Pilot Test for Nitrogen Foam Flooding in Low Permeability Reservoir

Due to the characteristics of reservoir formation,the producing level of low permeability reservoir is relatively very low.It is hard to obtain high recovery through conventional development schemes.Considering the tight matrix,complex fracture system,low production level of producers,and low recovery factor ofMblock in Xinjiang oilfield,it is selected for on-site pilot test of nitrogen foam flooding.Detailed flooding scheme is made and the test results are evaluated respectively both for producers and injectors.The pressure index,filling degree,and fluid injection profile are found to be all improved in injectors after injection of nitrogen foam.The oil production,water cut and liquid production file are also improved in most of the producers,with the natural decline rate in the test area become slow.Results show that nitrogen foam flooding technology can be good technical storage for enhanced oil recovery in low permeability reservoir.

Research on Well Testing Interpretation of Low Permeability Deformed Dual Medium Reservoir

Considering the influence of quadratic gradient term and medium deformation on the seepage equation, a well testing interpretation model for low permeability and deformation dual medium reservoirs was derived and established. The difference method was used to solve the problem, and pressure and pressure derivative double logarithmic curves were drawn to analyze the seepage law. The research results indicate that the influence of starting pressure gradient and medium deformation on the pressure characteristic curve is mainly manifested in the middle and late stages. The larger the value, the more obvious the upward warping of the pressure and pressure derivative curve;the parameter characterizing the dual medium is the crossflow coefficient. The channeling coefficient determines the time and location of the appearance of the “concave”. The smaller the value, the later the appearance of the “concave”, and the more to the right of the “concave”.

Temperature Control and Simulation of Temperature-Altitude Test System

The temperature-Altitude Test System(TATS) supplies various testing environments.The traditional PID method controls the temperature in TATS Temperature-Pressure Cabin(TPC) over a long adjusting time and with a large overshoot.In order to solve this problem simply,a temperature control strategy with temperature difference corresponding factors is presented through a dynamic analysis and modeling of TPC temperature change.The TPC temperature descending process is simulated,and the results show that this control strategy can allot the proportion of PID heating controller and PID cooling controller in the whole control process and TPC temperature can be controlled at a set point quickly and effectively.

Similarity model tests of movement and deformation of coal-rock mass below stopes

For a study of the movement and deformation of coal-rock mass and low protected seams below a stope,as well as for fracture developments and rules of evolution of permeability,we designed a plane strain model test stand to carry out model tests of similar materials in order to improve the effect of gas drainage from low protected seams and to measure the movement and deformation of coal-rock mass using a method of non-contact close-range photogrammetry.Our results show that 1) using paraffin melting to take the place of coal seam mining can satisfy the mining conditions of a protective seam;2) coal-rock mass under goafs has an upward movement after the protective seam has been mined,causing floor heaving;3) low protected seams become swollen and deformed,providing a good pressure-relief effect and causing the coal-rock mass under both sides of coal pillars to become deformed by compression and 4) the evolution of permeability of low protected seams follows the way of initial values→a slight decrease→a great increase→stability→final decrease.Simultaneously,the coefficient of air permeability increased at a decreasing rate with an increase in interlayer spacing.

Association of hypoglycaemia in screening oral glucose tolerance test in pregnancy with low birth weight fetus

BACKGROUND Gestational diabetes mellitus(GDM) is a common metabolic derangement in pregnant women. In the women identified to be at high risk of GDM, a 75 g oral glucose tolerance test(OGTT) at 24-28 wk gestation is the recommended screening test in the United Kingdom as per National Institute for Health and Care Excellence(NICE). Hypoglycaemia following the glucose load is often encountered and the implication of this finding for the pregnancy, fetus and clinical care is unclear.AIM To determine the prevalence of hypoglycaemia at any time during the screening OGTT and explore its association with birth weight.METHODS All deliveries between 2009 and 2013 at the local maternity unit of the University hospital were reviewed. Of the total number of 24,154 women without preexisting diabetes, those who had an OGTT for GDM screening based on NICE recommended risk stratification, who had a singleton delivery and had complete clinical and demographic data for analysis, were included for this study(n =3537). Blood samples for fasting plasma glucose(FPG), 2-hour plasma glucose(2-h PG) and HbA1 c had been obtained. Birth weight was categorised as low(≤ 2500 g), normal or Macrosomia(≥ 4500 g) and blood glucose ≤ 3.5 mmol/L was used to define hypoglycaemia. Binary logistic regression was used to determine the association of various independent factors with dichotomized variables; the differences between frequencies/proportions by χ~2 test and comparison between group means was by one-way ANOVA.RESULTS Amongst the study cohort(3537 deliveries), 96(2.7%) women had babies with LBW(< 2500 g). Women who delivered a LBW baby had significantly lower FPG(4.3 ± 0.6 mmol/L, P = 0.001). The proportion of women who had a 2-h PG ≤ 3.5 mmol/L in the LBW cohort was significantly higher compared to the cohorts with normal and macrosomic babies(8.3% vs 2.8% vs 4.2%; P = 0.007). The factors which predicted LBW were FPG, Asian ethnicity and 2-h PG ≤ 3.5 mmol/L,whereas maternal age, 2-h PG ≥ 7.8 mmol/L and HbA1c were not significant predictors.CONCLUSION A low FPG and 2-h PG ≤ 3.5 mmol/L on 75-gram OGTT are significantly associated with low birth weight in women identified as high risk for GDM.Women of ethnic backgrounds(Asians) appear to be more susceptible to this increased risk and may serve as a separate cohort in whom we should offer more intensive follow up and screening for complications. Cost implications and resources for follow up would need to be looked at in further detail to support these findings.

