靠“定力”维护品牌核心价值——打造强势大品牌的黄金法则之二

假如戴妃换部车……英国戴安娜王妃因一场车祸去世,笔者那几天刚好出差在珠海,闲暇时,买了一份《澳门日报》。发现上面登了一幅沃尔沃的广告,标题赫然写着:'如果乘坐的是沃尔沃,戴妃会香消玉殒吗?',并且从技术上洋洋洒洒地分析了一番后得出结论:'以沃尔沃的安全技术,戴妃能保全性命',再加上几乎所有的新闻都报道了当时戴妃乘的是奔驰车,言下之意无非是说沃尔沃比奔驰还安全。够准、够狠、够绝的一招,把安全这一核心利益点传达得淋漓尽致。

Gated Neural Network-Based Unsteady Aerodynamic Modeling for Large Angles of Attack

Modeling of unsteady aerodynamic loads at high angles of attack using a small amount of experimental or simulation data to construct predictive models for unknown states can greatly improve the efficiency of aircraft unsteady aerodynamic design and flight dynamics analysis.In this paper,aiming at the problems of poor generalization of traditional aerodynamic models and intelligent models,an intelligent aerodynamic modeling method based on gated neural units is proposed.The time memory characteristics of the gated neural unit is fully utilized,thus the nonlinear flow field characterization ability of the learning and training process is enhanced,and the generalization ability of the whole prediction model is improved.The prediction and verification of the model are carried out under the maneuvering flight condition of NACA0015 airfoil.The results show that the model has good adaptability.In the interpolation prediction,the maximum prediction error of the lift and drag coefficients and the moment coefficient does not exceed 10%,which can basically represent the variation characteristics of the entire flow field.In the construction of extrapolation models,the training model based on the strong nonlinear data has good accuracy for weak nonlinear prediction.Furthermore,the error is larger,even exceeding 20%,which indicates that the extrapolation and generalization capabilities need to be further optimized by integrating physical models.Compared with the conventional state space equation model,the proposed method can improve the extrapolation accuracy and efficiency by 78%and 60%,respectively,which demonstrates the applied potential of this method in aerodynamic modeling.

浅议我国行政行为公定力界限的立法选择——以《中华人民共和国公务员法》第54条为焦点

行政行为公定力的界限一直是学术界争论的问题之一,《中华人民共和国公务员法》的出台为其界限的确定提供了一条分析路径。该法第54条的规定以行政行为是否明显违法为界限,确立了行政行为的有限公定力说。本文在分析这一规定的弊端后认为,这一规定既不利于行政相对人和公务员的权利保护,也不利于公务员和上级机关的职权行使和责任承担。建议在立法上采用完全公定力说,以避免上述弊端。

Three-dimensional pseudo-dynamic reliability analysis of seismic shield tunnel faces combined with sparse polynomial chaos expansion

To address the seismic face stability challenges encountered in urban and subsea tunnel construction,an efficient probabilistic analysis framework for shield tunnel faces under seismic conditions is proposed.Based on the upper-bound theory of limit analysis,an improved three-dimensional discrete deterministic mechanism,accounting for the heterogeneous nature of soil media,is formulated to evaluate seismic face stability.The metamodel of failure probabilistic assessments for seismic tunnel faces is constructed by integrating the sparse polynomial chaos expansion method(SPCE)with the modified pseudo-dynamic approach(MPD).The improved deterministic model is validated by comparing with published literature and numerical simulations results,and the SPCE-MPD metamodel is examined with the traditional MCS method.Based on the SPCE-MPD metamodels,the seismic effects on face failure probability and reliability index are presented and the global sensitivity analysis(GSA)is involved to reflect the influence order of seismic action parameters.Finally,the proposed approach is tested to be effective by a engineering case of the Chengdu outer ring tunnel.The results show that higher uncertainty of seismic response on face stability should be noticed in areas with intense earthquakes and variation of seismic wave velocity has the most profound influence on tunnel face stability.

