Advanced Materials Research Vols. 433-440

Abstract: The problem of low frequency oscillations (LFOs) parameters identification in power system with the method of improved Hilbert-Huang transform (HHT) is addressed. LFOs probably cause the great potential threat to the stable operation of power system, so identifying the parameters of LFOs is very important to develop the control strategies of restraining oscillations. In this paper, the LFOs signal is first processed by empirical mode decomposition (EMD) which is improved by the approach of endpoint extension used AR data prediction, stop shifting criterion and end condition via energy difference factor. The improved EMD is able to avoid the energy leakage and damping loss and also make the intrinsic mode functions (IMFs) closer to the true oscillations. Then the approach of parameters identification using least squares (LS) fitting algorithm based on the results of IMFs’ Hilbert transform is presented. Finally, case studies demonstrate the effectiveness of improved HHT process and LS parameters identification methods used in LFOs analysis of power system.

Abstract: The Adult Preventive Care Service had been starting to practice since 1996 in Taiwan, which hoped to find the dangerous factors for unhealthy early by regular health examination. Previous studies have shown that hypertension, high cholesterol and hyperglycemia are three common diseases and the complications for Cerebro Vascular Disease, heart diseases and diabetes are also ranked 2 to 4 of ten reasons of death in Taiwan. The phenomenon of hyperglycemia, hyperlipidemia, hypertension and obese are the metabolic syndromes. This study discussed the related factors of the metabolic syndrome prevalence by analyzing health examination results of people who undergone health examination and the age range of 40 to 64 and understanding demographic characteristics of local. The Mann-Whitney test revealed a significant difference between the metabolic syndrome prevalence in males and females. This prevalence also increases with age and to the peak at the age range of 60 to 64 (21.3%). The percentage indicating both body mass index(BMI)-defined overweight (24≦BMI＜27) and obese (BMI＞27) also increases with age and to the peak at the age range of 60 to 64 (68.0%). The experiment results showed that the prevalence of total cholesterol abnormalities ranked highest among all with its value at 51.4%. People health was influenced by the rate of health examination in the past and the metabolic syndrome prevalence and BMI are increase with age.

Abstract: The threat of heavy metal pollution in water sources becomes increasingly serious. Toxic hexavalent chromium is harmful for health. Chitosan is a non-toxic and pollution-free substance, it is a cationic coagulant after protonated in diluted acid solution, it also can complex for many heavy metal ion. The study on removal of Cr (Ⅵ) and turbidity in drinking water by chitosan in this paper was performed. The results showed that the removal efficiency of Cr (Ⅵ) decreased with increasing pH, the removal rate of Cr (Ⅵ) was as high as 100% at pH4 using the chitosan concentration of 1.0g/L, but in these conditions, the turbidity was not removed. The removal efficiency of Cr (Ⅵ) bore relationship to stirring time of slow mixing step and initial concentration of Cr (Ⅵ). The best stirring time was 4 hours. To attain a good removal efficiency of Cr (Ⅵ), the dosage of chitosan must increase with the initial concentration of Cr (Ⅵ) increasing. At pH7, low chitosan dosage had good turbidity removal.

Abstract: 2,6-dinitrotoluene (2,6-DNT) is the preferential toxicants stipulated by OECD and EPA of USA. The present study was conducted to determine the effect of 2,6-DNT chemical on acute toxicity and subacute toxicity in common carp (Cyprinus carpio). The 24h, 48h, 72h and 96h LC50 values of common carp by 2,6-DNT were 1.137±0.023mg/L, 0.830±0.024mg/L, 0.661±0.019mg/L and 0.479±0.020mg/L, respectively. The subacute experiment shows that C. carpio are rarely affected by 0.0251mg/L 2,6-DNT, but significantly affected by 0.0398, 0.0631, 0.0794mg/L 2,6-DNT in contrast to the controlled sample (p liver > kidney.

Abstract: As a result, CYP1A expression in fishes is frequently used as a biomarker of exposure to aromatic hydrocarbon contaminants and early biological effect. We determined EROD activity and cytochrome P4501A protein level in liver of feral fish, common carp, Cyprinus carpio inhabiting a nitrotoluene contaminated environment in this study. The results show that feral C. carpio caught from contaminated water(nitrotoluene)in Songhua River displayed induction of CYP1A at two levels of expression, namely, apoprotein level and catalytic activity in liver.

Abstract: Ultrasonic cavitations can control algal growth. Considering water ecosystem protection and characteristics of ultrasonic technology, low frequency and low power ultrasonic was especially suitable to control algal growth in water bodies. Effects of low-frequency and low-power ultrasonic irradiation on natural blend algal growth were investigated. The algae spices were collected from a fresh water body. It mainly consists of Cyanophyta, Bacillariophyta and Chlorophyta. The results showed that ultrasonic irradiation with frequency of 60KHz, power of 0.24W/cm² and irradiation time of 1min, inhibited algal growth significantly. Inhibition of ultrasonic irradiation on algal growth enhanced with ultrasonic power increased. Inhibition did not increase again When ultrasonic power exceeds 0.24W/cm². The effect of algal control was sustainable by ultrasonic irradiation with interval period of 2-4 days.

Abstract: In order to optimize coefficient of heat pump, the finite time thermodynamic optimization theory is applied in this paper. By introducing area ratio of the condenser and evaporator, the analytical expressions for the optimal allocation of heat exchanger area for the irreversible Carnot heat pump with variable-temperature heat reservoirs are derived. For illustration, a real vapor compression heat pump example is utilized. Empirical results show that the optimal values for real vapor-compression heat pump cycles are obtained when area ratio is equal to 0.916. The results can guide the evaluation of existing heat pump plants or influence design practice for future plants.The results can guide the evaluation of existing heat pump plants or influence design practice for future plants.

Abstract: Based on studying wavelet neural network (WNN) training algorithm and geometrical structure, a new WNN optimization algorithm-hybrid hierarchy genetic is introduced. The algorithm is combined by hierarchy genetic algorithm and linear multi-regress. Hybrid hierarchy genetic algorithm (HHGA) can determine the structure and parameters of WNN from data at one time. The method has the merits of faster learning speed, higher precision. It is compared with traditional BP algorithm in this paper. The effectiveness of the algorithm is demonstrated.

Abstract: An optimization algorithm of urban traffic signal coordinated control with bus priority, which is aiming at achieving optimal comprehensive traffic efficiency, is proposed in this paper. Six kinds of key parameters that dominate signal control effects are extracted from abundant factors. Based on these parameters, an advance and flexible coding scheme which can generate detail signal control information in QGA is put forward. Considering travel time, no wait passing rate, crossing delay, green wave effect and other factors, a new fitness function is constructed. Verified by simulations in PARAMICS, the optimized signal control scheme can obviously improve comprehensive regional traffic efficiency.

Abstract: Wireless network distributed systems have become commonplace due to the wide availability of low-cost, high performance computers and network devices. With the increase of slave nodes of distributed systems, the performance of distributed systems often fall significantly or management infrastructure of distributed systems often does not scale well. Wireless network distributed system design method of using artificial life cooperation principle is proposed. Design principle of mutual cooperation among slave nodes and open wireless communication links of wireless network distributed systems make the topology of distributed system is able to handle the dynamic increase of system size and recover the unexpected failure of system services. The proposed design method for constructing distributed systems could optimize the scalability and reliability of distributed systems.