A dual-period response of the Kuroshio Extension SST to Aleutian Low activity in the winter season

Based on our previous work, the winter sea surface temperature（SST） in the Kuroshio Extension（KE） region showed significant variability over the past century with periods of ~6 a between 1930 and 1950 and ~10 a between1980 and 2009. How the activity of the Aleutian Low（AL） induces this dual-period variability over the two different timespans is further investigated here. For the ~6 a periodicity during 1930–1950, negative wind stress curl（WSC）anomalies in the central subtropical Pacific associated with an intensified AL generate positive sea surface height（SSH） anomalies. When these wind-induced SSH anomalies propagate westwards to the east of Taiwan, China two years later, positive velocity anomalies appear around the Kuroshio to the east of Taiwan and then the mean advection via this current of velocity anomalies leads to a strengthened KE jet and thus an increase in the KE SST one year later. For the ~10 a periodicity during 1980–2009, a negative North Pacific Oscillation-like dipole takes2–3 a to develop into a significant positive North Pacific Oscillation-like dipole, and this process corresponds to the northward shift of the AL. Negative WSC anomalies associated with this AL activity in the central North Pacific are able to induce the positive SSH anomalies. These oceanic signals then propagate westward into the KE region after 2–3 a, favoring a northward shift of the KE jet, thus leading to the warming of the KE SST. The feedbacks of the KE SST anomaly on the AL forcing are both negative for these two periodicities. These results suggest that the dual-period KE SST variability can be generated by the two-way KE-SST-AL coupling.

Activity Enhancement of Vanadium Catalysts with Ultrasonic Preparation Process for the Oxidation of Sulfur Dioxide

The effect of ultrasonic cavitations on the activity of vanadium catalysts atlow temperatures for the oxidation of sulfur dioxide, in which refined carbonized mother liquor hadbeen added, was investigated. Twenty minutes were needed to produce obvious cavitations when thecatalyst raw material was treated in the 50 W ultrasonic generator. However, only 10 minutes wouldbe needed in a 150 W ultrasonic generator. The higher the temperature of the wet material, the lesstime was needed to produce cavitations, and the optimal temperature was 60℃. The water content inthe wet material mainly affected the quantity of cavitations. Ls-8 catalyst was prepared usingultrasonic. Its activity for conversion of SO_2 reached to 52.5% at 410℃ and 4.2% at 350℃. Thedifferential thermal analyses indicate that both endothermic peaks and exothermic peaks noticeablyshifted forward compared with Ls catalyst prepared without ultrasonic, and SEM results show auniform pore size distribution for Ls-8 catalyst.

Thermal Activation Analyses of Dynamic FractureToughness of High Strength Low Alloy Steels

A formula is derived for determining the influence of temperature and loading rate on dynamic fracture toughness of a high strength low alloy steel (HQ785C) from thermal activation analysis of the experimental results of three-point bend specimens as well as introducing an Arrhenius formula. It is shown that the results obtained by the given formula are in good agreement with the experimental ones in the thermal activation region. The present method is also valuable to describe the relationship between dynamic fracture toughness and temperature and loading rate of other high strength low alloy steels.

CLSTM-KF reconstruction method for a low-activity moving radiation source localization and tracking with a coded-aperture gamma camera

Background Accurate localization of a low-activity moving radiation source plays an important role in nuclear security and safety.The coded-aperture gamma camera is generally applied to detect a radiation source,but its reconstruction methods may have some limitations when the radiation source is motional and weak.Purpose The purpose of this paper is to improve the quality of the reconstruction images and the localization accuracy when detecting a low-activity moving radiation source with a gamma camera.Method The CLSTM-KF method consists of the CLSTM network and the Kalman filter.The CLSTM network is applied to improve the CNR of reconstruction images by making an adaptive superposition for sequential reconstruction images decoded by the correlation analysis method.After the CLSTM network,a series of sequential positions would be filtered by the Kalman filter.Results By comparing with the traditional methods of the gamma camera,the CLSTM-KF method performs well in improving both the CNR of reconstruction images and the localization accuracy.Moreover,the computation time of the CLSTM-KF method can also meet the application requirements.Conclusion In summary,the CLSTM-KF method provides a better choice than the traditional methods in locating and tracking a low-activity moving radiation source.