Strength and plasticity improvement induced by strong grain refinement after Zr alloying in selective laser-melted AlSiMg1.4 alloy

In order to enhance the mechanical properties of the selective laser-melted(SLM) high-Mg content AlSiMg1.4 alloy,the Zr element was introduced.The influence of Zr alloying on the processability,microstructure,and mechanical properties of the alloy was systematically investigated through performing microstructure analysis and tensile testing.It was demonstrated that the SLM-fabricated AlSiMg1.4-Zr alloy exhibited high process stability with a relative density of over 99.5% at various process parameters.Besides,the strong grain refinement induced by the primary Al3Zr particle during the melt solidification process simultaneously enhanced both the strength and plasticity of the alloy.The values for the yield strength,ultimate tensile strength,and elongation of the SLM-fabricated AlSiMg1.4-Zr were(343±3) MPa,(485±4) MPa,and(10.2±0.2)%,respectively,demonstrating good strengthplasticity synergy in comparison to the AlSiMg1.4 and other Al-Si-based alloys fabricated by SLM.

Effects of Cr content on microstructure and mechanical properties of single crystal superalloy

Two experimental single crystal superalloys with 2% Cr and 4% Cr (mass fraction) were cast in a directionally solidified furnace, while other alloying element contents were kept unchanged. The effects of Cr content on the microstructure, phase stability, tensile properties at 1100 °C and stress rupture properties at 1070 °C and 160 MPa of the single crystal superalloy were investigated. The results show that the size ofγ′ phase particles become small and uniform, and the cubic shape turns a little regular with the increase of Cr content. Theγ′ directional coarsening and rafting were observed in the 2% Cr and 4% Cr alloys after long term aging (LTA) at 1100 °C. The rafting rate ofγ′ phase increased with increasing Cr content. Needle-shaped topologically close packed (TCP) phases precipitated and grew along fixed direction in both alloys. The precipitating rate and volume fraction of TCP phases significantly increased with the increase of Cr content. The tensile property of the alloy increased and the stress rupture properties of the alloy decreased with the increase of Cr content at high temperature. The increase of Cr content increased the partition ratio of TCP forming elements, Re, W, and Mo, and the saturation degrees of these elements inγ phases increased. Therefore, the high temperature phase stability of the alloy decreased with the increase of Cr content.

Heat-treated wood and its development in Europe

Efficient use of timber is a vital concern problem, especially in these regions where the forestry coverage ratio is decreasing. Studies on physical modification of wood have been taken more attention due to the increasing attentions on environmental protection. Thermal modification is emphasized and developed quickly in developing countries, especially in European countries. A large number of researches have been conducted and some industrial production plants have been built. This paper reviewed the history of heat treatment, exemplifies the industrial developments in several European countries, summarized the basic principle of heat treatment and describes the environmental characteristics. The properties of heat-treated wood and its usage are also summed up.

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.

The Influence of Plant Diversity and Functional Composition on Ecosystem Stability of Four Stipa Communities in the Inner Mongolia Plateau

The main purpose of this study was to examine the effects of plant species diversity and functional composition (the identity of the plant functional groups) on ecosystem stability of Stipa, communities in the Inner Mongolia Plateau. The research work was based on a 12-year study (from 1984 to 1995) of species abundance, diversity, and primary productivity of four Stipa communities, i.e. S. baicalensis Roshev., S. grandis P. Smirn., S, krylovii Roshev., and S. klemenzii Roshev. respectively. The Shnnon-Wiener index was used as a measurement of plant diversity, while functional composition was used to differentiate the functional groups that were included in the communities. The plant species of four Stipa communities were classified into functional groups based on the differences in life forms and ecological groups, which influence their performance in resource requirements, seasonality of growth, tolerance to water stress, and life history. Plant species were classified into five functional groups based on their differences in life form, shrubs and half shrubs, perennial bunch grasses, perennial rhizome grasses, forbs, annuals and biennials. Based on their differences in water requirement these species were classified into four functional groups: xerads, intermediate xerads, intermediate mesophytes, and mesophytes. The results showed: 1) Plant species diversity stabilized ecosystem processes. Shannon-Wiener index were 2.401 4, 2.172 0, 1.624 8, 0.354 3 from S. baicalensis community to S. grandis, S. krylovii and S. klemenzii community, respectively. The dynamics of the aboveground net primary productivity (ANPP) for a 12-year's period showed a reverse pattern, the coefficients of variation of the four communities were 21.94%, 20.63%, 29.21% and 39.72% respectively. 2) The Life form functional group component of diversity was a greater determinant of the ecosystem processes than the species component of diversity. The effects of perennial bunch grasses, perennial rhizome grasses and forbs on community stability were highly significant. 3) The ecological group component of diversity was also a great determinant of the ecosystem processes. The effects of xerads, intermediate xerads, and mesophytes on community stability were also very strong.

