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Doping–dedoping chemistry lays the cornerstone for converting heteroatom dopants into intrinsic defects as the emerging active sites of carbon catalysts, but the defect content is yet hindered by inadequate doping efficiencies. Comprehending crucial factors behind the doping of pristine carbon and their correlation to the catalytic properties of dedoped carbon is thus of high significance. Here, the overlooked impact of native defects in pristine carbon on dopant‐mediated defect engineering of carbon catalysts is explicitly unveiled. Intact fullerene (C60), C60‐derived carbon, and carbon black in distinct pentagon/edge defect states are employed as respective precursors to undergo a nitrogen doping–dedoping treatment. Theoretical and experimental evidence consistently indicates that native pentagons change the preferred N doping site from the edge to the basal plane, leading to a substantially higher doping level. Importantly, in addition to pentagons from the removal of zigzag‐edged pyridinic N, N dopants in in‐plane pentagons are more easily dedoped than those in hexagons, generating even more pentagons in a new pentagon–heptagon–pentagon structure as oxygen reduction active sites. The optimized defect‐rich carbon gives an outstanding half‐wave potential of 0.834 V (0.846 V for Pt/C) via the four‐electron pathway, excellent long‐term durability, and prospective applicability in zinc–air batteries. [ABSTRACT FROM AUTHOR]

Two novel N‐doped nonalternant nanoribbons (NNNR‐1 and NNNR‐2) featuring multiple fused N‐heterocycles and bulky solubilizing groups were prepared via bottom‐up solution synthesis. NNNR‐2 achieves a total molecular length of 33.8 Å, which represents the longest soluble N‐doped nonalternant nanoribbon reported to date. The pentagon subunits and doping of N atoms in NNNR‐1 and NNNR‐2 have successfully regulated their electronic properties, achieving high electron affinity and good chemical stability enabled by the nonalternant conjugation and electronic effects. When applied a laser pulse of 532 nm, the 13‐rings nanoribbon NNNR‐2 shows outstanding nonlinear optical (NLO) responses, with the nonlinear extinction coefficient of 374 cm GW−1, much higher than those of NNNR‐1 (96 cm GW−1) and the well‐known NLO material C60 (153 cm GW−1). Our findings indicate that the N‐doping of nonalternant nanoribbons is an effective strategy to access another type of excellent material system for high‐performance NLO applications, which can be extended to construct numerous heteroatom‐doped nonalternant nanoribbons with fine‐tunable electronic properties. [ABSTRACT FROM AUTHOR]

Two novel N‐doped nonalternant nanoribbons (NNNR‐1 and NNNR‐2) featuring multiple fused N‐heterocycles and bulky solubilizing groups were prepared via bottom‐up solution synthesis. NNNR‐2 achieves a total molecular length of 33.8 Å, which represents the longest soluble N‐doped nonalternant nanoribbon reported to date. The pentagon subunits and doping of N atoms in NNNR‐1 and NNNR‐2 have successfully regulated their electronic properties, achieving high electron affinity and good chemical stability enabled by the nonalternant conjugation and electronic effects. When applied a laser pulse of 532 nm, the 13‐rings nanoribbon NNNR‐2 shows outstanding nonlinear optical (NLO) responses, with the nonlinear extinction coefficient of 374 cm GW−1, much higher than those of NNNR‐1 (96 cm GW−1) and the well‐known NLO material C60 (153 cm GW−1). Our findings indicate that the N‐doping of nonalternant nanoribbons is an effective strategy to access another type of excellent material system for high‐performance NLO applications, which can be extended to construct numerous heteroatom‐doped nonalternant nanoribbons with fine‐tunable electronic properties. [ABSTRACT FROM AUTHOR]

One-dimensional (1D) novel pentagonal materials have gained significant attention as a new class of materials with unique properties that could influence future technologies. In this report, we studied the structural, electronic, and transport properties of 1D pentagonal PdSe2 nanotubes (p-PdSe2 NTs). The stability and electronic properties of p-PdSe2 NTs with different tube sizes and under uniaxial strain were investigated using density functional theory (DFT). The studied structures showed an indirect-to-direct bandgap transition with slight variation in the bandgap as the tube diameter increased. Specifically, (5 × 5) p-PdSe2 NT, (6 × 6) p-PdSe2 NT, (7 × 7) p-PdSe2 NT, and (8 × 8) p-PdSe2 NT are indirect bandgap semiconductors, while (9 × 9) p-PdSe2 NT exhibits a direct bandgap. In addition, under low uniaxial strain, the surveyed structures were stable and maintained the pentagonal ring structure. The structures were fragmented under tensile strain of 24%, and compression of −18% for sample (5 × 5) and −20% for sample (9 × 9). The electronic band structure and bandgap were strongly affected by uniaxial strain. The evolution of the bandgap vs. the strain was linear. The bandgap of p-PdSe2 NT experienced an indirect–direct–indirect or a direct–indirect–direct transition when axial strain was applied. A deformability effect in the current modulation was observed when the bias voltage ranged from about 1.4 to 2.0 V or from −1.2 to −2.0 V. Calculation of the field effect I–V characteristic showed that the on/off ratio was large with bias potentials from 1.5 to 2.0 V. This ratio increased when the inside of the nanotube contained a dielectric. The results of this investigation provide a better understanding of p-PdSe2 NTs, and open up potential applications in next-generation electronic devices and electromechanical sensors. [ABSTRACT FROM AUTHOR]