Research on Diamond Enhanced Tungsten Carbide Composite Button

At the present, the cutters used in button bits and rock bits are mainly cobalt tungsten carbide in our country. Because of its low abrasive resistance, the bit service life and drilling efficiency was very low when the hard and extremely hard formations were being drilled. Owing to its high abrasive resistance, the diamond composite material is widely used in drilling operations. However, its toughness against impact is too low to be used in percussion drilling, only can it be used in rotary drilling. In order to solve the problems encountered by DTH hammer in hard rock drilling, make bit life longer, increase rate of penetration and decrease drilling cost, a new type diamond enhanced tungsten carbide composite button with high abrasive resistance and high toughness against impact, which may be used in percussion drilling, has been developed. The key problems to make the button are to improve the thermal stability of diamond, to increase the welding strength between diamond and cemented tungsten carbide, and to lower the sintering temperature of tungsten carbide. All these problems have been solved effectively by pretreatment of diamond, low temperature activation hot-press sintering and high sintering pressure. (1) To plate tungsten on the surface of diamond. Diamond suffers easily from erosion in the environment of high temperature containing oxygen and iron family elements. There is very high energy between the interface of diamond and bonding metal and so the metallurgical bond can’t form at the interface between diamond and bond metal. This will lower greatly the bending strength and the toughness against impact of diamond enhanced tungsten carbide composite button. In order to improve thermal stability of diamond and increase the bonding strength of the interface between diamond and bond metal, to plate tungsten on the surface of diamond by vacuum vapor deposit is adopted. (2) To lower the sintering temperature by adding nickel, phosphorus and boron etc into conventional mixed powder. In general, the sintering temperature of cemented tungsten carbide is more than 1 350 ℃ in which diamond will suffer from serious heat erosion, so the sintering temperature must be lowered. To add nickel, phosphorus and boron etc into cobalt-base bond whose melting point is more than 1 350 ℃ will lower the sintering temperature to about 1 050 ℃. To add phosphorus can lower the temperature of liquid phase occurring and promote the densification of matrix alloy in advance because the co-crystallization temperature of Ni-P and Co-P is 880 ℃ and 1 020 ℃ respectively. The proper adding amount of nickel, phosphorus and boron etc is a key problem. To substitute nickel for partial cobalt can improve the toughness against impact of diamond enhanced tungsten carbide composite button and lower the sintering temperature. To add boron is helpful for sintering and improving the toughness against impact of diamond enhanced tungsten carbide composite button. (3) To increase the sintering press. Under the same sintering temperature, to improve the sintering press can improve the density and strength of sintering products. In this study to increase the sintering press 35 MPa in the usual conditions to 50～60 MPa in sintering diamond enhanced tungsten carbide button by adopting ceramic material as pressing rod has improved the sintering quality effectively. The properties of the button have been measured under lab conditions. The testing results show that its hardness is more than HRA86 and that its abrasiveness resistance is 100 times more than conventional cemented tungsten carbide, and its toughness against impact is more than 100J. All these data theoretically show that the button has very good mechanical properties that can meet the need of percussion drilling, and can solve the problems encountered with button bit of conventional cemented tungsten carbide.

Preparation of Cs-Rb-V series sulphuric acid catalyst

Cs Rb V series low temperature sulphuric acid catalyst was prepared for the first time by using carbonized mother liquor containing alkali metal salts. The results show that the conversion of SO 2 on catalyst prepared directly with carbonized mother liquor could reach to 24.8% at 410?℃. If n (Na)/ n (V) was adjusted properly, the conversion of SO 2 could be increased to 35.6% at 410?℃. Refined carbonized mother liquor could make the catalytic activity even higher at low temperature, the conversion of SO 2 could be increased to 36.65% at 410?℃. The catalyst was examined with differential thermal analysis. It was found that both endothermic peaks and exothermic peaks of catalyst shifted forward obviously and the catalyst possessed higher activity at low temperature.

Designing and characteristics analysis of electric suspensions with symmetrically arranged two slider-rods

An innovative design of electric suspensions was developed in this study to help realize slow active suspension easily and quickly.This design was driven by screw through double slider-rod arranged symmetrically as a substitute for two springs.Based on a mathematical modeling,suspension parameters were introduced for a certain type of wheeled vehicles.The functions and its mechanism in regulating terrain clearance and adjusting attitudes were subsequently explained respectively,together with its semi-active control mechanism and characteristics In conclusion,our data in the study show that the new mechanical design of suspensions not only could realize adjusting terrain clearance and static vehicle pose,but also had an ideal stiffness that could realize a semi-active suspension function through adjusting suspension＇s stiffness.Therefore it can bequite suitable for off-road wheeled vehicles and military wheeled vehicles.