Novel disturbance compensating dynamic positioning of dredgers based on adaptive backstepping

In order to deal with the dynamic positioning system control problems of dredgers working under strong dredging reaction or harsh environments,an adaptive backstepping method is proposed.Disturbances are estimated and compensated for by the adaptive method without extra sensors on dredging equipment,and the control mechanism is simplified.Adaptive control is used to compensate for the reaction and environmental disturbances on the dredger,so the dredger can maintain the desired position with a minimum error and shock.The proposed adaptive robust controller guarantees the global asymptotic stability of the closed-loop system and rapid position tracking of the dredger.The simulation results show that the proposed controller has superior performance in position tracking and robustness to large disturbances.

MULTI-BODY AEROELASTIC STABILITY ANALYSIS OF TILTROTOR AIRCRAFT IN HELICOPTER MODE

The muhi-body analysis of the aeroelastic stability of the tiltrotor aircraft is presented. Muhi-body dynamic differential equations are combined with the equations of the unsteady dynamic inflow model to establish the complete unsteadily aeroelastic coupling analytical model of the tiltrotor. The stability of the tiltrotor in the helicopter mode is analyzed aiming at a semi span soft-inplane tihrotor model with an elastic wing. Parametric effects of the lag stiffness of blades and the flight speed are analyzed. Numerical simulations demonstrate that the multibody analytical model can analyze the aeroelastic stability of the tiltrotor aircraft in the helicopter mode.

On simulation of precise orbit determination of HY-2 with centimeter precision based on satellite-borne GPS technique

The HY-2 satellite carrying a satellite-borne GPS receiver is the first Chinese radar altimeter satellite, whose radial orbit determination precision must reach the centimeter level. Now HY-2 is in the test phase so that the observations are not openly released. In order to study the precise orbit determination precision and procedure for HY-2 based on the satellite- borne GPS technique, the satellite-borne GPS data are simulated in this paper. The HY-2 satellite-borne GPS antenna can receive at least seven GPS satellites each epoch, which can validate the GPS receiver and antenna design. What＇s more, the precise orbit determination processing flow is given and precise orbit determination experiments are conducted using the HY-2-borne GPS data with both the reduced-dynamic method and the kinematic geometry method. With the 1 and 3 mm phase data random errors, the radial orbit determination precision can achieve the centimeter level using these two methods and the kinematic orbit accuracy is slightly lower than that of the reduced-dynamic orbit. The earth gravity field model is an important factor which seriously affects the precise orbit determination of altimeter satellites. The reduced-dynamic orbit determination experiments are made with different earth gravity field models, such as EIGEN2, EGM96, TEG4, and GEMT3. Using a large number of high precision satellite-bome GPS data, the HY-2 precise orbit determination can reach the centimeter level with commonly used earth gravity field models up to above 50 degrees and orders.

