EGD级环保型润滑油及其生物降解性

 经生物降解性评定和粘度测量确定了EGD级生物降解二冲程润滑油复合基础油的组成；通过发动机清净性试验确定了添加剂组成配方和总添加量。在此基础上，研制了生物降解二冲程油(Oil B)，其达到了ISO EGD级二冲程油标准中规定的6个发动机性能指标和2个理化性能指标，生物降解性达到73.1%。     

CSTN-LCD用铬版清洗效果的改善

利用铬版清洗机对CSTN-LCD用铬版进行清洗处理,分析了清洗过程中出现的铬层脱落现象,铬层脱落与轴向喷射压力和水平切力密切相关,通过调整转速和喷射压力探索了安全使用条件:在转速不超过1000r/min,喷射压力低于0.5×105Pa的情况下使用铬版清洗机进行清洗是相对安全的。同时采用预清洗处理的方法满足清洁要求,使换线时间由平均3h缩短到平均1h以内,年产能提高270000片。     

基于多抽样率信号处理的无源雷达MTD方法

以数字电视信号为机会照射源的雷达系统研究为背景 ,提出用以多抽样率信号处理为基础的多级抽取信号处理算法解决运动目标检测中海量数据处理问题。文中叙述了数字电视广播信号回波的数学模型、多级抽取基本原理、目标检测算法 ,以数字电视信号为反射回波做了仿真 ,对运动目标进行检测 ,并对仿真结果做了分析。     

Prolonged tamoxifen exposure selects a breast cancer cell clone that is stable in vitro and in vivo

The effects of long-term tamoxifen exposure on cell growth and cell cycle kinetics were compared between oestrogen receptor (ER)-positive (MCF-7) and ER-negative (MDA-MB-231) cell lines. In the MCF-7 cell line, prolonged tamoxifen exposure (0.5 mumol/l for > 100 days) blocked cells in G0-G1 of the cell cycle, and slowed the doubling time of cells from 30 to 59 h. These effects corresponded to an increase in the cellular accumulation of tamoxifen over time [mean area under concentration curve (AUC) = 77.92 mumoles/10(6)/cells/day]. In contrast, in the MDA-MB-231 cell line, long-term tamoxifen exposure had no obvious effect on the doubling time, and reduced cellular tamoxifen accumulation (mean AUC = 50.50 mumoles/10(6)/cells/day) compared to the MCF-7 cells. Flow cytometric analysis of MDA-MB-231 cells demonstrated that a new tetraploid clone emerged following 56 days of tamoxifen exposure. Inoculation of the MDA-MB-231 tetraploid clone and MDA-MB-231 wildtype cells into the opposite flanks of athymic nude mice resulted in the rapid growth of tetraploid tumours. The tetraploid tumours maintained their ploidy following tamoxifen treatment for nine consecutive serial transplantations. Histological examination of the fifth transplant generation xenografts revealed that the tetraploid tumour had a 25-30 times greater mass, area of haemorrhage and necrosis, a slightly higher mitotic index and was more anaplastic than the control neoplasm. The control wildtype MDA-MB-231 tumours maintained a stable ploidy following tamoxifen treatment until the eighth and ninth transplantation, when a tetraploid population appeared, suggesting that tamoxifen treatment may select for this clone in vivo. These studies suggest that prolonged tamoxifen exposure may select for new, stable, fast growing cell clones in vitro as well as in vivo.     

新疆平原区降水入渗补给地下水研究

以新疆昌吉地下水均衡试验站测得的降水入渗补给地下水量资料为基础 ,讨论了影响降水入渗补给地下水的因素 ,计算了潜水年降水入渗补给系数 ,建立了年降水入渗补给系数与潜水埋深间的经验公式     

Dy3+激活的几种硼酸盐在VUV-VIS范围的光谱性质

本文报道了SrAl2B2o7:Dy^3 、BaAl2B2O7:Dy^3 、SrAl3BO7:Dy^3 、La2CaB10O19:Dy^3 的紫外－真空紫外（UV－VUV）激发光谱和UV激发下的发射光谱。根据发射光谱讨论了Dy^3 离子在这几种基质中发光的黄蓝比（Y／B）。在VUV激发光谱中推测了Dy^3 的f-d跃迁及电荷迁移态（CTS）和基质吸收的位置。     

Photoluminescence and X-ray Diffraction of Distributed Bragg Reflector

Spectral and structural characteristics of distributed Bragg reflector (DBR) in vertical-cavity surface-emitting lasers were studied with photoluminescence and double- crystal X- ray diffraction measurement. The expected high quality epitaxial DBR structure was verified. In the X- ray double- crystal rocking curves of DBR the zeroth- order peak, the first and second order satellite peaks were measured. Splitting of diffraction peak appeared in the rocking curves was analyzed. The effects of introduced deep energy levels on the structural perfection and optical properties were discussed.     

引水发电系统无压隧洞中弃水堰位置的数值模拟研究

水电站引水发电系统无压隧洞中的水力过渡过程是近年来电站设计中出现的一个新课题,特别是流域梯级电站开发中经常遇到。结合工程实例应用扩散法,给出了无压隧洞水力过渡过程数值模拟的基本方程以及上下游及弃水堰等边界附加方程,模拟了弃水堰布置在不同位置下,无压隧洞内的水位变化过程。研究成果和讨论对实际工程应用具有参考意义。     

Accuracy of using computed tomography to identify pedicle screw placement in cadaveric human lumbar spine

STUDY DESIGN: Utility of using computed tomography to predict pedicle screw misplacement. OBJECTIVE: This study defines the sensitivity and specificity of predicting pedicle screw placement by experienced clinicians using a CT scan image. SUMMARY OF BACKGROUND DATA: In clinical and research settings, the method most commonly used to evaluate pedicle screws placement has been computed tomography. However, no current literature describes the accuracy of this method of evaluating screw placement. METHOD: Cobalt-chrome and titanium alloy pedicle screws of identical size were placed in six cadaveric human lumbar spine. Wide laminectomy was performed to allow complete visualization of the pedicles. Three consecutive lumbar levels were instrumented in each spine, giving 36 pedicle screw placements to identify. The instrumented spines were imaged, and four orthopaedic spine surgeons and a musculoskeletal radiologist were asked to read the images to identify the accuracy of screw placement within the pedicles. RESULTS: The sensitivity rate of identifying a misplaced screw was 67 +/- 6% for cobalt-chrome screws compared with 86 +/- 5% for titanium screws (P < 0.005). The specificity rates of radiographic diagnosis of misplaced pedicle screws were 66 +/- 10% for cobalt-chrome screws and 88 +/- 8% for titanium screws (P < 0.005). Similarly, a statistically significant difference was found in the sensitivity rates of identifying screws placed correctly in the pedicle: 70 +/- 10% for cobalt-chrome screws versus 89 +/- 8% for titanium screws (P < 0.005). Overall accuracy rates were 68 +/- 7% for cobalt chrome screws versus 87 +/- 3% for titanium screws (P < 0.002). CONCLUSION: Reliance on the computed tomography scan data alone in determining accuracy of pedicle screws can lead to inaccuracies in both clinical and research conditions.