Effect of Lanthanum and Cerium on Expression of RSCU-PA-32k Gene in Saccharomyces Cerevisiae

Lanthanum chloride can promote expression efficiency of rscu-PA-32k gene in yeast. 2 and 5 mmol·L -1 LaCl 3 increase the activities of the expression product by 13% and 20% (from 14.6 to 16.5 and 17.5 U·ml -1). Cerium chloride can decrease the activity of expression product. 2 and 5 mmol·L -1 CeCl 3 decreases the activities of the expression product by 21% and 33% (from 14.6 to 11.5 and 9.8 U·ml -1).

Screening Psychrophilic Fungi of Cellulose Degradation and Characteristic of Enzyme Production

A fungus（WR-C1） decomposed cellulose was isolated from a hypothermal litter layer using Congo red medium as the preliminary screening culture medium and then using a filter as the secondary screening medium at low temperature. The experiment showed that the weight loss rate of filter paper on the 15 th days could reach 30.69%. A morphologic and ITS gene sequence analysis suggested that CF-C1 was Cladosporium. We mainly studied the effects of culture time, inoculation amount, initial p H and different sources of carbon, nitrogen and inorganic salt on the cellulase production of strain WR-C1. Under optimum cultural condition, the highest value of WR-C1 enzyme production and filter paper enzyme were 3.27 U · m L～（-1） and 0.51 U · m L～（-1）.

First Results of Characterization of 9Cr-3WVTiTaN Low Activation Ferritic/Martensitic Steel

Ferritic/martensitic steels with Cr of 9%-12% （in mass percent） are favourable candidates for fuel cladding tube and in-core components of supercritical water-cooled reactor. 9Cr-3WVTiTaN low activation ferritic/martensitic steel, designated as China Nuclear Steel- I （CNS- I ）, was patterned after T91 steel （modified 9Cr-lMo） for the reactor. The idea of low activation material and microalloy technology was introduced into the design of the steel. The hardening, tempering and transformation behaviour of CNS- I steel was investigated. The steel has advantages in tensile properties at elevated temperature relative to zircaloy that has been widely used as cladding material for conventional light water reactors. CNS- I steel exhibits tensile properties and impact toughness comparable to T91 steel which exhibits availability in the present fission reactors and fast breeder reactor but includes undesired radioactive elements such as molybdenum and niobium.

Effect of zirconium on inclusions and mechanical properties of China low activation martensitic steel

The effects of 0.01–0.11 wt.%Zr on the inclusions,microstructure,tensile properties,and impact toughness of the China low activation martensitic steel were investigated.Results showed that Zr exhibits good deoxidation and desulfurization abilities.The scanning electron microscope was used to examine the inclusions in the ingots.The main inclusions in the alloys were Zr–Ta–O,Zr–O,and Zr–O–S.However,some blocky Zr-rich inclusions appeared in Zr-2 and Zr-3 alloys.Typical martensitic structures were observed in the alloys,and average prior austenite grain sizes of 21.1,15.7,and 14.8µm were obtained for Zr-1,Zr-2,and Zr-3 steels,respectively.However,increasing Zr content of the steels deteriorated their mechanical property,owing to the blocky inclusions.The alloy with 0.01%Zr resulted in excellent mechanical properties due to the fine inclusions and the precipitation of Zr3V3C carbides.Values of 576 and 682 MPa were obtained for the yield strength and ultimate tensile strength of Zr-1 alloy,respectively.Furthermore,the ductile–brittle transition temperature of the alloy decreased to−85℃.

Metallurgical characterization of Ti-bearing 9Cr low activation martensitic steel

Two heats of low activation martensitic （LAM） steels with Ti and Ta （denominated as 9Cr-Ti and 9Cr-Ta）, respectively, developed as candidate structure materials for nuclear reactor were characterized. This paper was focused on the effect of titanium on the microstructures and mechanical properties of 9Cr LAM steel in as-received condition （normalized at 950 ℃ for 30 min with water quenching plus tempered at 780 ℃ for 90 min with air cooling）. Chemical analysis and microstructure observation were conducted on 9Cr-Ti and 9Cr-Ta with optical microscopy, X-ray diffraction analysis, scanning electron microscopy and transmission electron microscopy. Impact properties and tensile strengths were measured with Charpy impact experiments and tensile tests. The results indicated that 9Cr-Ti and 9Cr-Ta were fully martensitic steels in as-received condition. MX type and M23C6 type precipitates were observed distributing along boundaries of prior austenite grains and martensite laths in 9Cr-Ti.The addition of titanium accelerated the precipitation of TiC and TiN, and produced much finer grains in 9Cr-Ti than 9Cr-Ta at the same normalization temperature. Mechanical properties tests showed the ductile brittle transition temperatures of 9Cr- Ti and 9Cr-Ta were about -90℃ and -85℃, respectively. The ultimate tensile strengths at room temperature and 600℃,were 680 MPa and 365 MPa for 9Cr-Ti, and 660 MPa and 335 MPa for 9Cr-Ta, respectively. The favorite impact toughness and tensile properties of 9Cr-Ti could be attributed to the fine grains in as-received condition.

