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Objective: This study was conducted to identify the types of minor ailments encountered by university students in Malaysia and the action taken in response to these ailments. Methods: A cross-sectional study was conducted on undergraduate students from the various faculties in a major private and a public university in Malaysia. A researcher stationed at different areas of the universities to recruit respondents. If the student agreed to participate, he/she would sign a consent form and then self-filled a structured questionnaire. Results: Of the 856 respondents included in this study, 68.6% were female and 60.6% rated their health status as ‘good’ or ‘very good’. During the one month period prior to the study, 87.4% of the respondents encountered at least one minor ailment. The five most common minor ailments encountered were headache (58.1%), common cold (42.8%), sore throat (42.6%), cough (40.3%) and back pain (27.6%). The main actions taken were rest at home and self-medication. The most common drug used for the treatment of minor ailments was paracetamol (49% of the respondents). Other drugs were used by less than 10% of the respondents. The main source of information was from parents (63.7%), followed by doctors (59.9%), internet (57.9%), pharmacists (33.9%) and friends (33.5%). Conclusion: Headache is more common among university students compared to the general population. Further studies are required to understand the cause of headache among this population.

In order to ensure the link stability of satellite laser communication, ongoing control of the received beam at the communication center is imperative. Due to the characteristics of high stiffness and fast response, the fast steering mirror driven by piezoelectric ceramics is widely used as an actuator in the fine tracking system of the satellite laser communication. However, it raises challenges to the closed-loop control of the fine tracking system. The traditional method adds a closed-loop control inside the fine tracking system to linearize the fast steering mirror, that in turn reduces the bandwidth of the fine tracking system considerably. Analyzing the structure of the fast steering mirror reveals that the symmetric hysteresis model could be employed to describe its hysteresis behavior. This study introduces a symmetric hysteresis modeling and compensation method based on Madelung’s rules, which can accurately describe and compensate the hysteresis characteristics of the fast steering mirror, and effectively improve the beam control bandwidth, along with the stability of the communication link. The theoretical simulation and experimental results show the effectiveness of the proposed method.

InGaAs is direct and narrow bandgap material with ultrahigh electron mobility, and is a promising candidate for optoelectronic device in the near-infrared region. The main objective of this manuscript is to design an InGaAs semiconductor-based photodetectors nanowire infrared photodetector, which would be manipulated in optical response wavelength range at room temperature with high-detective and fast-responsive performances. Considering into account mature technology in laser device and for maximizing 1.55 um optical communication performance, the design of achieved bandwidth is >1 Gbps. According to the theoretical calculations, the fundamental parameters of the InGaAs core-shell nanowire APD photodetector device are obtained, with certain values of single nanowire diameter, lateral size and applied voltage,r=100 nm,l=1 μm,Vbias=10 V. Meanwhile, we deal with the electrons mobility of the internal nanowire based on three factors, size effect, temperature and electric field effect. The results demonstrate that the InGaAs nanowire APD is potential candidatefor high rate in satellite laser communication field.

During the research of local stress distribution of polyline pretensioned beams by 3-D nonlinear finite element method, a problem of curve prestressed reinforcement simulation is discovered. If the line of prestressed reinforcement is curve, the calculated result of local stress distribution is greatly affected by element size, because of the tectonic stress concentration by the coupling between the linear element and body element. Then, the validity and applicability of the model couldn't be judged. To eliminate the harmful effect, the curve prestressed reinforcement is determined to simulate by body element. The result shows that it will solve the problem thoroughly, and the calculated result is truthful and reliable. This research presents a new thought and method about the local stress analysis of the prestressed concrete structure.

To research the local stress state of the polyline pretensioned beams, the 3-D nonlinear finite element model is established by FEA software ANASYS. The results show that the existence of the inflection point on the prestressed reinforcement is the main reason of local stress distribution, and the corner radius R is the primary influential factor of the local stress distribution phenomenon. Then, the variation law of the stress and stress distribution by the corner radius R is illustrated clearly. With the increasing of R, the maximum local stress has decreased, and the stress distribution curve has increasingly become smoothly and gently. Considered the variation law of local stress and various of construction requirement in engineering practice, R=600mm is selected as the optimal radius.

This paper studied the influence of neutron irradiation on the characteristics of 980nm pumped erbium-doped fiber amplifier(EDFA). After 7 days neutron irradiation, with the total fluence of 1.5×1013n/cm2, radiation induced loss changed little compared with pre-irradiation, maximum difference of single signal and WDM signal between pre-irradiation and post- irradiation are 0.5dB and 0.6dB, respectively. EDFA affected by neutron irradiation got less loss when the input signal power is higher.

Based on the real construction technology, process and environment of Yuquanxi Bridge, the finite element method was applied in the research to make sure the crack mechanism and find out the impact of improper construction procedure on cracks of Block No.0. By comparing the numerical results with actual cracks condition, the impact of improper construction procedure on cracks of Block No.0 is uncovered clearly and it proves that to master of correct construction procedures and methodology is of great importance in construction a bridge.

In this paper, burst errors in uplink communication due to lags of the tracking system control in Satellite to Ground optical link was analyzed in detail. In order to make sure how about these bursts in uplink communication are affected by control frequency can, system model of the satellite terminal was founded, parameters of a satellite in sun synchronous Low Earth Orbit and detectors were set to initialize the simulations. The zenith angle of the link was set in the range of [0°, 70°]. The simulation results showed that the bursts due to lags of the tracking system control were different for communication links, but the bursts can be avoided by raising the control frequency to a certain level if it accessible.

Considering the slender property, the reinforcement is always simulated by linear element in conventional FEA of concrete structures. But to the curve prestressed reinforcement, it will lead to the problem that the calculated result of local stress distribution is greatly affected by element size, because of the tectonic stress concentration by the coupling between the linear element and body element. To eliminate the harmful effect, the curve prestressed reinforcement can be simulated by body element. The result shows that it will solve the problem thoroughly, and the calculated result is truthful and reliable. Certainly, as a kind of slender component, there are some key point must be recognized when the curve prestressed reinforcement is simulated by body element. To reflect the mechanical properties of prestressed reinforcement and solve the key challenges of modeling, some key techniques of modeling and some special notices about element property settings are discussed detailedly in this paper.

A gain-modulated laser range imaging technology is generalized and its range accuracy is deduced. Theoretical results indicate that the range accuracy is proportional to the ratio of gain function to the derivative of the gain function and inverse proportional to output SNR. A gain-modulated laser range imaging system is established in our laboratory. It consists of a pulsed laser which is capable of generating laser pulses with a pulse width of 10ns and a center wavelength of 532 nm, and a receiver which is a digital 256×256 CCD sensor coupled to a GEN II intensifier with a 10nm bandwidth optical filter. Image intensifier is electronically driven and can be set to three modulated gain or constant gain. A range image of the target can be extracted by processing an intensity image with modulated gain and an intensity image with constant gain. Some indoor experiments are performed with sinusoidal, linear and exponential gain functions. The range images of the targets from 52 m to 58 m is taken and analyzed. Experimental results demonstrate the range accuracy with both sinusoidal and linear gain function depends on the relative range but one with exponential gain function independent of relative range. Specially, in the exponential gain function case the relatively small time constant can contribute to relatively high range accuracy.