°和90°),通过高低温极限摸底试验获得了复合材料经历不同梯度高低温后的拉伸性能数据,通过数据比对分析获得了高低温影响拉伸强度衰减的规律。同时,提出了一种高低温极限摸底试验的可靠性评估方法。结果表明,在-50~100℃范围内,试样拉伸强度及断裂伸长率变化较小;当温度高于100℃时,纤维和树脂的性能发生衰减,导致拉伸强度明显降低;当温度低于-50℃时,树脂的性能发生衰减,纤维受到的影响较小。试样高低温极限摸底试验的可靠度大于0.999,表明采用拉伸试样高低温拉伸强度数据的替代方式具有较高的等效性。

深层地热能丛式多分支U型井采热技术及传热算法

深层地热能是一种分布广、资源量大具有发展前景的可再生新能源,当前的主要开采方法有增强型地热系统(EGS)、环绕式井筒换热系统(AGS)、断层带流体循环开采和同轴套管开采法,但存在采热功率不稳定、地震风险高和采热效率低等难题。针对当前深层地热开采技术面临的瓶颈问题,本文以开采过程只有能量交换而没有物质交换为原则,以深层干热岩地热规模化可持续稳定开发为目标,提出了深层地热能丛式多分支U型井采热方法(UMW-DGS)及关键技术,在此基础上建立了井筒轴对称热传导模型,以青海共和盆地恰卜恰深部干热岩储层为背景,提出了高温高压岩石热导率测试新方法,计算了在定井径条件下井周温度场和采热功率的时空演化规律,分析了温度差、热导率和井径等3个敏感因素对采热功率的影响。此外,针对UMW-DGS定解问题,研发了基于有限体积法(FVM)的三维热流固耦合数值算法,研究了UMW-DGS单水平井段换热效率和在不同泵注量条件下温度场时空演化。通过分析不同流量的有效换热量、换热时长和功率发现:泵注流量的增加会导致有效换热能量和有效换热时长的降低,并且使有效换热功率先增加后减少。研究结果表明,深层地热能开发需要在平衡换热温度和功率的条件下设计注入排量,从而得到最优的换热效果。

煤的温压吸附试验方法与等温吸附试验方法比较研究

为了研究煤的温压吸附试验方法在煤层气吸附方面的可行性,本文对煤的温压吸附试验方法与煤的高压等温吸附试验方法进行了比较研究。分别取12个、10个、8个、和6个温压吸附试验点作为四组不同温度和相应不同压力作为温压吸附试验点,记为V_(实测)。使用温度-压力-吸附方程(Temperature-Pressure-AbsobingEquation(TPAE)),将方程转化为二元一次方程后进行线性回归计算其余三个参数,将所得的四个参数记为V_(计算)。通过计算_(实测)与V_(计算)之间的平均相对误差和标准偏差以衡量温压吸附试验方法的可行性。

无引线封装的SOI高温压力传感器设计

为解决高温环境下的压力监测问题,对无引线封装压力传感器进行了研究。首先,对高温压力敏感芯片进行设计,使用绝缘体上硅(SOI)材料提高了敏感芯片的高温稳定性;使用Ti⁃Pt⁃Au复合电极提高了金属电极与硅引线之间欧姆接触的可靠性。使用导电银浆实现敏感芯片电极和基座引脚的电连接,使用玻璃浆料实现芯片与基座的耐高温封装。利用同步热分析仪对导电银浆和玻璃浆料进行了DSC⁃TG同步分析,并借助扫描电镜对其微观形貌进行对比观察,确定其最佳烧结工艺曲线。对封装后的压力传感器进行测试,结果表明:传感器在25~300℃范围内具备优异的性能,综合精度可达0.25%FS。

