This paper presents a nonlinear robust control design method for a generic rotorcraft unmanned aerial vehicle (RUAV). The control objective is to let the RUAV track some pre-defined time-varying position and heading trajectories. The proposed controller employs feedback linearization process to realize the dynamic decoupling control and applies adaptive sliding mode control to compensate for the parametric uncertainties and external disturbances. The global asymptotical stability is proved via stability analysis. Compared with the cascaded controller, the proposed controller demonstrates a superior tracking performance and robustness through numerical simulation in the presence of parametric uncertainties and unknown disturbances.

Using beam propagation method (BPM), key optical design parameters of InP/AlGaInAs multiple quantum well (MQW) ring laser were numerically analyzed. The influences of waveguide dimensions, curvature radius and gap size on the coupling efficiency were discussed. An InP/AlGaInAs MQW ring laser with radius of 350 μm was designed and realized. The experimental results show that the designed device, lasing at 1 563.2 nm with side mode suppression ratio higher than 20 dB, exhibited unidirectional bistability between the clockwise and counterclockwise modes.

Under an in-phase assumption, the complete charging for an energy harvesting system is studied, which consists of a piezoelectric energy harvester (PEH), a bridge rectifier, a filter capacitor, a switch, a controller and a rechargeable battery. For the transient charging, the results indicate that the voltage across the filter capacitor increases as the charging proceeds, which is consistent with that reported in the literature. However, a new finding shows that the charging rate and energy harvesting efficiency decrease over time after their respective peak values are acquired. For the steady-state charging, the results reveal that the energy harvesting efficiency can be adjusted by altering the critical charging voltage that controls the transition of the system. The optimal energy harvesting efficiency is limited by the optimal efficiency of the transient charging. Finally, the relationship between the critical charging voltage and the equivalent resistance of the controller and rechargeable battery is established explicitly.

Based on the study of existing typical micro-milling tools and the actual demand for micro-milling tools, the P³ design principle and design flow for ultra-hard micro-milling tool were introduced to give basic guidance for the optimization of micro-milling tools. Then, according to the P₃ design flow, the manufacturing process of polycrystalline diamond (PCD) micro-milling tool was proposed, and the PCD micro-milling tool with diameter of 0.5 mm was developed. Finally, the micro-milling test on the slot was carried out to study the milling performance of PCD micro-milling tool.

A direction-based adaptive switching (DBAS) filter is presented for the removal of high-density impulse noise in images. The extrema detection and 28-directional detection are employed to discriminate the pixels as noisy or noise-free. If a pixel is classified as noisy, it will be replaced by a median or a mean value within an adaptive filter window with respect to different noise densities. Simulation results show that the miss-detection ratio and false-alarm ratio are both very low even at noise level as high as 90%. At the same time, better results are obtained in terms of the qualitative and quantitative measures. The peak signal-to-noise ratios increase by nearly 1 dB compared with other existing algorithms. In addition, the computation time is around 10 s for test images with resolutions of 512 × 512 since the proposed approach has low complexity.

The behaviors of YAG laser welding process of ferritic stainless steel with activating fluxes were investigated in this study. Some conventional oxides, halides and carbonates were applied in laser welding. The results showed that the effect of oxides on the penetration depth was more remarkable. Most activating fluxes improved the penetration more effectively at low power than that at high power. The uniform design was adopted to arrange the formula of multicomponent activating fluxes, showing that the optimal formula can make the penetration depth up to 2.23 times as large as that without flux, including 50% ZrO₂, 12.09% CaCO₃, 10.43% CaO and 27.48% MgO. Through the high-speed photographs of welding process, CaF₂ can minimize the plasma volume but slightly improve the penetration capability.

A combined cycle fatigue (CCF) testing system with ultrasonic frequency component was developed to evaluate the CCF properties of S350 steel welded joints in this study. The fatigue testing results indicated that the S-N curves of CCF did not have fatigue limit, which agreed with those of pure high frequency fatigue of welded joints. The S-N curves showed that the CCF strength of welded joints dropped greatly with the increasing interaction between high and low frequency fatigue loading. An approximation design method of CCF was presented using amplitude envelope as the stress range.

The joining of aluminum alloy sheets with thickness less than 2.0 mm is difficult via conventional friction stir welding owing to the defects in the joint, such as root flaw, keyhole and lazy S. In the present research, a newly designed pinless tool with involute grooves on its shoulder surface was applied to weld 1.5 mm thick AA2024-T3. The effects of the rotating speed and welding speed on the microstructure and mechanical properties of the joints were analyzed. The experimental results showed that the root flaw and keyhole were successfully eliminated. The lazy S was also eliminated under the optimized welding parameters. The maximum tensile strength of the joints was 326 MPa, which is about 74.1% that of the base material. Moreover, all the tensile samples fractured from the retreating side. Two fracture modes were observed during the tensile tests, which are related with the lazy S.

