Multi-level effects in the high-order harmonic generation driven by intense frequency-comb laser fields

High harmonic generation（HHG） driven by intense frequency-comb laser fields can be dramatically enhanced via multiphoton resonance by tuning the carrier-envelope phase（CEP） shift, without increasing the driving intensity. However,the multiphoton-resonant enhancement（MRE） factor in the realistic atomic hydrogen is much smaller than that in a twolevel system. To study the deviation, we present a theoretical investigation of the multiphoton resonance dynamics of three-level systems driven by intense frequency-comb laser fields. The many-mode Floquet theorem（MMFT） is employed to provide a nonperturbative and exact treatment of the interaction between the quantum system and the laser fields. The investigations show that the dipole interaction of a two-level system with the third level affects the multiphoton resonance dynamics and enhances the HHG spectra. It is the dipole interaction of the excited level of the two-level system with other levels that results in the smaller MRE factor in the realistic atomic system.

实践视域下英国T Level课程建设的研究与探索

T Level课程是以职业教育为导向的全日制课程体系,是英国中学阶段与A Level课程及学徒制并驾齐驱的“第三条道路”。本研究基于实践背景,从经济、市场、社会三个维度分析英国T Level课程建设的现实动因。结合具体教学实践,从招生指向、课程设置、师资配置、实习实践四个方面探讨T Level课程建设的实践路径。T Level课程建设产生的政策效应包括强化雇主在技能人才培养中的主导地位、建立学术与技术路径之间自由转换机制、明确职业地图与职业坐标的相对应关系、确立以能力为导向的多元化学业评价标准。反思T Level课程建设,发现有其独特的价值意蕴,也面临争议挑战,能为我国职业教育提供经验启示。

RELATIVE SEA LEVEL RISE AND ITS EFFECTS ON ENVIRONMENT AND RESOURCES IN CHINAS COASTAL AREAS

Due to global climate warming and natural and man-made land subsidence etc., relative sea level rise in the coastal plains of China will exceed 2-3 times over the golbal mean value during the first half part of the 21st century. It will result in a series of adverse impacts on evolution of natural environment and socioeconomic development of the coastal area. This paper analyses environmental and resource effects induced by relative sea level rise in China's coastal areas on the basis of rough estimate of future relative sea level rise. These effects include inundating tidal flat and wetlands and increase in inundated risk of coastal habitable land,exacerbating storm surge. coastal erosion, flooding and salt water intrusion hazards.as well as endangering land. water. tourism and living resources and their utilization.

Influence of Doppler broadening and spontaneously generated coherence on propagation effect in a quasi lambda-type four-level system

In this paper we study influences of Doppler broadening, spontaneously generated coherence, and other system parameters on propagation effect in a quasi lambda-type four-level atomic system. It is shown that when the Doppler broadening is present, generally speaking, the values of gain and intensity of lasing without inversion （i.e. the probe field） in the co-propagating probe and driving fields case are much larger than those in the counter-propagating case; considerably larger gain and intensity of lasing without inversion than those without the Doppler broadening can be obtained by choosing appropriate values of the Doppler broadening width and spontaneously generated coherence strength. The gain and intensity of lasing without inversion increase with the increase of spontaneously generated coherence strength; when spontaneously generated coherence is present, much larger gain and intensity of lasing without inversion than those in the case without spontaneously generated coherence can be obtained. Choosing suitable values of the probe detuning, Rabi frequencies of the driving and pump fields at the entrance of the medium also can remarkably enhance the gain and intensity of lasing without inversion.

Effect of Konjac Food on Blood Glucose Level in Patients with Diabetes

Seventy-two type II diabetic subjects were given Konjac food for 65 days. The data analyzed by multiple F test indicate that the fasting blood glucose (FBG) and the 2-h postprandial blood glucose (PBG) on the 30th and the 65th days after the food was ingested were significantly reduced (P = 0.001, P < 0.001, respectively), as was the glycosylated hemoglobin level at the end of the trial (P < 0.05). The final FBG and PBG of the subjects with initial FBG-O >200 mg% decreased on the average by 51.8 and 84.6 mg%. respectively; those with FBG-0 150-200 mg% decreased by 24.1 and 68.7 mg%; and those with FBG-O < 150 mg% decreased by 4.8 and 21.4 mg%. No significant changes in blood lipid indexes were observed, except that the triglycer-ide values of subjects with hypertriglyceridemia (>200 mg%) significantly decreased by 118.7 mg%. It was concluded that Konjac food is very useful in the prevention and treatment of hyperglycemia. (C)1990 Academic Press. Inc.

