梯度膜作为高功率激光反射膜的初步研究

 对渐变折射率薄膜替代均匀膜系作为高功率激光反射膜的可行性进行了理论研究。以较容易获得的线性共蒸法制备的光学膜在中心波长为1 064 nm的激光作用为例，分析了薄膜与基体之间波长的匹配、场强分布等问题。提出了通过改变微小单元获得梯度膜匹配厚度的数值方法，将之运用在14个周期结构的梯度膜中，并由膜系计算软件验证了所获得结果。最后通过分析Maxwell方程，计算了梯度膜中与薄膜损伤密切相关的电场强度分布。结果表明：周期性结构梯度高反射膜中的电场分布与传统高反射膜具有相似性，但相对于传统高反射膜容易在界面处出现损伤的情形而言，梯度膜更容易在表面出现损伤，使梯度膜表面反射相移接近π是高功率梯度高反射膜的设计方向。     

应用圆二色光谱研究电场对超氧化物歧化酶二级结构的影响

超氧化物歧化酶经不同强度的电场作用,采用圆二色光谱研究了不同强度的电场对超氧化物歧化酶二级结构的影响.结果表明：在1.0 kV/cm～6.0 kV/cm范围, 不同强度的电场对超氧化物歧化酶的α-螺旋、β-折叠、β-转角及无规卷曲相对含量的影响程度不同.与对照组相比,处理组的β-折叠和β-转角含量降低,降幅范围分别为2.5%～15.1和0.9%～3.5%；α-螺旋和无规卷曲含量增加,增幅范围分别为3.1%～18.8%和1.0%～8.9%.电场作用具有使超氧化物歧化酶的二级结构中β-折叠、β-转角向α-螺旋及无规卷曲转化的趋势.     

Electron–phonon effect on the ground-state binding energy of hydrogenic impurity in quantum-well wire in presence of an electric field

The hydrogenic impurity binding energy in rectangular quantum well wire including both barriers of finite height and an applied electric field are studied. The polaron effects on the ground-state binding energy in electric field are investigated by means of Landau-Pekar variation technique. The results for the binding energy as well as polaronic correction are obtained as a function of the size of the wire, the applied electric field and the position of the impurity. Our calculations are compared with previous results in quantum wires of comparable dimensions.     

3D FDTD Implementation for Scattering of Electric Anisotropic Dispersive Medium Using Recursive Convolution Method

The finite-difference time-domain method based on recursive convoltion method (RC-FDTD) for the electric anisotropic dispersive medium is discussed in detail. To exemplify the availability of the three-dimensional RC-FDTD algorithm, the backscattering Radar-Cross-Section(RCS) of a non-magnetized plasma sphere is computed, and the numerical results are the same as the one of the Shift Operater-FDTD method, and show that the RC-FDTD method is correct and efficient. In addition, the co-polarized and cross-polarized backscattering time-domain of a magnetized plasma sphere are obtained by the RC-FDTD algorithm. The results show that when the external magnetic field is implemented, the cross-polarized component appear, evidently.     

蒙药心舒安中锗的差分脉冲极谱研究

在pH=1.30的H2SO4和3,4-二羟基苯甲醛(DHB)底液中,采用差分脉冲极谱法,测得无机锗的脉冲极谱波.其峰电位为Ep=-0.53V.Ge(Ⅳ)浓度在1.03×10-3-1.04×10-4mol·L-1范围内与峰电流呈线性关系,样品中总锗和无机锗的回收率分别是95.72%和96.43%.     

The origin of spectral distortion in electric field modulation spectroscopy based on scanning tunneling microscopy

Electric field modulation spectroscopy using scanning tunneling microscopy (STM-EFMS) measurements were performed for a Si(1 1 1) surface with epitaxially-grown β-FeSi₂ islands. STM-EFMS spectra acquired around the indirect energy gap of Si reproduced the photon energy peak position observed in conventional macroscopic EFMS experiments. However, a considerable discrepancy was found in the energy position of the accompanying spectral dip. We examined two possibilities for the cause of this discrepancy. The first interpretation is that the STM-‘EFMS’ spectra may simply reflect the local density of states based on essentially the same principle as that of tunneling spectroscopy. However, this interpretation is ruled out by the facts that almost identical STM-EFMS spectra are obtained also out of the regime of tunneling. The second interpretation is a spectral distortion due to a large electric field steadily built in the sample surface, which is supported experimentally by a spectral shift of the dip energy that is induced by altering the tip-induced band bending.     

Phase-shift analysis of electric conductance through nanostructure bridges

We present our theoretical studies of electric conductance through nanostructure bridges. A simple expression of the electric conductance is obtained by using the phase-shift analysis. The phase-shifts are given by solving the characteristic equation obtained by extending the method applied to the single impurity problem in the metal. It is shown that the importance of the effect due to multiple orbitals in nanostructures. The conductance of the chain consisting atoms with sp_z character such as Al is given.     