To explore the effect of particle size on the quality uniformity and in vitro release performance of Strychnos nux-vomica powder, seven samples of Strychnos nux-vomica powder with different particle sizes were prepared. Microstructures and particle sizes were analyzed, and high performance liquid chromatography (HPLC) was used to test the contents and in vitro release performances of brucine and strychnine in the samples. Results showed that the contents and the in vitro release rates of brucine (or strychnine) in different samples were different since there are different proportions of endosperms to epidermal cells in Strychnos nux-vomica powder with different particle sizes. Brucine and strychnine in each sample were promptly released in the first ten minutes and their cumulative release rates were higher than 70% after ten minutes. Eighty minutes later, the cumulative release rate tended to be a constant. Considering the quality uniformity and safety of Strychnos nux-vomica powder used as traditional Chinese medicine, it would be better to control the particle size of Strychnos nux-vomica powder between 100 and 140 mesh in which the maximum cumulative release rate in vitro of brucine and strychnine can be relatively low within this range.

Aflatoxins are the most popular hepatotoxicants. Chronic exposure to aflatoxins leads to a wide variety of liver diseases, such as hepatocellular carcinoma. In this study, we analyzed the genome wide expression profiles of aflatoxin B1-induced rat hepatic epithelial cells. The expression of 325, 184 and 199 special genes was altered when exposed to 0.03, 0.1 and 0.2 μmol/L aflatoxin B1 respectively, and 239 genes were commonly expressed. After the functional analysis on these dose-special genes, we determined several key pathways related to hepatotoxicity, such as TGF-beta signaling pathway, tight junction, adherens junction, the regulation of actin cytoskeleton, ErbB signaling pathway, p53 signaling pathway, pathways in cancer and axon guidance. Common genes were mainly associated with focal adhesion, ECM-receptor interaction, and cell adhesion molecules. Gene ontology annotations showed a good concordance with these pathways. The quantitative real-time polymerase chain reaction(PCR) analysis of selected genes showed similar patterns in microarrays. The toxicogenomic study provides a better understanding of molecular mechanisms of aflatoxins.

An economic and effective method of preparing enriched ¹⁰B boric acid was established by chemical reaction of enriched ¹⁰BF₃ and CaCO₃. A process of boron trifluoride reacting with water was investigated under certain conditions. Calcium carbonate was selected to counteract hydrofluoric acid followed on. Some key operation factors were investigated, such as temperature, reaction time and the ratio of CaCO₃ to ¹⁰BF₃. The results showed that the yield of enriched ¹⁰B boric acid could reach 97.2% and the purity was up to 94.1% under the following conditions: the temperature was 50–60 °C, the reaction time was 28 h and the ratio of CaCO₃ to ¹⁰BF₃ was 4. In addition, after recrystallization and titration analysis, the purity of the product could reach over 99.2% from 94.1%.

Groundwater recharge significantly affects soil moisture redistribution through capillary rise. In this study, the soil matric potential at depths of 5, 10, 20 and 30 cm above the groundwater tables of 10, 30 and 60 cm were measured for 5 d. Soil hydraulic properties were analyzed by using the Philips and de Vries model. Results showed that evaporation mainly influenced the matric potential of the shallow layer at the 5 cm depth regardless of the saturation of the layer. Groundwater recharge mainly affected soil moisture at the depth of 20 cm or more. A constant matric potential layer existed between the evaporation front and capillary rise front where moisture content did not change. The isothermal-liquid hydraulic conductivity (K _Lh) and the thermal-vapor hydraulic conductivity (K _vT) were the dominant hydraulic conductivities in the liquid and vapor phases. At the groundwater table depths of 10, 30 and 60 cm, the mean peak values of K _Lh were 2.32×10⁻⁷, 1.63×10⁻⁷ and 0.29×10⁻⁷ m/s, respectively, whereas the mean peak values of K _vT were 2.7×10⁻⁷, 2.4×10⁻⁷ and 1.8 ×10⁻⁷m/s, respectively.

Both fuzzy temporal constraint and flexible resource constraint are considered in project scheduling. In order to obtain an optimal schedule, we propose a genetic algorithm integrated with concepts on fuzzy set theory as well as specialized coding and decoding mechanism. An example demonstrates that the proposed approach can assist the project managers to obtain the optimal schedule effectively and make the correct decision on skill training before a project begins.