Dependence of single event upsets sensitivity of low energy proton on test factors in 65 nm SRAM

In order to accurately predict the single event upsets （SEU） rate of on-orbit proton, the influence of the proton energy distribution, incident angle, supply voltage, and test pattern on the height, width, and position of SEU peak of low energy protons （LEP） in 65 nm static random access memory （SRAM） are quantitatively evaluated and analyzed based on LEP testing data and Monte Carlo simulation. The results show that different initial proton energies used to degrade the beam energy will bring about the difference in the energy distribution of average proton energy at the surface and sensitive region of the device under test （DUT）, which further leads to significant differences including the height of SEU peak and the threshold energy of SEU. Using the lowest initial proton energy is extremely important for SEU testing with low energy protons. The proton energy corresponding to the SEU peak shifts to higher average proton energies with the increase of the tilt angle, and the SEU peaks also increase significantly. The reduction of supply voltage lowers the critical charge of SEU, leading to the increase of LEP SEU cross section. For standard 6-transitor SRAM with bit-interleaving technology, SEU peak does not show clear dependence on three test patterns of logical checkerboard 55H, all＂ 1＂, and all ＂0＂. It should be noted that all the SEUs in 65 nm SRAM are single cell upset in LEP testing due to proton＇s low linear energy transfer （LET） value.

High-frequency interference waves in low strain dynamic testing of X-section concrete piles

Stress waves propagate along vertical,radial and circumferential directions when a non-uniformly distributed load is applied at one end of a three-dimensional shaft.As a result,the receiving signals are usually mixed with undesired interference components,often featuring as high-frequency fluctuations.Previous studies have revealed that sectional geometry(shape and size)greatly affects the high-frequency interference.In this study,low strain dynamic testing on full-scale X-section concrete is conducted in order to investigate the influences of high-frequency interference on velocity responses at the pile head.Emphasis is placed on the frequency and peak value of interference waves at various receiving points.Additionally,the effects of the geometrical,and mechanical properties of the pile shaft on high-frequency interference are elaborated on through the three-dimensional finite element method.The results show that the measured wave is obscured by interference waves superposed by two types of high-frequency components.The modulus and cross-sectional area are contributing factors to the frequency and peak value of the interference waves.On the other hand,the position with the least interference is determined,to some extent,by the accurate shape of the X-section.

Effect of Verbal Instructions in Pain Assessment during a Passive Straight Leg Raise Test in People with Chronic Low Back Pain

The most prevalent issue in physical therapy is pain. Due to the subjective nature of pain, assessment tools are essential in understanding it as objective data. However, assessment of pain may result in distress for the patient. A physical therapist (PT) should conduct these tests as quickly and accurately as possible. Straightforward instructions are vital in such cases. This study aimed to clarify the effect of verbal instructions for pain assessment during a passive straight leg raise (PSLR) test for participants with chronic low back pain (CLBP). This study included 22 participants who provided informed consent and received three consecutive PSLR tests with measurement of the hip flexion range of motion (HFROM) and were instructed to cease the test at submaximal pain before the first test. Following the second and third tests, participants were given specific verbal instructions to remember pain intensity, quality, and location. After each test, participants were to circle the pain location on the body chart and rate their pain intensity on a numeric rating scale (NRS) and pain quality. All participants were then interviewed about the differences between having and not having specific verbal instructions. The results of HFROM, NRS, and pain extent were not significantly different between the first and second tests or between the second and third tests using a paired t-test. Eleven changes in pain location were found in the second test compared to those in the first test. In the third test, only three participants circled a different area than in the second test. Ten participants showed similar changes with pain location in pain quality in the three PSLR tests. This study revealed the effect of specific verbal instructions prior to PSLR tests. Particularly, participants could notice exact pain location. Our findings may help PT to understand pain cause and reduce patients’ stress during pain assessment in clinical settings.

