Search

Study of exciton recombination process is of great significance for the optoelectronic device applications of two-dimensional transition metal chalcogenides (TMDCs). This research investigated the decoupling MoS

Effective restoration measures are required to protect earthen sites in historical heritage locations. In this study, sticky rice paste was added to in situ site soils and the water resistance and disintegration of the modified soils were investigated. Further, the influences of freeze–thaw, dry–wet, and Na2SO4-corrosion cycles on the compressive strength of the modified soil and its morphology were assessed. The results obtained indicate that the modified soil exhibited the highest water resistance and strength after 30 freeze–thaw and dry–wet cycles and 20 Na2SO4-corrosion cycles. This work is expected to provide future guidance on improved restoration and protection of earthen sites.

Sticky rice paste is a viscous material commonly used in traditional Chinese construction. It has the basic properties of high viscosity and viscoelasticity, good corrosion and weather resistance, ...

Calcined ginger nuts admixed by fly ash and quartz sand (CGN-(F+S)) has been validated to be basically compatible to earthen sites as an anchor grout. Accelerated ageing tests including water stability test, temperature and humidity cycling test, soundness test and alkali resistance test are conducted with the objective to further research the property changes of CGN-(F+S) grout. Density, surface hardness, water penetration capacity, water permeability capacity, soluble salt, scanning electron microscopy (SEM) images and energy dispersive spectrometry (EDS) spectrum of these samples have been tested after accelerated ageing tests. The results show that densities of samples decrease, surface hardness, water penetration capacity and water permeability capacity of samples increase generally. Besides, soluble salt analysis, SEM and EDS results well corroborate the changes. Based on the results it can be concluded that property changes are most serious after temperature and humidity cycling test, followed by water stability, soundness and alkali resistance test in sequence. But in general, CGN-(F+S) still has good durability.

Diatomite and glass fiber are used for modifying asphalt concrete in this paper. Besides, wet and dry processes are adopted to achieve the composite modified asphalt concrete. Meanwhile, experimental investigation has been done on its fatigue properties and dynamic mechanical property, it indicates that diatomite-glass fiber modified asphalt concrete has a better capacity to resist fatigue damage. Compared with matrix asphalt concrete, the modified asphalt concrete has higher fatigue life. Thus, its mechanical parameter of fatigue property changes obviously so as to provide a reference basis for the durability design of pavement materials.

This paper reviews the present situation of research on earthen architecture sites protection in China from the diseases of the earthen architecture sites, reinforcement technologies and materials, non-destructive testing technology and seismic stability reinforcement, and points out the main existing problems. The author holds that China should carry out the top design of the protection research topics as soon as possible to identify the core scientific problems and strengthen the cultivation of the research team; construct the earthen site simulation laboratory in field to research the disease mechanism in a large scale from multi-field coupling analysis; start the scientific research work on the traditional reinforcement materials and techniques and emphasize the application of the traditional reversible reinforcing technique; establish the post evaluation system on the reinforcement effect and make the long-term tracking of the protective effect of the existing reinforcing projects to put an end to the protective destruction; supports the development and application of the non-destructive technology in the field of heritage preservation.

采用高温固相法制备了KNaCa 2 (PO 4 ) 2 :Eu 2+ 蓝色荧光粉, 并研究了材料的发光特性. 在400 nm近紫外光激发下, 材料呈非对称的单峰发射, 主峰位于470 nm. 监测470 nm发射峰, 对应的激发光谱覆盖200~450 nm, 主峰位于400 nm, 说明材料能够很好的吸收紫外-近紫外光, 发射蓝色光. 利用van Uitert公式计算了Eu 2+ 取代KNaCa 2 (PO 4 ) 2 中Ca 2+ 时所占晶体学格位, 得出461和502 nm发射分别归属于八配位和六配位的Eu 2+ 发射. 研究了Eu 2+ 掺杂浓度对KNaCa 2 (PO 4 ) 2 :Eu 2+ 材料发射强度的影响, 结果显示Eu 2+ 的最佳掺杂浓度为1mol%, 利用Dexter理论得出其浓度猝灭机理为电偶极-电偶极相互作用.

采用高温固相法合成了KBaPO 4 :Tb 3+ 绿色发光荧光粉, 并研究了材料的发光性质. KBaPO 4 :Tb 3+ 材料呈多峰发射, 发射峰位于437、490、545、586和622 nm, 分别对应Tb 3+ 的 5 D 3 → 7 F 4 和 5 D 4 → 7 F J =6, 5, 4, 3跃迁发射, 主峰为545 nm; 监测545 nm发射峰, 所得激发光谱由4 f 7 -5 d 1 的宽带吸收(200~330 nm)和4 f -4 f 电子吸收(330~400 nm)组成, 主峰为380 nm. 研究了Tb 3+ 掺杂浓度, 电荷补偿剂Li + 、Na + 、K + 和Cl - , 及敏化剂Ce 3+ 对KBaPO 4 :Tb 3+ 材料发射强度的影响. 结果显示, 调节激活剂浓度、添加电荷补偿剂或敏化剂均可在很大程度上提高材料的发射强度. 上述结果表明KBaPO 4 : Tb 3+ 材料是一种很好的近紫外光激发型高效绿色发光荧光粉.

