晶体中稀土离子f-d跃迁光谱的数值模拟

在介绍晶体中稀土离子4fN-15d组态的能级结构、4fN组态和4fN-15d组态之间f-d跃迁线强以及相应的声子伴随跃迁的基础之上,讨论了国际上用于数值化模拟稀土离子f-d跃迁光谱的扩展f-shell程序的使用细节,总结了使用该程序在模拟f-d跃迁光谱方面的工作,并简单探讨了进一步的工作设想.最后,给出了一个氟冰晶石掺Er3+离子f-d跃迁光谱的数值模拟示例.     

干扰力作用下潜艇近水面运动的仿真

潜艇近水面运动时受一介波浪力和二阶波浪力的影响较大，本文对一阶波浪力、二阶波浪力和海流力进行了数值计算，然后把这些干扰力作为干扰项加入静水中的潜艇六自由度运动方程得到潜艇近水面运动模型。最后对潜艇近水面运动模型和压水及操舵对消除波浪力的影响进行了仿真分析，仿真结果与实际情况吻合，说明文中提出的潜艇近水面运动仿真模型是合理有效的。     

等温淬火处理对铸造GCr15钢机械性能的研究

利用废旧GCr15钢材进行熔炼,直接用砂型浇铸得到成形铸件,研究了经等温淬火工艺对铸造GCr15钢机械性能的影响.结果表明等温淬火处理可以较大幅度提高铸造GCr15钢的抗拉强度及冲击韧性.在240~300℃温度下等温淬火,硬度可以保持在HRC50以上,冲击韧性在12J/cm2到24 J/cm2之间.     

Deciphering cryptic proteases

Proteases are deeply involved in physiology and pathology. For most, the mechanism is well defined but several fail to display typical protease features (as is the case of the four proteases contained in fibronectin, the inhibitor-resistant mesotrypsin and the proteosomal deubiquitinating enzyme) or have unclear physiological function (such as calpain-like proteins, transthyretin and factor seven activating protease). In other cases, such as in peroxisomal processing proteases, although substrates are defined, the enzyme remains undiscovered. Furthermore, several proteases were identified in pathological conditions, namely secretases in Alzheimers disease and gross cystic disease fluid protein 15 kDa in breast cancer, when most likely their physiological substrate is still hidden. Lastly, the evolutionary conservation of proteolytic enzymes raises questions related to the origin of biological events, such as the origin of cystein proteases and cell death responses. In this review we will discuss the above cryptic enzymes, as they will probably be relevant in the future.Received 7 December 2004; received after revision 5 January 2005; accepted 10 January 2005 Available online 09 March 2005     

Determination of trophic relationships within a Bohai Bay food web using stable δ15N and δ13C analysis

This study measured stable carbon and nitrogen isotope ratios in phytoplankton, zooplankton, five invertebrates species, eight fishes species and three seabirds species collected in Bohai Bay. δ^13C ranged from -25.38‰ to -11.08‰ showing a relative low enrichment in the food web from Bohai Bay. The mean δ^13C of mullet is higher than that of other organisms, and this might be due to that mullet is migration fish and feeds mainly on inshore sources. δ^15N ranged from 4.08‰ to 13.98‰, and showed a step-wise enrichment with trophic level of 3.8‰. The δ^15N enrichment factor was used to construct an isotopic food web model to establish trophic relationships within this marine food web. According to this model, exact trophic levels of all organisms were estimated as 1.46-2.10, 1.91-3.32, 2.55-4.23 and 2.98-4.28 for plankton, invertebrates, fishes, and seabirds.     

基于COOH/SBA-15的谐振式氨气传感器气敏性能研究

针对化工生产过程中易出现的氨气泄露等问题,采用共聚法合成了羧基功能化介孔硅材料(COOH/SBA-15),并将其作为敏感材料设计了一种石英晶体微天平(Quartz Crystal Microbalance,QCM)式氨气传感器.利用扫描电子显微镜、透射电子显微镜、X射线衍射仪、全自动比表面积和孔隙度分析仪、傅里叶变换红外光谱仪等对敏感材料的形貌和结构进行了表征,并系统地研究了基于COOH/SBA-15的QCM传感器的气敏性能.测试结果表明该传感器对氨气(NH3)的检测限可达到10-6(体积分数),所合成的COOH/SBA-15-2样品对体积分数为20×10-6的NH3响应恢复时间分别为5s和7s.同时,该传感器对NH3具有较高的化学选择性和稳定性,具有较高的实用价值.     

负载型磷钨酸催化剂在癸二酸二辛酯合成中的应用

将介孔材料SBA-15与磷钨酸溶液在80℃水浴条件下蒸发浓缩制备负载型磷钨酸催化剂HPW-SBA-15作为合成癸二酸二辛酯的催化剂,并分析其酸催化性能及磷钨酸的负载量、温度、反应时间、酸醇比等因素对合成癸二酸二辛酯的影响.结果表明,在催化合成癸二酸二辛酯时,最佳反应条件为:磷钨酸负载量为50%,反应时间为2.5h,n(癸二酸)∶n(异辛醇)=1∶3.此时,酯化率最高为95.47%.     

香蕉番茄与常规番茄品种生长发育的对比试验

为了解香蕉番茄的生长发育规律,进行了香蕉番茄与冀东地区当地主栽番茄品种佳粉十五和中杂9号的田间对比试验。通过对出苗时间、苗高、苗粗、叶片数、花序着生节位、每一花序中的花数、座果率、抗病性、单果重、产量等各项指标进行的比较,结果表明：香蕉番茄出苗比佳粉十五和中杂9号晚．株高低;茎粗小,但差异不显著;第一花序着生节位介于中杂9号和佳粉十五之间,差异不显著;座果率高．差异显著;单果重低．差异极显著;产量略低,但差异不显著。香蕉番茄出苗所需时间较长．栽培时播种期应适当提前;长势中等．株高较低,单果重小,座果率高．产量略低但经济价值高;发生侧枝能力较强．应及时摘除侧枝。     

海水温度采集电路设计

根据海上气象预报的需要,设计了基于STC15F204EA单片机的海水温度采集电路。本文首先分析单片机特性,然后根据项目需要进行了海温采集电路硬件的设计,结论表明海温数据稳定可用。