Effect of Quasi-Fermi Level on the Degree of Electron Spin Polarization in GaAs

With spin-polarized-dependent band gap renormalization effect taken into account, the energy-dependent evolu- tion of electron spin polarization in GaAs is calculated at room temperature and at a low temperature of 1OK. We consider the exciting light with right-handed circular polarization, and the calculation results show that the degree of electron spin polarization is dependent strongly on the quasi-Fermi levels of ｜1/2） and ｜- 1/2） spin conduction bands. At room temperature, the degree of electron spin polarization decreases sharply from 1 near the bottom of the conduction band, and then increases to a stable value above the quasi-Fermi level of the ｜- 1/2） band. The greater the quasi-Fermi level is, the higher the degree of electron spin polarization with excessive en- ergy above the quasi-Fermi level of the ｜- 1/2） band can be achieved. At low temperature, the degree of electron spin polarization decreases from 1 sharply near the bottom of the conduction band, and then increases with the excessive energy, and in particular, up to a maximum of i above the quasi-Fermi level of the ｜1/2） band.

Effects of topiramate and carbamazepine on thyroid hormone level in adults with epilepsy

BACKGROUND: It has been demonstrated that traditional antiepileptics, such as phenytoin, carbamazepine (CBZ), phenobarbital, etc., can result in the decrease of thyroid hormone of epileptic patients. However, there is still no sufficient evidence for the studies about the effect of new-type antiepileptics, such as topiramate (TPM), on thyroid hormones. OBJECTIVE: To observe the effects of TPM and CBZ on the level of thyroid hormones in serum of adults with epilepsy. DESIGN: A comparative observation. SETTING: Department of Neurology, Sichuan Provincial People's Hospital. PARTICIPANTS: Totally 100 outpatients or inpatients newly diagnosed to have epilepsy were selected from the Department of Neurology, Sichuan Provincial People's Hospital from July 2003 to August 2005, including 60 males and 40 females, aged 18-70 years. All the patients were accorded with the standard for the classification of epilepsy set by International League Against Epilepsy (ILAE) in 1981; Had been Informed and agreed with the detection; Had no history of thyroid gland disease; Had not taken any drugs could affect the thyroid function. Meanwhile, 40 adult healthy examinees were selected from our hospital as the control group, including 24 males and 16 females, aged 18-65 years. METHODS: ① The 100 epileptic patients were randomly divided into TPM group (n =50) and CBZ group (n =50), and they were treated with TPM (Xian-Janssen Pharmaceutical, Ltd.; Batch number: 03AS032, Norm: 25 mg/tablet) and CBZ (Shanghai Sunve Pharmaceutical Co., Ltd.; Batch number: 030201, Norm: 100 mg/tablet) respectively. The initial dosage of TPM was 25 mg per day, increased by 25 mg every week, the objective dosage of 100-200 mg per day was maintained when the symptoms were satisfactorily controlled. The dosage of CBZ was 6-8 mg/kg per day. All the patients were administrated for 1 year. ② The serum levels of total thyroxine (TT4), free thyroxine (FT4), total triiodothyronine (TT3), free triiodothyronine (FT3) and thyroid stimulating hormone (TSH) in the epileptic patients were detected by means of chemiluminescence before treatment and at 3, 6 and 12 months after treatment respectively. ③Standards for judging curative effects: Controlled by without seizure, the frequency of seizure reduced by ≥ 75% was taken as significant effect, reduced by 50%-74% as effect, and reduced by < 49% as invalid, whereas increased by more than 20% was taken as aggravation. ④ The intergroup and intragroup differences of the measurement data were compared by the analysis of variance and paired t test respectively. MAIN OUTCOME MEASURES: Serum levels of thyroid hormones before treatment and at different time points after treatment of TPM and CBZ. RESULTS: All the 100 epileptic patients and 40 healthy subjects were involved in the analysis of results. ① Changes of serum levels of thyroid hormones: The serum levels of TT3, TT4, FT3, FT4 and TSH were close between the epileptic patients and normal subjects before treatment (P > 0.05). In the CBZ group, the serum levels of FT4 at 3, 6 and 12 months after treatment [(16.87±3.77), (16.34±3.98) , (16.97±3.95) pmol/L] were significantly decreased as compared with those before treatment [(18.00±3.54) pmol/L, t =2.74, 3.50, 2.26, P < 0.05]; The levels of TT3 at 3, 6 and 12 months [(2.09±0.54), (1.99±0.49), (1.84±0.47) nmol/L] were significantly decreased as compared with those before treatment [(2.22±0.63) nmol/L, t =2.73, 2.78, 5.18, P < 0.05]. The levels of TT3 at 6 and 12 months [(109.65±23.98), (107.72±23.90) nmol/L] were significantly decreased as compared with those before treatment [(118.98±28.48) nmol/L, t =3.11, 3.30, P < 0.05]. TT4 level in serum at 3 months and the levels of FT3 and TSH at each time point after CBZ treatment had no obvious changes as compared with those before treatment (P > 0.05). In the TPM group, the levels of thyroid hormones at each time point had no obvious changes as compared with those before treatment (P > 0.05). ② Curative effects: Of the 100 epileptic patients, it was controlled in 12 cases, significantly effective in 30 cases, effective in 39 cases and invalid in 19 cases, the total effective rate was 81% (81/100). CONCLUSION: CBZ treatment can lead to the decreases of thyroid hormones in adult epileptic patients. Epilepsy itself and TPM treatment cannot change the thyroid hormones in adult epileptic patients, which suggests that TPM treatment is safer for the thyroid function of adult epileptic patients.

