毛细管气相色谱法测定丙烯腈中丙烯醛、丙酮、乙腈的含量

丙烯腈中有机杂质丙烯醛、丙酮、乙腈是其重要指标，现在丙烯腈的国标测试方法用填充柱气相色谱法分析丙烯腈中有机杂质丙烯醛、丙酮、乙腈的含量，此法分析时间长，灵敏度低。为了及时准确提供分析数据，用毛细管气相色谱法测定丙烯腈中有机杂质的含量。     

运营商内部数据通信网的VPN技术

针对电信运营商在构建内部数据通信网(DCN)时遇到的各应用系统的隔离问题，详细介绍了目前几种主流的虚拟专用网(VPN)技术，并进行分析比较，最后提出了运营商内部数据通信网的VPN解决方案。     

Gamma-irradiation-induced Ag/SiO2 composite films and their optical absorption properties

Small Ag particles or clusters dispersed mesoporous SiO₂ composite films were prepared by a new method: First the matrix SiO₂ films were prepared by sol-gel process combined with the dip-coating technique, then they were soaked in AgNO₃ solutions followed by irradiation of γ-ray at room temperature and in ambient pressure. The structures of these films were examined by X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), and optical absorption spectroscopy. It has been shown that the Ag particles grown within the porous SiO₂ films are very small, and they are isolated and dispersed from each other with very narrow size distributions. With increasing the soaking concentration and an additional annealing, an opposite peakshift effect of the surface plasmon resonance (SPR) was observed in the optical absorption measurements.     

地杂波O．94μm激光后向反射率测试研究

通过对地杂波O．94μm激光后向反射率的测试，获取不同入射角的多背景后向反射率测试数据。通过对测试数据的分析处理提供特征信息，为激光探浏器设计提供依据。     

低温脂肪酶产生菌的筛选、鉴定及其部分酶学性质

从南极乔治王岛冻土来源的76株低温细菌中筛选到13株低温脂肪酶产生菌，对其中的BTsl0022菌株进行鉴定。通过生理生化特征、16s rDNA基因序列的同源性和系统发育分析发现，菌株RTsl0022属于假单胞菌属(Pseudomonas)，但与已定名的假单胞菌有一定的差异，与未定名的Pseudomonas sp．PsB的亲缘关系最接近，故将其暂定名为Pseudomonas sp．BTsl0022。对该菌脂肪酶的酶学性质初步研究表明，酶的最适作用温度为24℃，对热敏感，60℃处理30min仅残留25％酶活性，酶的适宜作用pH范围在7．0～9．0，最适pH为8．0。     

An intelligent web-page classifier with fair feature-subset selection

The explosion of on-line information has given rise to many manually constructed topic hierarchies (such as Yahoo!!). But with the current growth rate in the amount of information, manual classification in topic hierarchies results in an immense information bottleneck. Therefore, developing an automatic classifier is an urgent need. However, classifiers suffer from enormous dimensionality, since the dimensionality is determined by the number of distinct keywords in a document corpus. More seriously, most classifiers are either working slowly or they are constructed subjectively without any learning ability. In this paper, we address these problems with a fair feature-subset selection (FFSS) algorithm and an adaptive fuzzy learning network (AFLN) for classification. The FFSS algorithm is used to reduce the enormous dimensionality. It not only gives fair treatment to each category but also has ability to identify useful features, including both positive and negative features. On the other hand, the AFLN provides extremely fast learning ability to model the uncertain behavior for classification so as to correct the fuzzy matrix automatically. Experimental results show that both FFSS algorithm and the AFLN lead to a significant improvement in document classification, compared to alternative approaches.     

PetroChina Drills Risk Exploration Wells in Africa

China National Oil Development Corporation （CNODC）, one of the subsidiaries under PetroChina responsible for the overseas oil exploration and development business, started to drill its first exploration well - Saha-1 on Tenere Block in Niger on October 30. This is another risk exploration well CNODC has drilled in this region following Bel E-I drilled on Block 350 in Algeria on September 15 and Heron-1 drilled on Block 20 in Mauritania on October 13. The drilling of those wells indicates a substantial stage of PetroChina＇s overseas large-scale risk oil and gas exploration in the Central and Northern Africa.     

可控震源施工中电台数据传输不良的原因分析及排除

可控震源在施工中,常常出现各种电台干扰,导致震源数据传输不正常或震源收不到仪器发出的遥控启动信号,影响正常施工.本文介绍了各种电台干扰引起的故障现象,分析了故障产生的原因,给出了故障的排除方法.     

SMA沥青混合料在皖北地区高速公路中的应用

皖北地区夏季高温多雨,冬季严寒,气候较为恶劣,在该地区宜推广应用SMA混合料铺筑表面层。在进行SMA配合比设计时,必须严格控制原材料的质量,经过精心设计、精心施工,才能修建出一条成功的SMA路面。     

A novel InP/InGaAs TEBT for ultralow current operations

A novel InP/InGaAs tunneling emitter bipolar transistor (TEBT) is fabricated and demonstrated. The studied device exhibits a very small collector-emitter offset voltage of 40 mV and an extremely wide operation regime. The operation region is larger than 11 decades in magnitude of collector current (10/sup -12/ to 10/sup -1/A). A current gain of 3 is obtained even if the device is operated at an ultralow collector current of 3.9 /spl times/ 10/sup -12/A (1.56 /spl times/ 10/sup -7/A/cm/sup 2/). Furthermore, the common-emitter breakdown voltage of the studied device is higher than 2 V. Consequently, the studied device shows a promise for low supply voltage, and low-power consumption circuit applications.