Passive millimeter-wave (PMMW) imaging technology is widely used in civilian and military applications. However, there are reflections similar to the optical band in PMMW images, which have negative influence on the target detection and recognition. In this paper, we present a reflection-based method to enhance the target features in PMMW images. The dividing line between target and reflection is obtained by the similarity of brightness temperature (TB). By combining the similarity and reflection principle, we propose a new method to obtain the feature points of target and reflection for registration. Then, the weighted method based on region TB is used to fusion target and reflection. Finally, to avoid interference with target detection and recognition, the reflection is removed. The experimental results show that the method can obtain higher contrast and more accurate target information.
Problematic internet use (PIU) is a concerning issue worldwide, and a considerable body of knowledge has accrued from research on the predictors of PIU; however, few studies have investigated the dynamic process by which the social environment impacts individuals’ PIU. Integrating a person–environment interactionist perspective with self-determination theory, we investigate how relational mobility impacts PIU by proposing a “permeating” mechanism of social interactions (i.e., interpersonal sensitivity) and basic psychological needs (i.e., relatedness satisfaction). In Study 1, using a large data set from the Chinese General Social Survey (N = 2,192), we found that relational mobility was negatively related to PIU. In Study 2, using a new sample (N = 392), we found that relational mobility alleviated PIU through interpersonal sensitivity. In Study 3, using a cross-lagged design and two-wave data (N = 298), we confirmed the chain-mediating roles of interpersonal sensitivity and relatedness satisfaction in the relationship between relational mobility and PIU.
Soil microbes assemble in highly complex and diverse microbial communities, and microbial diversity patterns and their drivers have been studied extensively. However, diversity correlations and co-occurrence patterns between bacterial, fungal, and archaeal domains and between microbial functional groups in arid regions remain poorly understood. Here we assessed the relationships between the diversity and abundance of bacteria, fungi, and archaea and explored how environmental factors influence these relationships. We sampled soil along a 1500-km-long aridity gradient in temperate grasslands of Inner Mongolia (China) and sequenced the 16S rRNA gene of bacteria and archaea and the ITS2 gene of fungi. The diversity correlations and co-occurrence patterns between bacterial, fungal, and archaeal domains and between different microbial functional groups were evaluated using α-diversity and co-occurrence networks based on microbial abundance. Our results indicate insignificant correlations among the diversity patterns of bacterial, fungal, and archaeal domains using α-diversity but mostly positive correlations among diversity patterns of microbial functional groups based on α-diversity and co-occurrence networks along the aridity gradient. These results suggest that studying microbial diversity patterns from the perspective of functional groups and co-occurrence networks can provide additional insights on patterns that cannot be accessed using only overall microbial α-diversity. Increase in aridity weakens the diversity correlations between bacteria and fungi and between bacterial and archaeal functional groups, but strengthens the positive diversity correlations between bacterial functional groups and between fungal functional groups and the negative diversity correlations between bacterial and fungal functional groups. These variations of the diversity correlations are associated with the different responses of microbes to environmental factors, especially aridity. Our findings demonstrate the complex responses of microbial community structure to environmental conditions (especially aridity) and suggest that understanding diversity correlations and co-occurrence patterns between soil microbial groups is essential for predicting changes in microbial communities under future climate change in arid regions.
Carbon nanotubes (CNTs) and their derivatives have been widely exploited to activate various oxidants for environmental remediation. However, the intrinsic mechanism of CNTs-driven periodate (PI) activation remains ambiguous, which significantly impedes their scientific progress toward practical application. Here, we found that CNTs can strongly boost PI activation for the oxidation of various phenols. Reactive oxygen species analysis, in situ Raman characterization, galvanic oxidation process experiments, and electrochemical tests revealed that CNTs could activate PI to form high-potential metastable intermediates (CNTs–PI*) rather than produce free radicals and 1O2, thereby facilitating direct electron transfer from the pollutants to PI. Additionally, we analyzed quantitative structure–activity relationships between rate constants of phenols oxidation and double descriptors (e.g., Hammett constants and logarithm of the octanol–water partition coefficient). The adsorption of phenols on CNT surfaces and their electronic properties are critical factors affecting the oxidation process. Besides, in the CNTs/PI system, phenol adsorbed the CNT surfaces was oxidized by the CNTs–PI* complexes, and products were mainly generated via the coupling reaction of phenoxyl radical. Most of the products adsorbed and accumulated on the CNT surfaces realized phenol removal from the bulk solution. Such a unique non-mineralization removal process achieved an extremely high apparent electron utilization efficiency of 378%. The activity evaluation and theoretical calculations of CNT derivatives confirmed that the carbonyl/ketonic functional groups and double-vacancy defects of the CNTs were the primary active sites, where high-oxidation-potential CNTs–PI* were formed. Further, the PI species could achieve a stoichiometric decomposition into iodate, a safe sink of iodine species, without the generation of typical iodinated byproducts. Our discovery provides new mechanistic insight into CNTs-driven PI activation for the green future of environmental remediation.
