Method of calculation of a methane concentration field in gob areas with a known velocity field based on the model of stream tubes

在有已知的速度域的嘴区域的煤气的集中地的控制方程是有可变系数的部分微分方程，谁的传统的数学计算方法是很复杂的。一个数字模拟方法能被用来计算煤气的集中地，但是它也需要计算机资源的可观的数量，在嘴区域的不同的点的煤气的集中的关系是未定义的。基于流试管的模型，在流试管以内的集体、煤气的部件的保存方程被用来与已知的速度域在一个嘴区域推出煤气的集中域的方程。一块煤气的集中地的计算的这个方法在一个嘴区域被使用， U 类型通风工作面对，它建议这个新方法有准确计算的优点简单操作并且有清楚的物理解释。

Flow field simulation and establishment for mathematical models of flow area of spool valve with sloping U-shape notch machined by different methods

Precise function expression of the flow area for the sloping U-shape notch orifice versus the spool stroke was derived.The computational fluid dynamics was used to analyze the flow features of the sloping U-shape notch on the spool,such as mass flow rates,flow coefficients,efflux angles and steady state flow forces under different operating conditions.At last,the reliability of the mathematical model of the flow area for the sloping U-shape notch orifice on the spool was demonstrated by the comparison between the orifice area curve derived and the corresponding experimental data provided by the test.It is presented that the bottom arc of sloping U-shape notch(ABU) should not be omitted when it is required to accurately calculate the orifice area of ABU.Although the theoretical flow area of plain bottom sloping U-shape notch(PBU) is larger than that of ABU at the same opening,the simulated mass flow and experimental flow area of ABU are both larger than these of PBU at the same opening,while the simulated flow force of PBU is larger than that of ABU at the same opening.Therefore,it should be prior to adapt the ABU when designing the spool with proportional character.

Numerical analysis of stability for mined-out area in multi-field coupling

There were differences between real boundary and blast hole controlling boundary of irregular mined-out area in underground metal mines. There were errors in numerical analysis of stability for goaf, if it was analyzed as regular 3D mined-out area and the influence of coupling stress-seepage-disturbance was not considered adequately. Taking a lead zinc mine as the background, the model was built by the coupling of Surpac and Midas-Gts based on the goaf model precisely measured by CMS.According to seepage stress fundamental equations based on the equivalent continuum mechanical and the theory about equivalent load of dynamic disturbance in deep-hole blasting, the stability of mined-out area under multi-field coupling of stress-seepage-dynamic disturbance was numerically analyzed. The results show that it is more consistent between the numerical analysis model based on the real model of irregular 3D shape goaf and the real situation, which could faithfully reappear the change rule of stress–strain about the surrounding rock under synthetic action of blasting dynamic loading and the seepage pressure. The mined-out area multi-field coupling formed by blasting excavation is stable. Based on combination of the advantages of the CMS,Surpac and Midas-Gts, and fully consideration of the effects of multi-field coupling, the accurate and effective way could be provided for numerical analysis of stability for mined-out area.

Prevention and Management of Soil Secondary Salinization in Paddy Field Irrigation Area

By analyzing the process of soil salt accumulation in irrigation area, and discussing the change of irrigation and drainage methods for drought transformed into water, the control scheme of soil secondary salinization in Wujiazi Irrigation Area was analyzed concretely, and the experience was summarized. After in-depth discussion, the importance of irrigation and drainage methods in the prevention and control of soil secondary salinization in irrigation areas was analyzed.

STUDY ON FLUXES OF CH4 EMISSION FROM PADDY FIELDS IN CHANGCHUN AREA

Little has been done in measurement and research of the flux of CH4 emission from paddy fields in Changchun area, Jilin Province, China before 1994. So the purpose of the study is to offer available regional data of CH4 emission flux and to discuss the factors which affect CH4 emission from paddy fields. Experimental paddy fields are chosen using TM pictures respectively in Xinlicheng (43° 49′ N, 125° 20′ E) of the Yitong River’s and in Wanchang (43° 44′ 10″ N, 125° 53′ 11″ E) of the Yinma River’s alluvial plain. The fluxes of CH4 emission from paddy fields are measured by the method of static chamber in Changchun area in 3 consecutive years. The research results show that the peak of CH4 emission from paddy fields occurs during the booting stage. The mean fluxes of CH4 emission are 7.056 mg/(m2· h) and 0.489 mg/(m2· h) in the paddy fields of flood and discontinuous irrigation respectively. The contrastive study holds that climate condition, the way of water management and fertilizer variation have significant influence on fluxes of CH4 emission from paddy fields. The difference of climatic conditions causes the interannual change of the flux of CH4 emission from paddy fields. In general, the flux of CH4 emission from paddy fields of flood irrigation is greater than that from paddy fields of discontinuous irrigation. To change the way of water management perhaps is an available way to reduce CH4 emission flux from paddy fields.

