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Converter transformer bushing as a piece of important power equipment in HVDC transmission, need to withstand AC voltage, DC voltage, and polarity reversal voltage during operation, the complexity of the operating conditions leads to high requirements on the insulation performance of the converter transformer bushing. The dry-type SF 6 gas-insulated DC bushing meets the requirement of no oil in the valve hall, is the bushing of the current mainstream converter transformer, and it uses SF 6 gas as the upper additional insulation. Analyze the electric field distribution in SF 6 gas of converter transformer bushing under different voltages, Especially important for the design of SF 6 gas internal voltage equalization device. This paper selects ±400kV dry-type SF 6 gas insulated bushing as the research object, establishes a simulation analysis model, and uses the finite element analysis method to calculate the electric field intensity distribution of the converter transformer bushing under different voltages. Mainly analyze the distribution law of electric field intensity in SF 6 gas. The results show that under DC excitation, the distribution of equipotential lines in SF 6 gas is relatively concentrated, and the electric field intensity near the top of the capacitor core is the highest. Under the condition of polarity reversal, the electric field intensity in SF 6 gas showed a downward trend.

In extreme environments, such as at ultrahigh or ultralow temperatures, the amount of tape used should be minimal so as to reduce system contamination and unwanted residues. However, tapes made from conventional materials typically lose their adhesiveness or leave residues difficult to remove under such conditions. Thus, the development of more versatile, lightweight, and easily removable tapes for applications in such extreme environments has received considerable attention. Here, we report that horizontally superaligned carbon nanotube (SACNT) tapes can be used to provide perfect van der Waals (vdW) interface contacts over a wide range of temperatures (from -196 to 1000 °C), yielding outstanding adhesiveness with specific adhesion strengths up to ∼1.1 N/μg. With a surface density of only 0.5-5 μg/cm2, hundreds of times lighter than the vertically aligned CNT adhesives, the SACNT tapes can be cost-effectively provided in hundreds of meters. They have multipurpose adhesive abilities for versatile materials and are also easily separated from samples even after exposure to extreme temperature regimes. First-principles calculations confirm the mechanism of vdW adhesion and reveal that ultraflat and nanometer-thick SACNT tapes may yield far greater adhesive abilities. These SACNT tapes show great potential for use in mechanical bonding, electrical bonding, and thermal dissipation in electronic devices.

The micro-machined gyroscope that uses Coriolis force to measure angular velocity has non-linear error,which makes the amplitude of angular velocity have a relationship with its frequency,and fabrication technology error,which leads gyroscope’s drive shaft and detection shaft not to be vertical.All kinds of errors severely restrict this kind of gyroscope’s measuring accuracy and application range.This article obtained the reason for the formation of all kind of gyroscope’s errors and their mathematical expressions through analyzing the principle of micromachined gyroscope,which uses Coriolis force to measure angular velocity.At the same time,the gyroscope mathematical model was established and used to emulate to analyze each error’s influence on the angular velocity measured by gyroscope.The conclusion obtained by theoretical analysis and simulation provides the basis for gyroscope’s error analysis and elimination,and it has an important significance in improving the measuring accuracy of gyroscope.

OBJECTIVE To investigate the effects of Liangxue Tongyu Formula (LXTYF), a compound traditional Chinese herbal medicine, on brain edema in rats with intracerebral hemorrhage and to explore the mechanism. METHODS Intracerebral hemorrhage was induced by using the intrastriatal autologous blood injection. Rats were randomized into sham-operated (SO) group, intracerebral hemorrhage (ICH) group and LXTYF group. Rats in the LXTYF group were intragastrically administered with LXTYF every day while the other two groups were given normal saline. Brain water content was determined at 24, 48, 72, and 120 h after intracerebral hemorrhage. Matrix metalloproteinase-9 (MMP-9) level, and MMP-9 and tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA expressions in perihematoma area were detected by gelatin zymography and fluorescence quantitative real-time polymerase chain reaction at the four time points, respectively. RESULTS Water content in the ICH group was highly elevated after intracerebral hemorrhage, and reached to the peak at 72 h. Compared with the ICH group, the LXTYF group had lower water contents at 48, 72 and 120 h after intracerebral hemorrhage (P

The imaging characteristic of non-periodic multilayer Kirkpatrick-Baez(KB) microscope is analyzed based on propagation of rays, and contrasted with single layer and periodic multilayer KB microscopes. Compared with single layer KB microscope, multilayer KB microscope has bigger grazing angle, and wider field of view at the same resolution and collection efficiency. The reflectivity and energy resolution of periodic multilayer KB microscope is better than that of non-periodic multilayer KB microscope, but the non-periodic multilayer element has wider angular bandwidth and more uniform reflectivity, which improves the field of view and uniformity of image. The non-periodic multilayer mirrors with a grazing angle of 1.133 0° possess 0.3° angular bandwidth. Backlit by 8 keV X-ray tube, the i

Objective: To evaluate whether base excision repair gene polymorphisms contributed to susceptibility of chromosomal damage induced by vinyl chloride monomer (VCM). Methods: Cytokinesis block micronucleus test was performed on 185 VCM-exposed workers to detect chromosomal damage in peripheral lymphocytes. The PCR-restriction fragment length polymorphism technique was applied to detect polymorphisms of TDG, PARPl, and APE1 genes. Univariate and multivariate Poisson regression analysis was performed. Results: There was a 1.198 fold increased micronucleus frequency for individuals carrying TDG 199G1y/Ser + Ser/Ser genotypes compared with those carrying Gly/Gly genotype (P < 0.05). Individuals with the combined genotypes of TDG 199G1y/Ser + Ser/Ser and APE1 64Ile/Val + Val/Val had a significantly increased micronucleus frequency compared with those carrying wild-type genotypes for both genes. Conclusion: VCM-exposed workers carrying TDG 199G1y/Ser + Ser/Ser genotypes were susceptible to chromosomal damage. A combination of TDG GLy199Ser and APE1 Ile64Val polymorphisms may modify the risk of chromosomal damage.

