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Spectral Analysis and Atmospheric Models of Microflares
By use of the high-resolution spectral data obtained with THEMIS on 2002 September 5, the spectra and characteristics of five well-observed microflares have been analyzed. Our results indicate that some of them are located near the longitudinal magnetic polarity inversion lines. All the microflares are accompanied by mass motions. The most obvious characteristic of the Hα microflare spectra is the emission at the center of both Hα and CaII 8542(A) lines. For the first time both thermal and non-thermal semi-empirical atmospheric models for the conspicuous and faint microflares are computed. In computing the non-thermal models, we assume that the electron beam resulting from magnetic reconnection is produced in the chromosphere, because it requires lower energies for the injected particles.It is found there is obvious heating in the low chromosphere. The temperature enhancement is about 1000-2200 K in the thermal models. If the non-thermal effects are included, then the required temperature increase can be reduced by 100-150 K. These imply that the Hα microflares can probably be produced by magnetic reconnection in the solar Iower atmosphere.The radiative and kinetic energies of the Hα microflares are estimated and the total energy is found to be 1027 - 4× 1028 erg....
2020-11-22 17:58:37浏览：37
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Timescale Analysis of Spectral Lags
A technique for timescale analysis of spectral lags performed directly in the time domain is developed. Simulation studies are made to compare the time domain technique with the Fourier frequency analysis for spectral time lags. The time domain technique is applied to studying rapid variabilities of X-ray binaries and γ-ray bursts. The results indicate that in comparison with the Fourier analysis the timescale analysis technique is more powerful for the study of spectral lags in rapid variabilities on short time scales and short duration flaring phenomena....
2020-11-22 17:58:37浏览：32
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Key Properties of Solar Chromospheric Line Formation Process
The distribution or wavelength-dependence of the formation regions of frequently used solar lines, Hα, Hβ, CaIIH and CaII8542, in quiet Sun, faint and bright flares is explored in the unpolarized case. We stress four aspects characterising the property of line formation process: 1) width of line formation core; 2) lineformation region; 3) influence of the temperature minimum region; and 4) wavelength ranges within which one can obtain pure chromospheric and photospheric filtergrams. It is shown that the above four aspects depend strongly on the atmo spheric physical condition and the lines used. The formation regions of all the wave length points within a line may be continuously distributed over one depth domain or discretely distributed because of no contribution coming from the temperature minimum reg:on, an important domain in the solar atmosphere that determines the distribution pattern of escape photons. On the other hand, the formation region of one wavelength point may cover only one height range or spread over two domains which are separated again by the temperature minimum region. Different lines may form in different regions in the quiet Sun. However, these line formation regions be come closer ir. solar flaring regions. Finally, though the stratification of line-of-sight velocity can alter the position of the line formation core within the line band and result in the asymmetry of the line formation core about the shifted line center, it can only lead to negligible changes in the line formation region or the line formation core width. All these results can be instructive to solar filtering observations....
2020-11-11 22:33:38浏览：68
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氨基改性硅油的合成与工艺研究
以八甲基环四硅氧烷（D4）和N–β–氨乙基–γ–氨丙基甲基二甲氧基硅烷（KH–602）为原料,用（CH3）4NOH作为催化剂,低粘度二甲基硅氧烷为封端剂,采用本体阴离子聚合法合成了侧氨基改性聚硅氧烷,并对其结构用红外光谱与紫外光谱进行了表征.研究了制备过程中聚合时间、KH–602、封端剂及催化剂用量等对氨基硅油技术指标的影响,得到了完整的工艺配方....
2020-10-26 22:14:25浏览：42
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葛粉的非等温动力学研究
利用TG/DTA技术,考察不同升温速率下葛粉的热分解特性,研究葛粉热分解动力学,运用Kissinger法、Coats-Redfern法和Achar法对非等温动力学数据进行了分析。研究结果表明：在氮气气氛下,葛粉在280℃左右开始分解,至400℃以上基本分解完毕,反应机理函数的积分形式和微分形式分别为：G（α）=[（1-α）-1/3-1]2和f（α）=3/2（1-α）4/3[（1-α）-1/3-1]-1,对应的机理为三维扩散模型。...
2020-08-30 18:25:27浏览：63
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循环流化床煤气化高温助燃的设计与应用
科达洁能清洁煤气化系统采用高温煤气预热混合气化剂，高温助燃气化剂温度可达到750℃，有效降低了煤耗。提高了煤气热值和气化效率。...