A Co3O4-activated chlorite (Co3O4/chlorite) process was developed to enable the simultaneous generation of high-valent cobalt species [Co(IV)] and ClO2 for efficient oxidation of organic contaminants. The formation of Co(IV) in the Co3O4/chlorite process was demonstrated through phenylmethyl sulfoxide (PMSO) probe and 18O-isotope-labeling tests. Both experiments and theoretical calculations revealed that chlorite activation involved oxygen atom transfer (OAT) during Co(IV) formation and proton-coupled electron transfer (PCET) in the Co(IV)-mediated ClO2 generation. Protons not only promoted the generation of Co(IV) and ClO2 by lowering the energy barrier but also strengthened the resistance of the Co3O4/chlorite process to coexisting anions, which we termed a proton enhancement effect. Although both Co(IV) and ClO2 exhibited direct oxidation of contaminants, their contributions varied with pH changes. When pH increased from 3 to 5, the deprotonation of contaminants facilitated the electrophilic attack of ClO2, while as pH increased from 5 to 8, Co(IV) gradually became the main contributor to contaminant degradation owing to its higher stability than ClO2. Moreover, ClO2– was transformed into nontoxic Cl– rather than ClO3– after the reaction, thus greatly reducing possible environmental risks. This work described a Co(IV)-involved chlorite activation process for efficient removal of organic contaminants, and a proton enhancement mechanism was revealed.
Peroxy radicals (RO2), which are formed during the oxidation of volatile organic compounds, play an important role in atmospheric oxidation reactions. Therefore, the measurement of RO2, especially distinct species of RO2 radicals, is important and greatly helps the exploration of atmospheric chemistry mechanisms. Although the speciated detection of RO2 radicals remains challenging, various methods have been developed to study them in detail. These methods can be divided into spectroscopy and mass spectrometry technologies. The spectroscopy methods contain laser-induced fluorescence (LIF), UV-absorption spectroscopy, cavity ring-down spectroscopy (CRDS) and matrix isolation and electron spin resonance (MIESR). The mass spectrometry methods contain chemical ionization atmospheric pressure interface time-of-flight mass spectrometry (CI-APi-TOF), chemical ionization mass spectrometry (CIMS), CI-Orbitrap-MS and the third-generation proton transfer reaction–time-of-flight mass spectrometer (PTR3). This article reviews technologies for the speciated detection of RO2 radicals and the applications of these methods. In addition, a comparison of these techniques and the reaction mechanisms of some key species are discussed. Finally, possible gaps are proposed that could be filled by future research into speciated RO2 radicals.
More than three decades after the release of his seminal work An Age in Motion: Popular Radicalism in Java, 1912–1926, Takashi Shiraishi finally published the long-awaited sequel, The Phantom World of Digul. Initially conceived with the self-explanatory title An Age of Normalcy, the monograph draws a sharp contrast with its prequel by investigating the interplay of the colonial regime’s political policing and the concurrent nationalist movement in the final years of the Dutch East Indies. While scholars commonly see the late 1920s and 1930s as a period of “peace and order” under the relatively stable rule of the Dutch Beambtenstaat—an “apolitical, administrative polity par excellence,” Shiraishi demonstrates that the colonial authority achieved such “normalcy” by “reducing the problem of nationalism to the question of police” (p. 16). Boven Digul, a remote penal colony established to intern recalcitrant communists and radical nationalists, stood out as a jarring antithesis to such “normalcy.” The mass internment camp served as both a metaphor and ground for the colonial regime’s policing and surveillance practices, epitomizing Dutch repressive colonial strategies that aimed to confine Indonesians’ political life within an extremely narrow space.
