电感耦合等离子体质谱法测定高纯氧化钆中痕量稀土杂质

考察了起因于钆基体的多原子离子干扰，当基体浓度为１ｇ／Ｌ时，基体质谱对相邻低质量同位素产生严重的峰前沿干扰，基体的多原子离子也会对待测稀土杂质同位素产生严重的谱干扰。研究了Ｇａ，Ｉｎ，Ｉ，Ｃｓ和Ｔｌ内标对基体抑制效应的补偿作用，加入内标元素Ｔｌ后，基本上克服了基体效应。     

准周期铁电光学超晶格多波长二次谐波的产生

准周期材料的研究是凝聚态物理学的热门课题之一。我们利用外电场室温极化技术，成功地制备了准周期ＬｉＴａＯ３超晶格，首次获得了高效，多波长的二次谐波输出。对应的基波波长分别为０．９７６２，１．０８４６，１．８３４，１．３６５０和１．５６９９μｍ。     

电感耦合等离子体质谱法测定高纯金中痕量杂质

建立了高纯金中40余种痕量杂质的电感耦合等离子体质谱测定方法。方法检出限为0．0006～0．21μg/L。考察了基体Au的谱干扰及基体效应,采用Cs内标补偿基体对待测信号的抑制作用。方法简单、快速、灵敏、准确。     

Studies on the electrochemical behavior of cytochrome c and its interaction with DNA at a Co/GC ion implantation modified electrode

The electrochemical behavior of cytochrome c (cyt c) and its interaction with DNA at a Co/glassy carbon (GC) ion implantation modified electrode were studied by linear sweep and cyclic voltammetry. In 0.005 mol dm(-3) Tris-0.05 mol dm(-3) NaCl buffer solution (pH = 7.10), a sensitive reduction derivative peak of cyt c was obtained by linear sweep voltammetry. The peak potential was 0.032 V (SCE). The peak current was proportional to the concentration of cyt c. The electrode process was quasi-reversible with adsorption. The electrode reaction rate constant k and the electron transfer coefficient a of cyt c were 4.42 s(-1) and 0.47, respectively. AES and XPS experiments showed that Co was implanted into the surface of the GC electrode (GCE). The implanted Co formed Co-C, which catalyzed the reduction of cyt c. The reaction of DNA with cyt c led to an electrochemically active complex, which resulted in an increase in the reduction current of cyt c. After adding DNA into the solution containing cyt c, the electrode process was still quasi-reversible with adsorption.     

用电感耦合等离子体质谱法测定高纯稀土中稀土杂质时的基体影响

考察了基体对待测稀土杂质元素信号的影响，研究了内标对基体效应的补偿作用。对于不同的基体元素最佳的内标元素是不一致的，Ｇａ、Ｉｎ、Ｉ、Ｃｓ和Ｔｌ是稀土纯度分析中合适的内标元素。内标法简便易行，效果好，其测定方法的精度和回收率令人满意。     

用ICP—MS测定高纯氧化镝中痕量稀土元素

考察了源于基体镝的多原子离子干扰。研究了基体对待测稀土杂质信号的影响，采用Ｔｌ内标能基本上补偿基体影响。建立了直接测定高纯氧化镝中痕量稀土杂质的电感耦合等离子体－质谱法。检测限为００１３～００８８μｇ／Ｌ，平均回收率为９２３％～１０１４％，相对标准偏差为２７％～９２％。方法简便、快速、灵敏。     

Comparative study on the analytical performance of three waveforms for the determination of several aminoglycoside antibiotics with high performance liquid chromatography using amperometric detection

A preliminary comparative study was carried out on the analytical performances of a new six-potential waveform and other two detection waveforms, triple-potential waveform and quadruple-potential waveform. The analytical performances compared included signal response, background noise, signal/noise ratio and signal stability. Compared with triple-potential waveform and quadruple-potential waveform, the new six-potential waveform had higher signal response, signal/noise ratio, and sensitivity. As for determination reproducibility, the six-potential waveform also exhibited a slightly better performance than the other two waveforms. Under the selected experimental conditions based on the six-potential waveform, there is a linear correlation between peak area and concentration over two to three orders of magnitude for nine aminoglycoside antibiotics with a correlation coefficients better than 0.998 and the detection limits measured as three times the peak height signal-to-noise ratio for the nine aminoglycoside antibiotics were in the range of 0.0198-0.889 microg/mL. The proposed method had been used to analyze real gentamicin sulphate drug sample.     

ADVANCE IN BIOMECHANICS OF HUMAN EAR AS HEARING SYSTEM

耳是人体重要的听觉器官. 人耳是一个典型的在声波激励下的传导振动,继而将振动转变成听神经纤维的脉冲发放结构. 建立完整有效的人耳结构生物力学模型,研究它的生物动力学行为,有助于我们认识和分析人耳的传音及感音机理,研究人耳病理状态下和手术后的传声及感音机制的变化,进一步为研究相关临床疾病的生物力学机制提供理论依据. 本文总结了人耳听力系统生物力学模型及临床应用的研究进展,并展望了今后的研究工作.     

Decay rate for a PH/M/2 queue with shortest queue discipline

In this paper, we consider a PH/M/2 queue in which each server has its own queue and arriving customers join the shortest queue. For this model, it has been conjectured that the decay rate of the tail probabilities for the shortest queue length in the steady state is equal to the square of the decay rate for the queue length in the corresponding PH/M/2 model with a single queue. We prove this fact in the sense that the tail probabilities are asymptotically geometric when the difference of the queue sizes and the arrival phase are fixed. Our proof is based on the matrix analytic approach pioneered by Neuts and recent results on the decay rates. AMS subject classifications: 60K25 · 60K20 · 60F10 · 90B22     

Tensor product varieties,perverse sheaves,and stability conditions

The space spanned by the class of simple perverse sheaves in Zheng (2008) without localization is isomorphic to the tensor product of a Verma module with a tensor product of irreducible integrable highest weight modules of the quantum enveloping algebra associated with a graph. Under the isomorphism, the simple perverse sheaves get identified with the canonical basis elements of the tensor product module. The two stability conditions coincide with the localization process in Zheng (2008), by using supports and singular supports of complexes of sheaves, respectively.