Comparison of the Noise Properties of Squeezed Probe Light in Optically Thick and Thin Quantum Coherence Media for Weak and Strong Coupling Lights

The output amplitude noises of one squeezed probe light which is at resonance throughout different optical depths media in strong- and weak-coupling-field regimes are investigated theoretically.By comparing the output quantum noises for different Rabi frequencies of coupling field and also for different optical depths,it is found that the optimal squeezing preservation of the probe light occurs in an optically thin medium with strong-coupling-field,where we can obtain the output squeezing close to the input one at nonzero detection frequency.

Design of a multi-voltage probe system for ICRF antenna coupling resistance measurement on EAST

A multi-voltage probe array system is designed to measure the coupling resistance of an ion cyclotron resonance frequency antenna. In the process of the antenna coupling resistance data extraction, the minimization algorithm, the original Levenberg–Marquardt algorithm, is replaced by the Broyden–Fletcher–Goldfarb–Shanno algorithm to achieve more stable and accurate results. Moreover, a simple model of the multi-voltage probe array was applied to simulate the performance of the Kalman filter, and to optimize the distance and position of the probes and probe number to mitigate the influence of the system noise on the rebuilt results. During the EAST experiment in 2019, a four-voltage probe array was applied to measure the coupling resistance of line 6 during high confined mode discharge. The measurement results by the multivoltage probe array system and the voltage/current probe pair show a good agreement.

Primary amine coupling on nanocarbon catalysts: Reaction mechanism and kinetics via fluorescence probe analysis

Non-metallic nanocarbon materials catalyzed coupling reactions of primary amines to produce imine is an efficient,green and sustainable synthetic route,which has a wide application prospect in fine chemicals or pharmaceutical molecules.In the present study,we show firstly the relatively high catalytic activity of graphene oxide in the reaction of oxidative coupling of benzylamine(OCB),which is even comparable with typical metal-based catalysts,indicating the great potential of nanocarbon materials in this reaction system.More importantly,a novel twophoton fluorescence probe molecule(N-propyl-4-hydrazinyl-1,8-naphthalimide,NA)with special chemical structure of hydrazine functionality was synthesized.The probe NA could selectively react with aldehyde or ketone compounds,leading to the photoluminescence enhancement via inhibition of photo induced electron transfer(PET)process.The synthesized NA was applied as probe in carbon catalyzed OCB system to predict the existence of reaction intermediate benzaldehyde(BA),indicating the reaction pathway of oxidation-deamination-condensation in nanocarbon catalyzed OCB process.The proposed luminescence-probe strategy for revealing the kinetics and mechanism may also shed light in other reaction systems concerning the intermediates or products of ketones or aldehydes.

Some recent advances in 3D crack and contact analysis of elastic solids with transverse isotropy and multifield coupling

Significant progress has been made in mixed boundary-value problems associated with three-dimensional（3D） crack and contact analyses of advanced materials featuring more complexities compared to the conventional isotropic elastic materials.These include material anisotropy and multifield coupling,two typical characteristics of most current multifunctional materials.In this paper we try to present a state-of-the-art description of 3D exact/analytical solutions derived for crack and contact problems of elastic solids with both transverse isotropy and multifield coupling in the latest decade by the potential theory method in the spirit of V.I.Fabrikant.whose ingenious breakthrough brings new vigor and vitality to the old research subject of classical potential theory.We are particularly interested in crack and contact problems with certain nonlinear features.Emphasis is also placed on the coupling between the temperature field（or the like） and other physical fields（e.g.,elastic,electric,and magnetic fields）.We further highlight the practical significance of 3D contact solutions,in particular in applications related to modern scanning probe microscopes.

Evaluation of TlOH Effect for Pd⁰-Mediated Cross-Coupling of Methyl Iodide and Excess Boronic Acid Ester toward Fabrication of [¹¹C]CH₃-Incorporated PET Tracer

The use of thallium(I) hydroxide (TlOH) as a base is known to extremely accelerate the Suzuki-Miyaura cross-coupling reaction using organoboronic acid or organoboronic acid ester as a substrate. Here, we investigated the effects of TlOH by comparing with other conventional bases such as KOH, K2CO3, and CsF for Pd0-mediated rapid cross-coupling reactions between CH3I and organoborane reagents, such as phenyl-, (Z)-4-benzyloxy-2-butenyl-, and benzylboronic acid pinacol esters under the conditions CH3I/borane/Pd0/base (1:40:1:3) in THF/H2O or DMF/H2O for 5 min with an aim to fabricate a PET tracer efficiently. Consequently, however, the use of TlOH was much less efficient than the other bases for the acceleration of cross-coupling reactions. Thus, it was reconfirmed that the milder and non-toxic conditions using K2CO3 or CsF so far developed by our group were most appropriate for the rapid C-methylations.

