Please wait a minute...

Current Issue

, Volume 4 Issue 1 Previous Issue    Next Issue
Mechanics & Civil Engineering
Three-dimensional analysis of a thick FGM rectangular plate in thermal environment
CHEN Wei-qiu, BIAN Zu-guang, DING Hao-jiang
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 1-7.   https://doi.org/10.1631/jzus.2003.0001
Abstract   PDF (0KB)
The thermal behavior of a thick transversely isotropic FGM rectangular plate was investigated within the scope of three-dimensional elasticity. Noticing many FGMs may have temperature-dependent properties, the material constants were further considered as functions of temperature. A solution method based on state-space formulations with a laminate approximate model was proposed. For a thin plate, the method was clarified by comparison with the thin plate theory. The influences of material inhomogeneity and temperature-dependent characteristics were finally discussed through numerical examples.
Theoretical solution of a spherically isotropic hollow sphere for dynamic thermoelastic problems
WANG Hui-ming, DING Hao-jiang, CHEN Wei-qiu
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 8-12.   https://doi.org/10.1631/jzus.2003.0008
Abstract   PDF (0KB)
The separation of variables method was successfully used to resolve the spherically symmetric dynamic thermoelastic problem for a spherically isotropic elastic hollow sphere. Use of the integral transform can be avoided by means of this method, which is also appropriate for an arbitrary thickness hollow sphere subjected to arbitrary thermal and mechanical loads. Numerical results are presented to show the dynamic stress responses in the uniformly heated hollow spheres.
Parametrically excited oscillation of stay cable and its control in cable-stayed bridges
SUN Bing-nan, WANG Zhi-gang, KO, J.M., NI, Y.Q.
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 13-20.   https://doi.org/10.1631/jzus.2003.0013
Abstract   PDF (0KB)
This paper presents a nonlinear dynamic model for simulation and analysis of a kind of parametrically excited vibration of stay cable caused by support motion in cable-stayed bridges. The sag, inclination angle of the stay cable are considered in the model, based on which, the oscillation mechanism and dynamic response characteristics of this kind of vibration are analyzed through numerical calculation. It is noted that parametrically excited oscillation of a stay cable with certain sag, inclination angle and initial static tension force may occur in cable-stayed bridges due to deck vibration under the condition that the natural frequency of a cable approaches to about half of the first model frequency of the bridge deck system. A new vibration control system installed on the cable anchorage is proposed as a possible damping system to suppress the cable parametric oscillation. The numerical calculation results showed that with the use of this damping system, the cable oscillation due to the vibration of the deck and/or towers will be considerably reduced.
Three-dimensional nonlinear flutter analysis of long-span suspension bridges during erection
ZHANG Xin-jun, SUN Bing-nan, XIANG Hai-fan
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 21-27.   https://doi.org/10.1631/jzus.2003.0021
Abstract   PDF (0KB)
In this work, the aerodynamic stability of the Yichang Suspension Bridge over Yangtze River during erection was determined by three-dimensional nonlinear flutter analysis, in which the nonlinearities of structural dynamic characteristics and aeroelastic forces caused by large deformation are fully considered. An interesting result obtained was that the bridge was more stable when the stiffening girders were erected in a non-symmetrical manner as opposed to the traditional symmetrical erection schedule. It was also found that the severe decrease in the aerodynamic stability was due to the nonlinear effects. Therefore, the nonlinear factors should be considered accurately in aerodynamic stability analysis of long-span suspension bridges during erection.
Transient response of piles-bridge under horizontal excitation
ZHU Bin, CHEN Ren-peng, CHEN Yun-min
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 28-34.   https://doi.org/10.1631/jzus.2003.0028
Abstract   PDF (0KB)
Moving ships and other objects drifting on water often impact a bridge\'s pile foundations. The mechanical model of the piles-bridge structure under horizontal forcing was established, and a time-domain approach based on Finite-difference Method was developed for analyzing the dynamic response of the piles-bridge structure. For a single pile, good agreement between two computed results validated the present approach. The slenderness ratio of the pile, the pile-soil stiffness ratio and the type of the structure influence the dynamic response of the piles-bridge structure. The computed results showed that the stiffness of the structure determines the dynamic response of the piles-bridge structure under horizontal forcing.