Deformation behavior of endangered earthen heritage slope makes sense to scientific conservation of earthen architecture. It realizes qualitative and quantitative description of diseases. Based on random process and description theory, deformation behavior of endangered earthen heritage slope (Jiaohe Ruins) is studied using high-accuracy, real-time, dynamic information obtained by deformation monitoring appliance. Research result indicates that mathematic model can be established by use of modern mathematic method. The mathematic model of Jiaohe slope proves that short-term deformation behavior owns periodicity (36h) and occasional mutation. Simultaneously, tendency deformation performs weakly. The conclusion lays foundation for the research on quantitative deformation behavior and the following forecasting of similar earthen heritage slope damages.

The information integration method of semantic web based on agent ontology (SWAO method) was put forward aiming at the problems in current network environment, which integrates, analyzes and processes enormous web information and extracts answers on the basis of semantics. With SWAO method as the clue, the following technologies were studied: the method of concept extraction based on semantic term mining, agent ontology construction method on account of multi-points and the answer extraction in view of semantic inference. Meanwhile, the structural model of the question answering system applying ontology was presented, which adopts OWL language to describe domain knowledge from where QA system infers and extracts answers by Jena inference engine. In the system testing, the precision rate reaches 86%, and the recalling rate is 93%. The experimental results prove that it is feasible to use the method to develop a question answering system, which is valuable for further study in more depth.

The traditional search engines return a large number of relative web pages rather than accurate answers. However, in a question answering system, users could use sentences in daily life to raise questions. The question answering system will analyze and comprehend these questions and return answers to users directly. Aiming at the problems in current network environment, such as low precision of question answering, imperfect expression of domain knowledge, low reuse rate and lack of reasonable theory reference models, we put forward the information integration method of semantic web based on pervasive agent ontology (SWPAO) method, which will integrate, analyze and process enormous web information and extract answers on the basis of semantics. With SWPAO method as the clue, we mainly study the method of concept extraction based on uniform semantic term mining, pervasive agent ontology construction method on account of multi-points and the answer extraction in view of semantic inference. Meanwhile, we present the structural model of the question answering system applying ontology, which adopts OWL language to describe domain knowledge base from where it infers and extracts answers by Jena inference engine, thus the precision of question answering in QA system could be improved. In the system testing, the precision has reached 86%, and recalling rate is 93%. The experiment indicates that this method is feasible and it has the significance of reference and value of further study for the question answering systems.

Multiagent-based scheduling is a new intelligent scheduling method based on the theories of multiagent system (MAS) and distributed artificial intelligence (DAI). Multiagent-based scheduling can dynamically and flexibly schedule manufacturing processes by means of cooperation and coordination among the agents. It has been considered that the Agent technology is an important method to build the model of distributed industrial system, the most natural way to design and implement the distributed Intelligent Manufacturing environment, and one of the significant technologies to construct the manufacturing system of next generation. On the basis of briefly summarizing the technology of Agent and Multiagent system, the architecture of Intelligent Manufacturing System based on Multiagent is put forward, among which, Agent represents the basic processing entity. The control strategy and scheduling optimization algorithm of Intelligent Manufacturing is provided, which is feasible proved by the result of stimulation experiment. Compared with the traditional artificial scheduling, it has distinct advantages. Finally, the model of communication and negotiation between Agents in the Intelligent Manufacturing System is studied, which utilizes the features of Agent such as autonomy, social interaction, response capability, preliminary capability, etc so that Intelligent Manufacturing System could make distributed decisions. The cooperation of system is completed by communication and negotiation. During the process of interaction, Agent is endowed with a role to meet the demand of flexibility of building models in the complicated process of Intelligent Manufacturing, as well as to construct an extended frame for reusable components. Experiments do prove that it is feasible to use the method to develop an Intelligent Manufacturing System, which is valuable for further study in more depth.

We present the spectral line narrowing effect in a Λ three-level atomic system where one transition is coupled by a coupling laser and the narrow feature is observed by probing the other transition with a weak laser. As coupling laser detuning increases the electromagnetically induced transparency resonance is observed to evolve into electromagnetically induced absorption resonance with sub-natural linewidth. The linewidth of the narrow spectral feature is studied as a function of coupling laser detuning and the atomic system parameters. The result is explained using density matrix density equation in the dressed-atom picture.

