Applied Mechanics and Materials Vols. 513-517

Abstract: A high speed, low offset fully differential comparator for high-speed analog-to-digital converter which can work at a sampling rate of 8GS/s is presented in this paper. The three-stage pre-amplifiers in the improved comparator structure is proposed to ameliorate its gain. The positive feedback regeneration circuit and the improved output buffer are used to ameliorate the comparator bandwidth. Operating with an input sine signal of 1GHz frequency, the circuit can oversample up to 8GS/s with 5bits of resolution. The simulated offset voltage of the comparator by Monte Carlo at 8GHz clock is 5.09mV.

Abstract: To meet the demand of low power multi-channel ADCs, a 10bit 4-channels SAR ADC using CSMC 0.35um 3.3V 2P4M technology was designed. By optimizing the power dissipation of the interior comparator and the interior DAC, the designed ADC costs only 300uW under 2V single supply with a sampling rate as high as 300KS/s. Meanwhile 1024 points FFT was used with MATLAB tools to analysis and calculate the converted results of the SAR ADC and the calculated results shown the SNR is about 60dB, ENOB is 9.6bit, DNL is 0.033LSB and the INL is 0.312LSB.

Abstract: A novel low-noise amplifier (LNA) suitable for COMPASS receiver applications is designed in SiGe-BiCMOS technology. Inductively degenerated technique and resistive feedback technique are employed to reduce the noise figure. With 1.8V power supply, the measured results achieve 17.23dB power gain and 2.58dB noise figure at 1.561GHz.

Abstract: In order to keep pace with the development of gigabits per second (Gbps) wireless communication and make the promising 60GHz band millimeter wave communication a reality, design of a DAC available to operate in the GS/s becomes a bottleneck problem. A 6-bit 5GS/s, power-efficient DAC is presented. A novel pseudo-thermometer architecture is proposed to realize a good compromise between the fast conversion speed and the chip area. Symmetrical and compact floorplannings and layout techniques including tree-like routing, cross-quading and common-centroid method are adopted. Post simulation results shows DNL errors and INL errors of the DAC can be controlled within±0.23LSB and±0.26LSB, respectively. SFDR at 5GHz clock frequency for a 273MHz output signal is about 21dB and the power dissipation is less than 37mW.

Abstract: A CMOS temperature compensation circuit within constant current charging cycle is proposed in the paper. The circuit is composed by a positive temperature coefficient current source, a current source with zero temperature coefficient and a relevant operational circuit, and can make balance between heat production and dissipation during trickle charging and constant current charging. Finally, with the CSMC 0.5um CMOS process, the simulation can get the temperature characteristic curve of intelligent heat adjusting current. The temperature compensation circuit is especially suitable for the application in different charging system.

Abstract: It was simulated the flow fields of the CLH-type marine centrifugal pump based on average N-S equations and standard k-ε turbulent model, using the ANSYS CFX12.1 code. With the calculation results, the velocity distribution of the flow field in the centrifugal pump is analyzed under different working conditions. The analogue results, which indicate the relationship between the total head, efficiency, shaft power and flow rate, are compared with performance experimental ones, and it shows that the simulation data coincides with experimental ones in allowable acceptance, which meet the requirements of practical application. Furthermore, in order to analyze the inner flow field distribution in the centrifugal pump in detail, and validate the simulation results, the inner flow field is tested by particle image velocimetry (PIV) measurement.

Abstract: The extraction separation is a main process to obtain the rare earth metals. In this paper, the distributions of the patent applications on the rare earth extraction separation techniques were analyzed. The main methods of the rare earth extraction separation including solvent extraction, precipitation and ion exchange were summarized. The existing problems in the rare earth industry were discussed and the development trend of rare earth industry was predicted. Furthermore, the effective patent strategy in this field was also brought forward.

Abstract: Ba-construction is a special structure in Chinese, it has a high utilization rate in patent documents and there is no corresponding sentence in English. Therefore, Ba-construction is a critical issue in machine translation. In this paper, based on the Hierarchical Network of Concept theory (HNC theory), we have an analysis of the Ba-construction in action sentence (XJ) and transfer sentence (TJ), and then conclude 4 main verbs translation formats from the semantic point of view according to corpus. The research results have been applied to our machine translation system and it has improved the correct rate of translation effectively.

Abstract: The processing of long sentences is a difficult problem in machine translation. Previous researchers used punctuation to deal with it. In this paper, we presented a rule-based method for sentence segmentation with conjunctions to improve the performance of long sentence machine translation in patent text. We divided conjunctions into different LEVELs according to semantic features of verbs which are before and behind them. Then, we formulated a number of rules based on the LEVELs of conjunctions to segment long Chinese sentence into separated shorter ones. We conducted experiments on 10 intact patent documents which contain 901 conjunctions. Consequently, our method achieves an accuracy of over 89% overall. The result indicates that our method can efficiently improve the performance of long patent sentence translation.

Abstract: Normal sub-sentence is a common language phenomenon. The differences between Chinese and English normal sub-sentence make a transformation processing necessary in machine translation. This paper proposed a method to recognize and transform normal sub-sentences to improve their translation performance in patent machine translation. First, we created a dictionary based on HNC theory to recognize the normal sub-sentence. Then, we compared Chinese normal sub-sentences to English ones and summarized the transformation rules based on the comparison. At last, we applied the method to an existing machine translation to test the processing effect. The experiment results show that the method can effectively recognize and transform normal sub-sentences. The Blue of the translation is raised by about 7%.