Study of interaction between shock wave and unsteady boundary layer
DONG Zhi-yong, HAN Zhao-yuan
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 35-39.   https://doi.org/10.1631/jzus.2003.0035
Abstract   PDF (0KB)
This paper reports theoretical and experimental study of a new type of interaction of a moving shock wave with an unsteady boundary layer. This type of shock wave-boundary layer interaction describes a moving shock wave interaction with an unsteady boundary layer induced by another shock wave and a rarefaction wave. So it is different from the interaction of a stationary shock wave with steady boundary layer, also different from the interaction of a reflected moving shock wave at the end of a shock tube with unsteady boundary layer induced by an incident shock. Geometrical shock dynamics is used for the theoretical analysis of the shock wave-unsteady boundary layer interaction, and a double-driver shock tube with a rarefaction wave bursting diaphragm is used for the experimental investigation in this work.
Information & Computer Technology
An adaptive ant colony system algorithm for continuous-space optimization problems
Li Yan-jun, Wu Tie-jun
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 40-46.   https://doi.org/10.1631/jzus.2003.0040
Abstract   PDF (0KB)
Ant colony algorithms comprise a novel category of evolutionary computation methods for optimization problems, especially for sequencing-type combinatorial optimization problems. An adaptive ant colony algorithm is proposed in this paper to tackle continuous-space optimization problems, using a new objective-function-based heuristic pheromone assignment approach for pheromone update to filtrate solution candidates. Global optimal solutions can be reached more rapidly by self-adjusting the path searching behaviors of the ants according to objective values. The performance of the proposed algorithm is compared with a basic ant colony algorithm and a Square Quadratic Programming approach in solving two benchmark problems with multiple extremes. The results indicated that the efficiency and reliability of the proposed algorithm were greatly improved.
Improvement of the termination criterion for subdivision of the rational Bézier curves
ZHANG Ren-jiang, WANG Guo-jin
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 47-52.   https://doi.org/10.1631/jzus.2003.0047
Abstract   PDF (0KB)
By using some elementary inequalities, authors in this paper makes further improvement for estimating the heights of Bézier curve and rational Bézier curve. And the termination criterion for subdivision of the rational Bézier curve is also improved. The conclusion of the extreme value problem is thus further confirmed.
Effects of structural parameters and rigidity of driving diaphragm on flow characteristics of micro valveless pump
XIE Hai-bo, FU Xin, YANG Hua-yong
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 53-57.   https://doi.org/10.1631/jzus.2003.0053
Abstract   PDF (0KB)
The structure and operating principle of micro valveless pump were investigated theoretically and experimentally. The mathematical model of pressure and flow rate within the micro nozzle/diffuser was established to analyze the effects of nozzle/diffuser parameters on the output flow rate of the micro valveless pump. The experiments were carried out with different structural parameters, driving frequencies, vibration amplitudes and stiffness of the driving diaphragms. Effects of the structural parameters and driving conditions on the operation performance of the pump are discussed in detail. The work provides useful reference for structure optimization selection of the driving diaphragm of micro valveless pump.
