提高球墨铸铁件表面球化质量的工艺改进

对某厂球墨铸铁铸件生产过程中出现的表面球化不良缺陷进行分析,通过改进铸造工艺,极大提高了球墨铸铁的表面球化质量,从而提高了其力学性能。

球墨铸铁件表面球化衰退的研究

研究了呋喃树脂砂对球墨铸铁件表面球化衰退的影响,并对球墨铸铁件表面产生球化衰退的机理进行了分析。结果表明,球铁件表面球化衰退层具有片状石墨及蠕虫状石墨的特征,表面球化衰退主要是由于苯磺酸受热气化进入熔融金属表面消耗表面层内残留的有效Mg引起的,氧也可能进入熔融金属表面消耗表面层内残留的有效Mg引起表面球化衰退。球铁件表面球化衰退片状石墨区消耗的有效Mg可能以MgS和MgO的形式存在。表面球化衰退层厚度随着浇注温度的升高、苯磺酸固化剂含量的增加及再生砂含量的增加等而增加。

球墨铸铁件表面球化衰退的微观组织特征及防止措施

研究了苯磺酸硬化呋喃树脂砂球铁件表面球化衰退的微观组织特征及防止措施,并对球墨铸铁件表面球化衰退层微观组织中的第二相粒子结构进行了分析。结果表明,表面球化衰退层微观组织中的第二相粒子是Mg S或(Mg,Mn)x Sy粒子,具有FCC结构及近球形八面体形貌特征。控制铸造工艺因素、使用低硫苯磺酸固化剂、防渗硫涂料、昆腾树脂、派普树脂以及碱酚醛树脂等,均可使表面球化衰退减轻,并且昆腾树脂、派普树脂及碱酚醛树脂用于防止球墨铸铁件表面球化衰退效果最佳。

灰口铸铁件表面球化涂料的研究

对灰口铸铁材质的模具采用表面球化复合工艺，可以提高综合性能和使用寿命。采用正交试验方法，确定了球化涂料配比，并对铁水预处理与否两种浇注工艺进行试验。通过金相检验，结果证明在灰口铸铁件铸型表面涂刷球化涂料，可使灰口铸铁件表面获得球化，达到预期的效果。

用稀土基涂料实现灰铁件表面层石墨球化工艺的研究

在铸型表面涂刷含有１＃稀土硅铁和７５硅铁的合金涂料，浇注普通灰铸铁成分的铁水，得到了表面层为球状的石墨，过渡层为蠕虫状石墨，本体为片状石墨的复合铸铁材料。表面层石墨球化的厚度可达到２．５ｍｍ以上。

用稀土镁基涂料实现灰铸铁件表面层石墨球化工艺的研究

研究利用含有稀土镁和镁混合球化剂的涂料，成功地实现了灰铸铁件表面层石墨的球化。其组织形态由表及里依次为球化区、过渡区和灰铸铁本体。并且研究了在原铁液不同碳当量和含硫量的情况下，灰铸铁件表面层石墨形态和组织的变化。

Synthesis of CuAPTPP-TDI-TiO2 Conjugated Microspheres and its Photocatalytic Activity

The metal complex 5-（4-aminophenyl）-10,15,20-triphenylporphyrin copper （CuAPTPP） was covalently linked on the surface of TiO2 microspheres by using toluene disocyanate （TDI） as a bridging bond unit. The hydroxyl group （-OH） of TiO2 microspheres surface and the amino group （-NH2） of CuAPTPP reacted respectively with the active -NCO groups of TDI to form a surface conjugated microsphere CuAPTPP-TDI-TiO2 that was confirmed by FT-IR spectra. The CuAPTPP-TDI-TiO2 microspheres were characterized with UV-visible, elemental analysis, XRD, SEM, and UV-Vis diffuse reflectance spectra. The effect of amounts of linked TDI on the performance of photocatalytic microspheres was discussed, and the optimal molar ratio of TDI：TiO2 was established. The photocatalytic activity of CuAPTPP- TDI-TiO2 was evaluated using the photocatalytic degradation of methylene blue （MB） under visible-light irradiation. The results showed that, TDI, as a bond unit, was used to form a steady chemical brigdging bond linking CuAPTPP and the surface of TiO2 microspheres, and the prepared catalyst exhibited higher photocatalytic activity under visible-light irradiation for MB degradation. The degradation rate of 20 mg/L MB could reach 98.7% under Xe- lamp （150 W） irradiation in 120 rain. The degradation of MB followed the first-order reaction model under visible light irradiation, and the rate constant of 5.1× 10^-2 min-1 and the half- life of 11.3 min were achieved. And the new photocatalyst can be recycled for 4 times, remaining 90.0% MB degradation rate.