Design for Low Power Testing of Computation Modules with Contiguous Subspace in VLSI

A kind of pseudo Gray code presentation of test patterns based on accumulation generators is presented and a low power test scheme is proposed to test computational function modules with contiguous subspace in very large scale integration （VLSI）, especially in digital signal processors （DSP）. If test patterns from accumulators for the modules are encoded in the pseudo Gray code presentation, the switching activities of the modules are reduced, and the decrease of the test power consumption is resulted in. Results of experimentation based on FPGA show that the test approach can reduce dynamic power consumption by an average of 17.40% for 8-bit ripple carry adder consisting of 3-2 counters. Then implementation of the low power test in hardware is exploited. Because of the reuse of adders, introduction of additional XOR logic gates is avoided successfully. The design minimizes additional hardware overhead for test and needs no adjustment of circuit structure. The low power test can detect any combinational stuck-at fault within the basic building block without any degradation of original circuit performance.

Pilot-test about Treatment of Low-concentration Organic Waste Gas Using a Fixed Biological Bed

[ Objective] The study aims to discuss the feasibility of using a fixed biological bed to treat low-concentration organic waste gas. [ Method] A fixed biological bed was used to treat low-concentration organic waste gas from a phosphate workshop, and then the waste gas treated was assessed by human sense of smell to determine the most economical empty bed contact time, thereby verifying the feasibility of using a fixed biolog- ical bed to treat low-concentration organic waste gas. [Result] When empty bed contact time was 60 s, the smell of the treated waste gas was acceptable, and COD value of recycled water in the fixed biological bed was essentially unchanged. It proved that organic load of the waste gas was consumed by microorganisms within 60 s. [ Conclusion] It is feasible to use a fixed biological bed to treat Iow-concantration organic waste gas from a phosphate workshop.

Pre-exposure effect of low-dose ^(16)O^(8+) or γ-rays on testicular endocrine of mice

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轻钢龙骨混凝土复合外挂墙板力学性能试验研究

复合墙板性能关系着结构的安全,在新设计建造的轻钢龙骨复合墙板投入使用前应进行力学性能试验,以评估其安全性能。为研究墙板的受力变形过程及破坏形态,对两片不同的轻钢龙骨混凝土复合外挂墙板分别进行四点弯曲试验和低周反复荷载试验。弯曲试验结果表明,弯曲过程中墙板出现裂缝时的计算等效均布荷载大于建筑风荷载标准值,抗弯性能满足受力要求。墙板经历了弹性阶段、弹塑性变形阶段和屈服破坏阶段,主要通过钢材屈服后的弹塑性变形和材料的破坏来实现耗能,屈服前耗能占总耗能的6.19%,屈服后累计耗能呈现二次抛物线增长,这一结果体现了墙板良好的抗震能力。研究结果可为实际应用提供依据。

寒冷地区Low-E节能玻璃检测与应用技术研究

通过对Low-E节能玻璃传热系数的检测,找出影响Low-E中空玻璃传热系数K值的因素,生产企业可以根据这些因素择优制作Low-E节能玻璃。本文还给出常用玻璃与窗框配合后整窗传热系数K值,绿色建筑、超低能耗绿色建筑所用外窗的适配窗框与Low-E节能玻璃一目了然。

基于碰撞特性的鲜食玉米摘穗装置对比试验

【目的】探究缓冲弹簧和柔性触穗表面两种摘穗机构在摘取果穗中的低损作用及机制。【方法】以传统玉米收获用板式摘穗机构和具有缓冲弹簧加柔性触穗表面的柔性摘穗机构为2种摘穗结构,以刚性触穗表面、柔性橡胶触穗表面、柔性发泡材料触穗表面为3种触穗表面,得出6种摘穗机构,进行鲜食玉米果穗碰撞试验,采集和分析碰撞时间、碰撞加速度峰值,计算碰撞冲量,统计籽粒破碎率。【结果】柔性摘穗机构能够有效降低鲜食玉米果穗受到的碰撞时间,从而降低鲜食玉米果穗的籽粒破碎率。缓冲弹簧可缩短鲜食玉米果穗的碰撞时间,当柔性摘穗机构表面为柔性橡胶和柔性发泡材料时,碰撞时间分别比板式摘穗机构降低了66.2%、70.1%和70.1%。碰撞冲量分别降低了67.6%、77.9%和79.7%。籽粒破碎率降低了71.2%、51.3%和83.6%。对于柔性摘穗机构,鲜食玉米果穗与柔性橡胶、柔性发泡材料触穗表面的碰撞时间比刚性触穗表面分别延长了58.7%和63.2%。碰撞加速度峰值分别降低了62.5%和68.7%。碰撞冲量分别降低了42.4%和54.5%。籽粒破碎率分别降低了47.4%和68.4%。【结论】通过降低收获过程中鲜食玉米果穗受到的碰撞时间和碰撞加速度,从而有效降低了鲜食玉米果穗的籽粒破碎率,为鲜食玉米低损收获机的研制提供理论依据和设计参考。