Adaptive terminal sliding mode control for high-order nonlinear dynamic systems
ZHUANG Kai-yu, SU Hong-ye, ZHANG Ke-qin,, CHU Jian
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 58-63.   https://doi.org/10.1631/jzus.2003.0058
Abstract   PDF (0KB)
An adaptive terminal sliding mode control (SMC) technique is proposed to deal with the tracking problem for a class of high-order nonlinear dynamic systems. It is shown that a function augmented sliding hyperplane can be used to develop a new terminal sliding mode for high-order nonlinear systems. A terminal SMC controller based on Lyapunov theory is designed to force the state variables of the closed-loop system to reach and remain on the terminal sliding mode, so that the output tracking error then converges to zero in finite time which can be set arbitrarily. An adaptive mechanism is introduced to estimate the unknown parameters of the upper bounds of system uncertainties. The estimates are then used as controller parameters so that the effects of uncertain dynamics can be eliminated. It is also shown that the stability of the closed-loop system can be guaranteed with the proposed control strategy. The simulation of a numerical example is provided to show the effectiveness of the new method.
Chemistry & Chemical Engineering
Dynamic balancing of dual-rotor system with very little rotating speed difference
YANG Jian, HE Shi-zheng, WANG Le-qin
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 64-68.   https://doi.org/10.1631/jzus.2003.0064
Abstract   PDF (0KB)
Unbalanced vibration in dual-rotor rotating machinery was studied with numerical simulations and experiments. A new method is proposed to separate vibration signals of inner and outer rotors for a system with very little difference in rotating speeds. Magnitudes and phase values of unbalance defects can be obtained directly by sampling the vibration signal synchronized with reference signal. The balancing process is completed by the reciprocity influence coefficients of inner and outer rotors method. Results showed the advantage of such method for a dual-rotor system as compared with conventional balancing.
Molecular dynamics simulation study on behaviors of liquid 1,2-dichloroethane under external electric fields
DU Zhi-qiang, CHEN Cheng-long
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 69-75.   https://doi.org/10.1631/jzus.2003.0069
Abstract   PDF (0KB)
Molecular dynamics simulation was carried out to study the behavior of liquid 1,2-dichloroethane molecules under external electric fields including direct current field, alternating current field and positive-half-period cosin field. The maximum applied field strength was 108 V/m, the maximum frequency of the alternating current field and that of the positive-half-period cosine field was 1012 Hz. The simulation revealed that the field type and field strength act on the population of the molecular configuration. In the strong direct current field, all trans forms converted completely into gauche forms. Order parameter and the correlation of the system torsion angle were also investigated. The results suggested that these two dynamical parameters depended also on the field type and the field strength. The maximum of order parameter was found to be at 0.6 in the strong direct current field.
Applied Mathematics
Construction of some hypergroups from combinatorial structures
Ali Reza Ashrafi, Ahmad Reza Eslami-Harandi
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 76-79.   https://doi.org/10.1631/jzus.2003.0076
Abstract   PDF (0KB)
Jajcay\'s studies (1993; 1994) on the automorphism groups of Cayley maps yielded a new product of groups, which he called, rotary product. Using this product, we define a hyperoperation ⊙ on the group Syme(G), the stabilizer of the identity e∈G in the group Sym(G). We prove that (Syme(G), ⊙) is a hypergroup and characterize the subhypergroups of this hypergroup. Finally, we show that the set of all subhypergroups of Syme(G) constitute a lattice under ordinary join and meet and that the minimal elements of order two of this lattice is a subgroup of Aut(G).
On the approximate zero of Newton method
HUANG Zheng-da
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 80-85.   https://doi.org/10.1631/jzus.2003.0080
Abstract   PDF (0KB)
A judgment criterion to guarantee a point to be a Chen\'s approximate zero of Newton method for solving nonlinear equation is sought by dominating sequence techniques. The criterion is based on the fact that the dominating function may have only one simple positive zero, assuming that the operator is weak Lipschitz continuous, which is much more relaxed and can be checked much more easily than Lipschitz continuous in practice. It is demonstrated that a Chen\'s approximate zero may not be a Smale\'s approximate zero. The error estimate obtained indicated the convergent order when we use |f(x)|<ε to stop computation in software. The result can also be applied for solving partial derivative and integration equations.
