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Pamidronate disodium-associated bone necrosis is poorly understood at the cellular and molecular levels. This study proposes a pathway leading to the pamidronate disodium-mediated inhibition of osteogenic differentiation of human bone marrow mesenchymal stem cells (BMMSCs) derived from the mandible in vitro.Primary human BMMSCs were isolated from the mandible and marrow tissue. A proliferation assay was performed to determine the experimental concentration of pamidronate disodium. Alkaline phosphatase (ALP) activity, ALP staining, and Alizarin red S (ARS) staining were assessed after treatment with pamidronate disodium (0, 0.1, 0.5, 1, 5, 10 μg/mL). Quantitative real-time polymerase chain reaction and western blotting specific for Wnt and β-catenin signaling genes or proteins were performed after treatment with pamidronate disodium 0.5 μg/mL. Wnt3a was used to observe the osteogenic differentiation of BMMSCs during treatment with pamidronate disodium 0.5 μg/mL.As expected, pamidronate disodium 1, 5, and 10 μg/ml were unfavorable for BMMSC growth (P .05), whereas 0.1 and 0.5 μg/mL did not affect BMMSC growth (P ≥ .05). BMMSCs treated with pamidronate disodium 0.5 μg/mL had lower ALP activity, ALP staining, and ARS staining (P .05), and BMMSCs treated with low concentrations (0.5 μg/mL) of pamidronate disodium had the same levels of ALP activity, ALP staining, and ARS staining as the control (0 μg/mL). Pamidronate disodium 0.5 μg/mL decreased the expression of genes and proteins involved in Wnt and β-catenin signaling. BMMSCs with Wnt3a and pamidronate disodium 0.5 μg/mL had higher ALP activity, ALP staining, and ARS staining (P .05).Pamidronate disodium inhibited Wnt and β-catenin signaling, which controls osteogenic differentiation in BMMSCs. Wnt3a, a Wnt and β-catenin signaling activator, reversed the negative effects caused by pamidronate disodium to salvage the osteogenic defect in BMMSCs.

A real-time digital simulation research and closed-loop testing platform for the security and stability control devices is built based on RTDS in this paper, which includes the simulation models for Lingzhou-Shaoxing (Lingshao) ±800 kV UHVDC transmission system, and the 3-level functions of the master control, pole control, and valve control is simulated. Based on the research and testing platform, the security and stability control strategies for N-2 faults occurring in AC transmission lines and other DC system faults of the Lingshao UHVDC system are tested. The research and testing results verify the accuracy of the control strategies and the accuracy of the simulation models. And the new research and testing method need no access to actual UHVDC control and protection system, which saves the testing cost and time significantly.

Real Time Dynamic Measure System (RTDMS) is widely used in China, which is also called Wide Area Monitoring System (WAMS) or Wide Area Monitoring Analysis Protection-control (WARMAP). Now the infrastructure of power optical fiber communication networks is mainly based on Synchronous Digital Hierarchy (SDH)/Synchronous Optical Network (SONET) in China. In the future, Optical Transport Network (OTN) will be a new generation data transmission technology, its operability, flexibility, reliability, and ease of management are better than SDH and SONET, and it will be used in Chinese state grid system and provide extra large capacity bandwidth and directly dispatch large-granule services.

Smart substation is the base of smart grid and it is made up of a lot of IEDs (intelligent electric device). Synchronized phasor measurement unit (PMU) plays a very important role in the smart grid, and a great deal of PMUs have been installed in China. The requirement of PMU in the smart substation is different from traditional substation. This paper introduces that the PMU is suitable for smart substation, there are several details that need to be complemented in IEC 61850 standards, and the paper gives some suggestion to improve it.

