新型橡胶防老剂6PPD合成催化剂

依托对氨基二苯胺和甲基异丁基甲酮一步法合成6PPD的合成工艺,研制出F04型缩合烷基化催化剂。强度试验表明,制备的催化剂使用后强度下降率低、无粉化和使用寿命长。在催化剂作用下,6PPD收率较高,产品合格0过渡期,甲基异丁基甲酮回收率大幅提高。

A new double reduction method for slope stability analysis

The core of strength reduction method(SRM) involves finding a critical strength curve that happens to make the slope globally fail and a definition of factor of safety(FOS). A new double reduction method, including a detailed calculation procedure and a definition of FOS for slope stability was developed based on the understanding of SRM. When constructing the new definition of FOS, efforts were made to make sure that it has concise physical meanings and fully reflects the shear strength of the slope. Two examples, slopes A and B with the slope angles of 63° and 34° respectively, were given to verify the method presented. It is found that, for these two slopes, the FOSs from original strength reduction method are respectively 1.5% and 38% higher than those from double reduction method. It is also found that the double reduction method predicts a deeper potential slide line and a larger slide mass. These results show that on one hand, the double reduction method is comparative to the traditional methods and is reasonable, and on the other hand, the original strength reduction method may overestimate the safety of a slope. The method presented is advised to be considered as an additional option in the practical slope stability evaluations although more useful experience is required.

The Influence of El Ni?o on MJO over the Equatorial Pacific

In this paper, the influence of E1 Nino event on the Madden-Julian Oscillation （MJO） over the equatorial Pacific is stud- ied by using reanalysis data and relevant numerical simulation results. It is clearly shown that E1 Nino can reduce the intensity of MJO. The kinetic energy of MJO over the equatorial Pacific is stronger before the occurrence of the E1 Nino event, but it is reduced rapidly after E1 v event outbreak, and the weakened MJO even can continue to the next summer. The convection over the cen- tral-western Pacific is weakened in E1 Nino winter. The positive anomalous OLR over the central-western Pacific has opposite variation in E1 Nino winter comparing to the non-ENSO cases. The vertical structure of MJO also affected by E1 Nino event, so the opposite direction features of the geopotential height and the zonal wind in upper and lower level troposphere for the MJO are not remarkable in the E1 Nino winter and tend to be barotropic features. El Nino event also has an influence on the eastward propa- gation of the MJO too. During E1 Nino winter, the eastward propagation of the MJO is not so regular and unanimous and there exists some eastward propagation, which is faster than that in non-ENSO case. Dynamic analyses suggest that positive SSTA （El Nino case） affects the atmospheric thickness over the equatorial Pacific and then the excited atmospheric wave-CISK mode is weakened, so that the intensity of MJO is reduced; the combining of the barotropic unstable mode in the atmosphere excited by external forcing （SSTA） and the original MJO may be an important reason for the MJO vertical structure tending to be barotropic during the E1 Nino.

Microstructure and mechanical properties of new metastable β type titanium alloy

A new metastable β type titanium alloy called TB-13 with the combination of excellent strength and ductility was developed successfully.In order to develop a perspective on this new alloy,the influence of several commonly used heat treatments on the microstructure and properties was studied.In solution-treated and quenched samples,a low-temperature aging at 480°C results in the precipitation of finerαphase.The precipitation of coarserαphase plate at higher aging temperature(560°C)leads to the increase of tensile ductility but reduction of strength.During low-temperature aging at 300°C,quite homogeneous distribution of fine isothermalωphase particles was found.The isothermalωphase provides nucleation sites forαphase during two-step aging process and makesαphase extremely fine and disperse uniformly in β matrix.Thus,TB-13 alloy is strengthened and its mechanical properties are improved.

Changes in Climate Factors and Extreme Climate Events in South China during 1961-2010

Daily climate data at 110 stations during 1961-2010 were selected to examine the changing characteristics of climate factors and extreme climate events in South China. The annual mean surface air temperature has increased significantly by 0.16℃ per decade, most notably in the Pearl River Delta and in winter. The increase rate of the annual extreme minimum temperature (0.48℃ per decade) is over twice that of the annual extreme maximum temperature (0.20℃ per decade), and the increase of the mean temperature is mainly the result of the increase of the extreme minimum temperature. The increase rate of high-temperature days (1.1 d per decade) is close to the decrease rate of low-temperature days (-1.3 d per decade). The rainfall has not shown any significant trend, but the number of rainy days has decreased and the rain intensity has increased. The regional mean sunshine duration has a significant decreasing trend of -40.9 h per decade, and the number of hazy days has a significant increasing trend of 6.3 d per decade. The decrease of sunshine duration is mainly caused by the increase of total cloud, not by the increase of hazy days in South China. Both the regional mean pan evaporation and mean wind speed have significant decreasing trends of -65.9 mm per decade and -0.11 m s-1 per decade, respectively. The decrease of both sunshine duration and mean wind speed plays an important role in the decrease of pan evaporation. The number of landing tropical cyclones has an insignificant decreasing trend of -0.6 per decade, but their intensities show a weak increasing trend. The formation location of tropical cyclones landing in South China has converged towards 10-19°N, and the landing position has shown a northward trend. The date of the first landfall tropical cyclone postpones 1.8 d per decade, and the date of the last landfall advances 3.6 d per decade, resulting in reduction of the typhoon season by 5.4 d per decade.