Biological Engineering
Surface plasmon resonance analysis to evaluate the importance of heparin sulfate groups\' binding with human aFGF and bFGF
WU Xiao-feng, XU Ya-xiang, SHEN Guo-xin, KAMEI Kaeko, TAKANO Ryo, HARA Saburo
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 86-94.   https://doi.org/10.1631/jzus.2003.0086
Abstract   PDF (0KB)
Human acidic and basic fibroblast growth factors (aFGF and bFGF) are classic and well characterized members of the heparin-binding growth factor family. Heparin is generally thought to play an extremely important role in regulating aFGF and bFGF bioactivities through its strong binding with them. In order to unravel the mechanism of the interactions between heparin and FGFs, and evaluate the importance of heparin sulfate groups\' binding with FGFs, surface plasmon resonance analyses were performed using IAsys Cuvettes System. Heparin and its regioselectively desulfated derivatives were immobilized on the cuvettes. aFGF and bFGF solutions with different concentrations were pipetted into the cuvettes and the progress of the interaction was monitored in real-time by Windows-based software, yielding kinetic and equilibrium constants for these interactions. In addition, in order to reduce the delicate difference among the cuvettes, inhibition analyses of mixture of FGFs and immobilized native heparin by modified heparins were also done. The data from these two methods were similar, indicating that all sulfate groups at 2-O, 6-O and N- in heparin were required for the binding to aFGF; and that their contribution to the binding was in the order 2-O, N- and 6-O-sulfate group. In contrast, definite contribution of the 6-O-sulfate group to the binding with bFGF was most apparent, while the other two sulfate groups appeared to be necessary in the order 2-O and N-sulfate group. These methods established here can be used for analysing the effect of sulfate groups in heparin on the binding with other human FGF members or other heparin-binding proteins.
Quantitative assessment of the infection rate of the entomophthoraceous fungus, Zoophthora anhuiensis against the green peach aphid Myzus persicae
FENG Ming-guang, XU Qian
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 95-100.   https://doi.org/10.1631/jzus.2003.0095
Abstract   PDF (0KB)
A two-step method was developed to quantitatively assess the infection rate of the entomophthoraceous fungus, Zoophthora anhuiensis (Li) Humber, on the green peach aphid, Myzus persicae (Sulzer). Firstly, a standard time-dose-mortality relationship, established by modeling data from bioassay 1 at varying conidial dosages (0.4-10.4 conidia/mm2) of Z. anhuiensis F97028, was used to yield an estimate of expected mortality probability at a given dosage. Secondly, bioassay 2 was conducted by simultaneously exposing six ≤4-day-old nymphal colonies to a shower of Z. anhuiensis conidia at each of four dosages (resulting from exposures of 0.3-8.0 min). Subsequently, the colonies were separately immersed in a 0.1% chlorothalonil solution for 0.5 min to disinfect all surviving conidia on the host integument from 1-12 h after exposure under temperature treatments of 15 and 20°C, respectively. The infection rate during a specific period from the end of the exposure to the immersion was then estimated as the ratio of the observed mortality over the expected mortality probability at a particular dosage. The results showed that the infection of M. persicae from Z. anhuiensis was highly rapid with little difference between aphid colonies maintained at 15 and 20°C before being immersed in the fungicidal solution after exposure. The first 6-hour period after exposure was most crucial to successful infection of the fungus with the infection rate greatly depending on conidial dosages. It took ≤1 h to infect>50% of the aphids at a dosage of >1.5 conida/mm2 and >90% at >50 conidia/mm2.
