聚氯乙烯在燃烧裂变过程的在线单光子离子化/共振增强多光子离子化飞行时间质谱

用单光子离子化 (SPI) /共振增强的多光子离子化 (REMPI) 飞行时间质谱法对PVC材料的燃烧裂变过程进行了在线研究 ,发现与其它有机材料不同 ,PVC涂层材料在 30 0℃时即发生裂变 ,生成苯系物、萘及少量多环芳烃。在空气条件下 ,产生酚类有机污染物。在 70 0℃和 80 0℃的低流速空气环境中检测到了二英的前体物———氯代苯 (MCB)、氯代酚及氯乙烯单体 ,预示着二英的形成 ,并可间接在线监测二英的浓度。在各温度条件下都有多环芳烃 (PAHs)产生 ,但在 70 0℃～ 80 0℃时 ,产生的数量最多。提高空气流速可大大降低MCB和PAHs的产生。在 1 0 0 0℃～ 1 1 90℃时 。

警惕:企业破产、裂变,银行贷款被悬空

为了适应社会主义市场经济体制的客观要求,我国加快了转换企业经营机制,建立现代化企业制度的步伐。企业破产、裂变已成为调整产业结构、优化生产要素组合、发展社会生产力的途径之一。但是,由于长期以来我国企业产权制度不健全,生产经营资金主要依赖银行贷款,再加上企业破产、裂变过程中存在着一些非经济化和非法制化的因素,从而导致了“企业宣布破产、裂变,银行代为受过”的尴尬局面。

小男孩的诞生

1945年7月16日,美国在本土的新墨西哥州沙漠中成功的试验爆炸了第一颗原子弹。接着美国第二颗名为“小男孩”的原子弹及于同年8月6日在日本广岛降临人世,刹那间使广岛这个城市的一切活动降低到了零点,有67％的建筑物遭到毁灭性的破坏,有92％的地方无法辨认出原貌,伤亡人数在16万以上。

新一代AlphaServerGS系列高端服务器

在网络时代,新技术层出不穷,COMPAQ公司以其AlphaServer系列服务器,成为一股推动信息科技的神奇力量。

Characterization of Basic Nitrogen Aromatic Species Obtained during Fluid Catalytic Cracking by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

The basic-nitrogen aromatic compounds in feedstocks and liquid products from the micro-reactor and soluble components of coke obtained during fluid catalytic cracking （FCC） process were analyzed by the micro-electrospray ioniza- tion （ESI） 9.4T Fourier transform ion cyclotron resonance mass spectrometry （FT-ICR MS） with an average mass resolving power of 300 000 at a mass range of 100--1 200. The analytical results revealed that the coker gas oil （CGO） contained a higher abundance of basic-nitrogen aromatic compounds with the type of-SN to -9N compared with those in deasphalted oil （DAO） and mixed FCC feedstock. After catalytic cracking, the abundance of lowly condensed basic-nitrogen aromatic compounds was much less than those of highly condensed aromatics in the liquid products, with the carbon number mainly ranging from 6 to 25 and the average carbon number of the side-chains equating to 1--5. On the contrary, with respect to the soluble components of coke, the abundance of lowly condensed basic-nitrogen aromatic compounds was more than those of highly condensed aromatics, and the carbon number ranged from 12 to 30, which was much smaller than that of the mixed FCC feedstock but slightly larger than that of the cracked liquid products. These results have provided some fundamental information on FCC process.

Experiment of dynamic property and transient magnetic effects of coal during deformation and fracture

Combining separated SHPB test device of Ф50 mm with ZDKT-type 1 transient magnetic resonance test system, long drop bar of 400 mm was used to impact coal specimens at four different speeds： 1.275, 3.287, 6.251, and 7.404 m/s. The change in waveform, the dynamic mechanical properties, and the generated effect of transient field during the coal deformation and fracture under the loads were discussed and analyzed. While magnetic signals during the coal fracture firstly needed EEMD, decomposition then had a FFT with Data Demon. The main results of the experiment are the following： the main frequency of magnetic signals was between 220 and 450 kHz and the instantaneous frequency during the damage of coal would have the instantaneous jump.

