水氢冷300MW发电机轴颈损伤实例处理和计算分析

以某电厂300MW汽轮发电机转子轴颈损伤故障为例,介绍了故障的检查、处理措施以及有父的计算分析。展示了汽轮发电机转子轴颈损伤的实物照片,介绍了修理步骤包括修理前的转子电气试验、发电机转子各关键部位的跳动检查及记录与标注,转子本体摆度的测量、转子上车床对轴颈进行车加工、砂修、硬度检查及着色探伤及超声波探伤,装配风叶及赐叶配重,转子清理,转子动平衡及1．1倍额定转速的超速试验,转子绕组电气试验,转子气密试验,喷漆及发运前的防护处理等。     

新型有机电致蓝色磷光器件的研究

设计了一种Ge/Si波导集成型雪崩光电二极管(APD)。器件采用将Si波导层置于Ge吸收层之下的结构,光经波导层进入吸收层只需一次耦合,降低了光的损耗,提高了光的吸收率和光电流。采用silvaco软件对器件的结构和性能进行仿真,结果表明:器件的雪崩击穿电压为-28V,最大内量子效率达到89%,在1.15~1.60μm范围内具有较高响应度,峰值波长位于1.31μm,单位响应度最高达0.74A/W,3dB带宽为10GHz。 更多还原     

核电站用发电机内部短路分析及PARK方程实例仿真计算

介绍了发电机内部短路故障的主要分类及产生原因。利用经典PARK方程法,进行了实例仿真计算。研究并掌握超大容量核电站用发电机短路故障原因和仿真计算,对发电机运维与设备管理技术人员具有指导作用。     

红色代码病毒及其变体的防杀策略

简要介绍了红色代码蠕虫病毒(red code)及其变体(red codeⅡ)和(red codeⅢ),并对它们的传播、危害、典型现象及其特征与运行过程做了说明,在此基础上分析论述了其发作机理,说明了红色代码病毒利用微软ⅡS的漏洞进行感染与传播,提出了针对网络端和用户端安全实用的检测及预防方案,最后说明了清除的详尽解决方案。     

利用镁渣制备混凝土膨胀剂的性能研究

通过分析镁渣的成分及其膨胀机理,以镁渣、粉煤灰、石灰等为原料,制备混凝土膨胀剂,按照GB 23439—2009《混凝土膨胀剂》规定测试限制膨胀率及胶砂试块强度。结果表明,以镁渣、粉煤灰和石灰制备混凝土膨胀剂是可行的;石灰可以促进镁渣的水化,且当石灰掺量增大时,混凝土的早期膨胀率增大,后期有收缩;随着镁渣掺量的提高,镁渣膨胀剂的限制膨胀率先增大后趋于平衡,而镁渣掺量的增大对胶砂试块的强度无明显影响。     

Tandem organic light-emitting diodes with buffer- modified C60/pentacene as charge generation layer

Buffer-modified C60/pentacene as charge generation layer (CGL) is investigated to achieve effective performance of charge generation. Undoped green electroluminescent tandem organic light-emitting diodes (OLEDs) with multiple identical emissive units and using buffer-modified C60/pentacene organic semiconductor heterojunction (OHJ) as CGL are demonstrated to exhibit better current density and brightness, compared with conventional single-unit devices. The current density and brightness both can be significantly improved with increasing the thickness of Al. However, excessive thickness of Al seriously decreases the transmittance of films and damages the interface. As a result, the maximum current efficiency of 1.43 cd.A-1 at 30 mA.cm-2 can be achieved for tandem OLEDs with optimal thickness of Al. These results clearly demonstrate that Cs2CO3/Al is an effective buffer for C60/pentacene-based tandem OLEDs.     

稻草纤维素水解机理及工艺条件的研究

以稻草秸杆为纤维素原料,用2%氢氧化钠对其进行预处理,选用纤维素酶作为催化剂对纤维素进行酶法水解,采用DNS法测定纤维素水解液还原糖的含量,并计算其糖化率。探讨了纤维素酶水解稻草秸秆纤维素的反应机理,研究了纤维素酶的添加量、反应温度、pH、反应时间、振荡等因素对稻草纤维素酶水解的影响。实验结果表明,当固液比为1∶30、纤维素酶添加量为40 mg、50℃、pH 4.8、振荡反应12h,纤维素酶解液的糖化率可达40%。     

Buffer-modified C60/pentacene as organic charge generation layer based on Al and MoO3

We demonstrate tandem organic light-emitting diodes (TOLEDs) with excellent performance using Al and MoO₃ buffer-modified C₆₀/pentacene as charge generation layer (CGL). Al and MoO₃ were used as the electron and hole injection layers of C60/pentacene CGL, respectively. Green phosphorescence TOLEDs with the structure of ITO/NPB/mCP:Ir(ppy)₃/TPBi/Al/C₆₀/pentacene/MoO₃/NPB/mCP:Ir(ppy)₃/TPBi/Cs₂CO₃/Al were fabricated. The results show that the inserted Al and MoO₃ can effectively increase the charge injection capacity of organic CGL, resulting the improvement of luminance and current efficiency of TOLEDs. The turn-on voltage of TOLEDs is much lower than that of single-unit device, and the current efficiency is more than 2 times larger than that of the single-unit device. TOLEDs can exhibit excellent photoelectric performance when the thicknesses of Al, C₆₀, pentacene and MoO₃ are 3 nm, 15 nm, 25 nm and 1 nm, respectively. The maximum luminance and current efficiency are 7 920.0 cd/m² and 16.4 cd/A, respectively. This work is significant to build new CGL structures for realizing high-performance TOLEDs.     

基于归一化植被指数反演地表比辐射率方法的对比研究

针对只有一个热红外通道的遥感数据,利用归一化植被指数与地表比辐射率具有较高的线性相关性进行地表比辐射率的遥感反演,介绍了基于归一化植被指数定量反演地表比辐射率的4种方法,以湖北省荆门市地区的Landsat5 TM数据为研究对象,精度0.01的MODIS LSE产品为标准数据,对比分析了4种基于NDVI的地表比辐射率反演方法,分别从像元尺度和分类尺度总结了4种地表比辐射率反演方法的普适性和精度。