Responses of ABA and CTK to soil drought in leafless and leafy apple tree
LI Yan, PAN Hai-chun, LI De-quan
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 101-108.   https://doi.org/10.1631/jzus.2003.0101
Abstract   PDF (0KB)
The authors tested the contents of ABA (abscisic acid), ZR (zeatin riboside), DHZR (dihydrozeatin riboside) and iPA (isopentenyl adenosine) in leafless and leafy apple trees (Red Fuji/Malus micromalus Makino) during soil drought stress. ABA concentration in drought stressed leafless trees increased significantly compared to the controls. ABA both in roots and xylem rose steadily in the earlier drought stage, reaching a maximum of 1.46±0.35 nmol g-1FW and 117 nmol l-1 after the 8th day. Similar change patterns of ABA concentration was observed in the leafy trees during soil drought stress; ABA concentrations in roots and xylem sap increased and reached the maximum in the first three days; after 8th day, it decreased slightly, whereas leaf ABA concentration increased steadily in drought stressed plants throughout the duration of the experiment. Between drought stressed and control trees, no significant differences were observed in concentration of ZR and DHZR in both leafless and leafy trees; whereas iPA concentration of the drought stressed leafless and leafy plants decreased markedly in the later stage of drought. These results showed that endogenous ABA originated mainly from the roots in the earlier drought stage, and mainly from the leaves in the later drought stage. Total CTK showed no reduction in the earlier drought stage and decreased in the later drought stage.
Influence of hydroxypropyl methylcellulose edible coating on fresh-keeping and storability of tomato
ZHUANG Rong-yu, HUANG Yao-wen
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 109-113.   https://doi.org/10.1631/jzus.2003.0109
Abstract   PDF (0KB)
The effect of application of cellulose-based edible coating, hydroxypropyl methylcellulose (HPMC) to mature-green tomatoes on the firmness and color was investigated. Tomatoes were stored at 20°C for up to 18 days. Firmness decreased as storage time increased in all treatments. However, application of HPMC edible coating delayed softening of tomatoes during 18 days of storage at 20°C. At days 7, 13 and 18, the firmness of tomatoes coated with HPMC was significantly (P≤0.05) greater than the firmness of uncoated tomatoes. The study also confirmed that HPMC coatings could significantly (P≤0.05) delay the changes in color of tomatoes stored at 20°C. The ripening of tomatoes from the pink stage to the red stage was successfully retarded. HPMC coating could extend the shelf life of fresh tomatoes. The retardation of the rate of loss of firmness could reduce the economic loss that would result from spoilage by mechanical injury during transportation of tomatoes.
Biomedicine
Study on the effect of doxorubicin on expressions of genes encoding myocardial sarcoplasmic reticulum Ca2+ transport proteins and the effect of taurine on myocardial protection in rabbits
HUANG Xian-mei, ZHU Wei-hua, KANG Man-li
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2003, 4(1): 114-120.   https://doi.org/10.1631/jzus.2003.0114
Abstract   PDF (0KB)
To investigate the effect of doxorubicin (DOX) on gene expression of the myocardial sarcoplasmic reticulum (SR) Ca2+ transport proteins and the mechanism of taurine (Tau) protecting cardiac muscle cells, 9 rabbits were injected with DOX, 8 rabbits with DOX and Tau, and 9 rabbits with normal saline. Cardiac function, concentration of calcium in cardiomyocytes (Myo[Ca2+]i), activity of SR Ca2+-ATPase(SERCA2a), level of SERCA2a mRNA and Ca2+ released channels(RYR2)mRNA were detected. The left ventricle tissues were observed by electron microscopy. The results showed that cardiac index, left ventricular systolic pressure, activity of SR Ca2+-ATPase and level of SERCA2a mRNA decreased, while Myo[Ca2+]i increased in DOX-treated rabbits. DOX could not affect the level of RYR2 mRNA. Tau intervention could alleviate the increase of left ventricular diastolic pressure, Myo[Ca2+]i and the decrease of SERCA2a mRNA induced by doxorubicin. The results suggested that downregulation of SERCA2a gene expression was an important mechanism of DOX-induced cardiomyopathy and that Tau could partially improve the heart function by reducing calcium overload and alleviating downregulation of SERCA2a mRNA.
19 articles

NoticeMore

Links