Solution of idle LBO problem for high FAR aero combustor

The paper sheds light on the idle lean blow off(LBO)problem for high fuel air ratio(FAR)com⁃bustor,which is impossible to be addressed with traditional aero combustor design.A significant improvement in aero combustor design is required to resolve the idle LBO issue.The authors detailed a practical and efficient solu⁃tion,which not only solved the idle LBO issue but also defined the aero-thermal design for high-FAR combustor.The design will usher in a new era of aero combustor.

采油螺杆泵直旋机构设计与仿真

利用原有采油系统的地面驱动装置或闲置设备驱动螺杆泵进行采油,提出一种新型的螺杆泵采油技术——螺杆泵直旋机构,输入为往复直线运动,输出为连续单向旋转。进行三维造型、虚拟装配,检查了装配和运动中的干涉现象。在考虑弹性变形的情况下,对直旋机构进行建模,并用matlab软件绘制出仿真曲线,对曲线进行分析。

CTM-30车丝机加工API标准螺纹的锥度误差分析

为解决CTM-30车丝机加工API大管径、高钢级、偏梯扣螺纹类型的钢管时螺纹锥度不规则变化的问题,对车丝刀盘的同圆度检测分析。发现了锥度不规则变化问题的根本原因。通过改进生产工艺、降低切削载荷来提高同圆度精度,保证管端螺纹锥度的精度稳定性,提高产品合格率。

Viscous warm pressure bulging process of AZ31B magnesium alloy with different ellipticity dies

Based on the bulging principle of different ellipticity dies, the methyl vinyl silicone rubber with excellent thermal stability and heat transfer performance was chosen as the viscous medium. The finite element analysis and experiments of viscous warm pressure bulging （VWPB） of AZ31B magnesium alloy were conducted to analyze the influence of different ellipticity dies on the formability of AZ31B magnesium alloy. At the same time, based on the grid strain rule, the forming limit diagram （FLD） of VWPB of AZ31B magnesium alloy was obtained through measuring the strain of bulging specimens. The results showed that at the temperature range of viscous medium thermal stability, the viscous medium can fit the geometry variation of sheet and generate non-uniform pressure field, and as the die ellipticity increases, the difference value of non-uniform pressure reduces. Meanwhile, according to the FLD, the relationship between part complexity and ultimate deformation was investigated.

高校校办企业谈判信任机制探析

谈判是高校校办企业经营管理工作的重要内容,谈判信任机制对成功谈判起着关键性的作用。文章提出并阐释了谈判信任关系概念,根据谈判信任关系形成和发展机理构建了以双赢谈判理念为核心,以谈判者协调行动为动力,以社会相关机制为保障的"同圆信任共生"的谈判信任关系模型,探索了建立谈判信任机制的途径和方法。文章对高校校办企业谈判信任机制的建立具有一定的参考作用。

Study on Ceruraphis Brner, 1926 with One New Species (Homoptera: Aphididae)

The genus Ceruraphis Brner, 1926 is investigated in this paper. One new species C. hippophaetrophis Zhang is described. A key to all four species including this new species is given. All the specimens examined are deposited in the Institute of Zoology, Academia Sinica, Beijing.

完善家校共育,创造和谐学习环境

孩子的道德品质、理想情操、价值追求、志趣爱好、个性修养、行为习惯、意志品格的形成都离不开家庭。孩子在上学之前一直与家里的人朝夕相处,所以家庭教育、家庭环境对孩子的成长显得尤为重要。很多家长认为小时候只要照顾好孩子的生活起居就行了,这种教育观念很不正确。教育环境应该是学校和家庭共同努力创设的,而且小孩子的模仿能力比较强,家长的一举一动都会影响孩子的成长。家长应该在这个过程中重视家庭教育,努力为孩子创设一个和谐、正能量的成长环境。众所周知,在中小学的教育过程中,家庭教育与学校教育均以其独特的优势发挥着重要作用。因此,家校共育对于孩子的发展是至关重要的。

