Wide‐Band Fine‐Resolution DCO with an Active Inductor and Three‐Step Coarse Tuning Loop

This paper presents a wide‐band fine‐resolution digitally controlled oscillator (DCO) with an active inductor using an automatic three‐step coarse and gain tuning loop. To control the frequency of the DCO, the transconductance of the active inductor is tuned digitally. To cover the wide tuning range, a three‐step coarse tuning scheme is used. In addition, the DCO gain needs to be calibrated digitally to compensate for gain variations. The DCO tuning range is 58% at 2.4 GHz, and the power consumption is 6.6 mW from a 1.2 V supply voltage. An effective frequency resolution is 0.14 kHz. The phase noise of the DCO output at 2.4 GHz is –120.67 dBc/Hz at 1 MHz offset.     

Highly stable tunable dual-wavelength Q-switched fiber laser for DIAL applications

We demonstrate a stable dual-wavelength Q-switched fiber laser for applications in differential absorption Lidar with tunability in absolute wavelength over several nanometers and discrete tuning in wavelength spacing from 1.1 to 3.3 nm. Single longitudinal-mode operation is also achieved by employing Sagnac loop saturable absorber filter. The delayed self homodyne linewidth measurement of the dual-wavelength continuous-wave laser shows a very narrow spectral linewidth and frequency jitter (<40 kHz). The advantages of tunable wavelengths, narrow linewidth, temperature insensitivity, and high stability in an efficient, cost effective, rugged, compact and light system make it a promising technology for airborne Lidar systems.     

Gate oxide reliabilities in MOS (metal-oxide-semiconductor) structures with Ti-polycide gates

We have investigated the thermal degradation of gate oxide in metal-oxide-semiconductor (MOS) structures with Ti-polycide gates. We found that the Ti-diffusion into the underlying polysilicon and consequently to the gate oxide occurs upon thermal cycling processes, which results in the dielectric breakdown of the gate oxide. We also found that the Ti-diffusion is suppressed by the employment of the thin (about 5 nm) titanium nitride (TiN) diffusion barrier layer, which consequently improved the reliability characterisitics of gate oxide significantly.     

探索龙门山前缘物探采集技术

四川盆地龙门山前缘地区地震地质条件复杂,资料信噪比低,勘探前景良好。为加快该区勘探进程,西南分公司进行了川西龙门山前缘地震勘探采集技术攻关,初步形成了适合龙门山前缘地区的地震资料采集技术,在龙门山前缘地区的地震勘探中发挥了重要作用,并发现大园包大型构造圈闭,取得了较好的勘探效果。     

Combustion and emission characteristics of a two-stroke diesel engine operating on alcohol

Though, as a renewable energy resource, alcohol fuel has many advantages in China, it is difficult for diesel engines to operate on alcohol due to its low cetane number and high latent heat of vaporization. This paper proposes an approach to its ignition problem by combining internal exhaust gas recirculation (EGR) with injection of small diesel fuel. Based on this approach, a two-stroke single-cylinder diesel engine was developed. Preliminary studies demonstrated that the engine can run on alcohol with almost zero level of smoke and low exhaust gas temperature, and that the engine operating on alcohol has lower nitrogen oxide (NO_x) emissions and 2–3% higher effective thermal efficiency than that operating on diesel fuel in moderate and high load zones.     

Forecast and evaluation of hot dry rock geothermal resource in China

Utilizing information from plate tectonics characteristics, volcanic activities, and geothermal anomaly, this paper identifies areas where hot dry rock (HDR) may exist as potential geothermal resource in China. Further investigations are also carried out in the paper based on results from regional tectonics, volcanic geology and lithology, as well as data from geothermal displays, geochemistry, geophysics, and shallow borehole temperature measurements. The study reveals several promising areas of HDR geothermal resource in China, including Tengchong of Yunnan province, Qiongbei of Hainan province, Changbaishan of Jilin province, Wudalianchi of Heilongjiang province, and the Southern Tibet area. A 3D static heat conduction model was developed to study the underground temperature gradient characteristics of the Rehai geothermal field in Tengchong and the Yangbajing geothermal field in Tibet. The model adopted is a geological block 10 km deep from the ground surface and 50 km wide in each of the horizontal directions (2500 km² area). The numerical simulation results in evaluations on the quantities of the HDR geothermal resource in Rehai and Yangbajing geothermal fields. The paper shows that there is abundant HDR geothermal resource with large exploitation value in China. If developed with a power capacity of 1×10⁸ kW, the Rehai and Yangbajing fields along would be able to generate electricity for 1560 years.     

油价下跌的根本原因和深远影响

上世纪后半期以来,世界油价变化已经历了4个阶段:第一阶段为二战后到1973年平稳的特低油价期,第二阶段为以两次石油危机为主体的油价剧烈动荡期,第三阶段为1986~1999年起伏的较低油价期,第四阶段为2000~2013年剧烈起伏的高油价期。此次油价下跌意味着进入了第五阶段——动荡中的油价较低期。它起因于国际石油市场供大于需的积累,雄厚的剩余产能和过量的石油储备是其两个明显标志;肇发于以沙特为首的海合会国家不愿看到自己的市场份额被侵占而不再减产保价,同时又叠加了世界经济疲软、美元指数走高的市场形势影响。市场供需将在新的低油价下达到新的平衡。低油价将首先对财政油价高且国内经济低迷的石油输出国产生强烈冲击,也将影响到生产成本低的石油输出国;而对石油消费国则是利大于弊,并将促进世界经济的回升;对于一些高成本的油气生产也会产生明显影响,最终将促使世界石油市场格局发生重大变化。低油价期的再次出现,还会使以化石能源为主体的时代比某些人预期的要长,但这也为多种新能源的发展争取了时间,从而使其更从容更健康地走向成熟。     

Discussion on the Network Method for Calculating Radiant Interchange Within an Enclosure

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Adaptive VM Management with Two Phase Power Consumption Cost Models in Cloud Datacenter

As cloud computing models have evolved from clusters to large-scale data centers, reducing the energy consumption, which is a large part of the overall operating expense of data centers, has received much attention lately. From a cluster-level viewpoint, the most popular method for an energy efficient cloud is Dynamic Right Sizing (DRS), which turns off idle servers that do not have any virtual resources running. To maximize the energy efficiency with DRS, one of the primary adaptive resource management strategies is a Virtual Machine (VM) migration which consolidates VM instances into as few servers as possible. In this paper, we propose a Two Phase based Adaptive Resource Management (TP-ARM) scheme that migrates VM instances from under-utilized servers that are supposed to be turned off to sustainable ones based on their monitored resource utilizations in real time. In addition, we designed a Self-Adjusting Workload Prediction (SAWP) method to improve the forecasting accuracy of resource utilization even under irregular demand patterns. From the experimental results using real cloud servers, we show that our proposed schemes provide the superior performance of energy consumption, resource utilization and job completion time over existing resource allocation schemes.     

The leakage current improvement in an ultrashallow junction NMOSwith Co silicided source and drain

The leakage current characteristics of the cobalt silicided NMOS transistors with a junction depth of 800 Å have been studied. In order to minimize the junction leakage current, the thickness of the CoSi₂ layer should he controlled under 300 Å and the Si surface damage induced by the gate spacer etch should be minimized. The post furnace annealing after the second silicidation by the rapid thermal annealing (RTA) process also affected the leakage current characteristics. The gate induced drain leakage (GIDL) current was not affected by the lateral encroachment of CoSi₂ layer into the channel direction when the gate spacer length was larger than 400 Å