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The electrical response of ferroelectric domain walls is often influenced by their geometry underneath the sample surface. Tomographic imaging in these material systems has therefore become increasingly important for its ability to correlate the surface‐level functional response with subsurface domain microstructure. In this context, AFM‐based tomography emerges as a compelling choice because of its simplicity, high resolution, and robust contrast mechanism. However, to date, the technique has been implemented in a limited number of ferroelectric materials, typically to depths of a few hundred nanometers or on relatively soft materials, resulting in an unclear understanding of its capabilities and limitations. In this work, AFM tomography is carried out in YbMnO3, mapping its complex domain microstructure up to a depth of ≈1.8 µm along with its current pathways. A model is presented, describing the impact of interconnected domain walls within the network, which act as current dividers and codetermine how currents distribute. Finally, challenges such as tip‐blunting and subsurface damage are identified through TEM studies, and strategies to address them are also put forward. This study highlights the potential of AFM tomography and can spur interest within the ferroics community for its use in the investigation of similar material systems. Complex networks of conducting domain wall interfaces exist hidden underneath the surface of ferroelectric hexagonal manganites. It reveals the morphology and conductive properties directly by 3D tomographic atomic force microscopy. It correlates the measured surface level conductance with subsurface domain wall structure, and discuss the existence (and removal) of a tip‐induced damage layer.

The hydrogenation experiments of the middle distillate (MD) of Chinese Huadian shale oil were carried out in a bench-scale trickle-bed reactor using a commercial catalyst Ni-Mo-W/[Al.sub.2][O.sub.3] under various operating conditions. Three kinds of lumping kinetic models were developed in order to compare their capabilities to predict the concentrations of sulfur and nitrogen in hydrotreated oil samples. The results showed that three-lump and four-lump models can be reasonably used to describe hydrodesulfurization (HDS) and hydrodenitrogenation (HDN), respectively. The predictions made using lumping models agreed well with experimental data. The discrepancies between experimental and predicted data are smaller than 5%. The three-lump model for HDS and the four-lump model for HDN were also utilized for predicting reactive features and obtaining suitable operating conditions for HDS and HDN of the middle distillate (MD) of Huadian shale oil. The species and distribution of sulfur and nitrogen compounds were also investigated.

Low international oil price, advance in renewable energy technology, development of energy storage technology and strict environ­mental regulations have presented encumbrance and opportunity for the current oil shale project development. Oil shale industry is at critical stage and facing challenges from competitive conventional energy, clean renew­able energy and more strict environmental regulations. Through an innovative design of the oil shale pyrolysis process model by utilizing a developed new advanced technology, the oil shale project could improve its resilience and sustainability with excellent social and economic performance. This paper investigated the shale oil production process in terms of technology selection, utilization of resource, energy efficiency, oil yield, and mining to improve the resilience of oil shale project economic performance facing lower oil price. Innovative design options for the oil shale production process model were discussed from the following aspects: 1) itemized cost analysis and comparison of shale oil production technologies; 2) develop­ment of a new oil shale pyrolysis process model with combination of the exist­ing vertical retort process (VRP) and horizontal rotary-kiln retort process (HRRP) technologies to improve the oil shale process economic gain; 3) discussion of innovative design options to improve the economic performance of the process by utilizing the current new advanced energy storage technology. Investigation of the applicability of the energy storage system (ESS) to the oil shale project was carried out with a sensitivity analysis of its cost-revenue.

Low international oil price, advance in renewable energy technology, development of energy storage technology and strict environmental regulations have presented encumbrance and opportunity for the current oil shale project development. Oil shale industry is at critical stage and facing challenges from competitive conventional energy, clean renewable energy and more strict environmental regulations. Through an innovative design of the oil shale pyrolysis process model by utilizing a developed new advanced technology, the oil shale project could improve its resilience and sustainability with excellent social and economic performance.

The hydrogenation experiments of the middle distillate (MD) of Chinese Huadian shale oil were carried out in a bench-scale trickle-bed reactor using a commercial catalyst Ni-Mo-W/Al2O3 under various operating conditions. Three kinds of lumping kinetic models were developed in order to compare their capabilities to predict the concentrations of sulfur and nitrogen in hydrotreated oil samples. The results showed that three-lump and four-lump models can be reasonably used to describe hydrodesulfurization (HDS) and hydrodenitrogenation (HDN), respectively. The predictions made using lumping models agreed well with experimental data. The discrepancies between experimental and predicted data are smaller than 5%. The three-lump model for HDS and the four-lump model for HDN were also utilized for predicting reactive features and obtaining suitable operating conditions for HDS and HDN of the middle distillate (MD) of Huadian shale oil. The species and distribution of sulfur and nitrogen compounds were also investi­gated.