A plasma analysis system comprised of Omni-X300 series grating spectrometer, CCD data acquisition system and optical fiber transmission system was utilized in the present paper to realize the real-time acquisition of plasma emission spectra during the process of radio frequency (RF) magnetron sputtering. The plasma emission spectra produced by NiTa, TiAl ceramic targets and NiA1, TiA1 alloy targets were monitored respectively, in addition, the behavior of analysis lines of Ta I 333.991 nm, Ni I 362.473 nm, Al I 396.153 nm and Ti I 398.176 nm with time was obtained, according to which the time of pre-sputtering of the four kinds of target materials was fixed. At the same time, for the TiAl alloy target as the research object, the influence of different powers and pressures on the time of pre-sputtering was studied.

Ba3SiO4Cl2 : Eu2+ was synthesized by a high temperature solid state method. BaCO3 (A. R.), BaCl2 (A. R.), SiO2 (99.99%) and Eu2O3 (99.99%) were used as the raw materials. The final phase was checked with a conventional X-ray diffraction (XRD) (D/max-rA, CuKalpha, 40 kV, 100 mA, lambda = 0.154 06 nm). The spectral characteristics of the phosphors were performed by using a Hitachi F-4600 fluorescence spectrophotometer equipped with a 450 W Xe lamp. Ba3SiO4Cl2 : Eu2+ showed broad emission bands at 445 and 510 nm under the 365 nm radiation excitation. For the two emission peaks, the excitation spectra have two different spectral distributions, and the excitation peaks locate at 350 and 400 nm, respectively. The results indicate that different Eu2+ emission centres exist in Ba3SiO4Cl2. The emission intensity of the 445 and 510 nm peaks is influenced by Eu2+ doped content. With increasing its content, the emission intensity of 445 nm gradually increases, and that of 510 nm decreases. With washing the phosphor, the 445 nm emission peak disappears, and the emission spectrum has only the 510 nm emission band, and its intensity is lower than that of the original phosphor.

A bluish green Ca7 (SiO4)2Cl6 : Eu2+ phosphor used for UV excited white LED was synthesized by high temperature solid state method. The XRD patterns and luminescence properties were investigated. The results indicated that the sample was single Ca7 (SiO4)2Cl6 phase; the emission spectrum included two emission peaks located at 418 and 502 nm, respectively. Monitoring for the two emission peaks, the excitation spectra were two broad band peaks centered at 290 and 360 nm respectively, which illustrated that Eu2+ ions located at two different crystal lattice sites. The influence of Eu2+ ions concentration on the luminescence intensity was studied and the optimal doping concentration was 0.75 mol%. The results showed that this phosphor was a better candidate bluish phosphor for UV based white LED.

The plasma emission spectra generated during the deposition process of Si-based thin films by radio frequency (RF) magnetron sputtering using Cu and Al targets in an argon atmosphere were acquired by the plasma analysis system, which consists of a magnetron sputtering apparatus, an Omni-lambda300 series grating spectrometer, a CCD data acquisition system and an optical fiber transmission system. The variation in Cu and Al plasma emission spectra intensity depending on sputtering conditions, such as sputtering time, sputtering power, the target-to-substrate distance and deposition pressure, was studied by using the analysis lines Cu I 324. 754 nm, Cu I 327. 396 nm, Cu I 333. 784 nm, Cu I 353. 039 nm, Al I 394. 403 nm and Al I 396. 153 nm. Compared with the option of experimental parameters of thin films deposited by RF magnetron sputtering, it was shown that emission spectra analysis methods play a guiding role in optimizing the deposition conditions of thin films in RF magnetron sputtering.

In order to improve laser-induced breakdown spectroscopy for low-level elements testing capability, the enhancement effects of KCl additive on the emission spectra of soil samples were studied. The laser spectrum analytical system is composed of a high-energy neodymium glass laser ablating samples, a multifunctional and automatic scanning spectrometer, and a CCD data acquisition system recording plasma spectra. The electron temperature and electron density of plasmas were calculated by measuring spectral line intensity and stark broadening respectively. The experimental results showed that with the increase in the KCl additive, the spectral intensity, signal-to-background ratio, the electron temperature and the electron density all went up firstly and then down. When 15% KCl was added, the radiation intensity of plasma reached the maximum value, the spectral lines intensity of element Mn, Fe, and Ti increased by 2.23, 1.13 and 2.04 than that without additive respectively, the spectral signal-to-background ratio increased by 1.33, 0.89 and 0.94 times respectively; while the electron temperature and electron density of plasmas were heightened by 14% and 38% respectively.