Numerical investigation of laminar heat transfer and nanofluid flow between two porous horizontal concentric cylinders

In this study, the laminar heat transfer and nanofluid flow between two porous horizontal concentric cylinders was investigated. The problem is investigated in two different geometries and the Re=10, 25, 50, 75, 100 and volume fraction 0, 0.2%, 0.5%, 2% and 5% that related to copper nanoparticles, and porous medium porosity of 0.5 and 0.9. Compared to the first geometry, the convective coefficient in the second geometry increases by 8.3%, 7% and 5.5% at Reynolds numbers of 100, 75 and 50, respectively. Comparison of the outlet temperatures for two heat fluxes of 300 and 1200 W/m^2 indicates a 2.5% temperature growth by a fourfold increase in the heat fluxes. Also, the higher Nusselt number is associated with the second geometry occurring at porosities of 0.9 and 0.5, respectively. In both geometries, the Nusselt number values at the porosity of 0.9 are higher, which is due to the increased nanofluid convection at higher porosities. The velocity of the nanofluid experiences a two-fold increase at the outlet compared to its inlet velocity in the first geometry and for both porosities. Similarly, a three-fold increase was achieved in the second geometry and for both porosities.

Treatment of Phenol Wastewater Using High Gravity Electrochemical Reactor with Multi-concentric Cylindrical Electrodes

A novel high gravity electrochemical reactor with multi-concentric cylindrical electrodes was used in the electrochemical treatment of 5 000 mg/L phenol-containing wastewater at a petrochemical plant, which can operate continuously and process in a large scale. The results show that the high gravity technology used in electrochemical treatment of phenol-containing wastewater can shorten the electrolysis time, decrease the electrolysis voltage, and reduce the energy consumption. The COD removal efficiency was high in the high-gravity field, and reached up to about 48%, which was about 2 times the value achieved in the normal gravity field at a processing capacity of 6 L, a high gravity factor of 80, a voltage of 12 V, an electrolysis time of 40 min, and a wastewater flowrate of 80 L/h.

Flow of a Jeffery-Six Constant Fluid Between Coaxial Cylinders with Heat Transfer Analysis

In the present investigation we have discussed the flow of a Jeffrey-six constant incompressible fluid between two infinite coaxial cylinders in the presence of heat transfer analysis. The governing equations of Jeffrey-six constant fluid along with energy equation have been derived in cylindrical coordinates. The highly nonlinear equations are simplified with the help of non-dimensional parameters and then solved analytically with the help of homotopy analysis method （HAM） for two fundamental flows namely Couette and Generalized Couette flow. The effects of emerging parameters are discussed through graphs. The convergence of the HAM solution has been discussed by plotting h-curves.

Comparison of Different Height Systems

Geopotential, dynamic, orthometric and normal height systems and the corrections related to these systems are evaluated in this paper. Along two different routes, with a length of about 5 kilometers, precise leveling and gravity measurements are done. One of the routes is in an even field while the other is in a rough field. The magnitudes of orthometric, normal and dynamic corrections are calculated for each route. Orthometric, dynamic, and normal height differences are acquired by adding the corrections to the height differences obtained from geometric leveling. The magnitudes of the corrections between the two routes are compared. In addition, by subtracting orthometric, dynamic, and normal heights from geometric leveling, deviations of these heights from geometric leveling are counted.