In recent years, with the rapid development of Wide Area Monitoring System (WAMS) and Wide Area Monitoring Analysis Protection-control (WAMAP) in China, more and more synchronized Phasor Measurement Units (PMU) have been put into services. So far nearly all the regional power systems have established systems to meet the requirement of sharing PMU synchrophasors among multiple parties. As PMU plays a significant role in the power system, selecting the models with excellent performance is of great importance. Therefore, PMU testing and evaluation have become a concerned subject by many professionals. A testing and evaluation (T&E) architecture should be built to do the integrated evaluation, including testing platform, testing method and result evaluation. This paper also put forward specific testing method and procedure for PMU, which are comprised of static performance testing and dynamic performance testing. Three testing sub-platforms will be introduced in this paper: the environment adaptability testing platform, Electromagnetic Compatibility (EMC) testing platform and performance testing platform. What's more, the evaluation method for PMU is described in detail in this paper, and examples of PMU device tested on these platforms is described in the paper.

Phasor Measurement Unit (PMU) devices, based on the synchronized measurement technology, are basic building blocks of Wide Area Monitoring System (WAMS) and Wide Area Monitoring Analysis Protection-control (WAMAP). Similar to the Remote Terminal Unit (RTU) in Energy Management System (EMS), PMU is becoming very important in the WAMS or WAMAP. This paper introduces the architecture of PMU testing and evaluation (T&E) in our laboratory. The integrated evaluation schemes include testing environment, performance testing method, conformance testing method and evaluation.

With large-scale implementation of smart grid, wide area measurement system (WAMS) based on PMU will become the basic platform to provide the online power system analysis, real-time monitoring and control. According to the extended CIM guidelines, a WAMS data model was established in this paper to realize data exchange and sharing between WAMS system and other systems. Combined with IEC 61970-404-speed data (HSDA) standard, a scheme of WAMS data exchange including data exchange framework, overall design of data exchange and data subscriptions was described in the paper. This scheme integrates WAMS system with other systems more effectively and makes other applications access WAMS data more easily.

SVC is an effective method to promote the transmitting capacity of transmission line and stabilize the voltage, it can also damp the low-frequency swing. But the control system of SVC is only based on local information at present, and it will bring out some problems in the power network when multi-SVCs are needed to control together. WAMS can get the synchronized data of the whole system very fast, which make it possible to monitor all the data of the system. The paper introduces the method to control the multi-SVC based on WAMS.

Time synchronism is a key technology of organizing digital signals in electric power automation system. Currently, the rapidly developing theory of digital automation system is based on ideal time domain. However, the time synchronism system, which provides time domain information, could be affected by various factors in implementation. When time information output can not meet the requirement, the calculated results based on it will deviate from the actual situation. Therefore, it is necessary to study the error of time synchronism system and its impact on digital automation system quantitatively. This paper uses the example of automation system in digital substation, quantitatively analyzes the operational status of power automation system with different time synchronism qualities and the redundancy of power automation system at typical failure or disturbance to time synchronism system. Experiments have been done with time synchronism system analyzers and digital substation emulation systems in CEPRI, and the results validate the analysis.

In traditional engineering applications, the internal voltage and power angle of generators are often measured by the electrical calculation method. The internal voltage and power angle of generators are calculated by direct-axis reactance Xd, quadrature-axis reactance Xq, terminal voltage and current which measured real-time. This calculation method may result in deviation because the value of Xd and Xq may be changed when the generator running in different status. This paper proposes a kind of rotor position measurement method. The internal voltage and power angle of generators are gotten by using generator phase keying signal and terminal voltages. This method is independent of generator equivalent calculative models and the value of synchronous reactance. It has high accuracy and suitable for real-time power angle measurement when power grid is in a disturbing or transient processing.

The rapid development of wind power puts forward higher requirements on the simulation of wind turbine generator dynamic characteristics. Based on the Wind Turbine (WT) and Wind Turbine Induction Generator (WTIG) models contained in MATLAB/Simulink, this paper constructs the corresponding fixed-speed WTIG model on RTDS/RSCAD platform firstly. Secondly, the simulation methods adopted by MATLAB and RTDS respectively are compared. Thirdly, based on a constructed One-Machine-Infinite-Bus (OMIB) system, a comparative validation of initial value, dynamic response of WTIG under wind and fault disturbance is made between MATLAB and RTDS platforms. The simulation results show that, RTDS can not only accurately implement and validate the WTIG model contained in other simulation platforms (e.g. MATLAB), but also provide more degrees of freedom and more detailed information about state variables in real time.