Optimal entropy squeezing sudden generation and its control for an effective two-level moving atom entanglement with the two-mode coherent fields

From the viewpoint of quantum information, this paper proposes a concept and a definition of the atomic optimal entropy squeezing sudden generation （AOESSG） for the system of an effective two-level moving atom which entangles with the two-mode coherent fields. It also researches the relationship between the AOESSG and entanglement sudden death of the atom-fields, and discusses the influences of atomic initial state on the AOESSG and obtains the system parameter which controls the AOESSG.

Bismuth Effects on Electronic Levels in GaSb(Bi)/AlGaSb Quantum Wells Probed by Infrared Photoreflectance

GaSb（Bi）/Alo.2Gao.sSb single quantum wells are characterized by a Fourier transform infrared spectrometer- based photoreflectance method at 77K. Spatially direct and indirect transitions between the electronic levels at and above the effective band gap are well resolved. The shifts of the electronic levels with Bi incorporation are identified quantitatively. The results show that the upshift of the valence band edge is clarified to be dominant, while the Bi-induced downshift of the conduction band edge does exist and contributes to the band gap reduction in the GaSbBi quantum-well layer by （29±6）%.

Effective Dose Levels from Computed Tomography of the Head during Contrast Studies in Nigeria

Background: Diagnostic reference levels for a number of common diagnostic radiological examinations against which individual centres could compare their performance have been recommended by relevant international agencies. Due to variations in different populations globally, local and national diagnostic reference levels are more reliable. To the best of our knowledge, no centre-specific study has been carried out and national surveys are not available. Objective: To establish a preliminary local and national diagnostic reference level in Nigeria. Methods: A pro-spective and cross-sectional study involving 30 conscious paediatrics and adult patients referred for head computed tomography scan. They were positioned supine and scanned according to the standard protocol for head computed tomography with manual mA selection. The total dose-length products were recorded at the end of the pre-contrast and post-contrast sequences respectively. The pre-contrast dose was taken into cognizance in the determination of the post-contrast value. The effective dose was established by multiplying the dose-length product by 0.0023 mSv.mGy-1.cm-1, a conversion coefficient for brain tissue adopted from the European Commission. Statistical Package for Social Sciences version 17.0 was used to analyze the data. Results: 30 paediatrics and adult patients of mixed gender participated in the study. Their ages ranged from 1 to 74 years with a mean age of 41.47 ± 23.30 years. The pre-contrast effective dose ranged from 1.93 mSv to 3.32 mSv with mean of 2.56 ± 0.51 mSv and 75th percentile of 3.11 mSv while the post-contrast effective dose ranged from 4.06 mSv to 6.97 mSv with mean of 5.27 ± 0.97 mSv and 75th percentile of 6.13 mSv. The mean effective dose from this work and two other isolated studies was 3.0 mSv. Conclusion: Although our quantified doses are below threshold limits for occupational exposures they are higher than the recommended level for the public. A further optimization of scanning protocols by the radiographers could lower the effective dose for patients undergoing contrast head computed tomography in our centre and in the country.

