Superconducting control for surge currents

Systems designed to use superconductors to limit fault currents in power grids are undergoing testing. The authors describe superconducting fault current limiters (SCFCL) which may be categorised into resistive or shielded core types. The features and operation of each type of device are outlined. Both the shielded-core and resistive types of SCFCL use the same amount of superconductor material to achieve a given limitation behavior. This is because the rated power per volume of conductor is determined by the product of fault-induced field and critical current, which is the same for both devices, assuming the same type of superconducting material is employed. The shielded-core limiter works only with AC currents and is much larger and heavier than the resistive SCFCL. While there is only one large program left in the low-temperature type of SCFCL, more than 10 major projects are under way worldwide on the high-temperature type of device. The main reason is the lower HTS cooling cost     

使用混合杆柱时抽油泵柱塞的超冲程

任何抽油杆柱在理论上都可能产生超冲程，只是大小不同而已。超冲程的存在，使泵柱塞的有效冲程增大，甚至会大于光杆冲程。首次提出了抽油泵柱塞相对超冲程和绝对超冲程的概念，这将有助于正确认识玻璃钢抽油杆的作用和玻璃钢抽油杆的推广使用。将抽油杆柱简化成上端受光杆的激振位移、下端带有集中质量的弹簧－质量力学模型，建立了抽油杆柱纵向振动的偏微分方程和边界条件，然后用固有函数法求解方程，得出了抽油泵柱塞超冲程的无穷级数解析计算式。     

外腔式半导体激光器的输出光谱

用射线法导出了两段式激光器的输出谱公式，分析了外腔式半导体激光器的输出光谱，计算了ＥＣＬＤ被调二极管模式的不同波长处振时的阈值，获得了ＥＣＬＤ模式的波长表达式，讨论了二极管靠近光栅的一面的反射率的波长特性对输出的影响。     

叠加能量C^＋注入SiO2薄膜的光致发光特性

首次采用叠加能量离子注入技术制备Ｃ＾＋注入ＳｉＯ２薄膜样品，室温下观测到很强的蓝光发射。通过测量样品的光致发光谱对退火条件的依赖关系，研究了样品的发光特性。对发光机制进行了初步探讨。     

Memory-related changes of nitric oxide synthase activity and nitrite level in rat brain

The changes of nitric oxide synthase (NOS) activity and nitrite level in rat brain regions after spatial learning were investigated. NOS activity was assayed by conversion of [3H]L-arginine to [3H]L-citrulline, and a sensitive fluorometric assay for quantification of nitrite was used. Compared with sham-trained rats, NOS activity and nitrite level in hippocampus and cortex, and also the nitrite level in cerebellum, was elevated significantly one day after rats had learnt a water-rewarded spatial alteration task. These results suggest a spatial memory-related changes of endogenous NO in rat brain, and support the idea that NO participates in learning and memory processes.     

注聚采出水分离用动态水力旋流器特性研究

原有的地面工艺和设备已不能满足聚合物驱采出水分离的要求。采用自行研制的动态水力旋流器，在增压与不增压两种工艺流程下，分别进行了流量和转数对分离效率的影响、转数与压力降的关系，以及入口压力与处理量的关系等项试验研究。试验结果表明，与静态水力旋流器相比，动态水力旋流器的分离效率明显提高，一般可提高10％左右；压力损失显著降低，约可减少0．1MPa，足见可在低压下工作，易于实现无泵运行；无泵运行明显比有泵增压运行的分离效率高，但处理量会有所降低。将动态水力旋流器应用于聚合物驱产出水的油－水分离处理是完全可行的。     

2,4-二氯氟苯的合成

论述了2，4－二氯氟苯合成的新方法。以对氯硝基苯为起站原料，经氟化反应、硝化反应及氯化反应制得2，4-二氯氟苯，总收率达59．0％。本合成路线工艺简单、操作安全、原料易得、成本低廉，适合于工业化生产。     

判断油气藏非均质性的新方法

非均质性是油气藏的基本特性,也是影响油气面采收率的重要因素.它是反映油气藏的渗透率、孔隙度、有效厚度及其连通性的综合特征参数.不同油气藏在投入开发后,其产量随时间变化的分布曲线与油气藏自身的非质均性有密切关系.利用伽马分布描述油气藏产量随时间的变化,研制了典型曲线的理论图版,通过拟会求解,可判断油气藏的非均质程度.     

消费品说明中警示信息有效性的工效学研究(Ⅰ)——警示信息对消费者危险感受与商品危险性之间关系的影响

该研究采用问卷法，通过对３０种消费品的调查，分析了消费者对消费品说明中警示信息的阅读倾向性，消费者的危险感受、消费者安全使用商品的自信度、遵守警示信息的可能性、主观危险估计和客观危险性这几项因素之间的关系。结果表明：消费者的危险感受与阅读警示信息的倾向性、遵守警告的要求之间存在高度的一致性；且与自信度呈负相关，所以可以通过研究消费者的危险感受来研究警示信息的有效性；消费者的危险感受、主观危险估计常与商品的客观危险性不一致，所以必须采取一些措施来矫正消费者的危险感受，以确保警示信息发挥应有的安全保障作用     

Should the same glucose values be targeted for type 1 as for type 2 diabetics in pregnancy?

OBJECTIVE: Our purpose was to determine whether the same maternal glycemic control is necessary to achieve similar perinatal outcomes for type 1 as for type 2 diabetics. STUDY DESIGN: The subjects were all women with pregestational diabetes mellitus delivered of live-born singletons. Glycemic control was achieved with diet and insulin. Self-monitoring of blood glucose was performed before meals and at bedtime. Target glucose values were 60 to 90 mg/dl fasting and 60 to 105 mg/dl at other times. RESULTS: Of 60,628 deliveries, 46 type 1 and 113 type 2 diabetic women met inclusion criteria. Respective differences were found between type 1 and type 2 diabetics in average daily glucose levels (112 mg/dl vs 97 mg/dl, p < 0.001), percent of values within target ranges (35% vs 57%, p < 0.001), and mean amplitude of glycemic excursion (48.1 mg/dl vs 24.9 mg/dl, p < 0.001). At least one daily glucose value was < 50 mg/dl during 19% of observation days for type 1 vs 2% of observation days for type 2 pregnancies (p < 0.001). There were no statistically significant differences between type 1 and type 2 diabetic pregnancies in neonatal macrosomia (30% vs 34%), proportion of cesarean deliveries during labor for arrest disorders (67% vs 69%), shoulder dystocia (2% vs 6%), and neonatal hypoglycemia (18% vs 26%). CONCLUSIONS: Less stringent maternal glycemic control may permit comparable maternal and neonatal outcomes for type 1 compared with type 2 diabetics. Higher target values for type 1 diabetics may decrease the frequency of maternal hypoglycemic episodes.