Study on the combination ability and stability of rice restore line Yihui1577

Yihui1577 was bred after over 10 generations by crossing R16 and Yunan purple rice. Many new hybrid rice varieties have been bred with Yihui1577, of which Gangyou1577. Ilyou1577, Nyou1577 and Yixiang1577 were certified by Sichuan Crop Variety Release Committee, Gangyou1577 and Yixiang1577 were certified by National Crop Variety Release Committee. The series varieties bred with Yihui1577 have been used widely with accumulated area of 1,200,000 ha. By using Yihui1577 as breeding material, an excellent restore line Yihui3003 and some other restore lines, such as Yihui1979 and Yihui315 with good quality and combination ability have been bred. Analysis of combination ability and stability of restore line Yihui1577 was made by using agricultural experimentation and statistical approach. The combination ability analysis was made by not complete dual crossing method with 4 CMS lines and 6 restorer lines. It shows that the general combination ability effect value of Yihui1577 is 0.226, while Minghui63 is -0.113. So the general combination ability of Yihui1577 is prior to that of Minghui63. Stability analysis shows that the F value of Gangyou1577 is 1.81378, while Sanyou63 is 1.40327, both doesn＇t reach significant level. So Gangyou1577 has the same stability as Sanyou63.The same conclusion is got in the stability analysis of the breeds of II you 1577, Yixiang1577, Nyou 1577 and so on.

Stability for the Manifold of Equilibrium State of the Autonomous Birkhoff System

Studies the stability for them manifold of equilibrium state of the autonomous Birkhoffsystem. Uses the Liapunov's direct method and the first approximation method to obtain thestability criterion for the manifold of equilibrium state of the system. Gives an example toillustrate the application of the result.

Identification and Cu Enrichment Capacity of TLSB_2-K, a Cu-tolerant Strain

[Objective] The Cu-tolerance and Cu enrichment capacity of TLSB2-K were investigated. [Method] The previously isolated TLSB2-K strain was identified though morphological observation, gram staining and 16S rDNA sequence alignment. In ad- dition, the effects of temperature, pH and osmotic pressure on the growth of strain were also investigated by using shaking culture. The Cu-tolerance and Cu enrich- ment capacity of TLSB2-K strain under Cu stress were also studied. [Result] The results showed TLSB2-K belongs to Bacillus spp., and its optimum growth conditions were as follows： temperature, 27 ~C; pH, 7.0; osmotic pressure, 1.1% NaCI. When the Cu concentration ranged from 100 mg/L to 500 mg/L, the strain grew well; when the Cu concentration ranged from 100 mg/L to 400 mg/L, the Cu content in bacteria was increased with the increase of Cu concentration; when the Cu con- centration was 400 mg/L and the incubation time was 30 h, the Cu content in bac- teria reached the peak （2 250 mg/kg）; the highest tolerant concentration was 700 mg/L. [Conclusion] TLSB2-K strain had relatively high Cu tolerance and Cu enrich- ment capacity. They had important theoretical research and engineering application values.

Identification of Strawberry Anthracnose Pathogens and Screening of Germicides

[Objective] This study aimed to identify strawberry anthracnose pathogens and screen appropriate germicides. [Method] Strawberry anthracnose pathogens in Jurong City of Jiangsu Province were isolated and identified. The toxicities of sever-al germicides to Col etotrichum fragariae were determined with indoor mycelial growth inhibition assay. Field control test was preformed to further verify the control efficacy of germicides. [Result] The isolated strawberry anthracnose pathogenic strains were identified as C. gloeosporioide from genus Col etotrichum of subphylum Deuteromycotina. Prochloraz, pyrazole Kresoxim and hexaconazole al exhibited good indoor control effects; 25% pyrazole Kresoxim EC2000-fold solution, 24% azoxys-trobin＆#183;hexaconazole （azoxystrobin∶hexaconazole=1∶2） SC1500-fold solution and 25%prochloraz EC1000-fold solution al exhibited significant field control efficacy. [Con-clusion] The study provides reference for the alternate use of germicides in actual production.