TWO FAST ALGORITHMS FOR COMPUTING POINT SCALAR MULTIPLICATIONS ON ELLIPTIC CURVES

The key operation in Elliptic Curve Cryptosystems(ECC) is point scalar multiplication. Making use of Frobenius endomorphism, Muller and Smart proposed two efficient algorithms for point scalar multiplications over even or odd finite fields respectively. This paper reduces the corresponding multiplier by modulo Υk-1 +…+Υ+ 1 and improves the above algorithms. Implementation of our Algorithm 1 in Maple for a given elliptic curve shows that it is at least as twice fast as binary method. By setting up a precomputation table, Algorithm 2, an improved version of Algorithm 1, is proposed. Since the time for the precomputation table can be considered free, Algorithm 2 is about (3/2) log2 q - 1 times faster than binary method for an elliptic curve over

Development of timer based on liquid level measurement system

This paper describes the design and development of the timer based on liquid level measurement system in which timer 555 is used in astable mode. The capacitor charging time i. e. the ON time pulse width of the timer output waveform which is measured using a digital storage oscillator （DSO）,is linearly proportional to the capacitance of a co-axial cylindrical capacitive transducer, and this capacitance once again linearly varies with the change in liquid level. Hence, we obtain a linear relationship between the liquid level and the capacitor charging time. The main advantages of this developed system are linear input-output relationship, small in size, easily portable, cost effective, and independent on the ambient temperature effect. The system can also be exploited to measure dielectric constant of liquid or solid in various process industries.

Two new species of the genus Cobitis Linnaeus(Teleostei:Cobitidae) from southern China

Two new species of the genus Cobitis from southern China,C.hereromacula from the Luohe River in Guangdong Province and C.baishagensis from the Nandujiang River in Hainan Province,are described and illustrated here.C.hereromacula can be distinguished from its congeners by possessing the following combination of characteristics;absence of the second and third pigmentary zones of Gambetta;13–16 oval blotches on the dorsum and 10–13 vertical,elongated triangular blotches below the midlateral line with more than 20 vertical dark brown bars between them;6–7 narrow rows of dark spots on the caudal fin;a vertical oval spot smaller than the eye diameter on the upper part of the caudal peduncle;pointed mental lobes of the lower lip pointed with a slightly filiform tip;one slender and long needle-shaped lamina circularis at the base of the first branched ray of the male pectoral fins.C.baishagensis can be distinguished from its congeners by the fourth Gambetta zone being covered by 10–12 transverse elongated blotches;4–5 narrow rows of dark spots on the caudal fin;a vertical blotch smaller than the eye diameter on the upper part of the caudal peduncle;males with a slender and long needle-shaped lamina circularis at the second branched pectoral fin ray in males;large scales with a slightly large focal zone;undeveloped mental lobes with a lower lip that does not end posteriorly in a filiform tip.

Deterministic and Stochastic Simulators for Non-Isotropic V2V-MIMO Wideband Channels

In this paper, we consider a novel two-dimensional(2D) geometry-based stochastic model(GBSM) for multiple-input multiple-output(MIMO) vehicle-to-vehicle(V2V) wideband fading channels. The proposed model employs the combination of a two-ring model and a multiple confocal ellipses model, where the signal is sum of the line-of-sight(Lo S) component, single-bounced(SB) rays, and double-bounced(DB) rays. Based on the reference model, we derive some expressions of channel statistical properties, including space-time correlation function(STCF), Doppler spectral power density(DPSD), envelope level crossing rate(LCR) and average fade duration(AFD). In addition, corresponding deterministic and stochastic simulation models are developed based on the reference model. Moreover, we compare the statistical properties of the reference model and the two simulation models in different scenarios and investigate the impact of different vehicular traffic densities(VTDs) on the channel statistical properties of the proposed model. Finally, the great agreement between simulation models and the reference model demonstrates not only the utility of simulation models, but also the correctness of theoretical derivations and simulations.