高低温交替海洋环境下NiCoCrAlY/AlSiY复合涂层的腐蚀失效机理

为探究NiCoCrAlY/AlSiY复合涂层在高低温交替海洋环境中的腐蚀损伤和退化机理,通过设计高-低温氧化交替和高温氧化-酸性盐雾交替试验,对NiCoCrAlY/AlSiY复合涂层腐蚀损伤开展研究。试验结果表明,经750℃高-低温交替氧化50次循环后,涂层在氧化试验中发生氧化侵蚀,但表面结构完整性并未受到破坏。试验结束后合金质量仅增加了3.87 mg/cm^(2),表明涂层有效抑制了氧气向内部发生扩散,避免了基体遭受氧化侵蚀。在50次高温氧化-酸性盐雾交替循环过程中,NiCoCrAlY/AlSiY复合涂层发生了严重的腐蚀降解,试验结束后合金质量高达13.52 mg/cm^(2)。氧化层结构因长期的盐雾侵蚀导致表面松动,萌生腐蚀孔洞甚至发生脱落。随着高温氧化-酸性盐雾交替循环次数的增加,引起涂层损伤的临界反应由氧化侵蚀转变为热腐蚀。混合盐共晶反应生成的氯气作为催化载体,加速了氧化产物的生长,证明NiCoCrAlY/AlSiY复合涂层在高温氧化-酸性盐雾交替环境下的抗腐蚀性能较弱。

低压静电场协同低温高湿解冻对牛肉嫩度和持水性的影响

为探究低压静电场协同低温高湿解冻对牛肉嫩度和持水性的影响,本研究以牛背最长肌为试验材料,分析了低压静电场解冻(电压2500 V,温度4℃,相对湿度50%)、低温高湿解冻(温度4℃,相对湿度98%)、低压静电场协同低温高湿解冻(电压2500 V,温度4℃,相对湿度98%)与低温解冻(温度4℃,相对湿度50%)四种解冻方式对冷冻牛肉剪切力、质构、水分分布、水分含量、持水性、感官评价的影响。结果表明:低压静电场协同低温高湿解冻的解冻时间最短(804 min),其中解冻损失(2.06%)、蒸煮损失(26.09%)与离心损失(15.00%)显著低于其余三种解冻方式(P<0.05),垂直肌纤维剪切力值(95.46 N)和平行肌纤维剪切力值(41.69 N)最低,自由水含量最低,水分迁移较少,水分含量(68.31%)最高,嫩度品质最优,该解冻方式样品的组织状态、气味、弹性及色泽均最优(总体可接受度最高);综上,低压静电场协同低温高湿解冻加快了牛肉解冻速率、减少了汁液流失,改善了牛肉持水性和嫩度,品质最佳。本研究结果将为低压静电场协同低温高湿解冻技术在冷冻牛肉解冻的产业应用提供理论依据。

龙凤山气田易漏井不承压泡沫水泥浆固井技术

中国石化龙凤山地区面临井温高、地层承压能力低、周期长、承压堵漏成本高等系列固井技术难题,导致固井周期长、费用高且固井质量无法保证等。为解决上述问题,在分析工区现有固井工艺的基础上,提出了不承压泡沫水泥浆固井设计思路,形成了龙凤山地区不承压泡沫水泥浆固井工艺,建立了泡沫水泥浆井内密度及恒密度注气固井计算方法与固井工艺;优选了发泡剂、降失水剂和早强剂等泡沫水泥浆关键外加剂,开发了新型低密度泡沫水泥浆体系,耐温性可达到120℃以上,泡沫半衰期大于420 s、水泥浆30 min失水32 mL、48 h强度13.3 MPa,各项性能均可满足中石化龙凤山气田高温、深井固井要求;形成了适合于龙凤山气田泡沫水泥浆固井技术。现场11口井应用表明,该项技术能够有效提高固井质量,避免了固井前承压、分级或尾管固井作业,平均节约承压堵漏周期7 d以上,经济效益显著。龙凤山气田泡沫水泥浆固井技术对解决中国石化其他工区深井、高温井固井漏失、承压堵漏等难题具有重要借鉴意义和可持续性推广价值。

空间可展开天线铰链热变形分析与试验验证

在轨热变形是影响空间可展开天线精度的关键因素之一,因此,空间可展开天线结构的在轨热变形分析具有十分重要的意义。随着空间探测任务要求的不断提高,铰链热变形对空间可展开天线指向精度的影响已经不可忽略。以某空间可展开天线的根部铰链和臂间铰链为研究对象,建立其有限元模型,计算铰链主弯方向和侧弯方向在温度每变化10℃时相对角度的变化。基于高低温箱和电子经纬仪构建铰链精度测试系统,开展铰链热变形试验。试验结果表明:根部铰链和臂间铰链在主弯方向和侧弯方向呈现纯结构热变形特性,仿真结果与试验分析结果基本一致,验证有限元模型和试验分析方法的正确性。根据铰链主弯和侧弯方向角度相对变化,评估热变形对铰链变形的影响。该建模和试验分析方法可为同类型空间可展开天线设计、分析和优化及类似可展开机构精度影响因素的分析提供参考。