Here we derive formula for the area of a quadrilateral with angle 45º between the diagonals, which is a special case of a more general formula for the area of a quadrilateral (Haimov 2022). Along the way we obtain formulas for the area of triangles with angle of 45º/135º. We also give formulas for the area of specific kinds of pentagons and hexagons, in the form of problems. [ABSTRACT FROM AUTHOR]

This study examines the evolving securitization of Unidentified Anomalous Phenomena (UAPs) in the United States (U.S.), utilizing the Copenhagen School’s theory to illustrate a significant shift in the Pentagon’s discourse, moving from outright dismissal to a nuanced acknowledgment of UAPs. By engaging with and expanding upon the UFO taboo discussions, this research sheds light on the contemporary debates on the role of materiality in securitization processes. The paper argues that the complexity of UAP securitization necessitates a multidisciplinary approach that integrates security, scientific inquiry, and global cooperation which will consequently provide a multidimensional understanding of UAPs within national and international security frameworks. [ABSTRACT FROM AUTHOR]

The Golden ratio ("phi" or "Ф") has been known to us for ages and its use in art and architectural designs has enhanced its exquisiteness. Even some of the astounding creations of nature do follow this principle of Golden or divine proportions. Three centuries ago the circle of Willis at the base of the brain was first described and illustrated by Thomas Willis. Classically it was described as being circular in shape, however, the gross anatomy reveals a slightly different picture. The components of this complex neurovascular structure are so arranged that it appears more like a pentagon than a circle. A regular pentagon, unlike a circle, is a Golden shape that mathematically obeys the laws of Golden proportions. Like most other marvelous structures in nature, the close resemblance of the circle of Willis to a pentagon is more of a conscious effort of nature to establish consonance with aesthetic perception, rather than just a mere coincidence. [ABSTRACT FROM AUTHOR]

X-ray photoelectron spectroscopy (XPS) is among the most utilized analytical methods for nitrogen-doped carbon materials. Clarifying the assignments of nitrogen-doped carbon materials with different degrees of carbonization, which relates to conjugated systems, is essential to correlate structures with the performance of various applications, but such precise assignments were challenging. In this work, precise analyses were conducted to overcome the difficulty to assign the peaks of carbon materials with different degrees of carbonization, different edges, and various nitrogen-containing functional groups in graphene nanoribbons (GNRs), such as nitrile, pyridinic, primary with/without charges, secondary with/without charge, tertiary without charges (graphitic nitrogen), and quaternary nitrogen. Electrons donated from hydrogen and Madelung potentials showed a higher correlation to the peak shift of C1s and N1s XPS spectra than Mulliken charges on nitrogen. Zigzag edges showed a greater influence on the peak shift of tertiary amine (graphitic nitrogen) than armchair edges on XPS spectra. Besides, as the degree of carbonization is increased from aromatic compound-like structures to GNRs, the peak positions of C–N in C1s and N1s XPS spectra shifted to higher binding energies. This research proved that XPS could be applied to the precise structural analyses of nitrogen-containing carbon materials. [Display omitted] [ABSTRACT FROM AUTHOR]

A graph G is F -free, if it contains no F as a subgraph. A Brualdi-Solheid-Turán type problem asks what is the maximum spectral radius of an F -free graph of order n ? Let K a , b • K 3 denote the graph obtained by identifying a vertex of K a , b belonging to the part of size b and a vertex of K 3. In this paper, we consider about a Brualdi-Solheid-Turán type problem on non-bipartite graphs. We prove that if G is a non-bipartite graph with order n ≥ 21 and ρ (G) ≥ ρ (K ⌈ n − 2 2 ⌉ , ⌊ n − 2 2 ⌋ • K 3) , then G contains a pentagon unless G ≅ K ⌈ n − 2 2 ⌉ , ⌊ n − 2 2 ⌋ • K 3. [ABSTRACT FROM AUTHOR]