Ba2B2P2O10 : Eu3+ phosphor was synthesized by high temperature solid-state method. BaCO3(A.R), NH4H2PO4 (A.R), H3BO3(A.R), Eu2O3 (99.99%), NH4Cl (A.R), Li2CO3 (A.R), Na2CO3 (A.R.) and K2CO3 (A.R.) were used for starting materials. After these individual materials were blended and grounded thoroughly in an agate mortar, the homogeneous mixture was heated at 1000 degrees C for 3 h, and the phosphors were obtained. The phase present of the samples were characterized by powder X-ray diffraction (XRD) (D/max-rA, Cu Kalpha, 40 kV, 40 mA, lamda = 0.15406 nm). The spectral characteristics of these phosphors were measured by a SHIMADZU RF-540 fluorescence spectrophotometer. Under the condition of 400 nm excitation, the emission spectrum of Ba2B2P2O10 : Eu3+ phosphor shows several bands at 600, 618, 627 and 660 nm respectively, which correspond to the electric dipole (5)D0--(7)F1, (7)F2, (7)F3 and (7)F4 transitions of Eu3+. The effect of Eu3+ concentration or charge compensator on the emission intensity of Ba2B2P2O10 : Eu3+ phosphor was investigated, and the result shows that the emission intensity of the phosphor increases with increasing Eu3+ concentration, viz. the concentration quenching has not existed. And the emission intensity of the phosphor was enhanced by doping charge compensator. All the results illuminate that Ba2B2P2O10 : Eu3+ phosphor is a promising red phosphor for white LEDs.

Ce3+, Tb3+ co-doped green phosphor Ca2SrAl2O6 was synthesized by solid state method and its excitation and emission spectra were measured and studied. The results showed that the emission spectrum is composed of four groups of narrow bands and the peaks are located at 497, 545, 595 and 623 nm. The strongest emission peak islocated at 545 nm and chromaticity coordinate (x, y) is (0.300 5, 0.500 2) at 4 mol% Ce3+ and Tb3+ doping, which indicate that Ca2SrAl2O6 : Ce3+, Tb3+ was a good green phosphor. The excitation spectrum for 545 nm was in the region of 320-400 nm, which indicated that this phosphor could be effectively excited by UVLED. Duo to the overlap of the Ce3+ emission bands and the Tb3+ excitation bands, the energy transfer between Ce3+ and Tb3+ is expected to be very efficient. The emission intensity of co-doped Ca2SrAl2O6 phosphor was stronger than that of Tb3+ doped phosphor. The luminescence intensity reached the maximum when the concentration of Ce3+ and Tb3+ was 4 mol%.

In order to improve the radiation characteristic of laser-induced plasma, with the national standard soil taken as the target sample, a laser spectrum analytical system which composed of a high-energy neodymium glass laser, a multifunctional and compact integrated spectrometer, and a CCD detector was used to detect the influence of the NaCl sample additive on the laser plasma radiation intensity. The electron temperature and the electron density of the plasmas were also calculated from the lines intensity and stark broadening of emission spectral line respectively. The experimental results indicated that with the increase in the NaCl additive, the spectral intensity, signal-to-background ratio, the electron temperature, and the electron density all went up firstly and then down. When 15% NaCl was added, the radiation intensity of the plasma reached the maximum value, the spectral lines intensity of element Mn, K, Fe, and Ti increased by 39.2%, 42.5%, 53.9% and 33.8% compared to that without additive respectively, the spectral signal-to-background ratio increased by 64.4%, 84.39, 44.55% and 58.2% respectively, while the electron temperature and the electron density of the plasmas were heightened by 0.17 times and 0.36 times respectively.

Alkali-alkaline earth borate LiCaBO3 : Ce3+, LiSrBO3 : Ce3+ and LiBaBO3 : Ce3+ were investigated by solid-state method. CaCO3 (99.9%), SrCO3 (99.9%), BaCO3 (99.9%), Li2 CO3 (99.9%), Na2 CO3 (99.9%), K2 CO3 (99.9%), H3BO3 (99.9%) and CeO2 (99.9%) were used as starting materials, After these individual materials were blended and ground thoroughly in an agate mortar, the homogeneous mixture was heated at 700 degrees C for 2 h in a reduced atmosphere (5 : 95 (H2/N2)), and these three phosphors were obtained. The excitation and emission spectra of these phosphors were measured by a SHIMADZU RF-540 fluorescence spectrophotometer. The spectral characteristics of Ce3+ in alkali-alkaline earth borate LiCaBO3, LiSrBO3 and LiBaBO3 were investigated. The emission spectra of Ce3+ in these three phosphors all exhibited a dissymmetrical band, and the emission peaks were located at 428, 436 and 440 nm, respectively. The excitation spectra for 428, 436 and 440 nm emission of these three phosphors showed a dissymmetrical band at 364, 369 and 370 nm, respectively. The effects of Li+, Na+ and K+ on the emission intensities of these three phosphors were studied. The results show that the emission intensities of these phosphors were enhanced, and the maximal emission intensity of doping Li+ is higher than that of Na+ and K+.

