3D building model reconstruction is of great importance for environmental and urban applications. Airborne light detection and ranging (LiDAR) is a very useful data source for acquiring detailed ...geometric and topological information of building objects. In this study, we employed a graph-based method based on hierarchical structure analysis of building contours derived from LiDAR data to reconstruct urban building models. The proposed approach first uses a graph theory-based localized contour tree method to represent the topological structure of buildings, then separates the buildings into different parts by analyzing their topological relationships, and finally reconstructs the building model by integrating all the individual models established through the bipartite graph matching process. Our approach provides a more complete topological and geometrical description of building contours than existing approaches. We evaluated the proposed method by applying it to the Lujiazui region in Shanghai, China, a complex and large urban scene with various types of buildings. The results revealed that complex buildings could be reconstructed successfully with a mean modeling error of 0.32 m. Our proposed method offers a promising solution for 3D building model reconstruction from airborne LiDAR point clouds.
A Pair of Cobalt(III/IV) Terminal Imido Complexes Mao, Weiqing; Fehn, Dominik; Heinemann, Frank W. ...
Angewandte Chemie (International ed.),
July 19, 2021, Letnik:
60, Številka:
30
Journal Article
Recenzirano
Odprti dostop
The reaction of the cobalt(I) complex (TIMMNmes)CoI(BPh4) (2) (TIMMNmes=tris‐2‐(3‐mesitylimidazolin‐2‐ylidene)methylamine) with 1‐adamantylazide yields the cobalt(III) imido complex ...(TIMMNmes)CoIII(NAd)(BPh4) (3) with concomitant release of dinitrogen. The N‐anchor in diamagnetic 3 features an unusual, planar tertiary amine, which results from repulsive electrostatic interaction with the filled d(z2)‐orbital of the cobalt ion and negative hyperconjugation with the neighboring methylene groups. One‐electron oxidation of 3 with FeCp2(OTf) provides access to the rare, high‐valent cobalt(IV) imido complex (TIMMNmes)CoIV(NAd)(OTf)2 (4). Despite a half‐life of less than 1 h at room temperature, 4 could be isolated at low temperatures in analytically pure form. Single‐crystal X‐ray diffractometry and EPR spectroscopy corroborate the molecular structure and the d5 low‐spin, S=1/2
, electron configuration. A computational analysis of 4 suggests high covalency within the CoIV=NAd bond with non‐negligible spin density located at the imido moiety, which translates into substantial triplet nitrene character.
Straightforward access to a cobalt(IV) terminal imido complex was provided by one‐electron oxidation of a cobalt(III) terminal imido precursor. The cobalt(IV) monoimido complex could be isolated at low temperatures in analytically pure form. Single‐crystal X‐ray diffractometry and EPR spectroscopy corroborate the molecular structure and the d5 low‐spin, S=1/2
, electron configuration.
Solar energy, as a clean and renewable resource is becoming increasingly important in the global context of climate change and energy crisis. Utilization of solar energy in urban areas is of great ...importance in urban energy planning, environmental conservation, and sustainable development. However, available spaces for solar panel installation in cities are quite limited except for building roofs. Furthermore, complex urban 3D morphology greatly affects sunlit patterns on building roofs, especially in downtown areas, which makes the determination of roof solar energy potential a challenging task. The object of this study is to estimate the solar radiation on building roofs in an urban area in Shanghai, China, and select suitable spaces for installing solar panels that can effectively utilize solar energy. A Graphic Processing Unit (GPU)-based solar radiation model named SHORTWAVE-C simulating direct and non-direct solar radiation intensity was developed by adding the capability of considering cloud influence into the previous SHORTWAVE model. Airborne Light Detection and Ranging (LiDAR) data was used as the input of the SHORTWAVE-C model and to investigate the morphological characteristics of the study area. The results show that the SHORTWAVE-C model can accurately estimate the solar radiation intensity in a complex urban environment under cloudy conditions, and the GPU acceleration method can reduce the computation time by up to 46%. Two sites with different building densities and rooftop structures were selected to illustrate the influence of urban morphology on the solar radiation and solar illumination duration. Based on the findings, an object-based method was implemented to identify suitable places for rooftop solar panel installation that can fully utilize the solar energy potential. Our study provides useful strategic guidelines for the selection and assessment of roof solar energy potential for urban energy planning.