Exciting Forces for a Wave Energy Device Consisting of a Pair of Coaxial Cylinders in Water of Finite Depth

Two coaxial vertical cylinders-one is a riding hollow cylinder and the other a solid cylinder of greater radius at some distance above an impermeable horizontal bottom,were considered.This problem of diffraction by these two cylinders,which were considered as idealization of a buoy and a circular plate,can be considered as a wave energy device.The wave energy that is created and transferred by this device can be appropriately used in many applications in lieu of conventional energy.Method of separation of variables was used to obtain the analytical expressions for the diffracted potentials in four clearly identified regions.By applying the appropriate matching conditions along the three virtual boundaries between the regions,a system of linear equations was obtained,which was solved for the unknown coefficients.The potentials allowed us to obtain the exciting forces acting on both cylinders.Sets of exciting forces were obtained for different radii of the cylinders and for different gaps between the cylinders.It was observed that changes in radius and the gap had significant effect on the forces.It was found that mostly the exciting forces were significant only at lower frequencies.The exciting forces almost vanished at higher frequencies.The problem was also investigated for the base case of no plate arrangement,i.e.,the case having only the floating cylinder tethered to the sea-bed.Comparison of forces for both arrangements was carried out.In order to take care of the radiation of the cylinders due to surge motion,the corresponding added mass and the damping coefficients for both cylinders were also computed.All the results were depicted graphically and compared with available results.

四种相等关系的妙用

对于圆心角、弧、弦、弦心距之间的关系,我们有以下定理和推论.定理:在同圆和等圆中,相等的圆心角所对的弧相等,所对的弦相等,所对的弦的弦心距相等.推论:在同圆和等圆中,如果两个圆心角、两条弧、两条弦或两条弦的弦心距中有一组量相等,那么它们所对应的其余各组量都分别相等.

Symmetry distribution of cities in China

The authors of this paper induced five principles of geographical symmetry based on the space distributions of cities and towns in China. There is a symmetry distribution of cities and towns. The symmetry characteristics are the following: (i) the average coordination number of the cities (including large cities, medium cities and county towns) is 6 ( i.g. rotation symmetry); (ii) the distribution of large and medium cities are shown to be the latticework in which two directions are parallel to two main tectonic ones in China, respectively; (iii) the distribution of county towns of a province is also shown to be the latticework in which two directions are parallel to two tectonic ones in this province (i. g. two-dimensional translation ) and (iv) the concentric circle distribution of cities (CCDC) is centered round a large city (i. g. rotation symmetry).

Fate of Basal N Under Split Fertilization in Rice with ^(15)N Isotope Tracer

Split fertilization strategy is popularly adopted in rice to synchronize soil nitrogen(N) supply and crop N demand. Attention has been paid more on mid-season topdressing N, but limited on basal N. A clearer understanding of the basal N fate under split fertilization is crucial for determining rational basal N split ratio to improve the yield and reduce the loss to environment. A two-year field experiment with two N rates of 150 and 300 kg Nha^(-1), two split ratios of basal N, 40% and 25%, and two rice varieties,Wuyunjing 23(japonica) and Y-liangyou 2(super hybrid indica), was conducted. Labelled ^(15) N urea was supplied in micro-plots as basal fertilizer to determine the plant uptake, translocation, soil residual, and loss of basal N fertilizer. The results showed that basal N absorbed by rice was only 1.6%–11.5% before tillering fertilization(8–10 d after transplanting), 6.5%–21.4% from tillering fertilization to panicle fertilization, and little(0.1%–4.4%) after panicle fertilization. The recovery efficiency of basal N for the entire rice growth stage was low and ranged from 18.7% to 24.8%, not significantly affected by cultivars or N treatments. Soil residual basal N accounted for 10.3%–36.4% and decreased with increasing total N rate and basal N ratio, regardless of variety and year. 43.8%–70.4% of basal N was lost into the environment based on the N balance. Basal N loss was significantly linearly positive related with the basal N rate and obviously enhanced by the increasing basal N ratio for both varieties in both 2012 and 2013. The N use efficiency and yield was significantly improved when decreasing the basal N ratio from 40% to 25%. The results indicated that the basal N ratio should be reduced, especially with limited N inputs, to improve the yield and reduce the N loss to the environment.

On the isomorphism classes of Legendre elliptic curves over finite fields

In this paper,the number of isomorphism classes of Legendre elliptic curves over finite field is enumerated.