原位生产复合材料的特点及其进展

与常规复合材料成形方法相比，原位生产复合材料的工艺具有制造成本低、工艺简单、产品性能好等优点。这种方法已引起国外许多著名航空企业的注意，并在积极谋求发展。

原位生产芬顿试剂处理石油采出水

为了降低石油采出水毒性,提高其可生化性,对阴极电芬顿反应器通过电极即时产生芬顿试剂处理石油采出水进行了研究。通过实验研究分析各因素对电芬顿体系原位生产芬顿试剂效果的影响。结果表明,阴极电芬顿法处理石油采出水的体系中,在反应条件为Fe^(2+)投加量1 mmol·L^(-1),pH值3,电解质浓度5 g·L^(-1),曝气强度1 L·min-1时,阴阳两极原位生产芬顿试剂的效果最好,此时阳极自产Fe^(2+)的浓度为46.2 mg·L^(-1),阴极自产H_2O_2的浓度为6.02 mg·L^(-1),此时对石油采出水COD的去除率达到78.4%,油脂的去除率达到89.6%。

等离子弧焊接铝基复合材料钛的原位增强作用

本文提出的用等离子孤焊接铝基复合材料,将原位生产反应的原理应用于等离子弧焊接中,使得增强相的生成与 焊接过程同步完成。通过试验使用N2与填充金属中的Ti发生反应生成TiN的增强颗粒,证实了使用N2同时填充金属Ti的方法可以明显 提高和改善铝基复合材料焊接接头性能。

Pilot scale test of producing nickel concentrate from low-grade saprolitic laterite by direct reduction-magnetic separation

The enrichment of Ni from a low-grade saprolitic laterite ore,which has been pre-treated by high pressure grinding roller（HPGR） to be 74% passing 0.074 mm and contains 0.92% Ni,18.47% Fe,10.61% MgO and 42.27% SiO2,was conducted by using pelletizing,rotary kiln reduction and magnetic separation process on a semi industrial scale,and the effects of reduction duration,mass ratio of coal to pellets（C/P）,the types of magnetic separator,the sections of grinding-separation and the grinding fineness on the recovery of Ni and Fe were examined.It is shown that nickel concentrate containing 3.13 % Ni and 59.20 % Fe was achieved at recoveries of 84.36 % and 71.51% for Ni and Fe,respectively under the following conditions：reducing at （1120±40） ℃ for 120 min,C/P being 1.0,wet grinding of reduced pellets up to 70%-87% passing 0.074 mm and a magnetic field intensity of 238.8 kA/m during the first section of grinding-magnetic separation,and a grinding fineness of 84%-91% passing 0.045 mm and a magnetic intensity of 39.8 kA/m during the second section of grinding-magnetic separation.The enriched Ni containing concentrate has a low content of S and P,and can be used for further processing to produce high-grade ferronickel alloy.

In situ synthesis and characterization of Ca–Mg–Al hydrotalcite on ceramic membrane for biodiesel production

In situ surface synthesis of Ca–Mg–Al hydrotalcite(HT) on inorganic ceramic membrane(CM) was investigated with urea as precipitator. The effects of molar ratio of raw materials, crystallization time, and temperature on surface synthesis of HT were examined. The as-prepared HT/CM samples were characterized by XRD and SEM and an in situ growth mechanism of HT on CM was proposed. KF/HT/CM obtained by loading potassium fluoride(KF) on the HT layer by impregnation and calcination method was used as catalyst for transesterification between palm oil and methanol. The comparison of KF/HT/CM and pure KF/HT powder under identical reaction conditions shows that the production of fatty acid methyl ester is equivalent, which means that the use of inorganic catalytic membrane in the transesterification is a viable alternative.

Evaluation of Pomegranate Pomace Using in Situ and Gas Production Techniques

This study was carried out to determine nutritive value of pomegranate pomace using in situ and gas production techniques. In this study, two fistulated wethers （38 ± 1.5 kg） were used in situ method. The gas production was measured at 2, 4, 6, 8, 12, 16, 24, 36 and 48 h and ruminal DM （dry matter） and CP （crude protein） disappearances were measured at 0, 2, 4, 6, 8, 12, 16, 24, 36, 48, 72 and 96 h. DM degradabilities of treated pomegranate pomace at 8 h to 96 h were larger than untreated pomegranate pomacewhich showed significant differences （p 〈 0.05）. CP degradabilities of treated pomegranate pomace at 96 h was 62.38% that showed significant differences （p 〈 0.05）. The metabolizable proteins of treated and untreated pomegranate pomace were 73 and 64.27 g/kg respectively that showed significant differences （p 〈 0.05）. The gas productions of treated and untreated pomegranate pomace at 48 h were 79.91 and 128.75 mL/g DM respectively that showed significant differences （p 〈 0.05）. It was concluded that the pomegranate pomace can be used largely as ruminant feeds.

