News Article | May 4, 2017
North China is one of the areas of strong earthquake activity on the Chinese mainland. In the 1960s~1970s, North China has undergone the 1966 Xingtai Ms7.2, 1969 Bohai Ms7.4, 1975 Haicheng Ms7.3 and 1976 Tangshan Ms7.8 earthquake, causing great losses to people's life and property, where the Tangshan earthquake caused casualties amounted to 240 thousand. In the past 50 years, Chinese seismologists have carried on the large-scale deep geophysical exploration and research, obtained the detailed crustal and upper mantle structure, and revealed the deep tectonic environment of strong earthquake in North China. The related research paper is entitled "Crustal and upper mantle structure and deep tectonic genesis of large earthquakes in North China" published in SCIENCE CHINA Earth Sciences, Vol.60, 2017, wrote by Professor Wang Chunyong at Institute of Geophysics, China Earthquake Administration. The research group reviewed the main achievements of the researches on the crustal and upper mantle structure as well as the seismogenic environment and tectonic patterns in North China since the 1966 Xingtai earthquake. Based on plate tectonics theory, geoscientists have successfully explained the patterns and mechanisms of earthquake activity on the global plate boundaries. However, plate tectonics theory has not explained the occurrence of earthquakes within the continental plate. North China is located within the Asian continent, and the geological structure, seismicity and focal mechanism show that the seismic activity is very different from that in the region of the plate boundary, indicating that the seismotectonics in North China is quite complex. The nucleation, occurence and development of continental earthquakes, and their relationship with the deep-seated structure of the earth are one of the most important subjects in the solid Earth Science. Seismologists have carried out numerous surveys of the crustal and upper mantle structure, and associated studies of seismic tomography in North China, finished 42 deep seismic souding profiles with total length of ~12000 km, and seismic tomography of three-dimensional crustal and upper mantle structure based on the seismic records at ~600 stations. Deep seismic reflection profiling results indicate a complex tectonic setting in the strong earthquake areas of North China, where a listric normal fault and a low-angle detachment in the upper crust coexist with a high-angle deep fault passing through the lower crust to the Moho beneath the hypocenter. Seismic tomography images revealed that the lithospheric structure in North China is highly inhomogeneous, where most of the large earthquakes occurred in the transition between the high- and low-velocity zones, and the Tangshan earthquake area is characterized by a low-velocity anomaly in the middle-lower crust. Comprehensive analysis of geophysical data identified that the deep seismogenic environment in the North China extensional tectonic region is generally characterized by a low-velocity anomalous belt beneath the hypocenter, inconsistency of the deep and shallow structures in the crust, a steep crustalal-scale fault, relative lower velocities in the uppermost mantle, and local Moho uplift. Earthquake prediction is one of the scientific problems in the Earth Science that have not yet been solved. A deep understanding of the deep tectonic environment of strong earthquakes will help to solve the problem of earthquake prediction. Seismologists Deng Qidong (2008) presented that the surface and shallow-deep tectonic features in the large earthquake area have been releaved by the combination of deep seismic reflection profiling and the surface geology and tectonic enviorment, thus we are able to obtain more comprehensive understanding of seismogenic tectonic conditions in the active fold area (the extension zone and the compression zone) of the normal or strike-slip normal fault and the reverse fault. He further pointed out that it is the right direction to combine the surface geological work with the deep structure and the deep material detection, and it is the key to understand the nucleation and occurrence of the large earthquake. The study of deep-seated structure and seismogenic environment in North China is an excellent model of the combination of deep geophysical exploration and surface seismic geologic research. Despite the deep seismic exploration and seismic tomography research has greatly enriched the knowledge of deep-seated structure and seismogenic environment, due to the complexity of continental seismotectonics, we still face some deep-seated problems, which need to further research. Wang C Y, Wu Q J, Duan Y H, Wang Z S, Lou H. 2017. Crustal and upper mantle structure and deep tectonic genesis of large earthquakes in North China. Science China Earth Sciences, 60: 821-857, doi: 10.1007/s11430-016-9009-1
North China Electrical Power University | Date: 2017-07-26
This Invention presents a series of novel MMC topologies with voltage self-balancing capability that consist of the Phase I module, Phase II module, Phase III module and the voltage self-balancing auxiliary circuit connected thereto, Said Phase I module, Phase II module and Phase III module respectively consist of two bridge arms, each of which comprise N bridge arm SM(s); in Approach 1, said voltage self-balancing auxiliary circuit comprise 6N+5 clamped diodes and two auxiliary capacitors (C_(1) and C_(2)) and two auxiliary insulated gate bipolar transistor (IGBT) modules (T_(1) and T_(2)); or, in Approach 2, said voltage self-balancing auxiliary circuit comprise 6N-3 clamped diodes and 4 interphase clamped diodes. The novel MMC topologies, have changed the characteristic of mutual independence among the MMC SM capacitors. As a result, without relying on special voltage balancing control algorithm, on basis of the completion of DC-AC energy conversion by MMC, the energy deviation among capacitors can be made to circulate within a phase or between phases, spontaneously realizing the voltage balancing of the SM capacitors.
