次因子

We performed a field experiment by the end of 2004, and based on the data of this experiment, we studied the amplitude degression and corresponding seismic attenuation factor of both single event waveform and cross-correlation function. It is found that, same as single event waveform, cross-correlation function could be used to assess the seismic attenuation.

依据野外现场实验的数据，我们分别以单次和多次激发为源，讨论了事件波形和互相关函数波形的振幅变化及相应的介质品质因子，结果发现，与事件波形一样，互相关函数波形也可以用于计算介质的衰减系数。

We performed a field experiment by the end of 2004, and based on the data of this experiment, we studied the amplitude degression and corresponding seismic attenuation factor of both single event waveform and crosscorrelation function. It is found that, same as single event waveform, crosscorrelation function could be used to assess the seismic attenuation.

依据野外现场实验的数据，我们分别以单次和多次激发为源，讨论了事件波形和互相关函数波形的振幅变化及相应的介质品质因子，结果发现，与事件波形一样，互相关函数波形也可以用于计算介质的衰减系数。

Employing the finite difference calculus, the cavitation bubble pulsating performance with the change of liquid viscosity, gas content, surface tension and condensability is obtained.

在系统地研究固壁面附近空泡溃灭过程的基础上，提出并研究了射流阈值、空泡在第一次和第二次脉动过程衰减蚀除机理以及空泡溃灭周期延长因子等问题。

In this thesis, several problems of time-dependent systems in various branches of physics are investigated by making use of the generalized invariant theory and the invariant-related unitary transformation formulation. The problems are given as follows:(1) Spin model and geometric phase factor in the fiber We investigate the fiber experiment performed by Chiao-Tomita and the Chiao-Wu theory concerning the geometric phase factor in the optical fiber, and then show that the investigation of the propagation of photons inside the noncoplanar optical fiber can be regarded as that of a second-quantization spin model.

本论文用推广的不变量理论和与不变量有关的幺正变换方法研究了一些物理分支中的几个含时系统问题：(1)自旋模型与光纤中光子几何相因子问题重新考察了Chiao-Tomita光纤实验和Chiao-Wu关于光纤中光子几何相因子的理论，证明了在非共面弯曲光纤中传播的光子运动问题实际上可以化为二次量子化含时自旋模型研究。

The influence of drying parameters of freeze-drying on quality of pteridium aquilinum drying was investigated, and the impact of drying board temperature, drying chamber pressure and material thickness on Vc content was studied by nonlinear regressional orthogonal design.

考察干燥因子对真空冷冻干燥蕨菜品质的影响，用二次正交旋转组合设计的试验方法，分析搁板加热温度、干燥室压力和物料层厚度对蕨菜Vc含量的影响规律，建立了冻干因子与Vc含量的回归模型。

During the establishment of sediment yield dynamic model at the watershed outlet, it was difficult for us to carry out dynamic monitoring of each impact factors in the whole basin, because it was a long time research and was in very large-scale watershed. Taking into account the interannual variability of sediment yield mainly affected by hydrological conditions of rainfall - runoff and underlaying surface changes caused by soil conservation measures, a combined influence factor which is related to surface runoff modulus and the implementation time of the water and soil conservation project was proposed for the first time. Furthermore, its specific expression was determined through dimensional analysis and non-linear regression multianalysis.

在流域输沙量动态模型的建立中，由于研究时段长、研究流域尺度大，对输沙量各影响因子进行全流域逐年动态监测十分困难，考虑输沙量的年际变化主要受降雨-径流水文条件和水土保持措施等土地管理活动的影响，首次提出与地表径流模数和治理时间相关的综合影响因子，并通过因次分析法和二元非线型回归法确定了具体的表达式。

Results: Antepartum hemorrhage and hypertension were the strongest risk factors for LBW or PTD history, and infection with syphilis had moderately increased risks. Female gender and primiparae were were also significantly associated with the risk of LBW infants.

结果：关於低出生体重儿方面，母亲产前出血及高血压是最强的危险因子，瘦小及肥胖的母亲、二次以上的自然流产经验、以前有低出生体重或早产儿、以及梅毒感染是中度的危险因子，女婴及初产妇亦与低出生体重儿有显著相关。

Results: Antepartum hemorrhage and hypertension were the strongest risk factors for LBW infants, and lean and obese mothers, two or more prior spontaneous abortions, previous LBW or PTD history, and infection with syphilis had moderately increased risks. Female gender and primiparae wer e also significantly associated with the risk of LBW infants.

结果：关於低出生体重儿方面，母亲产前出血及高血压是最强的危险因子，瘦小及肥胖的母亲、二次以上的自然流产经验、以前有低出生体重或早产儿、以及梅毒感染是中度的危险因子，女婴及初产妇亦与低出生体重儿有显著相关。

Several main results on the evolutions of the life and environment on early earth are summarized as follows:(1) the oxygenation of surface environment didn''t cease until a stable stage for 0.4Ga appeared after 1.6Ga;(2) compared to the isotopic compositions of kerogens and coexisted carbonates, the differences between two can effectively carrier the signals from local environments and bio-assemblages;(3) multiple isotopic relationships between kerogens and individual alkanes in Proterozoic samples were observed, which would depend on the specific biogeochemical processes;(4) repeated biogeochemical changes were observed accompanying Neoproerozoic glaciations, which suggesting that environmental rather than evolutionary forces were driving the biogeochemical changes;(5) the bio-radiations after Neoproterozoic glaciations were definitely suggested by molecular and isotopic data to be at the early Cambrian and after the middle of Doushantuo deposition with different triggers for them.

研究获得以下重要认识：（1）古元古代地表环境的氧化可能一直持续到中元古代早期(约1.6Ga)，而在此之后的4亿年里则保持相对稳定；（2）相对于传统的干酪根和碳酸盐的碳同位素组成，二者之差则能更好反映区域环境的演化特征；（3）在元古代干酪根与单体烷烃类之间存在多种碳同位素组成关系；而其与不同的生物地球化学过程有关；（4）全球海洋生物地球化学特征随新元古代多次冰期出现循环波动，这显然为环境因子的驱动；（5）在新元古代大冰期之后，分子与同位素数据显示地球生命在陡山沱中后期和早前寒武纪出现两次大辐射，然而两次生命辐射的本质却是不同的。

Considering the design parameters of the BEPCⅡ, in the case of one cavity type being adopted, the thesis analyzes the RF performance of accelerating mode, the suppression of higher order modes , and the restriction caused by HOMs against beam current threshold.

结合BEPCⅡ的设计参数，论文对其中一种腔型在BEPCⅡ上使用时加速模式的微波性能、高次模的抑制效果以及高次模对储存流强阈值的限制等方面进行了分析，并在铝模型腔上测量了加铁氧体高次模抑制器前后，超导腔中各种谐振模式的有载品质因子及其频率的分布。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。