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Introduction: External Beam Radiation Therapy (EBRT), a type of whole breast radiation therapy, has been widely used in patients with early-stage breast cancer, however it is associated with longer treatment periods and higher toxicity.

A high-sensitivity N2O photoacoustic sensor using a 4.53 μm quantum cascade laser was developed. Sharply enhancement of photoacoustic signal of N2O with the increasing of humidity was investigated experimentally. Finally, 2.3 % water vapor was added to the analyzed sample to improve the vibrational-translational (V T) relaxation rate of N2O molecule transition, and therefore enhance the N2O photoacoustic signal. High performance with a minimum detection limit of 28 ppbv in 1 s and a measurement precision of 34 ppbv have been achieved, respectively. Kalman adaptive filtering was used to remove the shot-to-shot variability related to the real-time noise in the measurement data and further improve the measurement precision. Without sacrificing the time resolution of the system, the Kalman adaptive filtering improves the measurement precision of the system by 2.3 times. The ability of the N2O photoacoustic sensor was demonstrated by continuous measurement of atmospheric N2O concentration for a period of 7 h.

Reduction of roll and pitch motions is critical in improving the safety and operability of a ship. In this paper, a predictive controller for a ship equipped with two pairs of active fins is proposed for joint pitch-roll stabilization. The proposed controller is developed on the basis of ship motion and hydrodynamic force prediction (SMHFP). The SMHFP controller consists of a short-term predictor, a force estimator, and a fin angle allocator. The short-term predictor adopts an autoregressive (AR) approach and serves to forecast ship motions. Then, predicted ship motions are used in an external hydrodynamic force estimator to evaluate the expected stabilizing forces. Finally, the optimal attack angles for active fins are allocated based on external hydrodynamic forces forecasts. The control system of the stabilizing fins and SMHFP controller is integrated into the sea-keeping program. The program was developed based on a weakly nonlinear 2.5D method, which shows better efficiency and accuracy compared with conventional 2D and 3D methods. To evaluate the performance of the proposed controller, numerical simulations of the joint pitch-roll stabilization under various sea states were investigated on a ship model. The results suggest that the SMHFP controller shows satisfactory performance in reducing pitch and roll motions simultaneously.

Most reservoirs in Sudan are medium to high porosity and permeability sandstone reservoirs, these reservoirs have been developed by natural depletion since put into production, and the development is characterized by sparse wells of high production, big pressure differential, delayed infill drilling and water flooding, and rapid investment recovery. H field, FN field and P field are bottom water drive light oil field, bottom water drive heavy oil field and stratified high pour point oil field respectively, and they are representative fields in Sudan. The production performance of the three oil fields features sparse well spacing and high plateau rate, short stable production period, rapid water cut increase and fast production decline. Commingled production results in poor inter-layer development and complicated residual oil distribution. On the basis of the above analysis, major affecting factors of Sudan sandstone reservoirs natural drive have been identified through lab experiments, field development plan and field monitoring. The high off-take rate is conducive to the increase of the contract period recovery and recovery factor; sparse well spacing based on crude mobility range and determining infill well production cutoff considering contract terms can be helpful for cost-effective development; barriers and inter-layers can be made use of to detain bottom water coning and to enhance the development effect of bottom water oilfields; and delayed water injection in stratified high pour point reservoirs has no effect on recovery factor during contract period. Key words: sandstone reservoir, depletion development, development characteristics, development policy, Sudan