大气压固体分析探针结合单四极杆质谱仪快速检测18种合成大麻素

本研究建立了一种大气压固体分析探针结合单四极杆质谱仪(ASAP-MS)快速检测18种合成大麻素(SCs)的方法。通过优化ASAP-MS锥孔电压,确定4种优化电压为15、25、35和50 V,以提供化合物全面的质谱信息。在优化条件下对一系列SCs标准溶液进行分析,建立了18种SCs的质谱库,并对本方法进行方法学验证,得到18种SCs的检出限为10~20 mg/L。应用该方法对缴获的15批次未知样品进行检测,9批次呈阳性。该方法具有前处理简单、分析速度快、匹配高效精准、定性准确的优势,可用于基层公安禁毒部门的分析检测。

松辽盆地砂岩型铀矿铀含量配分比例的半定量分析

钱家店铀矿是位于松辽盆地南部的复成因砂岩型铀矿,受表生淋滤、辉绿岩中低温热液和深部油气等多流体影响,目前铀矿物赋存状态尚有一定争议,铀在矿石内不同矿物中的配分尚不明确。为了进一步明确铀赋存状态和在不同矿物中的配分,计算钱家店矿石中不同矿物中铀的配分比例,本文运用岩矿鉴定、铀化学逐级提取、电子探针和激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)微区原位分析技术开展综合测试分析。明确了钱家店铀矿物的赋存状态,认为钱家店铀矿物以吸附态为主,约占总铀含量的80%,结合态铀矿物或含铀矿物约占比20%。其中吸附态铀矿物主要富集在方解石等碳酸盐矿物中,占总铀含量的47.86%,其次是在黏土矿物中占17.94%,在铁锰氧化物矿物中占12.21%。独立铀矿物是与黄铁矿密切共生的沥青铀矿为主,约占铀总含量的9.07%,另有少量含钛铀矿物和铀石约占5.08%。这种矿石中各碎屑组分中铀的占比量化研究,为矿床地浸开采及资源量计算提供依据。

直流电弧等离子体炬数值模拟与诊断

直流电弧等离子体炬内部物理过程复杂且具动态性,较难对其进行准确描述与深入研究,且其工作温度较高,其状态参数难以使用常规方式测量。针对直流电弧等离子体炬,建立流动、传热和电磁相互耦合的数值模型,基于Fluent软件对直流电弧等离子体炬进行三维数值模拟和特性分析,设计并搭建了一套热焓探针实验系统,完成对直流电弧等离子体炬射流参数的测量分析。结果表明:建立的数值模型模拟结果与实验测量结果吻合较好,误差在10%以内;炬内温度与速度最大值与工作气流量呈正相关,均出现在靠近阴极区域,且沿轴线逐渐降低;等离子体炬内高温区与高电流密度区重合。

Ion Density Distribution in an Inductively Coupled Plasma Chamber

The ion density distribution in the reaction chamber was diagnosed by a Langmuir probe. The rules of the ion density distribution were obtained under the pressures of 9 Pa, 13 Pa, 27 Pa and 53 Pa in the reaction chamber, different radio-frequency powers and different positions. The result indicates that the ion density decreases as the pressure increases, and increases as the power decreases. The ion density of axial position z =0 achieves 5.8×1010 on the center of coil under the power of 200 w and pressure of 9 Pa in the reaction chamber.

Plasma Uniformity in a Dual Frequency Capacitively Coupled Plasma Reactor Measured by Optical Emission Spectroscopy

Local measurement of plasma radial uniformity was performed in a dual frequency capacitively coupled argon plasma （DF-CCP） reactor using an optical probe. The optical probe collects the light emission from a small separate volume in plasma, thus enabling to diagnose the plasma uniformity for different experimental parameters. Both the gas pressure and the low- frequency （LF） power have apparent effects on the radial uniformity of argon plasma. With the increase in either pressure or LF power, the emission profiles changed from a bell-shaped to a double-peak distribution. The influence of a fused-silica ring around the electrodes on the plasma uniformity was also studied using the optical probe. Possible reasons that result in nonuniform plasmas in our experiments are discussed.