Factors influencing the pyrolysis of Yaojie oil shale, such as pyro­lysis temperature, residence time, heating rate and particle size, were investigated. Pyrolysate yield was influenced most of all by pyrolysis tem­perature and residence time, followed by heating rate and particle size. Pyro­lysis temperature and residence time had a great effect on the composi­tion of retorting gas, while the influence of heating rate and particle size was less significant, corresponding to a change of oil yield of only 0.6% and 0.5%, respectively. The oil and gas yields were less affected when the oil shale sample was pressed into balls. The oil shale ball with a bentonite content of 6% was optimal.

In this paper, the basic principle and features of the process carried out in a Sanjiang(SJ)-type rectangular pilot-scale retort have been described. The suitability of the SJ retort for processing oil shale from Yaojie (YJ) county, Gansu province, China was investigated to find optimal condi­tions for an effective recovery of shale oil. The pyrolysis of lump YJ oil shale was carried out in the SJ pilot retort with a daily processing capacity of 24 tons of oil shale. It was found that the heat value of the pyrolysis gas pro­duced from YJ oil shale was sufficient to provide the heat needed for retort­ing. The pyrolysis temperature fluctuated between 550 and 700 oC, with an average of 610 oC. The results of the study demonstrate that the shale oil yield from YJ oil shale is high, accounting for about 85% vs. Fisher assay. The shale oil consists mainly of diesel and heavy fractions, and the spent shale is of high calorific value.

Methods of acid-base separation and extrography were used to decompose shale oil of Longkou oil shale (LSO), Shandong province, and coal tar of Shenmu coal (SCT), Shanxi province, both China, into acid, base and neutral fractions. The molecular structure and mass distribution of the oxygen compounds present in LSO and SCT were investigated using gas chromatography-mass spectrometry (GC-MS) and negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). The results of GC-MS showed that oxygen compounds in the acid fractions of LSO and SCT were phenols, indanols, naphthols, phenyl­phenols, fluorenols and phenanthrenols, and their derivatives, while oxygen compounds in neutral fractions 4 and 5 were aliphatic ketones, esters and minor aromatic ketones. The results of ESI FT-ICR MS demonstrated that in LSO, O1, O2, O3, N1O1, N1O2, N1 and N2 compounds were determined with O1 and O2 compounds as the most abundant. SCT contained O1, O2, O3, O4, O5 and O6 compounds, while O2 and O3 compounds dominated.

Factors influencing the pyrolysis of Yaojie oil shale, such as pyrolysis temperature, residence time, heating rate and particle size, were investigated. Pyrolysate yield was influenced most of all by pyrolysis temperature and residence time, followed by heating rate and particle size. Pyrolysis temperature and residence time had a great effect on the composition of retorting gas, while the influence of heating rate and particle size was less significant, corresponding to a change of oil yield of only 0.6% and 0.5%, respectively. The oil and gas yields were less affected when the oil shale sample was pressed into balls. The oil shale ball with a bentonite content of 6% was optimal.

Methods of acid-base separation and extrography were used to decompose shale oil of Longkou oil shale (LSO), Shandong province, and coal tar of Shenmu coal (SCT), Shanxi province, both China, into acid, base and neutral fractions. The molecular structure and mass distribution of the oxygen compounds present in LSO and SCT were investigated using gas chromatography-mass spectrometry (GC-MS) and negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). The results of GC-MS showed that oxygen compounds in the acid fractions of LSO and SCT were phenols, indanols, naphthols, phenylphenols, fluorenols and phenanthrenols, and their derivatives, while oxygen compounds in neutral fractions 4 and 5 were aliphatic ketones, esters and minor aromatic ketones. The results of ESI FT-ICR MS demonstrated that in LSO, [O.sub.1,] [O.sub.2,] [O.sub.3,] [N.sub.1] [O.sub.1,] [N.sub.1] [O.sub.2,] [N.sub.1] and [N.sub.2] c compounds were determined with [O.sub.1] and [O.sub.2] compounds as the most abundant. SCT contained [O.sub.1], [O.sub.2], [O.sub.3], [O.sub.4], [O.sub.5] and [O.sub.6] compounds, while [O.sub.2] and [O.sub.3] compounds dominated. Keywords: oxygen compound, shale oil, coal tar, GC-MS, FT-ICR MS.