Mechanical effects of light on the ■-type three-level atom in a high-finesse optical cavity

A theoretical study is carried out for the modification and implication of the effect on the type three level atom in a high-finesse optical cavity driven by light field including spontaneous emission and the cavity decay. Analytic expressions for the dipole force, the friction force, the optical potentials and the friction coefficient are obtained. Then the numerical and graphical methods are used to investigate the friction coefficient with the controlling parameters. It is shown that the friction coefficient is strongly dependent on the controlling parameters. The cooling rate can increase by one order of magnitude more than that of a two-level atomic system. The reason can be given using the dressed states and the Sisyphus cooling mechanism, which would stimulate further experimental investigations.

Study on Communication Effect of Food Safety Risk in Social Media:the Influence of Response Effort Level on Consumption Willingness Change

By constructing influence model for communication effect of food safety risk in social media environment,the influences of different response manners taken by relevant enterprises on consumers' cognition and purchasing intention are analyzed,and influence mechanisms of response effort level,interaction and content reliability on consumers' attitudes are revealed. Based on quasi-experimental study with three kinds of response effort levels,it is found that content reliability,interaction and effort degree of enterprise response under negative information of food safety event have significant impacts on communication effect and consumers' purchasing intention.

Effect of Increasing CO_2 on the Stratospheric Level of CO and O_3

Production and destruction processes of carbon monoxide (CO) and ozone (O3) are examined in the light of increasing amount of atmospheric carbon dioxide (CO2). It is found that doubling of CO2 will increase the stratospheric concentration of CO and will have positive effect on O3 concentration.

Fermi level pinning effects at gate–dielectric interfaces influenced by interface state densities

The dependences of Fermi-level pinning on interface state densities for the metal-dielectric, ploycrystalline silicon-dielectric, and metal silicide-dielectric interfaces are investigated by calculating their effective work functions and their pinning factors. The Fermi-level pinning factors and effective work functions of the metal-dielectric interface are observed to be more susceptible to the increasing interface state densities, differing significantly from that of the ploycrystalline silicon-dielectric interface and the metal silicide-dielectric interface. The calculation results indicate that metal silicide gates with high-temperature resistance and low resistivity are a more promising choice for the design of gate materials in metal-oxide semiconductor（MOS） technology.

Stark and Kerr Effects on the Dynamics of Moving N-Level Atomic System

We have investigated numerically the dynamics of quantum Fisher information (QFI) and quantum entanglement (QE) for N-level atomic system interacting with a coherent field in the presence of Kerr (linear and non-linear medium) and Stark effects. It is observed that the Stark and Kerr effects play a prominent role during the time evolution of the quantum system. The evolving quantum Fisher information (QFI) is noted as time grows under the non-linear Kerr medium contrary to the QE for higher dimensional systems. The effect of non-linear Kerr medium is greater on the QE as we increase the value of Kerr parameter. However, QFI and QE maintain their periodic nature under atomic motion. On the other hand, linear Kerr medium has no prominent effects on the dynamics of N-level atomic system. Furthermore, it has been observed that QFI and QE decay soon under the influence of Stark effect. In short, the N-level atomic system is found prone to the change of the Kerr medium and Stark effect for higher dimensional systems.

