悟空试丹

话说当年悟空大闹天宫．搅得天宫一团糟：还闯进了太上老君的炼丹房…… “禀玉帝，‘宽容丹’被那泼猴盗去了!”一白胡子老头急道。

城市轨道交通空载试运行解析及优化措施

空载试运行阶段是城市轨道交通新线投入试运营前的核心阶段,对新线安全稳定地运行起着关键作用。通过对新线空载试运行的组织要求、实施前置条件、总体计划安排、试运行跑图、试运行基本条件评审准备等方面进行分析,提出完整的空载试运行组织思路及优化措施。

试井环空静压仪器在试井中的技术研究

试井工作当中需要通过环空静压仪器进行测试油套管环形空间的压力,能够为油田的生产提供资料,保证油田能够顺利生产。在测试的过程中往往会出现仪器缠绕的问题,出现这种问题就会导致测试结果不能为油田开采提供资料。因此只有采取合理有效的措施解除缠绕才能保证测试能够顺利进行,只有这样才能够完成测试任务。

气压试验装置在内压缩空分分馏塔系统试压中的应用

本文以某厂52000Nm3/h内压缩空分装置分馏塔系统氧气管道试压为例,阐述了采用气压试验装置结合低压洁净空气的供气方式进行试压,可为同类高压管道试压提供参考。

台试制动性能检测限值和方法的缺陷

为了进一步完善汽车台试制动性能检测标准,对相关国家标准关于台试制动性能的限值和检测方法进行了分析,通过试验验证了现有制动力平衡限值易造成许多错判,提出了对制动力增长阶段和稳定阶段规定不同的制动力平衡限值、台试整车制动力限值与路试制动减速度和制动距离的限值等效、对不同车型的后轴制动力和限制最低要求、正确规定制动力检测取样终点时刻、将车辆满载路试作为对台试制动性能质疑进行复检的唯一方法等完善建议。

关于沙漠空滤器性能标准的分析

本文指出了沙漠空滤器性能不合格的由来,分析了空滤器阻力形成原因,沙漠滤空气流量—阻力特性,怎样正确定发动机的空气流量。文中对沙漠滤试验室寿命,从概念,标准,试验方法,到试验室寿命的合理限值做了深入分析,对沙漠滤技术条件提出修改的具体建议。

Performance analysis of three-stage liquid desiccant deep dehumidification processor driven by heat pump

A new type of a heat pump driven three-stage lithium bromide liquid desiccant deep dehumidification processor is presented,which can dehumidify the outdoor humid air to a rather dry state,even when there is no available indoor exhaust air.The test results show that with an outdoor air temperature of 28 to 31 ℃ and an outdoor air humidity ratio of 11 to 14 g/kg,the supply air temperature and the supply air humidity ratio are 1.6 to 2.6 ℃ and 2.6 to 3.0 g/kg,respectively,and the coefficient of performance（COP）of the processor is 1.8.During the test,a liquid pipeline link problem leading to mixture losses of hot and cold liquid desiccants is found.These pipelines are modified.Then,the performance of the modified processor is investigated.And the experimental results show that with an outdoor air temperature of 25 to 32 ℃ and an outdoor air humidity ratio of 18 to 21 g/kg,the supply air temperature and the supply air humidity ratio are 3.2 to 4.0 ℃ and 3.4 to 3.6 g/kg,respectively,and the COP is 2.8.Finally,a mathematical model of the processor is established.The comparison of the simulation results and the test results of the processor exhibits that the pipeline modification improves the performance by about 20%.

Life prediction for vacuum fluorescent display using maximum likelihood estimation

In order to obtain the life information of the vacuum fluorescent display （VFD） in a short time, a model of constant stress accelerated life tests （CSALT） is established with its filament temperature increased, and four constant stress tests are conducted. The Weibull function is applied to describe the life distribution of the VFD, and the maximum likelihood estimation （MLE） and its iterative flow chart are used to calculate the shape parameters and the scale parameters. Furthermore, the accelerated life equation is determined by the least square method, the Kolmogorov-Smirnov test is performed to verify whether the VFD life meets the Weibull distribution or not, and selfdeveloped software is employed to predict the average life and the reliable life. Statistical data analysis results demonstrate that the test plans are feasible and versatile, that the VFD life follows the Weibull distribution, and that the VFD accelerated model satisfies the linear Arrhenius equation. The proposed method and the estimated life information of the VFD can provide some significant guideline to its manufacturers and customers.