Exhibiting as a combination of viscous, elastic, and plastic behavior, rheology is a branch of physics and is majorly concerned with continuum mechanics for flow characterizations, particularly non-Newtonian flow like foam. However, most existing studies of foam rheology are primarily focused on water-based foam, while oil-based foam rheology lacks adequate understanding, plus few comprehensive experimental analyses have been done. This study, for the first time, investigates the rheological behavior of oil-based nitrogen foam with full foam quality and shallow reservoir conditions through a newly-designed visualized capillary rheometer. Basically, the effects of foam quality and shear rate on foam morphology and apparent viscosity were elucidated, and the foam rheology at different temperatures and pressures was evaluated. More specifically, with increasing shear rate, the apparent viscosity of nitrogen foam decreases in a concave-down parabola pattern. With the foam quality of 86 %, the apparent viscosity of the foam flow is found to reach its maximum value, 58.4 mPa·s, at the flow rate of 4 mL/min, temperature of 25 °C and pressure of 5 MPa. The foam flow gradually becomes uniform and dense and the apparent viscosity elevates with increasing foam quality up to 86 %. After that, the foam flow tends to be slug flow and its stability becomes worse with linearly-decreasing apparent viscosity. With increasing pressure, the apparent viscosity and consistency coefficient increase, which result in the increase of rheological index and decrease of non-Newtonian property. The temperature effects on the foam flow are absolutely opposite but stronger in comparison to pressure effects as aforementioned. In addition, the rheological equations of nitrogen foam are determined by fitting the consistency coefficient and rheological index with foam quality. Overall, thorough investigations of the rheology of oil-based nitrogen foam would be of great importance for foam theory and practice.
Antibiotics are emerging pollutants that have detrimental effects on both target and non-target organisms in the environment. However, current methods for environmental risk assessment primarily focus on the risk to non-target organisms in ecosystems, overlooking a crucial risk of antibiotics - the induction of resistance in targeted bacteria. To address this oversight, we have incorporated resistance (R) risk with persistence, bioaccumulation and toxicity (PBT) to establish a more comprehensive PBTR (persistence, bioaccumulation, toxicity, and resistance) framework for antibiotic-specific risk assessment. Using the PBTR framework, we evaluated 74 antibiotics detected in Chinese seawater from 2000 to 2021, and identified priority antibiotics. Our analysis revealed that the priority antibiotics with R risk accounted for the largest proportion (50% to 70%), followed by P risk (40% to 58%), T risk (16% to 35%) and B risk (0 to 13%). To further categorize these priority antibiotics, we assigned them a risk level according to their fulfillment of criteria related to P, B, T, and R. Antibiotics meeting all four indicators were classified as Grade I, representing the highest risk level. Grade II and Grade III were assigned to antibiotics meeting three or two indicators, respectively. Antibiotics meeting only one indicator were classified as Grade IV, representing the lowest risk level. The majority of priority antibiotics fell into Grade IV, indicating low risk (55% to 79%), followed by Grade III (16% to 45%). The highest risk antibiotic identified in this study was clindamycin (CLIN), categorized as Grade II, in the East China Sea. Our findings aligned with previous studies for 25 antibiotics, affirming the validity of the PBTR framework. Moreover, we identified 13 new priority antibiotics, highlighting the advancement of this approach. This study provides a feasible screening strategy and monitoring recommendations for priority antibiotics in Chinese seawater.
Abstract Different adverse health effects of submicron (PM1) and fine particles (PM2.5) may be attributed to their chemical differences, requiring a better understanding of size-resolved composition. Herein, extensive online measurements were conducted across seasons in Beijing by two aerosol mass spectrometers, one of which alternately sampled PM1 and PM2.5. Source apportionment of organic aerosol (OA) indicated that traffic- and cooking-related OA together accounted for ∼20%−30% of the OA mass in PM2.5, showing insignificant seasonal variations. Coal-combustion and biomass-burning-related OA had minor contributions. The two secondary OA (SOA) factors together accounted for 59%−73% of the OA mass in PM2.5. The mass distributions of particulate components in PM1 and PM2.5 varied greatly across seasons. Secondary formation played a key role in particle size growth during cold seasons. During severe hazes with high aerosol liquid water content (ALWC), the supermicron mass fraction (MF1−2.5) of secondary components reached ∼40%−50% while those for primary OA remained at ∼20%. Heterogeneous uptake, aqueous processing, and dissolution likely all contributed to the enhanced concentration of secondary components, and the former two were perhaps more important. The increase of MF1−2.5 for secondary components with increasing ALWC in spring was less than that in winter, possibly due to the shorter duration of stagnant conditions limiting secondary formation. Early autumn showed higher MF1−2.5 values than cold seasons with insignificant changes as ALWC varied, plausibly explained by intensive new particle formation hindering persistent particle growth. Our results highlight the importance of heterogeneous uptake and aqueous processing in distributing SOA in supermicron mode in polluted areas.