新形势下航天装备环境试验技术的未来发展趋势

从航天装备面临的实战化考核、数字化建设和低成本控制等新形势与新要求出发,梳理了环境试验技术在航天装备试验鉴定中存在的实战化考核能力不足、全寿命周期环境效应考核不充分等技术难题,结合航天装备环境试验的国内外发展现状,系统分析了航天装备环境试验技术的未来发展趋势,试验环境综合化、试验设计一体化、试验手段数字化在提升航天装备环境试验水平、缩短装备试验周期、降低试验成本方面具有显著优势,也是航天装备环境试验未来发展的重要方向。

基于长标距光纤光栅传感技术的智能碳纤维筋性能研究

光纤光栅(FBG)传感技术以其抗干扰、传感与传输一体化等优点,成为CFRP拉索智能监测重点研究方向之一。然而,传统CFRP拉索智能监测属于点式或局部传感,难以满足服役全时感知及高量程监测需求。因此,提出将长标距FBG传感技术与螺旋倾斜式技术复合,研制一种智能CFRP筋,并通过循环静力拉伸、低周疲劳(高应力状态下)与极限静力拉伸试验,探究各试验条件下智能CFRP筋的力学及传感性能和试验后性能损失情况。试验表明:智能CFRP筋应变传感性能在不同工况(15 kN、42 kN)下3次循环拉伸的线性相关系数均大于0.99,说明智能CFRP筋应变传感性能较好,具有可重复性,同时将FBG监测值与应变片监测值进行对比,表现出较好的吻合性。低周疲劳试验过程中FBG监测值与疲劳荷载变化规律一致,且监测值与理论应变上下限误差少于8%,试验过程中未出现数据异常、应变感知迟滞等现象,FBG存活率达到100%,验证了智能CFRP筋良好的应变传感性能,可实现智能CFRP筋轴向动应变的监测。在极限静力拉伸试验中,FBG最大波长变化量达13 454 pm,监测应变达到了11 000με以上,可实现智能CFRP筋更大量程应变的监测。经过3次循环静力拉伸和低周疲劳试验后智能CFRP筋的FBG监测值线性相关系数相比对照组试件有所提高,智能CFRP筋极限荷载有所降低,FBG应变监测量程受影响较小,前期试验主要对智能CFRP筋筋材造成了累积损伤。试验结果可为CFRP拉索智能监测的理论设计和研究提供重要的依据。

基于OCV模型优化的磷酸铁锂电池SOC估计

锂离子电池荷电状态(SOC)与开路电压(OCV)的关系曲线(OCV曲线)是影响其SOC估计精度的核心因素。针对小电流OCV(LO)测试耗时短但数据精度较低的问题,提出一种OCV模型及其优化方法。该方法基于LO测试的OCV数据,采用道格拉斯-普克算法和分段线性函数建立OCV模型。并将OCV曲线上的4个OCV点作为变量,建立了其他OCV点的随动模型,使曲线能够运用粒子群优化算法进行优化。基于优化后的OCV曲线,动态工况下的端电压估计绝对平均误差降低83.5%,采用自适应扩展卡尔曼滤波的SOC估计误差小于0.3%。该方法能够基于耗时短的LO测试获取准确OCV曲线,降低锂离子电池研究与应用的测试成本。

水平双轴加载下带翼缘RC 剪力墙抗震性能试验研究

为了揭示双轴耦合效应对不同截面形式带翼缘RC剪力墙多维抗震性能的影响,对3个T形截面和2个L形截面RC剪力墙分别沿其主轴方向进行了低周往复加载试验,对比分析了水平单、双轴加载下带翼缘RC剪力墙的破坏特征、滞回特性、承载力、延性、极限位移角、耗能能力与钢筋应变。研究表明:T形墙和L形墙的破坏均呈现出明显的非对称性,即破坏集中于墙肢自由端,双轴加载加重了带翼缘RC剪力墙的开裂和损伤程度,且易引起剪力墙局部损伤集中;与单轴加载相比,双轴加载不仅削弱了带翼缘RC剪力墙各受力方向的承载力与变形能力、增大了腹板塑性铰区弯曲变形在总变形中的占比、加速了耗能进程、降低了单个方向的耗能能力,并且增大了腹板与翼缘竖向钢筋的应变以及翼缘的剪力滞后效应;双轴耦合效应对L形墙损伤的影响较T形墙更为显著,并导致双轴加载下L形墙各抗震性能指标的衰减程度大于T形墙。考虑双轴受力后,中国抗震规范关于RC剪力墙层间位移角的限值仍较为安全,但安全冗余度降低。