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In order to suppress the effect of the temperature variation on the wavefront of the laser communication terminal, the secondary mirror support with flexure hinges is designed. The series-wound straight-circle flexure hinge is designed to achieve the maximal variation range of the flexibility or stiffness with the limit of flexure hinges geometrical size. The position and quantity of the flexure hinges are determined to control the deformation direction of the secondary mirror. In order to search the direction in which the wavefront aberration is minimum, the flexure hinges parameters are optimized with the system wavefront aberration as the optimization objective. The prototype of the laser communication terminal is constructed and the value of the wavefront aberration is measured under the condition of 20 ± 2°C. Experimental results show that the value of the wavefront aberration root mean square (RMS) is reduced from 0.066λ to 0.042λ, meeting the requirement of RMS less than 1/20λ (λ=632.8 nm). The athermal design method presented in this paper provides a novel way for the athermal design of the small aperture mirror support in off-axis optical systems.

Cucumber mosaic virus (CMV) has an extensive host range, however there are few reports of CMV infecting fruit crops in China. In this study, CMV was detected using RT-PCR and Western blot from six kinds of fruit crops including pear in Heilongjiang province, apricot, grape, peach, Castanea mollissima and Malus spectabilis in Shandong province in China. This is the first report of CMV naturally infecting these six fruit crops in China. In addition, this is also the first report of CMV in Heilongjiang province which is the northest province of China.

In this paper, we present a sharp upper bound for the least signless Laplacian eigenvalue of a graph involving its domination number. Moreover, we determine some extremal graphs which attain the sharp bound.

There are deviations between real parameters and thermal design parameters on thermophysical attribute of focal plane assembly (FPA). The parameters are difficult to be determined accurately and the thermal design scheme will be affected with the values of the parameters. The thermal design problem of FPA is described by means of system sensitivity theory. The in-orbit heat balance equations are established, and the thermal design parameters, which might affect the temperature distribution of the FPA, are given. As an example, the sensitivity of thermal design parameters is analyzed for a FPA in a space spectral imaging instrument. A basis to determine the structural and thermophysical parameters for FPA is gotten, furthermore, an analytical method is provided for reliability validation of thermal design and operating reliability on orbit. It is shown that contact heat-transfer coefficient between mounted surfaces and surface emissivity are the main parameters affecting mean temperature of Charge converse device (CCD). The power of the inner heat source, thermal conductivity and inner contact heat-transfer coefficient are the primary parameters affecting temperature difference between CCD and the heat-transfer block. The thermal test is set up, and it is illuminated that the sensitivity analysis strategy based on the thermal design scheme is effective and feasible.

By an edge-coloring induced by generalization of Paley graph and computer searching, we show that that Ramsey numbers of Kn − e in three colors for n = 6, 7, 8, 9 are at least 472, 1102, 3208, 5962, respectively.

In this paper, a series of nanoparticle bonded metalloporphyrins with different saturation magnetization were synthesized by a modified silanation method. Under geomagnetic field (5 × 10−5 T), with the increase of the saturation magnetizations, the growth rate of yields of cyclohexanol in the cyclohexane oxidation with iodosylbenzene catalyzed by these nanoparticle bonded metalloporphyrins followed the order of ironporphyrin > manganeseporphyrin > cobaltporphyrin. A series of nanoparticle bonded metalloporphyrins with different saturation magnetization were synthesized by a modified silanation method. Under geomagnetic field (5 × 10−5 T), with the increase of the saturation magnetizations, the growth rate of yields of cyclohexanol in the cyclohexane oxidation with iodosylbenzene catalyzed by these nanoparticle bonded metalloporphyrins followed the order of ironporphyrin > manganeseporphyrin > cobaltporphyrin.

Denote by $${\mathcal{T}(2k)}$$ the set of trees of order 2k with perfect matchings. GUO [Guo, Linear Algebra Appl. 368:379–385, 2003.] determined the largest value of Laplacian spectral radii μ(T) of the trees T in $${\mathcal{T}(2k)}$$ and gave the corresponding tree T in $${\mathcal{T}(2k)}$$ whose μ(T) reaches this largest value. In this paper, we determine the second to the sixth largest values of μ(T) of the trees T in $${\mathcal{T}(2k)}$$ and also give the corresponding trees T in $${\mathcal{T}(2k)}$$ whose μ(T) reach these values.

Wenger’s graph Hm(q) is a q-regular bipartite graph of order 2qm constructed by using the m-dimensional vector space Fqm over the finite field Fq. The existence of the cycles of certain even length plays an important role in the study of the accurate order of the Turan number ex(n; C2m) in extremal graph theory. In this paper, we use the algebraic methods of linear system of equations over the finite field and the “critical zero-sum sequences” to show that: if m ≥ 3, then for any integer l with l ≠ 5, 4 ≤ l ≤ 2ch(Fq) (where ch(Fq) is the character of the finite field Fq) and any vertex v in the Wenger’s graph Hm(q), there is a cycle of length 2l in Hm(q) passing through the vertex v.

Mesoscale eddy plays an important role in the ocean circulation. In order to improve the simulation accuracy of the mesoscale eddies, a three-dimensional variation (3DVAR) data assimilation system called Ocean Variational Analysis System (OVALS) is coupled with a POM model to simulate the mesoscale eddies in the Northwest Pacific Ocean. In this system, the sea surface height anomaly (SSHA) data by satellite altimeters are assimilated and translated into pseudo temperature and salinity (T-S) profile data. Then, these profile data are taken as observation data to be assimilated again and produce the three-dimensional analysis T-S field. According to the characteristics of mesoscale eddy, the most appropriate assimilation parameters are set up and testified in this system. A ten years mesoscale eddies simulation and comparison experiment is made, which includes two schemes: assimilation and non-assimilation. The results of comparison between two schemes and the observation show that the simulation accuracy of the assimilation scheme is much better than that of non-assimilation, which verified that the altimetry data assimilation method can improve the simulation accuracy of the mesoscale dramatically and indicates that it is possible to use this system on the forecast of mesoscale eddies in the future.