Seed Health Status of Sweet Corn (Zea mays L. saccharata Sturt) from Five Areas in China and Effect on Field Seedling Emergence

The health status of 18 sweet corn (Zea mays L. saccharata Sturt) hybrids classified to two types, collected from five areas in China, was examined by PDA method, and factors influencing seed health and relationships between seed health and field seedling emergence were studied. Seventeen fungal genera were isolated and Fusarium was the most frequently isolated. There were significant differences both in incidence of Fusarium and in percentage of infected seeds among 18 hybrids. Research also showed that significant and consistent differences both in seed-borne fungal taxa and in percentage of infected seeds existed between two types of sweet corn. Sugar enhanced corn is more slightly infected than super sweet corn both in fungal taxa (13 and 16, respectively) and in percentage of infected seeds (62.0 and 79.2%, respectively). There were also significant differences both in seed-borne fungal taxa and in percentage of infected seeds among five areas. Seeds from South China were most severely infected, for there were 14 fungal genera detected and the percentage of infected seeds was highly 99.1% while those from Northwest China were slightly infected, for there were 10 fungal genera detected and the percentage of infected seeds was only 14.3%. Further research showed that there were significant negative correlations both between incidence of Fusarium and percentage of field seedling emergence and between percentage of infected seeds and percentage of field seedling emergence. Percentage of field seedling emergence could be estimated by regression equations built by regression analysis.

Body area communication based on quasi-electrostatic field and spread spectrum

Based on the electrical model of body area communication, the change tendency of chan nel gain in 100 kHz 10 MHz band was experimentally analyzed and verified. Results show that chan nel gain was flat and signal attenuation was approximately 43 dB in 1 MHz 10 MHz band. The char acteristics of the channel were taken into account in the design of body area spread spectrum com munication and its multiuser receiver issue. BER Eb/No curves of single user and multiuser were de rived by simulation. The characteristics of body area commutation channel were studied and the fea sibility of introducing spread spectrum theory to body area communication was verified.

Characteristic Analysis of Atmospheric Electric Field in Contaminated Areas

[Objective] The research aimed to analyze characteristics of atmospheric electric field in polluted area. [Method] By using data of atmospheric electric field meter in Taiyuan in 2009, daily and annual changes of atmospheric electric field in Taiyuan were analyzed. [ Result] Atmospheric electric field intensity in Taiyuan was higher than that in other areas. Daily change was double-peak double-valley type. The first highest value appeared at nightfall, and the second highest value was before the noon. The first lowest value appeared in early morning, while the second low- est value appeared after the noon. Annual change was single-peak single-valley type. The maximum appeared in winter, while the minimum ap- peared in summer. [ Conclusion] When forecasting thunderstorm, in the area with higher aerosol content, alarm threshold of electric field should be adjusted via comparison with actual observation, which had very strong regional characteristics. By analyzing real-time monitoring data of atmospheric electric field, thunderstorm forecast could be realized, and timeliness and accuracy of warning and forecast could be increased.

The Test Area of Suizhong 36-1 Oil Field Fully Under Commission

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Research into the Regional Characteristics of the Tectonic Stress Field in Jiashi, Xinjiang and Its Surrounding Areas

Jiashi and its surrounding areas are composed of many structural zones. Using the focal mechanism solutions of 59 moderately strong earthquakes in Jiashi and its surrounding areas, and combining these with the calculation results of system cluster and stress field inversion, we analyzed the evolvement characteristics of the stress field for different times and different regions. The results were as follows: The earthquakes in Jiashi are mainly strike-slip. However, those of the Kalpin block are mainly reverse events, showing an obvious thrusting. The regional characteristics are different from other areas. The direction of the regional principal stress field is near NS. However, under different tectonic backgrounds, the directions of the stress fields are different. The direction of the principal compress stress is near NS in the Kashi-Wuqia area. But before and after the 3 earthquakes with M7.0, dynamic evolution from NW to NS and then to NE with time process was observed. The Kalpin block has been dominated by a consistent stress field in the NW direction for a long time. However, the direction of the stress field of the Jiashi region is NE. Since 1996, the direction of the regional stress field has changed obviously. The direction of the P axis was deflected towards the NE, and the plunge angle increased. The result shows clearly the regional characteristics and variation of the distribution pattern of the stress field in different tectonic environments.

Control Measures of Soil Erosion in a Typical Construction Project Area ( Dina 2 Gas Field)

To treat the relationship between project construction and ecological environment and effectively prevent new soil erosion during the construction, according to the project layout, soil erosion distribution as well as natural and socio-economic conditions, the control measures of newly increased soil erosion along the project were carried out based on site survey and analysis of relevant information. In addition, adhering to the prin- ciple of partition prevention and treatment, some guiding prevention and control measures of the natural zone passed by the project and soil erosion control district were determined, which provided scientific references and technical support for the rational layout of water and soil conservation and ecological restoration measures in Dina 2 gas field.