Changes of the electron dynamics in hydrogen inductively coupled plasma

Changes of the electron dynamics in hydrogen （H2） radio-frequency （RF） inductively coupled plasmas are investigated using a hairpin probe and an intensified charged coupled device （ICCD）. The electron density, plasma emission intensity, and input current （voltage） are measured during the E to H mode transitions at different pressures. It is found that the electron density, plasma emission intensity, and input current jump up discontinuously, and the input voltage jumps down at the E to H mode transition points. And the threshold power of the E to H mode transition decreases with the increase of the pressure. Moreover, space and phase resolved optical emission spectroscopic measurements reveal that, in the E mode, the RF dynamics is characterized by one dominant excitation per RF cycle, while in the H mode, there are two excitation maxima within one cycle.

Determination of phase diagrams using the diffusion couple technique

It has been demonstrated that the diffusion couple technique is a powerful and efficient approach in establishing phase relationships of ternary systems. Accurate data on the phase equilibria can be obtained if the appropriate alloys are employed as end members of the diffusion couple. It is desirable to combine the diffusion couple technique with an investigation of the afterwards selected equilibrated alloys so that the precision and reliability of the obtained information about a ternary isotherm could be guaranteed.

Investigation of Capacitively Coupled Argon Plasma Driven by Dual-Frequency with Different Frequency Configurations

Low pressure argon dual-frequency （DF） capacitively coupled plasma （CCP） is generated by using different frequency configurations, such as 13.56/2, 27/2, 41/2, and 60/2 MHz. Characteristics of the plasma are investigated by using a floating double electrical probe and optical emission spectroscopy （OES）. It is shown that in the DF-CCPs, the electron temperature Te decreases with the increase in exciting frequency, while the onset of 2 MHz induces a sudden increase in Te and the electron density increases basically with the increase in low frequency （LF） power. The intensity of 750.4 nm emission line increases with the LF power in the case of 13.56/2 MHz, while different tendencies of line intensity with the LF power appear for other configurations. The reason for this is also discussed.

Electronic dynamic behavior in inductively coupled plasmas with radio-frequency bias

The inflexion point of electron density and effective electron temperature curves versus radio-frequency （RF） bias voltage is observed in the H mode of inductively coupled plasmas （ICPs）. The electron energy probability function （EEPF） evolves first from a Maxwellian to a Druyvesteyn-like distribution, and then to a Maxwellian distribution again as the RF bias voltage increases. This can be explained by the interaction of two distinct bias-induced mechanisms, that is： bias- induced electron heating and bias-induced ion acceleration loss and the decrease of the effective discharge volume due to the sheath expansion. Furthermore, the trend of electron density is verified by a fluid model combined with a sheath module.

Spatial variation behaviors of argon inductively coupled plasma during discharge mode transition

A Langmuir probe and an ICCD are employed to study the discharge mode transition in Ar inductively coupled plasma. Electron density and plasma emission intensity are measured during the E （capacitive discharge） to H （inductive discharge） mode transitions at different pressures. It is found that plasma exists with a low electron density and a weak emission intensity in the E mode, while it has a high electron density and a strong emission intensity in the H mode. Meanwhile, the plasma emission intensity spatial （2D an asymmetric profile in the E mode. Moreover, the at high pressure, but increase almost continuously at image） profile is symmetrical in the H mode, but the 2D image is electron density and emission intensity jump up discontinuously the E to H mode transition under low pressure.

Abnormal Enhancement of N_2^+ Emission Induced by Lower Frequency in N_2 Dual-Frequency Capacitively Coupled Plasmas

Nitrogen dual-frequency capacitively coupled plasmas （DF-CCPs） with different fre- quency configurations, i.e., 60/2 MHz and 60/13.56 MHz, are investigated by means of opticM emission spectroscopy （OES） and a floating double probe. The excited nitrogen molecule ion N＋（B） is monitored by measuring the emission intensity of the （0,0） bandhead of the first neg- ative system （FNS） at 391.44 nm. It is shown that in the discharge with 60/13.56 MHz, the N＋ emission intensity decreases with the increase in pressure. In the discharge with 60/2 MHz, however, an abnormal enhancement of N＋ emission at higher pressure is observed when a higher power of 2 MHz is added. Variation in the ion density shows a similar dependence on the gas pressure. This indicates that in the discharge with 60/2 MHz there is a mode transition from the alpha to gamma type when a higher power of 2 MHz is added at high pressures. Combining the measurements using OES and double probe, the influence of low frequency on the discharge is investigated and the excitation route of the N＋（B） state in the discharge of 60/2 MHz is also discussed.