This study aims at assessing the relative impacts of four major components of the tropical Pacific Ocean observing system on assimilation of temperature and salinity fields. Observations were collected over a period between January 2001 through June 2003 including temperature data from the expendable bathythermographs (XBT), thermistor data from the Tropical Ocean Global Atmosphere Tropical Atmosphere-Ocean (TOGA-TAO) mooring array, sea level anomalies from the Topex/Poseidon and Jason-1 altimetry (T/P-J), and temperature and salinity profiles from the Array for Real-time Geostrophic Oceanography (ARGO) floats. An efficient three-dimensional variational analysis-based method was introduced to assimilate the above data into the tropical-Pacific circulation model. To evaluate the impact of the individual component of the observing system, four observation system experiments were carried out. The experiment that assimilated all four components of the observing system was taken as the reference. The other three experiments were implemented by withholding one of the four components. Results show that the spatial distribution of the data influences its relative contribution. XBT observations produce the most distinguished effects on temperature analyses in the off-equatorial region due to the large amount of measurements and high quality. Similarly, the impact of TAO is dominant in the equatorial region due to the focus of the spatial distribution. The Topex/Poseidon-Jason-1 can be highly complementary where the XBT and TAO observations are sparse. The contribution of XBT or TAO on the assimilated salinity is made by the model dynamics because no salinity observations from them are assimilated. Therefore, T/P-J, as a main source for providing salinity data, has been shown to have greater impacts than either XBT or TAO on the salinity analysis. Although ARGO includes the subsurface observations, the relatively smaller number of observation makes it have the smallest contribution to the assimilation system.

This paper fist gives an investigation on trusted computing on mainstream operation system (OS). Based on the observations, it is pointed out that Trusted Computing cannot be achieved due to the lack of separation mechanism of the components in mainstream OS. In order to provide a kind of separation mechanism, this paper proposes a separated domain-based kernel model (SDBKM), and this model is verified by non-interference theory. By monitoring and simplifying the trust dependence between domains, this model can solve problems in trust measurement such as deny of service (DoS) attack, Host security, and reduce the overhead of measurement.

A new 3DVAR-based Ocean Variational Analysis System (OVALS) is developed. OVALS is capable of assimilating in situ sea water temperature and salinity observations and satellite altimetry data. As a component of OVALS, a new variational scheme is proposed to assimilate the sea surface height data. This scheme considers both the vertical correlation of background errors and the nonlinear temperature-salinity relationship which is derived from the generalization of the linear balance constraints to the nonlinear in the 3DVAR. By this scheme, the model temperature and salinity fields are directly adjusted from the altimetry data. Additionally, OVALS can assimilate the temperature and salinity profiles from the ARGO floats which have been implemented in recent years and some temperature and salinity data such as from expendable bathythermograph, moored ocean buoys, etc. A 21-year assimilation experiment is carried out by using OVALS and the Tropical Pacific circulation model. The results show that the assimilation system may effectively improve the estimations of temperature and salinity by assimilating all kinds of observations. Moreover, the root mean square errors of temperature and salinity in the upper depth less than 420 m reach 0.63°C and 0.34 psu.

In many applications of 3DVAR, the balance constraints can be considered via two main approaches: weak constraint method which adds penalty terms to the cost function; and proper definition of the background error covariance matrix with non-zero cross-correlation sub-matrices. The weak constraint approach requires determining the weighting matrices of the penalty terms. The background error covariance approach does not require determining those additional weighting matrices. However, it is only applicable to those linear or linearized balance constraints. A novel approach is proposed based on the background error covariance approach by generalizing the so-called Derber-Bouttier formulation. An assimilation experiment of estimating temperature and salinity from the sea surface dynamic height observation is given to illustrate the proposed treatments of nonlinear balance constraints.

A security kernel architecture built on trusted computing platform in the light of thinking about trusted computing is presented. According to this architecture, a new security module TCB (Trusted Computing Base) is added to the operation system kernel and two operation interface modes are provided for the sake of self-protection. The security kernel is divided into two parts and trusted mechanism is separated from security functionality. The TCB module implements the trusted mechanism such as measurement and attestation, while the other components of security kernel provide security functionality based on these mechanisms. This architecture takes full advantage of functions provided by trusted platform and clearly defines the security perimeter of TCB so as to assure self-security from architectural vision. We also present function description of TCB and discuss the strengths and limitations comparing with other related researches.

Methods for studying oceanic circulation from hydrographic data are reviewed in the context of their applications in the South China Sea. These methods can be classified into three types according to their different dynamics as follows: (1) descriptive methods, (2) diagnostic methods without surface and bottom forcing, and (3) diagnostic methods with the above boundary forcing. The paper discusses the progress made in the above methods together with the advancement of study in the South China Sea circulation.

A novel sesquiterpenoid was isolated from the whole plant of Ecdysanthera rosea Hook. et Arn. Its structure was elucidated as tricyclo[5,3,1,0(2,4)]-3-aldehyde-3,11-dimethyl-8-methanoic acid on the basis of spectral evidence (1D and 2D NMR) and was named ecdysanthblic acid.