Electron Beam Application for Regeneration of Catalysts Used in Refinery Cracking Units

A catalyst is a substance that alters the rate of a reaction. The process of catalysis is essential to the modem day manufacturing industry, mainly in FCC （Fluid Catalytic Cracking） process units. However, long-term exploitation of oil and gas processing catalysts leads to formation of carbon- and sulfur-containing structures of coke and dense products on the catalyst surface. They block reactive catalyst sites and reduce the catalytic activity. The main advantage of radiation processing by EB （electron beam） and gamma rays is chain cracking reaction in crude oil. Otherwise, under exposure to ionize radiation, considerable structure modification of equilibrium silica-alumina catalyst from FCC process may occur, in addition to the removal of impurities. The conditions applied in the irradiation range （20-150 kGy） of gamma rays and EB were not sufficient to alter the structure of the catalyst, whether for removal of the contaminant nickel, a major contaminant of the FCC catalyst, either to rupture of the crystalline structure either for the future reutilization of chemical elements. ATR-FTIR （Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy and EDXRFS （Energy Dispersive X-Ray Fluorescence Spectrometry） analysis were used to characterize and evaluate effects of radiation processing on equilibrium catalysts purification. To evaluate and comprehend the reactive catalyst sites, SEM （Scanning Electron Microscopy） and particle size distribution analyses were carried out.

Preliminary analysis on the source properties and seismogenic structure of the 2017 M_s7.0 Jiuzhaigou earthquake

At GMT time 13：19, August 8, 2017, an M1.0 earthquake struck the Jiuzhaigou region in Sichuan Province, China, causing severe damages and casualties. To investigate the source properties, seismogenic structures, and seismic hazards, we systematically analyzed the tectonic environment, crustal velocity structure in the source region, source parameters and rupture process, Coulomb failure stress changes, and 3-D features of the rupture plane of the Jiuzhaigou earthquake. Our results indicate the following： （1） The Jiuzhaigou earthquake occurred on an unmarked fault belonging to the transition zone of the east Kunlun fault system and is located northwest of the Huya fault. （2） Both the mainshock and aftershock rupture zones are located in a region where crustal seismic velocity changes dramatically. Southeast to the source region, shear wave velocity at the middle to lower crust is significantly low, but it rapidly increases northeastward and lies close to the background velocity across the rupture fault. （3） The aftershock zone is narrow and distributes along the northwest-southeast trend, and most aftershocks occur within a depth range of 5-20 km. （4） The focal mechanism of the Jiuzhaigou earthquake indicates a left-lateral strike-slip fault, with strike, dip, and rake angles of 152~, 74~ and 8~, respectively. The hypocenter depth measures 20 km, whereas the centroid depth is about 6 kin. The co-seismic rupture mainly concentrates at depths of 3-13 km, with a moment magnitude （Mw） of 6.5. （5） The co-seismic rupture also strengthens the Coulomb failure stress at the two ends of the rupture fault and the east segment of the Tazang fault. Aftershocks relocation results together with geological surveys indicate that the causative fault is a near vertical fault with notable spatial variations： dip angle varies within 660-89~ from northwest to southeast and the average dip angle measures -84~. The results of this work are of fundamental importance for further studies on the source characteristics, tectonic environment, and seismic hazard evaluation of the Jiuzhaigou earthquake.

Discontinuous deformation and displacement analysis: From continuous to discontinuous

A discontinuous deformation and displacement(DDD) analysis method is proposed for modelling the rock failure process. This method combines the rock failure process analysis(RFPA) method(based on finite element method) and discontinuous deformation analysis(DDA) method. RFPA is used to simulate crack initiation, propagation and coalescence processes of rock during the small deformation state. The DDA method is used to simulate the movement of blocks created by the multiple cracks modelled by the RFPA. The newly developed DDD method is particularly suitable for modelling both crack propagation and block movement during the rock failure process because of the natural and convenient coupling of continuous and discontinuous deformation analyses. The proposed method has been used to simulate crack initiation, propagation and coalescence within a slope as well as the block movement during the landslide process. Numerical modelling results indicate that the proposed DDD method can automatically simulate crack propagation and block movement during the rock failure process without degrading accuracy.

Abnormal strain changes observed at Guza before the Wenchuan earthquake

An YRY-4 type borehole strainmeter at Guza station on the southwest end of the Longmenshan fault zone recorded anomalous changes from time to time since about one year before the Wenchuan earthquake.The anomaly is characterized by steps and/or asymmetrical pulses of short-periods(minutes-hours).Among about one hundred stations over the mainland of China,only Guza,the nearest one to the seismic area,observed such changes.A self-check function of the strainmeter helps confirm the credibility of the observation.The anomalous signals do not correspond to seasonal changes.The consistency in the sense of strain among long-term,anomalous interfering and coseismic changes suggests that they all resulted from the background tectonic movement.Results of an Overrun Rate Analysis further illustrate a close temporal relevance of the anomaly to the Wenchuan earthquake:its increase before,and decrease after the biggest changes during the main shock.The abnormal changes are attributed to local small-scale fractures with an evidential clue that the only Ms4.5 foreshock near Guza station on February 27,2008 produced the biggest anomalous change.By means of Wavelet Decomposition,it is revealed that longer period portion of the anomaly took place later before the main shock,consistent with the idea that scales of small fractures increase during earthquake preparation process.The anomalous strain changes are analogous to the stress changes observed before the 1976 Tangshan earthquake.