Urban China in Transformation:Hybrid Economy,Juxtaposed Space,and New Testing Ground for Geographical Enquiries

History has brought us into a significant moment when the majority of the human kind has taken up resi-dence in urban settlements. The focus of global urbanization has shifted to the developing world and the center of manufacturing is no longer confined to the Global North. This paper provides a periodical assessment of the current status of China's urban transformation in the global context of a shifting emphasis of industrialization and urbaniza-tion. China's phenomenal urban transformation deserves a special attention not only because of its unparalleled scale and speed but also because of its distinct trajectory of growth that does not conform to normal theoretical ex-pectations. The results of assessment revealed an urban economy with remarkable hybridity, a society that is in-creasingly stratified, polarized, and segregated, and a juxtaposed urban space undergoing restless and pervasive transformation. A decentering world should entail a decentering knowledge production. A critical reflection upon the Chinese patterns and processes of urban transformation has identified 4 main issues with great potentials for inno-vative knowledge production, namely: 1) privatization and economic development; 2) state, society, and space; 3) urbanization of capital, labor, and land; and 4) the environment and Chinese political ecology. The paper closes with the remark that a rapidly transforming urban China has presented itself as a fertile and resourceful testing ground for critical and innovative geographic enquiries.

Aerodynamic coefficient of vehicle-bridge system by wind tunnel test

The changes of three components of aerodynamic force were discussed with the attack angle conversion for three kinds of section models. Based on the project of Shanghai Yangtze River Bridge, the wind tunnel test was conducted to obtain its three components of aerodynamic force including 75 conditions of the construction stage, the bridge without vehicles and the bridge with vehicles from - 12 degrees to ＋ 12 degrees. For the bridge with vehicles, the drag force coefficient and the absolute value of both lift coefficient and moment coefficient were decreased by the vehicles. The test resuh shows that the bridge railing and vehicles have much influence on the three components of aerodynamic force of the vehicle-bridge system for Shanghai Yangtze River Bridge.

In-Tunnel Blast Pressure Empirical Formulas for Detonations External, Internal and at the Tunnel Entrance

In order to define the loading on protective doors of an underground tunnel, the exact knowledge of the blast propagation through tunnels is needed. Thirty-three scale high-explosive tests are conducted to obtain in-tunnel blast pressure for detonations external, internal and at the tunnel entrance. The cross section of the concrete model tunnel is 0.67 m2. Explosive charges of TNT, ranging in mass from 400 g to 4 600 g, are detonated at various positions along the central axis of the model tunnel. Blast gages are flush-installed in the interior surface of the tunnel to record side-on blast pressure as it propagates down the tunnel. The engineering empirical formulas for predicting blast peak pressure are evaluated, and are found to be reasonably accurate for in-tunnel pressure prediction.

Nanoindentation tests on single crystal copper thin film with an AFM

Nanoindentation tests performed in a commercial atomic force microscope have been utilized to directly measure the elastic modulus and the hardness of single crystal copper thin films fabricated by the vacuum vapor deposition technique. Nanoindentation tests were conducted at various indentation depths to study the effect of indentation depths on the mechanical properties of thin films. The results were interpreted by using the Oliver-Pharr method with which direct observation and measurement of the contact area are not required. The elastic modulus of the single crystal copper film at various indentation depths was determined as (67.0±(6.9) GPa) on average which is in reasonable agreement with the results reported in literature. The indentation hardness constantly increases with decreasing indentation depth, indicating a strong size effect.

Spatial acoustic emission evolution of red sandstone during multi-stage triaxial deformation

Multi-stage triaxial compression tests for cylindrical red sandstone specimens(diameter of 50 mm,height of 100 mm) were carried out with a rock mechanics testing system and spatial acoustic emission(AE) locations were obtained by adopting an AE monitoring system.Based on spatial AE distribution evolution of red sandstone during multi-stage triaxial deformation,the relation between spatial AE events and triaxial deformation of red sandstone was analyzed.The results show that before peak strength,the spatial AE events are not active and distribute stochastically in the specimen,while after peak strength,the spatial AE events are very active and focus on a local region beyond final microscopic failure plane.During multi-stage triaxial deformation with five different confining pressures,the spatial AE distribution evolution in the red sandstone was obtained.The obtained spatial AE locations of red sandstone at the final confining pressure agree very well with the ultimate failure experimental mode.Finally,the influence of confining pressure on the spatial AE evolution characteristics of red sandstone during triaxial deformation was discussed.The AE behavior of red sandstone during multi-stage triaxial deformation is interpreted in the light of the Kaiser effect,which has a significant meaning for predicting the unstable failure of engineering rock mass.

Numerical simulation on turbulent flow field in convergentdiveroent nozzle

Because of the complication of turbulence＇s mechanism and law as well as the jet pressure in nozzle is difficult to test by experiment, five turbulent models were applied to numerically simulate the turbulent flow field in convergent-divergent nozzle. Theory analysis and experiment results of mass flow rates conclude that the RNG k-ε model is the most suitable model. The pressure distribution in the convergent-divergent nozzle was revealed by computational fluid dynamic （CFD） simulating on the turbulent flow field under different pressure conditions. The growing conditions of cavitation bubbles were shown; meanwhile, the phenomena in the experiment could be explained. The differential pres- sure between the upstream and downstream in nozzle throat section can improve the cavitating effect of cavitation water jet.