Design of an Expert Control System for Biogas Fermentation Process

Controlling the biogas fermentation process is the key for maintaining stable operation of biogas system and increasing gas yield. Aiming at features of biogas fermentation process and difficulties of control, a practical control scheme is proposed combining the abundant experience of biogas experts. And it discussed the structural design and hardware configuration of the expert control system, established the database and role base, and designed the control strategy of production system inference. The design scheme with ZigBee and PDA technology as core is employed so as to solve problems of environmental factor detection and data transfer management. The test result shows that the deviation of temperature is controlled within ± 0.9℃, the deviation of pH is controlled within ±0.3, the deviation of oxidation-reduction potential is controlled within ±30mV, the deviation of gas production is controlled within ± 9mL and that of methane concentration is controlled within ±4.5%. This system is easily expandable and applicable to biogas engineering at various scales.

Measurement of Viscosity Alteration for Emulsion and Numerical Simulation on Bitumen Production by SAGD Considering In-situ Emulsification

A thermal steam stimulation process, such as steam-assisted gravity drainage （SAGD）, induces water-in-oil emulsion of heavy oil or bitumen throughout the production. The present study investigated the effects of in-situ emulsification in the oil sands reservoir for SAGD process. The viscosities of water-in-oil emulsions produced were measured with respect to water-oil ratio （W/O）, shear rates, pressures and temperatures. The results therefore were employed to develop the numerical model of viscosity alteration. Numerical simulations of the SAGD bitumen production considering viscosity alteration were also carried out to investigate distribution characteristics of emulsion, water, and bitumen at steam chamber boundary and effects of in-situ emulsification on bitumen production behavior. With a model named SAGD-Emulsion Model, it was found that the net recovery factor of bitumen for this model is 5 to 10% higher than that of conventional SAGD simulation. Ultimately, it was found that the recovery factor of bitumen increased with W/O of emulsion generated in the reservoir since higher water content would invariably allow bitumen to flow at higher relative permeability, while the increase in viscosity merely delayed bitumen production.

In situ electrochemically converting Fe_2O_3-Ni(OH)_2 to NiFe_2O_4-NiOOH:a highly efficient electrocatalyst towards water oxidation

To develop low-cost, earth-abundant NiFe- based materials as highly efficient oxygen evolution reaction （OER） electrocatalysts and to probe new catalytic species are still great challenges to now. Here, an in situ forma- tion of OER active NiFe2O4-NiOOH nanosheet arrays is demonstrated as a highly efficient OER electrocatalyst by the anodization of Fe203 domains anchored on Ni（OH）2 nanosheet arrays. The as-converted product can deliver the current density of 30 mA cm-2 with a small overpotential of 240 mV, and only requires an overpotential of 410 mV to achieve an amazing huge current density of 3000 mA cm-2. In situ potential-dependent Raman spectroscopy reveals that Ni（OH）2 in the composite is easier to be oxidized to NiOOH than pure Ni（OH）2, and the newly formed NiOOH reacts with the nearby Fe2O3 to produce hybrid NiFe2O4-NiOOH. It is found that the cooperative effect of the in situ formed NiFe2O4 and NiOOH as well as the hydrophilic and aero- phobic electrode surface make main contribution to the outstanding OER activity of the catalyst. This work will bring new perspectives to the recognition of the origin of NiFe composite materials for OER and provide a mild method to synthesize amorphous spinel materials at room temperature.

In situ synthesis of graphitic-C3N4 nanosheet hybridized N-doped TiO2 nanofibers for efficient photocatalytic H2 production and degradation

Graphitic carbon nitride nanosheets （g-C3N4 NSs） hybridized nitrogen doped titanium dioxide （N-TiO2） nanofibers （GCN/NT NFs） have been synthesized in situ via a simple electrospinning process combined with a modified heat-etching method. The prepared GCN/NT NFs were characterized by a variety of methods and their photocatalytic activities were evaluated by hydrogen （H2） production from water splitting and degradation of rhodamine B in aqueous solution. It was found that the GCN/NT NFs have a mesoporous structure, composed of g-C3N4 NSs and N-doped TiO2 crystallites. The g-C3N4 NSs synthesized after heat-etching were found to be embedded in, and covered, the hybrid NFs to form stable interfaces. The partial decomposition of g-C3N4 releases its nitrogen content which eventually gets doped into the nearby TiO2 skeleton. The GCN/NT NFs give a high photocatalytic H2 production rate of 8,931.3 μmol·h^-1·g^-1 in aqueous methanol solution under simulated solar light. Such a highly efficient photocatalytic perfor- mance can be ascribed to the combined effects of g-C3N4 NSs and N-doped TiO2 with enhanced light absorption intensity and improved electron transport ability. Also, the large surface area of the mesoporous NFs minimizes light reflection on the surface and provides more surface-active sites. This work highlights the potential of quasi-one dimensional hybrid materials in the field of solar energy conversion.