2020-07-12 21:36:56浏览：58
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三元流节能技术在循环水泵的应用分析
介绍了中石化洛阳分公司循环水系统设备的运行现状，并在能源利用方面进行了详细分析，指出存在的不合理现状，重点介绍了对在循环水泵上使用三元流技术的可行性进行了探讨，提出改进方案，并就方案实施后带来的经济效益进行了初步的估算。...
2020-07-10 14:39:05浏览：32
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A Possible Pumping Mechanism for Interstellar Class Ⅱ107 GHz Methanol Masers
It is recognized that the interstellar methanol-107GHz masers and OH-4.765 GHz masers towards Class Ⅱ sources are associated with each other and coexist towards ultracompact HII regions. Therefore we suggest a new pumping mechanism - methanol masers without population inversion. It can explain the formation of 107 GHz methanol masers, with the 4.765 GHz OH masers acting as a driving coherent microwave field. It is argued that this mechanism is compatible with the astronomical conditions....
2020-07-08 21:52:19浏览：51
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Statistical Properties of 6.7 GHz Methanol Maser Sources
We present a statistical analysis of 482 6.7 GHz methanol maser sourcesfrom the available literature, on their maser emission and the characteristics oftheir associated infrared sources. On the color-color diagram, more than 70% ofthe objects fall within a very small region (0.57 ≤ [25 - 12] ≤ 1.30 and 1.30 ≤[60 - 12] ≤ 2.50). This suggests that 6.7 GHz methanol maser emission occurs onlywithin a very short evolutionary phase during the earliest stage of star formation.The velocity ranges of the masers belong to two main groups: one from 1 to 10km s-1, and one from about 11 to 20 km s-1. These velocity ranges indicate thatthe masers are probably associated with both disks and outflows. The correlationsbetween the maser and infrared flux densities, and between the maser and infraredluminosities, suggest that far-infrared radiation is a possible pumping mechanismfor the masers which most probably originate from some outer molecular envelopesor disks....
2020-07-08 21:52:19浏览：63
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Methanol Distillation System: Process Analysis and Column Design
Base on industrial research and experience, the process of methanol distillation is analyzed,and above all, a new concept of high pressure flowsheet and low pressure flowsheet is defined. The new configuration helps to handle problems encountered in many factories in China. The inter influence between process and column internal pattern is also pointed out. Recommendation of new column internal designs is given. Finally, industrial examples tell the how the new concept works and the possibility of combining process to give more opens to solve engineering problems....
2020-07-08 21:52:19浏览：76
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带有热量集成的乙醇-水萃取精馏过程模拟
使用Aspen Plus，首先对乙醇-水萃取精馏过程的7种萃取剂的分离效能进行了模拟比较，结果显示：丙三醇> DMSO >乙二醇> DMF >糠醛>苯甲醛> NMP；接着，以丙三醇为萃取剂，设计了最优的萃取精馏工艺流程，并确定了萃取精馏过程中萃取精馏塔（理论板数：16，回流比：2，原料进料位置：12，萃取剂的进料量：230 kmol/hr和进料位置：4）和溶剂回收塔（理论板数：7，进料位置：3和回流比：3）的最佳工艺条件；最后，本文还利用热量集成的方法对系统的废热进行了回收利用，不但节约能耗3262.72 kW，还顺产1 MPa低压蒸汽127 kmol/hr。本研究为乙醇-水萃取精馏分离工艺的工业化提供了理论依据和设计参数。...
2020-06-12 15:40:22浏览：1425
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2-噻吩乙醇的合成及工艺改进
以噻吩为起始物料，氢溴酸经氧化剂氧化、溴化、格式反应制得格式试剂，格式试剂与环氧乙烷反应，水解得到2－噻吩乙醇，总收率可达72％以上。与溴素溴化相比该改进更适合工业化生产，环境更友好。...
2020-06-12 15:08:20浏览：1474
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热重与其他方法联用技术在煤热解研究中的应用
对热重-红外（TG-FTIR）、热重-质谱（TG-MS）、热重-色谱（TG-GC）等仪器联用技术的特征性能进行了综述，重点总结了其在煤热解、热解气体等分析研究中的应用。...
2020-06-12 14:57:39浏览：1433
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