Detecting Global Vegetation Changes Using Mann-Kendal(MK) Trend Test for 1982–2015 Time Period

Vegetation is the main component of the terrestrial ecosystem and plays a key role in global climate change. Remotely sensed vegetation indices are widely used to detect vegetation trends at large scales. To understand the trends of vegetation cover, this research examined the spatial-temporal trends of global vegetation by employing the normalized difference vegetation index(NDVI) from the Advanced Very High Resolution Radiometer(AVHRR) Global Inventory Modeling and Mapping Studies(GIMMS) time series(1982–2015). Ten samples were selected to test the temporal trend of NDVI, and the results show that in arid and semi-arid regions, NDVI showed a deceasing trend, while it showed a growing trend in other regions. Mann-Kendal(MK) trend test results indicate that 83.37% of NDVI pixels exhibited positive trends and that only 16.63% showed negative trends(P < 0.05) during the period from 1982 to 2015. The increasing NDVI trends primarily occurred in tree-covered regions because of forest growth and re-growth and also because of vegetation succession after a forest disturbance. The increasing trend of the NDVI in cropland regions was primarily because of the increasing cropland area and the improvement in planting techniques. This research describes the spatial vegetation trends at a global scale over the past 30+ years, especially for different land cover types.

Influence factors on stress corrosion cracking of P 110 tubing steel under CO2 injection well annulus environment

Stress corrosion cracking （SCC） behavior of P 110 tubing steel in simulated C02 injection well annulus environments was investigated through three-point bent tests, potentiodynamic polarization and EIS measurements. The results demonstrate that SCC of P110 tubing steel could occur in acidulous simulated environment, and the sensitivity of SCC increases with the decrease ofpH, as well as increase of sulfide concentration and total environmental pressure. Both anodic dissolution and hydrogen embrittlement make contributions to the SCC. Adequate concentration of corrosion inhibitor can inhibit the occurrence of SCC on account of the inhibition of localized anodic dissolution and cathodic hydrogen evolution.

Mechanical property of calcareous sand under action of compaction

Calcareous sand is a kind of special medium which is composed of calcium carbonate and other difficult soluble carbonate substances. Because of its rich in inner pore space and easy crashed,the mechanical property is very different from conventional quartz sand. Based on the compaction test and direct shear test of calcareous sand,by means of data fitting,the coupling relationship between compaction density and mechanical property under different water contents was obtained; meanwhile,the shear strength expression was built on the basis of the relationship between water content and dry density.

FEM analysis of vacuum hot bulge forming of Hastelloy C-276 thin-walled cylindrical workpiece

A stress relaxation test has been carried out for Hastelloy C-276 at temperature of 800 ~C and initial stress level of 250 MPa. Based on the experimental stress relaxation curve, the relationship between creep strain rate and stress has been derived. Then, a set of creep constitutive equations has been built and the values of constants arising in the constitutive equations have been determined by fitting the creep strain rate-stress curve. Close agreement between computed results and experimental ones is obtained for stress relaxation data. The creep constitutive equation set has been integrated with the commercial FE （finite element） solver MSC.Marc via the user defined subroutine, CRPLAW, for the vacuum hot bulge forming process modelling of Hastelloy C-276 thin-walled cylindrical workpiece. The temperature field, the radius-direction displacement field and the stress-strain field are calculated and analyzed. Furthermore, the bulging dimension and the final internal diameter of workpiece are predicted and the test results verify the reliability of the finite element method.

Orthogonal tests of lead-clad tin bimetal continuous casting by air pressure core-filling

To provide theoretical basis and practical guidance for preparing composite rods of external diameter no larger than 12 mm by directly continuous casting,low melting point materials of lead and tin were selected to prepare composite rods of external diameter 12 mm and inner diameter 8 mm with air pressing core filled continuous casting process.The orthogonal tests consisting of three factors and three levels were designed to investigate the parameters of melting lead temperature,continuous casting speed and air pressure that affect the performance of the composite rods.The results show that melting lead temperature is the most important factor that influences the solid/liquid interface location;continuous casting speed is the most important factor that influences the surface quality and lead and tin inter-diffusion amount;air pressure can improve the surface quality obviously and make the rods easily drawn out,but the surface quality cannot get obvious improvement when the air pressure is above 0.03 MPa.The composite rods have excellent surface quality,obvious intermediate layer,even thick clad,and metallurgical bonding interface under the condition of melting lead temperature of 375 °C,continuous casting speed of 10 mm/min,and air pressure of 0.03 MPa.