Determine Stress Field of the Shirband Area by Geometric and Kinematic Analysis of Faults and Folds (North Damqan, Iran)

In this paper faults and folds of shirband area (north of damqan) investigated to determine the orient of the stress field. The study area is limited between the two faults with E-W strike and northward slip. Investigations result show major faults of the area have sinisteral mechanism. Waterways displacement and slicken slip of faults approve this issue. Three main folds of area has approx-imately same trend along major faults (E-W). Orientation of stress field investigated and classified by using from some large and medium scale faults and folds. Analysis of stress field investigated by inversion method show that compression axis in the study area have approximately NE-SW strike.

基于行车风险场的快速路短交织区车辆交互风险识别

为更加准确和直观地识别快速路短交织区行驶车辆之间的交互风险,解决传统风险识别模型无法连续识别换道时车辆间交互风险的问题,本文利用无人机采集快速路短交织区内车辆轨迹数据,并利用Tracker进行读取,筛选跟驰车辆对和换道车辆对,在现有行车风险场理论的基础上,综合考虑车辆面积、车辆前进时前后方风险差异、转弯时左右方风险差异以及车辆之间横向距离,适应性改进现有行车风险场模型DRF(Driving Safety Field),利用遗传算法和波良可夫模型标定模型参数。对比改进后行车风险场模型、车头时距倒数(THWI)、碰撞时间倒数(TTCI)对车辆间跟驰交互风险与换道交互风险的识别情况,验证该模型的有效性。结果表明,本文模型较THWI和TTCI更符合驾驶员的驾驶心理,且感知风险变化先于驾驶员,对车辆换道交互风险的识别率较THWI提升52.45%,较TTCI提升83.66%,本模型在换道交互风险的识别性能上表现的更加优越。基于本文模型对短交织区区域内多车共同作用产生的风险进行可视化,可辅助交通管理部门确定需要精细化组织的关键区域,也可作为评价管理措施改善效果的可视化手段。

基于神经辐射场的苗期作物三维建模和表型参数获取

苗期作物三维结构的精准高效重建是获取表型信息的重要基础。传统的三维重建大多基于运动恢复结构-多视图立体视觉(Structure from motion and multi-view stereo,SFM-MVS)算法,计算成本高,难以满足快速获取表型参数的需求。本研究提出一种基于神经辐射场(Neural radiance fields,NeRF)的苗期作物三维建模和表型参数获取系统,利用手机获取不同视角下的RGB影像,通过NeRF算法完成三维模型的构建。在此基础上,利用点云库(Point cloud library,PCL)中的直线拟合和区域生长等算法自动分割植株,并采用距离最值遍历、圆拟合和三角面片化等算法实现了精准测量植株的株高、茎粗和叶面积等表型参数。为评估该方法的重建效率和表型参数测量精度,本研究分别选取辣椒、番茄、草莓和绿萝的苗期植株作为试验对象,对比NeRF算法与SFM-MVS算法的重建结果。结果表明,以SFM-MVS方法重建点云为基准,NeRF方法重建的各植株点云点对距离均方根误差仅为0.128~0.395 cm,两者重建质量较接近,但在重建速度方面,本文研究方法相比于SFM-MVS方法平均重建速度提高700%。此外,该方法提取辣椒苗株高、茎粗决定系数(R^(2))分别为0.971和0.907,均方根误差(RMSE)分别为0.86 cm和0.017 cm,对各苗期植株叶面积提取的R^(2)为0.909~0.935,RMSE为0.75~3.22 cm^(2),具有较高的测量精度。本研究提出的方法可以显著提高三维重建和表型参数获取效率,从而为作物育种选苗提供更为高效的技术手段。

Analysis of Space-time Characteristics of Energy Field of Seismicity in Jiangsu and Its Neighboring Areas

The paper analyzes the variation characteristics of energy fields of seismicity 2.1≤M L ≤4.5 in Jiangsu and its neighboring areas during the period between January 1970 and December 2007.It also analyzes the variations of time "weight" coefficients of the major typical energy fields,using random function theory with seismic energy fields as a space-time random function field based on Empirical Orthogonal Function (EOF) expansion methods.The results show that the expansion accuracy of the first seven typical fields is 0.9244.The strength of seismic energy varies remarkably in different tectonic blocks in the study area.High value areas are in middle and southern Jiangsu,and the south Yellow Sea.The distribution of the typical fields also shows that it is an area that affects most significantly the seismic energy fields of the study region.The time "weight" coefficients of the first six typical fields vary with time,and the amplitude of the variations has strong temporal correlations with moderate-strong earthquakes in the region.