High temperature can cause many problems in OIP transformer bushing, such as aging of insulation and partial discharge, which will obviously reduce the lifetime of bushing. This contribution calculates the total loss in bushing under both voltage and current loads using the finite elements method(FEM) and then obtains the temperature distribution though the finite volume method (FVM). Computation results indicates that the total loss in 550kV bushing is 1203.89W, among which the 4.5% is dielectric loss. The peak value of temperature rise reaches 76.27 °C, which appears in the center pilot. Measurement of temperature rise is taken to check the calculation method, in which 16 points on the center pilot and nine points on the surface of umbrellas are taken into the comparison. Among the 25 compared points, error stays within 5% on 16 points, between 5% and 10% on 4 points, between 10% and 15% on three points. It can be concluded that the methods used in this contribution is proper and can support the designing and analyzing of OIP bushing.

The converter transformer bushing is one of the key devices in high voltage direct current (HVDC) system, which has a complex insulation system. To comprehensively evaluate the insulation properties of ±600 kV dry DC bushing, a finite element model is built and the electric field distributions under complex voltage are calculated. Results show that: the electric field concentrates more in the epoxy resin under AC voltage while concentrates more in the SF6 gas under DC voltage. Space charge will accumulate in the DC field, which can lead a tremendous change of electric field under the polarity reversal voltage. During the polarity reversal process, the maximum values of electric field in different materials appear depend on their material properties. Electric field calculation can provide advice to the insulation design of DC dry bushing.

The electron cyclotron resonance heating (ECRH) experiments on HL-1 tokamak with 300 kW of power generated by a gyrotron are described. With ECE diagnostics, a 30% increase of electron temperature has been obtained. The following phenomena have been observed with various diagnostics during ECRH: increase of radiation intensity of soft x-ray; amplitude change and period elongation of sawtooth oscillation; MHD instability suppression; increase of Hα spectral line intensity and ionized impurity radiation from edge plasma; increase of the temperature and density of edge plasma. Although the total plasma energy content increases, the energy confinement time is decreased. Initial results of low voltage start-up experiments have also been obtained.

An eight-beam 0.351-µm laser with pulse duration of about 1.0ns and energy of 260 J per beam was injected into a cylindrical cavity to generate intense x-ray radiation on the Shengguang II high power laser facility. A mixture foil of gold and gadolinium and a gold foil were attached on portion of a diagnostic hole in the mid-plane of the cavity and ablated by the intense x-ray radiation. The propagating time of the radiation heat wave in the mixture and the pure gold foil were measured with soft-x-ray spectrometer and by adopting space- and time-resolved measurement technology, respectively. The results show that the mixture of gold and gadolinium has higher Rosseland mean opacity than the gold sample in our experiment.

Eight beams 0.35 µm laser with pulse duration of about 1.0 ns and energy of 260 J per beam was injected into a cylindrical cavity to generate intense x-ray radiation on the ``Shengguang II'' high power laser facility. Gold foils with a thickness in the range of 0.09-0.52 µm were attached on the diagnostic hole of the cavity and ablated by the intense x-ray radiation. The propagating radiation heat wave in the high-Z gold plasma was observed clearly. For comparison, we also simulated the experimental results.

Using high dynamic range X-ray framing camera, the radiation driven ablative Rayleigh-Taylor instability facing backlight radiography on SHENGUANH (SG) II device is studied. In the SG II that has eight beams with the 2 ns laser pulse and the ninth beam for Mo backlight, two-dimensional space-time ablation RT growth process for the cycle 20 m and the initial perturbation 1 m are observed clearly, and the non-linear growth process is also observed by the doping Br ratio of 1.1% in samples. The result lays a good foundation for quantitative characterization and numerical simulation of RT instability in inertial confinement fusion (ICF) experiments.

This paper describes the diagnostic techniques and experimental methods used for investigating the properties of implosion compression in direct drive . Several diagnostic techniques with fine time, space and spectrum resolution are employed to obtain the information concerning implosion, such as radiation un iformity on the capsule, compression symmetry, volume compression ratio, implosi on time, implosion velocity and average electron temperature of the capsule shell. Some of the typical results measured in the experiments are presented and as imple discussion is also given.

Supersonic radiation transport, where the ratio of the radiation wave front velocity to the material sound speed was more than 10, has been investigated experimentally in the low-density foam. Four beams of 0.35μm laser with pulse d uration of 1ns and 2kJ of total energy entered into a hohlraum to create intense x-ray radiation that heated C66H12