The effects of dulaglutide and a calorie-restricted diet (CRD) on visceral adipose tissue (VAT) and metabolic profiles in polycystic ovary syndrome (PCOS) have not been extensively investigated. In ...this study, we investigated whether dulaglutide combined with CRD could further reduce VAT and promote clinical benefits as compared with a CRD regimen alone in overweight or obese PCOS-affected women. Between May 2021 and May 2022, this single-center, randomized, controlled, open-label clinical trial was conducted. Overall, 243 participants with PCOS were screened, of which 68 overweight or obese individuals were randomly randomized to undergo dulaglutide combined with CRD treatment (
= 35) or CRD treatment alone (
= 33). The duration of intervention was set as the time taken to achieve a 7% weight loss goal from baseline body weight, which was restricted to 6 months. The primary endpoint was the difference in the change in VAT area reduction between the groups. The secondary endpoints contained changes in menstrual frequency, metabolic profiles, hormonal parameters, liver fat, and body composition. As compared with the CRD group, the dulaglutide + CRD group had a considerably shorter median time to achieve 7% weight loss. There was no significant between-group difference in area change of VAT reduction (-0.97 cm
, 95% confidence interval from -14.36 to 12.42,
= 0.884). As compared with CRD alone, dulaglutide + CRD had significant advantages in reducing glycated hemoglobin A1c and postprandial plasma glucose levels. The results of the analyses showed different changes in menstruation frequency, additional metabolic profiles, hormonal markers, liver fat, and body composition between the two groups did not differ significantly. Nausea, vomiting, constipation, and loss of appetite were the main adverse events of dulaglutide. These results emphasize the value of dietary intervention as the first line of treatment for PCOS-affected women, while glucagon-like peptide 1 receptor agonist therapy provides an efficient and typically well tolerated adjuvant therapy to aid in reaching weight targets based on dietary therapy in the population of overweight/obese PCOS-affected women.
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•Introducing pendant donors changes electronic and steric features of β-diketiminates.•Some challenging rare-earth metal complexes were synthesized by using these ligands.•Hemilabile ...property of pendant arms balances complexes’ stabilization and reactivity.
By using the β-diketiminato ligands bearing pendant nitrogen or oxygen donors, a series of rare-earth metal complexes containing reactive metal-bound functionalities have been synthesized. The most notable is the synthesis of subvalent scandium complex, scandium terminal imido complexes, four-coordinate scandium phosphinidene complex, non-pincer-type mononuclear scandium alkylidene complexes, scandium nitrilimine complex, yttrium hydride-PhSiH3 complex, and dialkyl complexes with larger rare-earth metal ions. The reactivity and catalytic activity of rare-earth metal complexes of β-diketiminato ligands bearing pendant donors are also briefly reviewed.
•A new indicator named Floor Green View Index (FGVI) is proposed for quantifying visual amenity of urban vegetation.•FGVI is defined as the area of visible urban vegetation observed from a certain ...floor in a building.•New methods are proposed for calculating the indicators.•FGVI of over 100 buildings in the Lujiazui region, Shanghai, are calculated and analysed.•FGVI can be used to facilitate the assessment and planning of urban construction projects.
Vegetation provides many environmental benefits to the city, and daily access to vegetation contributes to the well-being and psychological status of urban residents. Understanding and measuring urban dwellers’ view-based exposure to greenery has become an important and much needed task for assessing the quality of urban life. This paper presents a new quantitative and objective indicator, the Floor Green View Index (FGVI). It is defined as the area of visible urban vegetation on a particular floor of a city building. The method for estimating FGVI consists of three steps: creating observation points and setting observation platform for each detected floor, conducting viewshed analysis and extracting visible urban green space, and computing the Floor Green View Index. The method is proposed and tested through a case study of the Lujiazui region, Shanghai, China, using airborne Light Detection and Ranging (LiDAR) data and aerial photographs. The new indicator and methods can be used as powerful quantitative tools for urban design, landscape architecture, urban green planning and management.
The reaction of the cobalt(I) complex (TIMMNmes)CoI(BPh4) (2) (TIMMNmes=tris‐2‐(3‐mesitylimidazolin‐2‐ylidene)methylamine) with 1‐adamantylazide yields the cobalt(III) imido complex ...(TIMMNmes)CoIII(NAd)(BPh4) (3) with concomitant release of dinitrogen. The N‐anchor in diamagnetic 3 features an unusual, planar tertiary amine, which results from repulsive electrostatic interaction with the filled d(z2)‐orbital of the cobalt ion and negative hyperconjugation with the neighboring methylene groups. One‐electron oxidation of 3 with FeCp2(OTf) provides access to the rare, high‐valent cobalt(IV) imido complex (TIMMNmes)CoIV(NAd)(OTf)2 (4). Despite a half‐life of less than 1 h at room temperature, 4 could be isolated at low temperatures in analytically pure form. Single‐crystal X‐ray diffractometry and EPR spectroscopy corroborate the molecular structure and the d5 low‐spin, S=1/2
, electron configuration. A computational analysis of 4 suggests high covalency within the CoIV=NAd bond with non‐negligible spin density located at the imido moiety, which translates into substantial triplet nitrene character.
Straightforward access to a cobalt(IV) terminal imido complex was provided by one‐electron oxidation of a cobalt(III) terminal imido precursor. The cobalt(IV) monoimido complex could be isolated at low temperatures in analytically pure form. Single‐crystal X‐ray diffractometry and EPR spectroscopy corroborate the molecular structure and the d5 low‐spin, S=1/2
, electron configuration.