This paper aims to analyze the novel The Armies of the Night, by Norman Mailer, as a record of a march on the Pentagon held on October 1967 in a great protest against the Vietnam War. But, before approaching the novel itself, it is important to present some social and historical data in order to contextualize Mailer's narrative within the historical frame. It is relevant to stress that some facts quoted in the beginning of this paper are cited in the novel. [ABSTRACT FROM AUTHOR]

In this paper it is described the mutual location of the pedal circles of an arbitrary point in the plane of an arbitrary quadrilateral and pentagon with respect to the triangles determined by their sides and diagonals. As a result it is defined Simson circle of a point in the plane of an arbitrary pentagon. Simson lines are found for points on determined lines in the plane of the pentagon. [ABSTRACT FROM AUTHOR]

This article examines the close historical and contemporary ties between the Pentagon and Hollywood from the 1920s until today. Drawing on the US military as an in-depth case study, the article shows the extent to which key military actors view the conduct of war as an arena that stretches well beyond the actual battlefields and includes the production of war movies, film documentaries, computer simulations and first person shooter video games. The article begins with an examination of the 'Military-Industrial Complex' and its evolution into what experts have dubbed 'The Military-Industrial-Media-Entertainment Network (MIME-Net).' It then focuses on the military's relationship with the filming industry, with the production of reality TV, and the commercial gaming industry. It thereby investigates, through in-depth interviews with key stakeholders, how this phenomenon has evolved over time and into new areas where games, simulators, and game technologies cross the boundaries between militaries, the defense industry, Hollywood and the commercial gaming sector. And it shows how the advent of digital new technologies have opened new platforms through which militaries seek to boost recruitment, to (re)write military history, and to influence the portrayal of the armed forces in the eyes of the public. [ABSTRACT FROM AUTHOR]

In the apse of the Church of Horta de Sant Joan (1316), there are a large mason marks squads. The objective is to determine the extent and proportionality of this instrument and its possible use in the medieval factory. The approach is to determine the performance of the squad rotation, especially in staking pentagonal apse. The squads are used as an abacus for constructing regular polygons. These instruments, by small adjustments and calibrations, allow very effective results for the construction of polygons 11, 13, 14, 17 or 19 sides, that do not appear in mathematicis sources, or in the few codices Practica Geometriae. [ABSTRACT FROM AUTHOR]

Since 9/11, the American policy towards Africa has been strongly influenced by national security interests and in particular by the fight against international terrorism and Islamic radicalisation. Traditionally, the American Africa policy has been the result of bureaucratic policymaking with the Pentagon and the State Department playing prominent roles. The paper argues that in the current century, evangelical Christian lobby groups have gained increasing influence on policymaking on Africa. Because policymaking has been influenced by a number of different actors, the American Africa policy may appear incoherent and ambiguous if judged narrowly on the expectation that it only aims to take care of US national security concerns and economic self-interests. The paper concludes that Africa was important to the United States during the presidencies of George W. Bush and Barack Obama because of the combination of strong security interests and strong domestic lobby groups that have pressured to place Africa on the US foreign policy agenda. [ABSTRACT FROM PUBLISHER]

Recent developments of rational strategies for the design of antiviral therapies, including monoclonal antibodies (mAbs), have naturally relied extensively on available viral structural information. As new strategies continue to be developed, it is equally important to continue to refine our understanding and interpretation of viral structural data. There are known limitations to the traditional (Caspar–Klug) theory for describing virus capsid structures that involves subdividing a capsid into triangular subunits. In this context, we describe a more general polyhedral framework for describing virus capsid structures that is able to account for many of these limitations, including a more thorough characterization of intersubunit interfaces. Additionally, our use of pentagonal subunits instead of triangular ones accounts for the intrinsic chirality observed in all capsids. In conjunction with the existing theory, the framework presented here provides a more complete picture of a capsid’s structure and therefore can help contribute to the development of more effective antiviral strategies. [ABSTRACT FROM AUTHOR]

This essay examines US empire in World War 2 and showcases how the American war was based on the extraction of colonial labour. It focuses on builders laying infrastructure and supply lines for the Pentagon in the colonial world – in the Navy Seabees, Air Transport Command and Army Corps of Engineers – to retrieve the history of the planet-spanning, trans-colonial system of labour and transit that Americans established during this period. They called this system ‘the five highways’. They knew its crucial labourer as the ‘native’. Across the wartime archive, the ‘native’ appears in these accounts, the author argues, as the trace of US settler colonialism, a resource continually renewed for imperial projects in the mid-twentieth century. Histories of racialised labour in colonial settings, meanwhile, followed the five highways home, linking the creation of a global racial capitalist US market during the war to the country’s abundant postwar economy and built environment. [ABSTRACT FROM AUTHOR]