The LiSrBO3:Dy3+ phosphor was synthesized by solid-state method. SrCO2 (99.9%), Li2CO3 (99.9%), H3BO3 (99.9%) and Dy2O3 (99.9%) were used as starting materials. After these individual materials were blended and grounded thoroughly in an agate mortar, the homogeneous mixture was heated at 700 degrees C for 2 h in air, and LiSrBO3:Dy3+ phosphors were obtained. The phase present of the samples was characterized by powder X-ray diffraction (XRD) (D/max-rA, Cu Kalpha, 40 kV, 40 mA, lamda = 0.15406 nm). The excitation and emission spectra of these phosphors were measured by a RF-540 photoluminescence spectrophotometer. The emission spectrum of LiSrBO3:Dy3+ phosphor shows several bands at 486, 578 and 668 nm, respectively. The excitation spectrum for 578 nm emission has several excitation bands at 331, 368, 397, 433, 462 and 478 nm, respectively. The effect of Dy3+ concentration on the emission intensity of LiSrBO3:Dy3+ was investigated, and the result shows that the emission intensity of LiSrBO3:Dy3+ phosphor firstly increases with increasing Dy2+ concentration, then decreases, viz. the concentration quenching exists. And the Dy3+ concentration corresponding to the maximal emission intensity is 3 mol%, and the concentration quenching mechanisms are the d-d interaction by Dexter theory.

LiM (M = Ca, Sr, Ba) BO3 : Tb3+ phosphors were synthesized by solid state reaction. The starting materials CaCO3, SrCO3, BaCO3, H3 BO3, Li2 CO3, Na2 CO3, K2 CO3 and Tb4 O7 (99.99% in mass) in appropriate stoichiometric ratio were mixed in the alumina crucible, then the mixed powders were calcined at 700 degrees C for 2 h, and LiCaBO3 : Tb3+, LiSrBO3 : Tb3+ and LiB-aBO3 : Tb3+ phosphors were obtained. The emission and excitation spectra were measured by a Shimadzu RF-540 ultraviolet spectrophotometer. All the photoluminescence properties of these phosphors were measured at room temperature. The emission spectra of LiM (M = Ca, Sr, Ba) BO3 : Tb3+ phosphors show several bands, and the main emission peaks correspond to the 5D4 --7F6(486, 486, 488 nm), 5D4 --F5 (544, 544, 544 nm), 5D4 --7F4 (590, 595, 593 nm) and 5D4 --7F3 (620, 620, 616 nm) typical transitions of Tb3+, and the typical transitions of Tb3+ happens to split because of the effects of LiM (M = Ca, Sr, Ba) BO3 crystals field. The excitation spectra for the 544 nm green emission of LiM (M = Ca, Sr, Ba)BO3 : Tb3+ phosphors illuminate that these kinds of phosphors can be effectively excited by ultraviolet (350-410 nm) light, and emit green light, therefore, they are promising phosphors for white light emitting diodes. Effects of activation and charge compensation on the luminescence intensities of LiM (M = Ca, Sr, Ba) BO3 : Tb3+ phosphors were studied, and the results show that the intensities were obviously effected.

Single pulses exported from high-energy neodymium glass laser were used to act on the same position of soil sample surface repeatedly, and the plasma emission spectra generated from sequential laser pulse action were collected by spectral recording system. The experimental results show that the laser-induced soil plasma radiation was enhanced continuously under the confinement effect of the crater walls, and the line intensities and signal-to-background ratios both had different improvements along with increasing the number of acting pulses. The photographs of the plasma image and crater appearance were taken to study the plasma shape, laser-induced crater appearance, and the mass of the ablated sample. The internal mechanism behind that laser-induced crater enhanced plasma radiation was researched. Under the sequential laser pulse action, the forming plasma as a result enlarges gradually first, leading to distortion at the trail of plasma plume, and then, its volume diminishes slowly. And also, the color of the plasma changes from buff to white gradually, which implies that the temperature increases constantly. The laser-induced crater had a regular shape, that is, the diameter increased from its bottom to top gradually, thus forming a taper. The mass of the laser-ablated substance descends along with increasing the amount of action pulse. Atomization degree of vaporized substance was improved in virtue of the crater confinement effect, Fresnel absorption produced from the crater walls reflection, and the inverse bremsstrahlung, and the plasma radiation intensity was enhanced as a result.