Effect of cooling rates on as-cast microstructures of Mg-9Al-xSi(x=1,3) alloys

The effects of cooling rates corresponding to different diameters of the steel mould and laser surface melting(LSM)on the as-cast microstructures of Mg-9Al-xSi(x=1,3)(mass fraction,%)alloys were investigated by XRD and OM.The results show that obvious refinement of the alloy microstructure is obtained with increasing cooling rate by conventional ingot metallurgy.However, no evident modified morphologies of both dendritic primary Mg2Si and Chinese script eutectic Mg2Si in the Mg-Al-Si alloy occurs. Surprisingly,the morphologies of Mg2Si phases within the laser-melted Mg-Al-Si alloy transform drastically from both coarse Chinese script shape for the eutectic Mg2Si and dendrite for the primary Mg2Si to fine spherical particles with an average size of about 3μm due to the rapid cooling of the melted layer,and the Mg2Si particulates distribute more uniformly in theα-Mg matrix.

Novel synthesis of nickel oxide microsphere with high surface area and its catalytic application for carbon dioxide reforming of methane

Nickel oxide(NiO)microsphere with a large surface area was novelly synthesized through nickel bicarbonate(Ni(HCO3)2)precursor.The obtained nickel oxide(NiO)microsphere was characterized by X-ray pattern diffraction,scanning electron microscopy,CO2 temperature-programmed desorption,H2 temperature-programmed reduction,N2 adsorption/desorption and laser scattering particle size distribution analyzer.It was found that nickel oxide(NiO)synthesized by the thermal decomposition of Ni(HCO3)2through area hydrolysis,presented very nice microsphere with high surface area.The catalytic properties of obtained nickel oxide(NiO)microsphere were studied in the reaction of carbon dioxide reforming of methane where 91.3% conversion of CH4 with 93% conversion of CO2 was observed.Besides,the catalyst maintained high stability over 200 h on the stream.

Global Water Vapor Content Decreases from 2003 to 2012： An Analysis Based on MODIS Data

Water vapor in the earth′s upper atmosphere plays a crucial role in the radiative balance, hydrological process, and climate change. Based on the latest moderate-resolution imaging spectroradiometer(MODIS) data, this study probes the spatio-temporal variations of global water vapor content in the past decade. It is found that overall the global water vapor content declined from 2003 to 2012(slope b = –0.0149, R = 0.893, P = 0.0005). The decreasing trend over the ocean surface(b = –0.0170, R = 0.908, P = 0.0003) is more explicit than that over terrestrial surface(b = –0.0100, R = 0.782, P = 0.0070), more significant over the Northern Hemisphere(b = –0.0175, R = 0.923, P = 0.0001) than that over the Southern Hemisphere(b = –0.0123, R = 0.826, P = 0.0030). In addition, the analytical results indicate that water vapor content are decreasing obviously between latitude of 36°N and 36°S(b = 0.0224, R = 0.892, P = 0.0005), especially between latitude of 0°N and 36°N(b = 0.0263, R = 0.931, P = 0.0001), while the water vapor concentrations are increasing slightly in the Arctic regions(b = 0.0028, R = 0.612, P = 0.0590). The decreasing and spatial variation of water vapor content regulates the effects of carbon dioxide which is the main reason of the trend in global surface temperatures becoming nearly flat since the late 1990 s. The spatio-temporal variations of water vapor content also affect the growth and spatial distribution of global vegetation which also regulates the global surface temperature change, and the climate change is mainly caused by the earth's orbit position in the solar and galaxy system. A big data model based on gravitational-magmatic change with the solar or the galactic system is proposed to be built for analyzing how the earth's orbit position in the solar and galaxy system affects spatio-temporal variations of global water vapor content, vegetation and temperature at large spatio-temporal scale. This comprehensive examination of water vapor changes promises a holistic understanding of the global climate change and potential underlying mechanisms.