This paper demonstrates successful application of parallel appraisal and development in G field, Niger. G field is a complicated stacked light oil reservoir with gas cap in its E2 major pool. After current operator's takeover in 2008, the government required realization of 10 KBOPD in this field within 3 years, leaving only 1 year for appraisal and development as field construction in this landlocked country at least takes 2 years. Whereas there was only 2D seismic and one well data (G-1) with RFT and testing, parallel appraisal and development strategy must be adopted and following 2 major challenges were identified: 1) Limited data and great uncertainties in gas-cap and well productivity; 2) development decision-making along with appraisal process. Appraisal and development have been optimized by following approaches: 1) RFT and wireline data were fully studied to identify oil-gas-contact in E2 pool and indicate possible oil in E3 pool; 2) appraisal wells placement based on new 3D seismic; 3) identify key uncertain development parameters and combine into appraisal campaign targets to gradually reduce uncertainties. Appraisal well G-2 confirmed the separation of block G-1 and G-2. The second appraisal well G-3 confirmed oil-gas-contact, encountered oil zone in lower E3 pool. The third appraisal well G-8 encountered oil zone in E2 and further firm up gas-cap area, laying firm foundation for subsequent development well placement.6 producers were placed out of gas cap and appraisal wells were transferred to development wells, all successfully commissioned in 2011, achieving desired production target. Conclusions drawn from successful parallel appraisal and development application were:1) utilization of all data available contributed to correct appraisal decision-making; 2) Combining 3D and appraisal well findings help reduce geological uncertainties; 3) Identify and reduce key development uncertainties during appraisal speed up appraisal process. For complicated fields at appraisal stage, the methodology in this paper is of strong reference value.

This paper presents a hierarchical control strategy for formation control of multiple four-wheel independently driving electric vehicles (4WIDEVs) under constant speed. The upper layer controller establishes formation mathematical model based on dynamic virtually leader-follower (DV-LF) method which transforms research for formation control into vehicle-following control and fuzzy PID algorithm is designed as vehicle following control strategy under constant speed. Considering the lateral stability of the following vehicle, the lower layer controller adopts torque distribution control strategy and the additional yaw moment controller is designed based on the static gain from the sideslip angle and yaw rate of the vehicle to improve the lateral stability in the process of forming the desired formation. In the end, in order to evaluate the performance of the proposed hierarchical control algorithm, the lane-change formation test condition under high constant speed is simulated in this paper and the simulation result shows that the coordination control strategy can achieve the desired formation control and improve the lateral stability of the following vehicle under high constant speed.

Jake field, discovered in July, 2006, contains 10 oil-producing and 12 condensate gas-producing zones. The total number of drilled was 19, including 5 updip wells penetrated oil and gas zones, the remaining 14 downdip wells completed at principal oil zones. A unique co-development project of oil and gas had been performed since the start-up of field in July, 2010, including three phases: Phase I: Prior to start-up of the field, In-situ gas injection was initiated. Single tubing string completion was utilized in updip wells, packer isolated oil and gas zones so that high-pressure gas could produce from the tubing and oil could produce from the annulus. After commencement, gas from updip wells was injected into downdip wells to maintain reservoir pressure and minimize water influx. The remaining gas was used to gas-lift at updip wells. Phase II: Following pressure depletion of oil and condensate gas zones, gas-lift wells became inefficient. The packerless tubing string was extended to the bottom of perforations for commingling production of oil and gas condensate zones at updip wells. Well stream was produced from the casing annulus while recycling gas was injectied from compressors into the tubing for gas lift. Nitrogen injection was conducted at downdip wells. Phase III: After water breakthrough, infill wells between updip and downdip wells were drilled for nitrogen injection to mitigate the water cut rising trend. Actual production performance of oil and gas co-development is better than sequential production of oil and gas. Initial well production at two producers reached over 10,000 BOPD, Current recovery factor for oil is 25% and gas is 36%. Oil is producing at the level of 18,000 BOPD with average offtake rate of 5.8%. Simulation confirmed that ultimate recovery factor for oil could be over 50%.

Room temperature single electron transistor structure is designed based on the ordered mesoporous thin film. The tunneling structure of three-dimensional six-party coulomb island array is analyzed. The tunneling barried width belonging to tunneling path with the least number of coulomb islands is always equal to skeleton width of ordered mesoporous thin film, which provides accurate structure control for single electron transistor.

Along with the application of computer and microelectronic technology in industrial production, the use of computer technology and microelectronic technology to control the stepping motor has gradually become a new technology. Stepper motor control system is designed based on AT89S51, including the hardware circuit design and software design. Keyboard input signal is used to control the stepper motor rotation direction and speed. The rotation direction is displayed by LED. The design has high reliability and strong stability, which can be applied to the field of disk drive, robots and automation instrument.