The Sr2SiO4 : Dy3+ phosphor was synthesized by the high temperature solid-state reaction method in air. Dy2O3 (99.9%), SiO2 (99.9%), SrCO3 (99.9%), Li2CO3 (99.9%), Na2CO3 (99.9%) and K2CO3 (99.9%) were used as starting materials, and the Dy3+ doping concentration was 2 mol%. The emission spectrum was measured by a SPEX1404 spectrophotometer, and all the characterization of the phosphors was conducted at room temperature. The emission spectrum of Sr2 SiO4 : Dy3+ phosphor showed several bands centered at 486, 575 and 665 nm under the 365 nm excitation. The effect of Li+, Na+ and K+ on the emission spectra of Sr2SiO4 : Dy3+ phosphor was studied. The results show that the location of the emission spectrum of Sr2SiO4 : Dy3+ phosphor was not influenced by Li+, Na+ and K+. However, the emission spectrum intensity was greatly influenced by Li+, Na+ and K+, and the evolvement trend was monotone with different charge compensation, i. e. the emission spectrum intensity of Sr2SiO4 : Dy3+ phosphor firstly increased with increasing Li+ concentration, then decreased. However the charge compensation concentration corresponding to the maximum emission intensity was different with different charge compensation, and the concentration is 4, 3 and 3 mol% corresponding to Li+, Na+ and K+, respectively. And the theoretical reason for the above results was analyzed.

The autoionization state of barium was observed by optics heterodyne between three-photon resonant nondegenerated six-wave mixing (NSWM) and two-photon resonant nondegenerated four-wave mixing (NFWM). In this way, optics heterodyne spectrum of 6p(3/2) 19d autoionization state of barium was measured. The suppression and enhancement of the NFWM signal was observed which was caused by the quantum interference between NFWM and NSWM. Our method is a pure nonlinear optic technique. It has the advantages of excellent spatial signal resolution and simple optical alignment. Here two-photon resonant NFWM is used as local oscillation, while three-photon resonant NSWM signal is used as signal beam. Detection of autoionization states of Ba was achieved by changing the frequency of signal beam. The phase matching condition of this technique is not so stringent and can be achieved over a very wide frequency range, which is very difficult in the general six-wave mixing. Furthermore, the signal is coherent light. Optics heterodyne spectrum is a Doppler-free spectroscopy when the incident lasers have narrow bandwidths.

In the present paper, the productions by applying laser-induced plasma spectral analysis technique in different research fields were summarized. Many examples of the application based on laser-induced breakdown spectroscopy (LIBS) and laser-induced plasma spectroscopy (LIPS) methods were introduced, including the substance composition and correlative characteristics of the solid samples (e.g. metal alloy, soil, concrete, mineral, fossil, medicine etc.), liquid samples (e.g. solution, pure water, liquid jets etc.), and gaseous samples (e.g. air, pure gas, vapor and aerosol etc.). Some other investigations and applications were also included. The factors, which influence the detection capability, were discussed. Laser wavelength, pulse energy, power density, environmental atmosphere, external electric field, carbon layer on sample surface, sample material characteristic, and so on all have effects on the precision and the limit of detection. Finally, a simple introduction of the improvements in experimental equipment and methods was also covered. The development of laser-induced plasma spectral analysis technique creates favorable conditions, such as convenience and shortcut, for many science and application researches. It plays an important role in the progress in science and technology.

In the present paper, the effects of the ethanol-water solution temperature (20, 40, and 60 degrees C) on the emission intensity of ICP source, plasma parameters (excitation temperature and electron density), physical properties (surface tension and viscosity) of sample solution, and nebulization (uptake rate, effective uptake rate and nebulization efficiency) were studied by using optical-to-electrical detection method. The experimental results showed that the velocity of the sample entering the plasma increased, so that the line intensity of the elements Zn, Fe, Mg, Si, and Sr in water increased obviously with increasing the content of ethanol and the rise of the corresponding solution temperature. And the excitation capacity in the plasma was strengthened with the rise of the ethanol-water solution temperature. The maximal spectrum intensity of the elements Zn, Fe, Mg, Si, and Sr at 60 degrees C was higher by 55.8%, 45.4%, 48.9%, 17.7%, and 21.6% than that at 20 degrees C, respectively. It's valuable for the detection of the trace element.

Laser micro-spectral analyzer, coupled with CCD spectrometer, was used to determine soil elements in argon atmosphere at reduced pressure in the authors' experiment. The accuracy and availability of this method were studied. With Al I 394.40 nm and Ca II 396.85 nm as spectral analysis lines, using "the three standard samples method", the contents of Al and Ca in soil were determined. The results show that the maximum of relative standard deviation (RSD) of quantitative analysis is 5.80%; the maximum of relative difference between the quantitative analysis result and the standard value is 7.65%, suggesting that the accuracy of determination of Al and Ca in soil meets the challenge of quantitative analysis.