Reaction of a scandium phosphoniomethylidene with carbon monoxide provides the first scandium phosphonioketene (1). X‐ray diffraction analysis shows that the complex has a very short Sc−C bond ...(2.138(2) Å), and DFT calculations indicate that this unusual short bond length is due to the significant contribution of ionic coulomb interaction between carbon and scandium and the η2‐O,C coordination fashion. Complex 1 is thermally stable, albeit shows high reactivity towards a series of unsaturated substrates, including carbon dioxide, ketone, imine, nitrile and isocyanide. In the reaction with tert‐butyl isocyanide, not only an insertion of tert‐butyl isocyanide into the Sc−C bond occur, but also a C−H activation on the phenyl ring. DFT calculations show that the reactivity of 1 operated by nucleophilic properties, and therefore the reaction mechanism favors the nucleophilic attack to isocyanide as a rate‐determining step, followed by the stepwise C−H activation through an interesting C−H deprotonation.
Sc‐intillating chemistry: The reaction of a scandium phosphoniomethylidene with carbon monoxide provides the first scandium phosphonioketene (1). Complex 1 shows high reactivity towards a series of unsaturated substrates, such as carbon dioxide as well as ketone, imine, nitrile and isocyanide, therefore showing an interesting coupling of CO with CO2 or an organic molecule. The bonding and reactivity of 1 were further highlighted by theoretical studies.
A series of monomeric rare‐earth metal silyl‐thiophosphinoyl‐alkylidene complexes LLn{C(SiR3)PPh2S} (5: Ln=Lu, R=Me; 6: Ln=Lu, R=Ph; 7: Ln=Y, R=Me; 8: Ln=Y, R=Ph; 9: Ln=Sm, R=Ph; 10: Ln=Sm, R=Me; 11: ...Ln=La, R=Ph; L=MeC(NDIPP)CHC(Me)(NCH2CH2N(Me)2)−, DIPP=2,6‐(iPr)2C6H3) have been synthesized and structurally characterized. The influences of rare‐earth metal ions, ancillary ligands, and alkylidene groups on the reactivity of complexes 5–11 and the related scandium complexes LSc{C(SiR3)PPh2S} (1: R=Me; 2: R=Ph) and L′Sc{C(SiR3)PPh2S} (3: R=Me; 4: R=Ph; L′=MeC(NDIPP)CHC(Me)(NCH2CH2N(iPr)2)−) have been studied. Reactions of these rare‐earth metal alkylidene complexes with PhCN give four kinds of products, the formation of which is dependent on the rare‐earth metal ions, ancillary ligands, and alkylidene groups of the complexes. In the reactions with tBuNC, unusual C−P bond cleavage of the alkylidene group and C≡C triple bond formation occur. Complexes 10 and 11 also react with PhSiH3 to form hydrides, which subsequently undergo Ln−H addition to the C=N bond of the ancillary ligand L. DFT calculations have been used to analyze the bonding in complex 10, which exhibits a polarized three centers Sm−C−P π interaction, and to rationalize the reactivity by computing reaction mechanisms. The difference in reactivity of PhCN and tBuNC is due to the electron density delocalization that is enabled by the phenyl group rather than the tBu group.
Rare‐earth complexes: Monomeric silyl‐thiophosphinoyl‐alkylidene complexes LLn{C(SiR3)PPh2S} of four different trivalent rare‐earth metals, which even include the rare‐earth meal ion with the largest ionic radius (La3+), are synthesized and structurally characterized (see picture). The influences of rare‐earth metal ions, ancillary ligands, and alkylidene groups on the reactivity of these complexes and the related scandium complexes are studied.
As key intermediates in metal-catalyzed nitrogen-transfer chemistry, terminal imido complexes of iron have attracted significant attention for a long time. In search of versatile model compounds, the ...recently developed second-generation
-anchored
-NHC chelating ligand
-2-(3-mesityl-
idazole-2-ylidene)-
ethylami
e (TIMMN
) was utilized to synthesize and compare two series of mid- to high-valent iron alkyl imido complexes, including a reactive Fe(V) adamantyl imido intermediate en route to an isolable Fe(V) nitrido complex. The chemistry toward the iron adamantyl imides was achieved by reacting the Fe(I) precursor (TIMMN
)Fe
(N
)
(
) with 1-adamantyl azide to yield the corresponding trivalent iron imide. Stepwise chemical reduction and oxidation lead to the isostructural series of low-spin (TIMMN
)Fe(NAd)
(
-
) in oxidation states II to V. The Fe(V) imide (TIMMN
)Fe(NAd)
(
) is unstable under ambient conditions and converts to the air-stable nitride (TIMMN
)Fe
(N)
(
) via N-C bond cleavage. The stability of the pentavalent imide can be increased by derivatizing the nitride (TIMMN
)Fe
(N)
(
) with an ethyl group using the triethyloxonium salt Et
OPF
. This gives access to the analogous series of ethyl imides (TIMMN
)Fe(NEt)
(
-
), including the stable Fe(V) ethyl imide. Iron imido complexes exist in a manifold of different electronic structures, ultimately controlling their diverse reactivities. Accordingly, these complexes were characterized by single-crystal X-ray diffraction analyses, SQUID magnetization, and electrochemical methods, as well as
Fe Mössbauer, IR vibrational, UV/vis electronic absorption, multinuclear NMR, X-band EPR, and X-ray absorption spectroscopy. Our studies are complemented with quantum chemical calculations, thus providing further insight into the electronic structures of all complexes.
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