NUMERICAL LOCALIZATION OF ELECTROMAGNETIC IMPERFECTIONS FROM A PERTURBATION FORMULA IN THREE DIMENSIONS

This work deals with the numerical localization of small electromagnetic inhomogeneities. The underlying inverse problem considers, in a three-dimensional bounded domain, the time-harmonic Maxwell equations formulated in electric field. Typically, the domain contains a finite number of unknown inhomogeneities of small volume and the inverse problem attempts to localize these inhomogeneities from a finite number of boundary measurements. Our localization approach is based on a recent framework that uses an asymptotic expansion for the perturbations in the tangential boundary trace of the curl of the electric field. We present three numerical localization procedures resulting from the combination of this asymptotic expansion with each of the following inversion algorithms： the Current Projection method, the MUltiple Signal Classification （MUSIC） algorithm, and an Inverse Fourier method. We perform a numerical study of the asymptotic expansion and compare the numerical results obtained from the three localization procedures in different settings.     

A revised model for the paired-electron gas plasma in a magnetic field and its application to experimental determinations on weakly ionized rare-gas plasmas

Summary The formation of electron pairs at the glass walls of the enclosing container in a low-pressure, high-frequency, electrodeless, rare-gas discharge is discussed. The pairs drift towards the discharge tube axis under the acceleration of the weak radial-space-charge electric field. The properties of the gas in an uniform magnetic field are outlined in a model which is subsequently applied to experimental data from four different experiments in four rare gases. Determinations of plasma parameters from the analyses of the experiments are found to agree. The values for the pair aggregation number,n′, for the excited plasmas on the tube axis range from one at low-power excitation to between ten and twenty at higher powers. In the afterglow plasmas following the cessation of the energizing current pulse (which is typically 20 ms in duration), the aggregation number varies from one in the body of the gas to between one and five on the tube axis. The direct evidence for the presence of electron pairs, and aggregates of electron pairs, is obtained from the ≪spin-flip≫ of single electrons of a pair in a magnetic field, an event which destroys the pair, or pair aggregate, and the associated experimental phenomena.

---

Riassunto Si discute la formazione di coppie di elettroni, sulle pareti di vetro del contenitore circostante in una discarica a bassa pressione, alta frequenza, senza elettrodi e a gas rari. Le coppie si spostano verso l’asse del tubo della discarica con l’accelerazione del campo elettrico debole con carica di spazio radiale. Le proprietà del gas in un campo magnetico uniforme sono sottolineate in un modello che è successivamente applicato a dati sperimentali da quattro diversi esperimenti in quattro gas rari. Si trova che i valori dei parametri del plasma dalle analisi degli esperimenti sono in accordo. I valori del numero di aggregazione della coppia,n′, per i plasma eccitati sugli assi del tubo variano da 1 ad eccitazione a bassa potenza a 10÷20 ad alte potenze. Nei plasmi a fluorescenza che seguono la cessazione dell’impulso di corrente energizzante (che dura tipicamente 20 ms) il numero di aggregazione varia da uno nel corpo del gas a 1÷5 sull’asse del tubo. La prova diretta della presenza delle coppie di elettroni, e di aggregati di coppie di elettroni è ottenuta dallo ≪spin-flip≫ di elettroni singoli di una coppia in un campo magnetico, un evento che distrugge la coppia, o l’aggregato di coppie, e dagli associati fenomeni sperimentali.

---

Резюме Обсуждается образование электронных пар на стеклянных стенках замкнутого контейнера при высокочастотном, безэлектродном разряде в разреженном газе при низком давлении. Пары дрейфуют по направлению к оси разрядной трубки под действием электрического поля слабого радиального пространственного заряда. Описываются свойства газа в однородном магнитном поле, используя модель, которая впоследствии применяется к экспериментальным данным из четырех различных экспериментов, проведенных для четырех разреженных газов. Обнаружено хорошее согласие при определении параметроб плазмы из анализа указанных экспериментов. Значения для числа электронных пар в агрегации,n′, для возбужденной плазмы на оси трубки изменяется от единицы при инзкой степени возбуждения до величины между десятью и двадцатью при высоких степенях возбуждения. При послесвечении плазмы, после прекращения возбуждающего имлульса тока (который обычно имеет длительность 20 мс), число пар в агрегации изменяется от единицы в объеме газа до величины между единицей и пятью на оси трубки. Получено прямое подтверждение для наличия электронных пар и агрегаций электронных пар из изменения ориентции спина отдельных злектронов пары в магнитном поле, т.е. из события, которое разрушает пару или агрегации рар, и из связанных экспериментальных явлений.