There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties * To whom correspondence should be addressed. Phone, 404-8940292; fax, 404-894-0294; e-mail, mostafa.el-sayed@ chemistry.gatech.edu. † Case Western Reserve UniversitysMillis 2258. ‡ Phone, 216-368-5918; fax, 216-368-3006; e-mail, burda@case.edu. § Georgia Institute of Technology. 1025 Chem. Rev. 2005, 105, 1025−1102

Chemistry and properties of nanocrystals of different shapes.

N-Heterocyclic Carbenes in Late Transition Metal Catalysis

Compounds having one of the general formulae:
 
   wherein:
 M is a metal; Z is selected from the group consisting of oxygen, sulphur, NR"" and PR""; R", R"' and R"" are each a radical independently selected from hydrogen,
C 1-6 alkyl, C 3-8 cycloalkyl, aryl and heteroaryl, or R" and R"' together form
an aryl or heteroaryl radical, each said radical being optionally substituted; R' is either as defined for R", R"' and R"" when included in a compound
having the general formula (IA) or, when included in a compound having the
general formula (IB), is selected from hydrogen, C 1-6 alkylene and C 3-8 
cycloalkylene, the said alkylene and cycloalkylene group being optionally
substituted; R 1 is a constraint steric hindrance group having a pK a of at least about 15; R 2 is an anionic ligand; R 3 and R 4 are each hydrogen or a radical selected from, among others, C 1-20 alkyl, C 1-20 alkenyl; R 3 and R 4 together may form a fused aromatic ring system, and y represents the number of sp 2 carbon atoms between M and the carbon
atom bearing R 3 and R 4 and is an integer from 0 to 3 inclusive 
are useful as catalysts for olefin metathesis and atom transfer radical
polymerization.

Metal carbene complexes, methods and intermediates for making them and their use in metathesis reactions

Transition-Metal-Free Base-Controlled C−N Coupling Reactions: Selective Mono Versus Diarylation of Primary Amines with 2-Chlorobenzimidazoles

Activated carbon (AC) and char derived from coconut shell were modified using urea and KOH to achieve N-doped AC. The effect of activated temperature and gas agent was studied. The series of adsorbents was characterized and it was found that the pore size and surface functional group were developed thoroughly. Paracetamol (PC) removal from aqueous solution was accomplished by adsorption in a batch system at 298 K. The intraparticle diffusion model was suitable to describe the kinetic PC removal from water rather than other models because of a complicated adsorption process in the pore connection of actual materials. The maximum capacity of these adsorbents was in a range of 39.9–357.1 mg/g, promoting them as an alternative adsorbent. Among them, the N-doped AC had the highest surface area (538 m 2 /g) and the highest PC adsorption capacity. The PC equilibrium uptakes in these samples were not pH-dependent, indicating that the pore size is the most dominant factor than the electrostatic charge of functional group on the solid surface for adsorption, which is evidenced in our simulation results. Furthermore, a Grand Canonical Monte Carlo simulation was used to study equilibrium adsorption. The effect of pore size and functional group type (carboxylic, hydroxyl, carbonyl, quaternary-N, pyrrolic-N, and pyridinic-N) were investigated on PC-water mixtures at 298 K. The heat contributions including fluid-fluid, fluid-solid, and fluid-functional group interactions of each adsorbate were investigated. The maximum capacity was found in the pore size of 0.70 nm, which was the best fit for complete monolayer coverage of PC molecules. The simulation confirmed that N-group types, especially pyridinic-N were more attractive than O-group types for enhanced PC removal. This work provided a new strategy to develop the optimal pore size and functional group type of ACs for high capacity of PC removal from aqueous solution. The estimated costs of production for char, AC, and N-doped AC were about 0.73, 2.63, and 3.83 U.S.$/kg respectively, indicating a highly competitive cost in the market. However, the N-doped AC was the cheapest price in order to remove the same amount of PC from aqueous solution. • Surface modification of N-doped activated carbon derived from coconut shell. • Nitrogen and oxygen functional group types were investigated using GCMC simulation. • The maximum capacity of paracetamol (PC) was found in pore width of 0.7 nm. • N-group types especially pyridinic-N gave the highest PC removal capacity. • The modification can enhance pyridinic-N group on the surface of N-doped AC. 

Paracetamol removal from water using N-doped activated carbon derived from coconut shell: Kinetics, equilibrium, cost analysis, heat contributions, and molecular-level insight

Novel Polymers Based on Dimethyl Esters of Norbornene Dicarboxylic Acids Synthesized Using Metathesis Ring-Opening Polymerization

Copolymerization of styrene (St) and 1-vinyl-3-ethylimidazolium bromide (VEIB), novel poly(St-co-VEIB) microspheres were generated. Owing to the presence of imidazolium groups, such microspheres having an average diameter of 125 nm, behave electropositively when dispersed in aqueous solution. Furthermore, due to the presence of imidazolium groups, having a capacity of ion-exchange and weak reducibility on the surface of the PS microspheres, [Fe(CN)₆]³⁻ was absorbed on the surface of poly(St-co-VEIB) microspheres, and simultaneously, Fe³⁺ was reduced to Fe²⁺. Thus, in situ growth of Prussian blue (PB) nanoparticles could occur on the surface of poly(St-co-VEIB) microspheres without the addition of any other reducing agent. This methodology, utilizing the ion-exchange and weak reducibility properties of the imidazolium groups on the surface of micro-/nanostructures is a novel general method for assembling hierarchical nanostructured materials. Finally, the electrochemical property of the strawberry-like PS/PB composite microspheres was also investigated by applying a glassy carbon electrode. A good repeatability of the cyclic voltammetry responses, having a good linearity and sensitivity, for the electrocatalytic reduction of H₂O₂ was obtained.

https://iopscience.iop.org/article/10.1088/0957-4484/24/21/215601/pdf

Francis Verpoort

Papers

Metal carbene complexes, methods and intermediates for making them and their use in metathesis reactions

Transition-Metal-Free Base-Controlled C−N Coupling Reactions: Selective Mono Versus Diarylation of Primary Amines with 2-Chlorobenzimidazoles

Paracetamol removal from water using N-doped activated carbon derived from coconut shell: Kinetics, equilibrium, cost analysis, heat contributions, and molecular-level insight

Novel Polymers Based on Dimethyl Esters of Norbornene Dicarboxylic Acids Synthesized Using Metathesis Ring-Opening Polymerization

Novel polystyrene microspheres functionalized by imidazolium and the electrocatalytic activity towards H2O2 of its Prussian blue composite