Wang Z.-G.,North China Electrical Power University
Nuclear Physics A | Year: 2017
In this article, we assign the Ds3 ⁎(2860) to be a D-wave cs¯ meson, and study the mass and decay constant of the Ds3 ⁎(2860) with the QCD sum rules by calculating the contributions of the vacuum condensates up to dimension-6 in the operator product expansion. The predicted mass MDs3 ⁎=(2.86±0.10) GeV is in excellent agreement with the experimental value MDs3 ⁎=(2860.5±2.6±2.5±6.0) MeV from the LHCb collaboration. The present prediction supports assigning the Ds3 ⁎(2860) to be the D-wave cs¯ meson. © 2016
Wang Z.-G.,North China Electrical Power University
Communications in Theoretical Physics | Year: 2016
In this article, we take the X(5568) as the diquark-antidiquark type tetraquark state with the spin-parity JP = 0+, construct the scalar-diquark-scalar-antidiquark type current, carry out the operator product expansion up to the vacuum condensates of dimension-10, and study the mass and pole residue in details with the QCD sum rules. We obtain the value MX = (5.57±0.12) GeV, which is consistent with the experimental data. The present prediction favors assigning the X(5568) to be the scalar tetraquark state. © 2016 Chinese Physical Society and IOP Publishing Ltd.
North China Electrical Power University, State Grid Corporation of China and State Grid Shanxi Changzhi Power Supply Company | Date: 2015-01-30
The disclosure relates to the crossing field between a power transmission of an ultra-high-voltage and a power system simulation, specifically a method for analyzing an operation state of a substation by combining a whole grid model with a local grid model is provided according to the disclosure. The method includes following steps: performing a load flow calculation for the provincial grid to which a ultra-high-voltage line belongs, wherein initial data of the load flow calculation employs a grid model with E format for national power grid dispatching control center; making an equivalent transform for the model, forming an island independently from the provincial grid to which a ultra-high-voltage line belongs, and making a load flow calculation for the island to acquire data of node voltages and line transmission power.
Wang W.,North China Electrical Power University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014
In this paper we investigate the parallel texture structures with cofactor zeros in the charged lepton and neutrino sectors. The textures cannot be obtained from arbitrary leptonic matrices by making weak basis transformations, which therefore have physical meaning. The 15 parallel textures are grouped as 4 classes where each class has the same physical implications. It is founded that one of them is not phenomenologically viable and another is equivalent to the texture zero structures extensively explored in previous literature. Thus we focus on the other two classes of parallel texture structures and study the their phenomenological implications. The constraints on the physical variables are obtained for each class, which is essential for the model selection and can be measured by future experiments. The model realization is illustrated in a radiated lepton mass model. © 2014.
Tan W.,North China Electrical Power University
IEEE Transactions on Power Systems | Year: 2010
A unified PID tuning method for load frequency control (LFC) of power systems is discussed in this paper. The tuning method is based on the two-degree-of-freedom (TDF) internal model control (IMC) design method and a PID approximation procedure. The time-domain performance and robustness of the resulting PID controller is related to two tuning parameters, and robust tuning of the two parameters is discussed. The method is applicable to power systems with non-reheated, reheated, and hydro turbines. Simulation results show that it can indeed improve the damping of the power systems. It is shown that the method can also be used in decentralized PID tuning for multi-area power systems. © 2009 IEEE.
North China Electrical Power University | Date: 2015-04-19
Apparatus and method are provided for the treatment of uranium-contaminated soil by using comprehensive joint technology. The apparatus include the pumping system, the electrokinetic remediation system, elution system, remediation-separation system and recharge system. The remediation technologies (i.e. chemical, photolysis and electrokinetic) are used to remedy the uranium-contaminated soil. First, extract uranium from the contaminated areas and make the ionized uranium extract from the soil phase to the solution phase. Then, use the electrokinetic remediation technology to drive uranium enrichment electromigrate to near the anode. Finally, return the repaired-soil and groundwater back to anode area and recharge well, respectively. This comprehensive joint apparatus can reduce the uranium volume in the contaminated soil or water, and recycle the obtained uranium, which are cleaning processes and have no secondary pollution.
North China Electrical Power University | Date: 2015-12-23
This embodiment of the invention announced a synchrophasor measurement method applied to P class Phasor Measurement Unit (PMU). First, said measurement method is based on the dynamic phasor mathematic model. The low pass digital filter for phasor factors is designed, which is combined with DFT. It eliminates the spectrum leakage caused by the dynamic phasor inputs, and the raw phasor measurements after the spectrum leakage being eliminated can be obtained; the dynamic phasor is fitted by using the second order Taylor series. The linear relationship between the measurement errors caused the DFT averaging effect and the second order coefficients of the Taylor series is explored. And, the linear relationship is used to compensate the raw measurement errors under a dynamic condition. And, the accurate dynamic phasor measurements can be gotten. This measurement method can measure phasor accurately and rapidly under both static and dynamic conditions. The precision of the method not only meets the requirements in relevant standards, but also is an order of magnitude higher than the requirements of the standards.
North China Electrical Power University | Date: 2015-12-17
The disclosure provides a mercury removal system for a coal-fired power plant comprising: a mercury content monitoring system configured to monitor a mercury concentration in flue gas; a fly ash collecting device configured to collect fly ash from an electrostatic precipitator in the coal-fired power plant; a modifying device configured to be supplied with the collected fly ash and prepare a mercury sorbent from the fly ash; a sorbent injector configured to inject the mercury sorbent into flues of the coal-fired power plant so as to mix and contact with the flue gas in the flue and adsorb the elemental mercury in the flue gas. Thus, the concentration of the mercury pollutant emission is decreased.