Effect of hot working on microstructure and mechanical properties of TC11/Ti_2AlNb dual-alloy joint welded by electron beam welding process

The influence of hot working on the microstructures of TC11/Ti2 Al Nb dual-alloy joints welded by electron beam welding(EBW) process was investigated. The tensile tests were performed at room temperature for specimens before and after thermal exposure. The results show that the fusion zone of TC11/Ti2 Al Nb dual-alloy joint welded by EBW is mainly composed of β phase. After deformation and heat treatment, the grain boundaries of the as-cast alloy are broken and the fusion zone mainly consists of β, α2and α phases. The fusion zone performs poor property in the tensile test. Specimens before and after thermal exposure all fail in this area under different deformation conditions. The ultimate tensile strength of specimens after heat treatment is up to 1190 MPa at room temperature. The joints by water quenching after deformation have better plasticity with an elongation up to 4.4%. After thermal exposure at 500 °C for 100 h, the tensile strength of the specimen slightly rises while the ductility changes a little. SEM observation shows that the fracture mechanism is predominantly transgranular under different deformation conditions.

Optimization of Artificial Rearing Methods for Plutella xylostella L.(Plutellidae)and Its Susceptibility to Five Types of Insecticides

[Objective] The research aimed to optimize laboratory artificial rearing methods for Plutella xylostella L. and to select out effective insecticides against this pest species. [Method] Brassica chinensis seedlings were cultivated in the laboratory at （25±1）℃, 60-75% RH, and a photoperiod of 14：10 （L：D） h. The green blow molding papers were used to collect eggs, and Brassica oleracea seedlings were cultivated to breed Plutella xylostella L. until the insects were ready for use. Mean-while, the susceptibility of 3rd instar larvae of Plutella xylostella L. to five types of insecticides was tested by leaf-dipping method. [Result] Plutella xylostella L. larvae were found well-grown and uniform in developmental stages with average pupa weight of 5.4 mg, pupa emergence percentage of 94.0 % and egg number of 135.1 per female. The LCso values of 3rd instar Plutella xylostella L. larvae against 200 g/L chlorantraniliprole SC, 20% flubendiamide WG, 150 g/L indoxacarb EC, 200 g/L tebufenozide SC and 1.8% abamectin EC, were 0.152, 0.223, 1.151, 93.340 and 0.128 mg/L, respectively. [Conclusion] This rearing method is easy to be implemented and of great practicality, suitable for mass propagation of P. xylostella L. Abamectin, chlorantraniliprole and flubendiamide showed high insecticidal activities, so these three insecticides can be used alternately for the field prevention and control of Plutella xylostella L.

Determination of Geopotential of Local Vertical Datum Surface

This paper first develops the approaches to determine the geopotential of the local mean sea level,and then investigates the offset of the 1985 vertical datum surface defined by the mean sea level of Yellow Sea at the Dagang Tide Gauge in Qingdao city using the developed approaches and GPS/leveling data.It shows that the geopotential of the local mean sea level at the tide gauge is equal to 62 636 853.5±0.2 m2·s -2 and that the 1985 vertical datum surface is 24.6±5.4 cm above the geoid realized by the geopotential W 0= 62 636 856.0±0.5 m2·s -2.

COMPARISON BETWEEN TWO ANALYTICAL MODELS OF HELICOPTER GROUND RESONANCE

The 2-dimensional equivalent model used in helicopter ground resonance analysis is convenient for its simplicity and clarity. The equivalent body mass, the stiffness and the damping are derived from the modal charaCteristics. In this paper, a 3-dimensional space model is constructed to analyse the ground resonance.There is little difference between the calculated results of the 2-dimensional equivalent model and those of the 3-dimensional space model. Hence, the 2-dimensional model is verified for the practical application. Generally, the linear lead-lag damping of the equivalent rotor blade at the modal frequency is derived from the lead-lag damper characteristics by a procedure of iteration. The transformation of the imaginary part of the complex modulus of the viscoelastic damper into a linear velocity damping is complicated in analysis. A method to use the complex modulus directly in the ground resonance analysis is derived and verified.