Radio Frequency Environment Effect Algorithms and Implementation in Signal-level Radar System Simulation

In radar system simulation,the reliability of simulation results depends not only on radar and target models,but also on radio frequency (RF) environment models,including clutter,multipath,diffraction,atmosphere refraction and attenuation.In traditional radar function simulation,all of these factors are grouped into a single pattern-propagation factor and can only give limited information for radar models.In signal-level simulation,radar models require simulated echoes should include information such as delay,doppler frequency,polarization,etc.By discussing and analyzing the principles and algorithms of RF environment effects (clutter,multipath,diffraction,atmosphere refraction and attenuation),this paper is supposed to provide a general RF environment model in signal-level.Algorithms for the Weibull clutter with Gaussian power spectral density (PSD) is discussed;A standard multipath and diffraction algorithm is analyzed,and the spherical earth and knife edge(SEKE)diffraction algorithm is introduced;The ray-tracing algorithm and the effective earth model are discussed;Algorithms for the absorption of oxygen and vapor are introduced;For certain algorithms,some practical advice is given.Finally,an object-oriented RF environment effects model is implemented,which has been dedicatedly designed for signal-level simulations and can provide relatively authentic simulated RF environment for the signal-level simulation of radar systems.Two simulation examples including clutter model and multipath and diffraction model are carried out and analyzed.

社会保障水平提升如何影响共同富裕?——基于省级面板数据的实证分析

基于2011—2020年中国31个省级行政区的面板数据,利用熵权TOPSIS法分别对社会保障水平和共同富裕水平进行测度,然后通过静态和动态面板回归计量模型实证检验了社会保障和共同富裕之间的关系。研究发现:中国社会保障水平和共同富裕水平在2011—2020年整体呈现增长趋势,其中社会保障水平在空间上呈现东部地区高于西部地区、西部地区高于中部地区的特征,共同富裕水平在空间上则呈现“东-中-西”逐级递减趋势。经检验,社会保障水平的提高能够显著促进共同富裕的实现,且这种促进作用具有边际效应递减的非线性特点。机制分析表明,社会保障可以通过提高居民消费水平和促进人力资本积累两条路径促进共同富裕的实现。进一步研究发现,社会保障水平对共同富裕水平的影响还存在区域异质性,中部地区社会保障水平的提升对共同富裕水平的影响程度大于东部和西部地区。

系统级单粒子效应试验方法研究

为评估星载电子系统抗单粒子效应敏感性及验证系统级加固方法有效性,本文开展了系统级单粒子效应试验方法的相关研究。验证了采用地面模拟装置以逐一辐照系统中器件方式评估系统功能中断率的可行性,提出可通过多种方式获取器件的敏感性数据,指出直接将系统中器件对应的功能中断截面进行加和求取系统截面曲线的不合理之处,本研究为开展系统级单粒子效应试验提供了技术支撑。

霍尔效应实验自主分层次教学探究

为了解决2023版《理工科类大学物理实验课程教学基本要求》中分层次教学要求与现有仪器设备不完全匹配问题,我们结合本校实际探索了一条低投入高效能的自主化分层次实验教学途径。本文以霍尔效应实验自主化分层次教学实践为例,探究了如何在现有B层次的实验仪器上,细挖深究结合动手改造,开展C层次研究性实验和D层次设计性实验。在霍尔效应副效应研究性实验中,我们评估了所有效应的阶数,并定量测量了副效应引起的附加电势差;在角度传感器设计性实验中,我们完成了基于霍尔效应的角度传感器设计,并发展了一套两参量最小二乘法误差处理方法。自主化分层次实验教学有助于因地制宜地开展实验教学改革,提升实验教学质量。

数字生态、金融发展与区域创新水平

数字化发展对经济社会产生了巨大影响,催生了新型商业模式。良好的数字生态激发了创新活力,给区域创新带来了根本性变化。基于2013—2020年31个省(区、市)的面板数据,探究数字生态与区域创新水平之间的关系。研究发现:数字生态对区域创新水平存在显著的正向影响,且这一结论在进行了一系列稳健性检验后仍然成立;在考虑区域异质性的情况下,东部地区数字生态对区域创新水平存在显著的正向影响,中部和西部地区数字生态对区域创新水平的影响并不显著;数字生态能通过促进金融市场的高水平发展,进而推动区域创新水平提高。基于研究结论,提出了相应的数字生态发展建议,以期带动区域创新发展。