Gas sensing performance of In2O3 nanostructures: A mini review

Effective detection of toxic and hazardous gases is crucial for ensuring human safety, and high-performance metal oxide-based gas sensors play an important role in achieving this goal. In2O3 is a widely used n-type metal oxide in gas sensors, and various In2O3 nanostructures have been synthesized for detecting small gas molecules. In this review, we provide a brief summary of current research on In2O3-based gas sensors. We discuss methods for synthesizing In2O3 nanostructures with various morphologies, and mainly review the sensing behaviors of these structures in order to better understand their potential in gas sensors. Additionally, the sensing mechanism of In2O3 nanostructures is discussed. Our review further indicates that In2O3-based nanomaterials hold great promise for assembling high-performance gas sensors

Occurrence of Perfluoroalkyl Compounds in Surface Waters from the North Pacific to the Arctic Ocean

Chinese Arctic and Antarctic Administration; National Natural Science Foundation of China [40776003]Perfluoroalkyl compounds (PFCs) were determined in 22 surface water samples (39-76 degrees N) and three sea ice core and snow samples (77-87 degrees N) collected from North Pacific to the Arctic Ocean during the fourth Chinese Arctic Expedition in 2010. Geographically, the average concentration of Sigma PFC in surface water samples were 560 +/- 170 pg L-1 for the Northwest Pacific Ocean, 500 +/- 170 pg L-1 for the Arctic Ocean, and 340 +/- 130 pg L-1 for the Bering Sea, respectively. The perfluoroalkyl carboxylates (PFCAs) were the dominant PFC class in the water samples, however, the spatial pattern of PFCs varied. The C-5, C-7 and C-8 PFCAs (i.e., perfluoropentanoate (PFPA), perfluoroheptanoate (PFHpA), and perfluorooctanoate (PFOA)) were the dominant PFCs in the Northwest Pacific Ocean while in the Bering Sea the PFPA dominated. The changing in the pattern and concentrations in Pacific Ocean indicate that the PFCs in surface water were influenced by sources from the East-Asian (such as Japan and China) and North American coast, and dilution effect during their transport to the Arctic. The presence of PFCs in the snow and ice core samples indicates an atmospheric deposition of PFCs in the Arctic. The elevated PFC concentration in the Arctic Ocean shows that the ice melting had an impact on the PFC levels and distribution. In addition, the C-4 and C-5 PFCAs (i.e., perfluorobutanoate (PFBA), PFPA) became the dominant PFCs in the Arctic Ocean indicating that PFBA is a marker for sea ice melting as the source of exposure

Spatial distribution of per- and polyfluoroalkyl compounds in coastal waters from the East to South China Sea

The spatial distribution of per- and polyfluoroalkyl compounds (PFCs) were investigated in coastal waters collected onboard research vessel Snow Dragon from the East to South China Sea in 2010. All samples were prepared by solid-phase extraction and analyzed using high performance liquid chromatography/negative electrospray ionization-tandem mass spectrometry (HPLC/(-)ESI-MS/MS). Concentrations of 9 PFCs, including C4 and C8 (PFBS, PFOS) perfluoroalkyl sulfonate (PFSAs), C 5-C9 and C13 (PFPA, PFHxA, PFHpA, PFOA, PFNA, PFTriDA) perfluoroalkyl carboxylates (PFCAs), and N-ethyl perfluorooctane sulfonamide (EtFOSA) were quantified. The 危PFC concentrations ranged from 133 pg/L to 3320 pg/L, with PFOA (37.5-1541 pg/L), PFBS (23.0-941 pg/L) and PFHpA (0-422 pg/L) as dominant compounds. Concentrations of PFCs were greater in coastal waters along Shanghai, Ningbo, Taizhou, Xiamen and along coastal cities of the Guangdong province compared to less populated areas along the east Chinese coast. Additionally, the comparison with other seawater PFC measurements showed lower levels in this study. 漏 2011 Elsevier Ltd. All rights reserved

Creating new path for Old Industrial Areas: A Case Study on Dalian city, China

The formation of new industries has recently been widely studied, but little research attention has been paid to the formation of new industries in old industrial districts, especially in transitional countries such as China. Based on fieldwork and rereading historical archives, this paper uses an example of Dalian tourism cluster to contribute to understanding the emergence of new economy in old industrial areas in a transitional country. The Section 2 of this paper will provide the theoretical framework from evolutionary economics for my empirical study. In Section 3, this paper will discuss the main characteristics of the decline of old industrial areas in Northeast China and the significances of developing new economy to revitalizing old industry areas. Section 4 will introduce the transitional history of Dalian economy from a high industrial region to a new economy city and also provides descriptive information about the development process of Dalian tourism industry. In Section 5, this paper will probe into the dynamics of the Dalian tourism cluster, from viewpoints of co-evolution and co-adaptation of firm, technology and institutions. Finally, we will give some policy suggestions of how to foster and promote new industries in old industrial areas, especially for transitional countries

Synthesis, Tunable Multicolor Output, and High Pure Red Upconversion Emission of Lanthanide-Doped Lu2O3 Nanosheets

Yb3+ and Ln3+ (Ln = Er, Ho) codoped Lu2O3 square nanocubic sheets were successfully synthesized via a facile hydrothermal method followed by a subsequent dehydration process. The crystal phase, morphology, and composition of hydroxide precursors and target oxides were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and energy-dispersive X-ray spectroscope (EDS). Results present the as-prepared Lu2O3 crystallized in cubic phase, and the monodispersed square nanosheets were maintained both in hydroxide and oxides. Moreover, under 980 nm laser diode (LD) excitation, multicolor output from red to yellow was realized by codoped different lanthanide ions in Lu2O3. It is noteworthy that high pure strong red upconversion emission with red to green ratio of 443.3 of Er-containing nanocrystals was obtained, which is beneficial for in vivo optical bioimaging

Evaluation of the diagnostic ratios for the identification of spilled oils after biodegradation

Biodegradation, one of the most important weathering processes, alters the composition of spilled oil, making it difficult to identify the source of the release and to monitor its fate in the environment. A laboratory experiment was conducted to simulate oil spill weathering process of microbial degradation to investigate compositional changes in a range of source- and weathering-dependent molecular parameters in oil residues, and the conventional diagnostic ratios for oil spill identification were also evaluated. The conventional diagnostic ratios of n-alkane displayed obvious changes after biodegradation, especially for Pr/n-C-17 and Ph/n-C-18 with relative standard deviation more than 118.84 %, which suggests they are invalid for oil source identification of the middle-serious spill. Many polycyclic aromatic hydrocarbons (PAHs) are more resistant to biodegradation process than their saturated hydrocarbon counterparts, thus making PAHs to be one of the most valuable fingerprinting classes of hydrocarbons for oil identification. Biomarker ratios of hopanes and steranes were also useful for source identification even after moderate biodegradation, and the diagnostic ratios from them could be used in tracking origin and sources of hydrocarbon pollution. Finally, the carbon isotopic type curve may provide another diagnostic means for correlation and differentiation of spilled oils, and be particularly valuable for lighter refined products or severely biodegraded oils, the source of which may be difficult to identify by routine biomarker techniques