Copper plasma was induced with a high energy neodymium glass laser(0-25J) beam ablating the Cu target in argon atmosphere. It was observed that the line intensity of the emission spectra increases when the ambient pressure(0.1-0.5 MPa) rises. In order to study the enhancement mechanism, with the model of local thermodynamic equilibrium, the electron temperature was measured in argon atmosphere. The experimental results showed that electron temperature increases as the pressure rises. In addition, spatially resolved electron temperature was measured in Ar atmosphere at 0.1, 0.3, 0.5 MPa.

In an attempt to inhance the emission intensity of ICP, a conventional concentric pneumatic nebulizer was used with increased pressure, and the aqueous aerosol was partially let out to modulate the flow velocity of sample solution into the flame of the ICP. In the present work, the emission spectra of elements Ca, Si, Sr and Zn in water samples were measured, and the results showed that corresponding emission intensities are the highest at 0.05 MPa under the conventional condition, and after increasing the nebulizer gas pressure to 0.07 MPa and letting out part of aqueous aerosol, the peak values grew by 38%, 79%, 45% and 70%, respectively. In addition, the stability of the plasma radiation was not affected by the higher nebulizer gas pressure.

In the present paper, the effects of argon atmosphere at high pressure (0. 2-1.1 MPa) on the radiation intensity of the plasma induced by a high energy neodymium glass laser (energy -30 J, pulse width 0.7 ms) were studied by recording the photograph and spectra of the plasma as well as measuring the ablated mass. The experimental results show that the volume of the plasma was compressed, the temperature increased, and the lightness enhanced significantly when pressure was raised. Under our experimental condition, the radiation intensities of the plasmas were enhanced with the increase in the gas pressure; but the ablated mass of the sample decreased. The measured results are discussed, combined with the process of the experiment.

In order to reduce the reflectance of laser beam on sample surface and enhance the radiation intensities of laser-induced metal plasma, a means has been studied for carbon coating on the surface of steel sample. The experimental results showed that the line intensities of the laser plasma formed when a high-energy neodymium glass laser (approximately 25 J) was used to generate the plasma in air at atmospheric pressure increased by a factor in the range of 10%-28% for the steel sample with the carbon coating. The excitation temperature of laser plasma was measured to explain the mechanism that the line intensities increase. In addition, it was found that the stronger intensity of atomic emission spectrum appeared at the radial location 1 mm in the laser plasma, not at the central place.

In the present paper, the effect of lens-to-sample distance (LTSD) on the radiative properties from the plasma induced by a high-energy neodymium glass laser (approximately 25J) in the argon ambient gas at a pressure of 0.43 x 10(5) Pa was studied. The experimental results showed that when the focus point of the focusing lens (f = 130 mm) shifts above and below the sample surface, the radiation intensities of the plasma, the excitation temperature, and the mass of ablated material are all changed, and their maxia appear at a focusing location of the laser beam, which is about 0.4 mm under the sample surface for alloyed-steel samples. If soil samples are used as the targets, the emission intensities of the laser plasma and the mass of ablated material have the maxima at a focus position about 0.2 mm below the sample surface. To investigate the influence of LTSD on the shape of the laser plasma, the images of the plasma formed have been shot in argon and air for the alloyed-steel samples. From these results, it was found that the properties of the laser plasma depend strongly on the LTSD.

A method for the determination of Eu in Long-aferglow of the SrAl2O4:Eu2+, Dy3+ phospher samples by laser microemission spectral analysis was developed. And the accuracy of this method was studied. Analyses of Eu in Long-aferglow of the SrA1204: Eu2+, Dy3+ phospher samples, using the Eu (11) line at 412.973 nm, show that RSD of relative intensity of spectral lines is 4.3%, RSD of quantitative analysis is 7.4%, the average of quantitative analysis is 2.13%. Compared with the content before samples synthesized, it can be concluded that the content of Eu in the SrAl2O4:Eu2+, Dy3+ phospher samples synthesized by high temperature solid phase reaction has an obvious increase.

The effect of solution temperature (20, 40 and 60 degrees C) on the emission intensity of ICP has been studied. The results show that the spectrum intensity of the elements Ba, Cu and Zn increases obviously with increasing the solution temperature. In addition, at different solution temperatures, the rule of the variation of the intensity with both observation height and nebulizer gas pressure has been obtained, which indicates that the best observation location is lowered when increasing the temperature, but the best nebulizer gas pressure is augmented.