Diagnosis of a low pressure capacitively coupled argon plasma by using a simple collisional-radiative model

This paper proposes a simple collisional-radiative model to characterise capacitively coupled argon plasmas driven by conventional radio frequency in combination with optical emission spectroscopy and Langmuir probe measurements. Two major processes are considered in this model, electron-impact excitation and the spontaneous radiative decay. The diffusion loss term, which is found to be important for the two metastable states （4s[3/2]2, 4s＇[1/2]0）, is also taken into account. Behaviours of representative metastable and radiative states are discussed. Two emission lines （located at 696.5 nm and 750.4 nm） are selected and intensities are measured to obtain populated densities of the corresponding radiative states in the argon plasma. The calculated results agree well with that measured by Langmuir probe, indicating that the current model combined with optical emission spectroscopy is a candidate tool for electron density and temperature measurement in radio frequency capacitively coupled discharges.

Experimental Characterization of Dual-Frequency Capacitively Coupled Plasma with Inductive Enhancement in Argon

The dual-frequency capacitively coupled plasma （DF-CCP） with inductive enhancement system is a newly designed plasma reactor. Different from the conventional inductively coupled plasma （ICP） reactors, now a radio frequency （rf） power is connected to an antenna placed outside the chamber with a one-turn bare coil placed between two electrodes in DF-CCP. This paper gives a detailed description of its structure of discharges in this apparatus were made via a Moreover, investigations on some characteristics Langmuir probe.

Time-resolved radial uniformity of pulse-modulated inductively coupled O_(2)/Ar plasmas

Time-resolved radial uniformity of pulse-modulated inductively coupled O_(2)/Ar plasma has been investigated by means of a Langmuir probe as well as an optical probe in this paper. The radial uniformity of plasma has been discussed through analyzing the nonuniformity factor β(calculated by the measured n_e, lower β means higher plasma radial uniformity). The results show that during the active-glow period, the radial distribution of ne exhibits an almost flat profile at the beginning phase, but it converts into a parabola-like profile during the steady state. The consequent evolution for β is that when the power is turned on, it declines to a minimum at first, and then it increases to a maximum, after that, it decays until it keeps constant. This phenomenon can be explained by the fact that the ionization gradually becomes stronger at the plasma center and meanwhile the rebuilt electric field(plasma potential and ambipolar potential) will confine the electrons at the plasma center as well. Besides, the mean electron energy( <ε>_(on)) at the pulse beginning decreases with the increasing duty cycle. This will postpone the plasma ignition after the power is turned on. This phenomenon has been verified by the emission intensity of Ar(λ = 750.4 nm). During the after-glow period, it is interesting to find that the electrons have a large depletion rate at the plasma center. Consequently, ne forms a hollow distribution in the radial direction at the late stage of after-glow. Therefore, β exhibits a maximum at the same time. This can be attributed to the formation of negative oxygen ion(O^(-)) at the plasma center when the power has been turned off.

Magnetic probe diagnostics of nonlinear standing waves and bulk ohmic electron power absorption in capacitive discharges

It is recognized that standing wave effects appearing in large-area,very-high-frequency capacitively coupled plasma(CCP)reactors cause center-high plasma non-uniformity.Using a high-frequency magnetic probe,we present a direct experimental diagnostic of the nonlinear standing waves and bulk ohmic electron power absorption dynamics in low pressure CCP discharges for different driving frequencies of 13.56,30,and 60 MHz.The design,principle,calibration,and validation of the probe are described in detail.Spatial structures of the harmonics of the magnetic field,determined by the magnetic probe,were used to calculate the distributions of the harmonic current and the corresponding ohmic electron power deposition,providing insights into the behavior of nonlinear harmonics.At a low driving frequency,i.e.13.56 MHz,no remarkable nonlinear standing waves were identified and the bulk ohmic electron power absorption was observed to be negligible.The harmonic magnetic field/current was found to increase dramatically with the driving frequency,due to decreased sheath reactance and more remarkable nonlinear standing waves at a higher driving frequency,leading to the enhancements of the ohmic heating and the plasma density in the bulk,specifically at the electrode center.At a high driving frequency,i.e.60 MHz,the high-order harmonic current density and the corresponding ohmic electron power absorption exhibited a similar node structure,with the main peak on axis,and one or more minor peaks between the electrode center and the edge,contributing to the center-high profile of the plasma density.