Effects of SO2 on the low temperature selective catalytic reduction of NO by NH3 over CeO2-V2O5-WO3/TiO2 catalysts

The CeO2-V2O5-WO3/TiO2 （CeO2-VWT） catalysts were prepared by one-step and two-step impregnation methods. The effects of different loading of CeO2 and different preparation methods on De-NOx activity of catalysts had been investigated. CeO2 helped to improve the De-NOx activity and sulfur resistance. The optimal loading of CeO2 was 3% with the De-NOx efficiency reached 89.9% at 140℃. The results showed that the De-NOx activity of 3% CeO2-VWT catalysts by one-step method was the same as two-step method basically and reached the level of industrial applications, the N2 selectivity of catalysts was more than 99.2% between 110℃ and 320℃. In addition, CeO2 promoted the oxidation of NO to NO2, which adsorbed on the Lewis acid site （V5＋-O） to form V5＋-NO3 and inspired the fast SCR reaction. Not only the thermal stability but also the De-NOx activity of catalysts decreased with excess CeO2 competed with V2O5. Characterizations of catalysts were carried out by XRF, BET, XRD, TG and FT-IR. BET showed that the specific surface area of catalysts decreased with the loading of CeO2 increased, the active components content and specific surface area of catalysts decreased slightly after entering SO2. Ammonium sulfate species were formed in poisoned catalyst which had been investigated by XRF, BET, TG and FT-IR. The largest loss rate of weight fraction was 0.024%.℃-1 at 380℃ 390℃, which was in accordance with the decomposition temperature of NH4HSO4 and （NH4）2SO4,

Morphology of Oxide Scale and Oxidation Kinetics of Low Carbon Steel

The oxidation kinetics and composition of oxide scales on low carbon steel （SPHC） were studied during i- sothermal oxidation. Thermogravimetric analyzer （TGA） was used to simulate isothermal oxidation process of SPHC for 240 min under air condition, and the temperature range was from 500 to 900 ℃. Scanning electron microscope （SEM） was used to observe cross-sectional scale morphology and analyze composition distribution of oxide scales. The morphology of oxide scale was classical three-layer structure. Fe2 03 developed as whiskers at the outermost lay- er, and interlayer was perforated-plate Fe3 04 while innermost layer was pyramidal FeO. From the oxidation curves, the oxidation mass gain per unit area with time was of parabolic relation and oxidation rate slowed down. On the ba- sis of experimental data, the isothermal oxidation kinetics model was derived and oxidation activation energy of SPHC steel was 127. 416 kJ/mol calculated from kinetics data.

Effect of alloying on the properties of 9Cr low activation martensitic steels

Two types of 9Cr low activation martensitic steels （named 9Cr-1 and 9Cr-2） were developed in University of Science and Technology Beijing. 9Cr-1 and 9Cr-2 were produced by vacuum induction melting method, and examinations of the microstruc- tures were carried out with X-ray diffraction analysis, optical microscopy, scanning electron microscopy and transmission electron microscopy. The ultimate tensile strength and yield tensile strength were evaluated with tensile tests. The impact properties were characterized with Charpy impact experiments. The results indi- cated that 9Cr-1 and 9Cr-2 on as-received condition （95 ~C/30 min/water quenching plus 780 ~C/90 min/air cooling） were flflly martensitic steels free of ^-ferrite. The ul- timate tensile strength of 9Cr-1 and 9Cr-2 were 695 MPa and 680 MPa, respectively. However, 9Cr-2 showed a fine grain size of 4.8 pm, and its value of ductile-brittle transition temperature （DBTT） was -90 ~C under as-received condition. The additions of vanadium, titanium and boron accelerated the formation of MX precipitates and resulted in fine grains and precipitates. The fine grains effectively reduced the value of DBTT from -60 ℃ to -90 ℃ with identical upper shelf energy （USE）. The decrease in silicon concentration of 9Cr-2 induced a slight reduction in ultimate tensile strength from 695 MPa to 680 MPa.