In this experiment, the effects of gas composition and pressure on the intensity and quality of the plasma induced by a high-energy neodymium glass laser were studied. The experimental results show that the spectral intensity of the plasma in the argon atmosphere is stronger than that in the air when the pressure is the same. For the steel alloy sample, the intensities of the emission spectrum reach the maximum values when the argon pressure is 0.8 x 10(5) Pa. The self-absorption phenomena of Al II 308.22 and Al II 309.27 nm lines strengthen with the increase of the pressure, and even serious self-reversal appears when the pressure is (0.8-0.9) x 10(5) Pa. The temperature of plasma also raises with the increase of the pressure. When the argon pressure is 0.93 x 10(5) Pa, t h e temperature is about 1500 K higher than that when the argon pressure is about 0.43 x 10(5) Pa.

According to mathematic statistics, data for laser microemission spectroscopic analysis were selected, which were collected with the use of CCD (charge-coupled device) in arg on atmosphere at reduced pressure. By selection, the effects of some factors, such as the difference of bore ablated on the sample surface by the laser, the distribution nonuniformity of element in the sample, and the fluctuation of output energy of the laser, etc. were reduced. The method that improves analytic precision of laser microemission spectroscopic analysis was studied. And quantitative analysis of Cu, Zn and Mg in aluminum alloy standard samples was performed, using the Cu (I) line at 324.7 nm, the Zn (I) line at 334.5 nm, and the Mg (I) line at 383.8 nm. The results show that the RSDs of relative intensity of the spectral lines of Cu, Zn, Mg are 1.80%, 4.35% and 6.29% respectively, and the RSDs of quantitative analysis of them are 10.1%, 6.98% and 8.17% respectively. The relative errors of the average of analysis of them are -3.76%, 3.62% and -1.62% respectively.

The article summarizes the progress in the experimental study on laser-induced plasma and its application to spectral analysis domestically and abroad in recent years. It emphatically elaborates the experimental research on the formation, radiation, electron temperature, electron density, and expansion velocity of laser-induced plasma under different conditions (gas composition and pressure, laser energy, laser wavelength, power density and observation height). In addition, in the respect of material composition analysis using the laser-induced plasma, the article mainly interprets two aspects: one is the way to collect directly the plasma emission so as to analyze solid, liquid and gaseous samples, the other is the spectrochemical analysis when laser ablation and ICP are used together. And the article also discusses the factors that influence the precision and the limit of detection.

The intensities of emission spectra of laser-induced alloy aluminum plasma, with the use of a neodymium glass laser (laser pulse energy is about 25 J), were experimentally studied in argon atmosphere. The effects of atmosphere pressure, height from the observed location of the plasma to the sample surface, operating voltage, and power density of the laser on the signal intensities of emission spectra were discussed. Experimental results showed that the intensities of emission spectra are strongest under 88 kPa of gas pressure. With the increase of the height from the observed location of the plasma to the sample surface, the intensities of emission spectra decrease clearly. At the pressure of 88 kPa and the height of 1.5-2 mm, the emission spectra have maximum intensities. In addition, the spectral line intensities are enhanced significantly with the increase of operating voltage and power density.

In this paper, the quality improvement of Laser Microprobe Emission Spectral Analysis (LMESA) lines in argon atmosphere at reduced pressure was experimentally investigated. The experimental setup consists of a YGJ-II laser micro-spectral analyzer and a photo-electro detection system. The temporal behavior and the intensity distribution of Cu I 324.7 nm and Cu I 327.4 nm lines of the copper alloy standard samples were studied. The results show that LMESA spectrum strongly depends on the environment gas, its pressure and the auxiliary excitation parameters. When the diameter at the end of graphite auxiliary electrodes is 1.5 mm, the distance between the electrodes is 4 mm, the center of the electrodes is 3 mm above the sample surface, the voltage of the auxiliary excitation is 1,300 V and the argon pressure is 33.2 Kpa, the emission time of Cu I 324.7 nm and Cu I 327.4 nm is about 500 microseconds longer than that in the air. The emission intensity of Cu I 324.7 nm and Cu I 327.4 nm is about 4 times higher than that in the air at the same pressure and is about 2 times higher than that in the air at normal pressure. The full width at half maximum of the spectral lines is obviously narrowed.

A series of SrIn2O4:Eu3+ phosphors are synthesized by a high temperature solid-state method, and their luminescent properties are investigated. They can be excited by 395-nm radiation, and produce red emission (619 nm); however, they have a low absorption of near-ultraviolet light with the wavelength of 400 nm?405 nm. When co-doped with A+ (A = Li, Na, K), the emission intensity of SrIn2O4:Eu3+ is significantly enhanced, but its emission and excitation spectral profile is unchanged. With co-doping Sm3+, not only is the emission intensity of SrIn2O4:Eu3+ enhanced, but also the absorption is broadened and strengthened in the range of 400 nm?405 nm. The effect of Sm3+-doped content on the emission intensity of SrIn2O4:Eu3+, Sm3+ is investigated, and the optimal Sm3+ content is 0.02 mol.