Growth of Scotch Pine （Pinus sylvestris L.） Plantation in Northern Mongolia

The growth of Scotch pine in Northem Mongolian plantations was studied to determine variation in heights, diameters at breast height （DBH）, and main and annual volume increment of stem volumes in relation to plantation age. The study was conducted in the Tujyin Nars region, where six plantations ranging from 9 to 25 years old were selected for the assessment. Results indicate that the growth of Scotch pine on the plantations did not vary by site, and that more intensive annual increment in height was observed on Scotch pine plantations between the ages of 8 to 15 years. The amount of annual height increment and radial growth improves regularly up to 9 to 11 years of age and then the intensity of annual increment declines due to competition for light and nutrients. Additionally, there was a reduction in the number of trees per ha. Results suggest that it is necessary to implement forestry thinning which aimed at improving growth of Scotch pine on the plantations because intensity of annual increment in height and diameter reduces regularly due to restriction of growing condition.

Tape casting of borosilicate glass/Al_2O_3 composites for LTCC substrate with various relative molecular masses of PVB

The dispersion, stabilization and rheological properties of the slurry with various relative molecular masses of PVB were studied. The sintering properties, microstructure and dielectric properties of borosilicate glass/Al203 composites were also investigated. The intensities of the typical vibrating bands decrease with the decrease of the relative molecular mass of PVB, which demonstrates that the content of butyral groups in PVB binders decreases correspondingly, leading to a rapid decrease in the viscosity of the mixed slurry. The solid content of samples increases with the decrease of the relative molecular mass of PVB, and this further leads to the increase of tape thickness, bulk density and dried-shrinkage coefficient of tapes. The bulk density, relative density, three-point strength and dielectric constant of sintered samples increase with the increase of the solid content, and the shrinkage and dielectric loss decrease. By contrast, samples for PVB-5s exhibit better properties of a bulk density of 3.10 g/cm3, a relative density of 98.1%, a three-point strength of 208 MPa, aεt value of 8.01, a tanδ value of 7.6× 10^-4 at 10 MHz and a well matching with Ag electrodes.

Simultaneous Measurements of Rainfall Intensity, Low Energy Neutrons and Gamma Radiation in Sao Jose Dos Campos, SP, Brazil

The article aims to study the possible correlation between the presence and intensity of rainfall X- and T-radiation and low energy neutrons at one specific location in S[io Jos6 dos Campos, SP, Brazil. Monitoring of these parameters was carried out from end February to half of June 2013 just in Physics Department of ITA （Technological Institute of Aeronautics）. By correlating the data of measurements of intensity of X and ）,-radiations with the rainfall it has been found that this meteorological parameter had a significant influence on the background of these radiation profile. A possible reason for this fact is associated with the presence of radon gas in the environment that is dragged to the surface during the occurrences of local rainfall. In relation neutrons, it was possible to note that the rainfall has small influence on this parameter measures.

Global distributions of OH and O_2 (1.27 μm) nightglow emissions observed by TIMED satellite

In order to investigate the global distributions of temporal variations of OH and O2 nightglow emissions,we statistically analyzed their variations with altitude,local time,and season,using the OH and O2 airglow emission rate data observed by the TIMED satellite between 2002 and 2009.The results indicated that the OH nightglow emission was stronger than dayglow emission and the O2 nightglow emission was weaker than dayglow emission.In the tropics,the OH nightglow intensity reached its maximum near midnight;at higher latitudes,the OH nightglow intensities after sunset and before sunrise were much strong.At the equinoxes,the O2 nightglow intensity in the tropics decreased with local time;at the solstices,the local time-latitude distribution of the O2 nightglow intensity had a valley(with weak emission).As for the altitude-latitude distributions of nightglow emission rates,the distribution for OH nightglow at the equinoxes had one peak(with strong emission)at the equator,with a peak height around 85 km;the peak for the March equinox was stronger than that for the September equinox.The distribution for O2 nightglow at the equinoxes had three peaks,lying at 30°in the spring and autumn hemispheres and at the equator,and the peak height at the equator was the lowest.The distributions for both OH and O2 nightglow emissions at the solstices had three peaks.Both nightglow intensities in the tropics had obvious annual and semi-annual variations,the peaks and valleys for semi-annual variations appeared near the equinoxes and solstices,respectively,and the peak at the March equinox was larger than that at the September equinox.The distributions of both OH and O2 nightglow intensities showed a hemispheric asymmetry.