Proliferation of renal mesangial cells induced by very low density lipoprotein is mediated by p42/44 mitogen activated protein kinase

Background The plasma concentration of very low density lipoprotein （VLDL） is negatively correlated to renal function in glomerular diseases. Effects of VLDL on renal function have been partially attributed to the proliferation of mesangial cells. This study examined the potential role of the p42/44 mitogen activated protein kinase （MAPK） in mesangial cell proliferation induced by VLDL. Methods Mesangial cells were treated with VLDL at different concentrations or for different time. The cell cycle of the mesangial cells was analyzed by Xl-r assay and flow-cytometry; MAPK activity was also assayed. In some experiments, cells were treated with VLDL together with or without 0.1 pmol/L PD 98059. Results Ten to 500 μg/ml VLDL stimulated the proliferation of mesangial cells cultured in vitro in a concentration-dependent manner. The effect was associated with an increase in p42/44 MAPK activity. Increased proliferation of mesangial cells by VLDL was significantly attenuated by PD98059, a specific p42/44 MAPK inhibitor. Conclusion These results indicate that the p42/44 MAPK pathway is an important regulator of mesangial cell proliferation and of renal functions.

A new process to improve short-chain fatty acids and bio-methane generation from waste activated sludge

As an important intermediate product, short-chain fatty acids（SCFAs） can be generated after hydrolysis and acidification from waste activated sludge, and then can be transformed to methane during anaerobic digestion process. In order to obtain more SCFA and methane,most studies in literatures were centered on enhancing the hydrolysis of sludge anaerobic digestion which was proved as un-efficient. Though the alkaline pretreatment in our previous study increased both the hydrolysis and acidification processes, it had a vast chemical cost which was considered uneconomical. In this paper, a low energy consumption pretreatment method, i.e. enhanced the whole three stages of the anaerobic fermentation processes at the same time, was reported, by which hydrolysis and acidification were both enhanced, and the SCFA and methane generation can be significantly improved with a small quantity of chemical input. Firstly, the effect of different pretreated temperatures and pretreatment time on sludge hydrolyzation was compared. It was found that sludge pretreated at 100°C for 60 min can achieve the maximal hydrolyzation. Further, effects of different initial p Hs on acidification of the thermal pretreated sludge were investigated and the highest SCFA was observed at initial p H 9.0with fermentation time of 6 d, the production of which was 348.63 mg COD/g VSS（6.8 times higher than the blank test） and the acetic acid was dominant acid. Then, the mechanisms for this new pretreatment significantly improving SCFA production were discussed. Finally,the effect of this low energy consumption pretreatment on methane generation was investigated.

Novel thioxanthone host material with thermally activated delayed fluorescence for reduced efficiency roll-off of phosphorescent OLEDs

2,7-Di（9,9-dimethyl-9H-fluoren-l-yl）-9H-thioxanthen-9-one （DMBFTX） with thermally activated delayed fluorescence （TADF） was well designed and synthesized. The phosphorescent organic lightemitting device （PHOLED） based on this novel TADF host material displays a stable red phosphorescence region, a peak external quantum efficiency （EQE） value of 12.9% and a low EQE roll-off of 38.8%at a luminance of 10000 cd/m2, which is benefited from the reverse intersystem crossing （RISC） of TADF host and less populated triplet exitons. Notably, the red device based on the TADF host DMBFrX exhibits superior electroluminescence performance and reduced efficiency roll-offcompared with the one hosted by commercially available host 1,3-bis（9-carbazolyl）benzene （mCP）, illustrating the high potential of employing the TADF host material with small energy gap to reduce efficiency roll-off in PHOLED.

Deposition and characterization of Pd-Ti thin film by sublimation

Introduction Pd/Ti double-layer thin film as non-evaporable getter(NEG)was deposited by sublimation,and its activation temperature was as low as 100℃.The Pd film was deposited in situ after Ti deposition to ensure no oxidization on Ti film.Pumping speed test and characterization method The pumping speed of the coated pipe was measured by a pumping speed test system.The sticking factor was calculated by Molflow.The surface morphology was observed by a scanning electron microscope(SEM).The chemical composition of the film was measured by an energy-dispersive spectrum inbuilt with the SEM.The crystalline structure of the film was measured using grazing incidence X-ray diffraction.Conclusion It was found that the pumping performance of the Pd/Ti film still remained high after 15 times of activation.The maximum pumping speed after heating at 100℃for 24 h was 1.1 L/s cm^(2)and 0.49 L/s cm^(2)for H_(2)and CO,respectively.It can be concluded that the key to reducing the activation temperature of NEG materials is to enhance the oxidation resistance of the surface of NEG.