Robust superhydrophobicity of hierarchical ZnO hollow microspheres fabricated by two-step self-assembly

Superhydrophobic and superhydrophilic surfaces have been extensively inves- tigated due to their importance for industrial applications. It has been reported, however, that superhydrophobic surfaces are very sensitive to heat, ultraviolet （UV） light, and electric potential, which interfere with their long-term durability. In this study, we introduce a novel approach to achieve robust superhydrophobic thin films by designing architecture-defined complex nanostructures. A family of ZnO hollow microspheres with controlled constituent architectures in the morphologies of 1D nanowire networks, 2D nanosheet stacks, and 3D mesoporous nanoball blocks, respectively, was synthesized via a two-step self-assembly approach, where the oligomers or the constituent nanostructures with specially designed structures are first formed from surfactant templates, and then further assembled into complex morphologies by the addition of a second co-surfactant. The thin films composed of two-step synthesized ZnO hollow microspheres with different architectures presented superhydrophobicities with contact angles of 150°-155°, superior to the contact angle of 103° for one-step synthesized ZnO hollow microspheres with smooth and solid surfaces. Moreover, the robust superhydrophobicity was further improved by perfluorinated silane surface modification. The perfluorinated silane treated ZnO hollow microsphere thin films maintained excellent hydrophobicity even after 75 h of UV irradiation. The realization of environmentally durable promising solution for their long-term irradiations. superhydrophobic surfaces provides a service under UV or strong solar light

Tremendous change of the earth surface system and tectonic setting of salt-lake formation in Yuncheng Basin since 7.1 Ma

The Yuncheng salt lake has formed under the setting of stepped subsidence of fault-blocks from the north to the south in Yuncheng Basin. In the phase of red clay accumulation during 7.1–3.6 Ma, the size of palaeo-lake was larger than the present salt lake, and palaeo-monsoon had formed. At 3.6 Ma, the northern basement in the basin raised abruptly due to the radiative effect of Qinghai-Tibet Plateau uplifting, and palaeo-lake was contracting southwards. At ca. 2.6 Ma ancient river flowed into the northern part of the basin. During ca. 2.0–1.9 Ma aerolian effect strengthened and loess started to accumulate on the most part of the basin. Since ca. 1.8–1.0 Ma the subsidence of the lake fault-block has been speeding up abruptly. As under the natural hydrogradient the salt lake received enough groundwater supply, and the rate of loess accumulation in the lake area was lower than that of subsidence of the lake fault-block, the lake could be preserved and becomes the only modern lake on Chinese Loess Plateau. Four large strengthening change records of the monsoon were found in the lake sequence of 5.8–1.9 Ma B.P.

Characteristics of dry-wet abrupt alternation events in the middle and lower reaches of the Yangtze River Basin and the relationship with ENSO

During recent decades, more frequent flood-drought alternations have been seen in China as a result of global climate change and intensive human activities, which have sig- nificant implications on water and food security. To better identify the characteristics of flood-drought alternations, we proposed a modified dry-wet abrupt alternation index （DWAAI） and applied the new method in the middle and lower reaches of the Yangtze River Basin （YRB-ML） to analyze the long-term spatio-temporal characteristics of dry-wet abrupt alterna- tion （DWAA） events based on the daily precipitation observations at 75 rainfall stations in summer from 1960 to 2015. We found that the DWAA events have been spreading in the study area with higher frequency and intensity since 1960. In particular, the DWAA events mainly occurred in May and June in the northwest of the YRB-ML, including Hanjiang River Basin, the middle reaches of the YRB, north of Dongting Lake and northwest of Poyang Lake. In addition, we also analyzed the impact of El Nifio Southern Oscillation （ENSO） on DWAA events in the YRB-ML. The results showed that around 41.04% of DWAA events occurred during the declining stages of La Nifia or within the subsequent 8 months after La Nina, which implies that La Nina events could be predictive signals of DWAA events. Besides, significant negative correlations have been found between the modified DWAAI values of all the rainfall stations and the sea surface temperature anomalies in the Nino3.4 region within the 6 months prior to the DWAA events, particularly for the Poyang Lake watershed and the middle reaches of the YRB. This study has significant implications on the flood and drought control and water resources management in the YRB-ML under the challenge of future climate change.