We study the trajectories generated by the articulated quadrangle, crank-rod and articulated pentagon mechanisms, each containing the Chebyshev dyad, characterized by the equality of three segments (two welded together), forming a RRR-type dyad. We chose mechanism sizes not mentioned by Chebyshev. We obtain symmetrical trajectories for the articulated quadrangle, trajectories formed of lines and circle arcs for the crank-rod mechanism and incomplete trajectories for the articulated pentagon because of not observing the geometrical conditions for a full rotation of the cranks. [ABSTRACT FROM AUTHOR]

The article assesses the strengths and weaknesses of the Middle East foreign policy of the U.S. Topics discussed include the author's assertion that U.S. intervention is part of the reason for the emergence of terrorist groups Isis in the Middle East, the problems with the structure of the U.S. military administration which makes decisions regarding the country's foreign military operations, according to the author, and the officials who made the decision for the U.S. to invade Iraq in 2003.

Atomic force microscopy (AFM) was used to investigate the self-assembly behavior of λ-DNA and histones at varying histone:DNA ratios. Without histones and at the lowest histone:DNA ratio (less than one histone per 1000 base pairs of DNA), the DNA appeared as individual (uncomplexed), double-stranded DNA molecules. At increasing histone concentrations (one histone per 500, 250 and 167 base pairs of DNA), the DNA molecules started to form extensive polygonal networks of mostly pentagons and hexagons. The observed networks might be one of the naturally occurring, stable DNA–histone structures. The condensing effects of the divalent cations Mg 2+ and Ca 2+ on the DNA–histone complexes were also investigated. The networks persisted at high Mg 2+ concentration (20 mM) and the highest histone concentration. At high Ca 2+ concentration and the highest histone concentration, the polygonal network disappeared and, instead, individual, tightly condensed aggregates were formed. [ABSTRACT FROM AUTHOR]

Wir untersuchen einen Schließungssatz, der sich auf die Schnittpunkte gewisser Seiten mit den entsprechenden Diagonalen des Pentagons bezieht, und zeigen, dass er in desarguesschen Ebenen allgemeingültig ist. [ABSTRACT FROM AUTHOR]

There are exactly eight edge-to-edge tilings of the sphere by congruent equilateral pentagons: three pentagonal subdivision tilings with 12, 24, 60 tiles; four earth map tilings with 16, 20, 24, 24 tiles; and one flip modification of the earth map tiling with 20 tiles. [ABSTRACT FROM AUTHOR]

We develop the basic tools for classifying edge-to-edge tilings of the sphere by congruent pentagons. Then we prove that, for the edge combination a 2 b 2 c , such tilings are three two-parameter families of pentagonal subdivisions of the Platonic solids, with 12, 24 and 60 tiles. We also prove that, for the edge combination a 3 b c , such tilings are two unique double pentagonal subdivisions of the Platonic solids, with 48 and 120 tiles. [ABSTRACT FROM AUTHOR]

There are fifteen edge-to-edge tilings of the sphere by congruent pentagons with the edge combination a 3 b 2 : five one-parameter families of pentagonal subdivision tilings, and ten flip modifications of three special cases of two pentagonal subdivision tilings. [ABSTRACT FROM AUTHOR]

Let S be a set of n points in the general position, that is, no three points in S are collinear. A simple k-gon with all corners in S such that its interior avoids any point of S is called a k-hole. In this paper, we present the first algorithm that counts the number of non-convex 5-holes in S. To our best knowledge, prior to this work there was no known algorithm in the literature except a trivial brute force algorithm. Our algorithm runs in time O (T + Q) , where T denotes the number of 3-holes, or empty triangles, in S and Q that denotes the number of non-convex 4-holes in S. Note that T + Q ranges from Ω (n 2) to O (n 3) , while its expected number is Θ (n 2 log n) when the points in S are chosen uniformly and independently at random from a convex and bounded body in the plane. [ABSTRACT FROM AUTHOR]

Recent geographical scholarship on military spending is characterized by a thunderous silence. This paper analyzes Pentagon contracts awarded to Southern counties in 2011, including the branch of the armed forces that awarded them. It opens with an overview of the changing literatures on this topic. Second, it maps the distribution of these funds, emphasizing their highly uneven concentration in a handful of places, focusing on major drivers of their allocation, such as large commercial contractors with close ties to the federal government and the presence of military bases. Next, the paper investigates several potential sociodemographic correlates with military contracts, including family income, ethnicity, and political affiliation. The conclusion notes that Southern military spending may contract during periods of sustained federal government budget retrenchment. [ABSTRACT FROM AUTHOR]

The end of President Barack Obama's first term provides an opportunity to assess what the administration's "strategic rebalancing" toward and within the Asia-Pacific region (sometimes called the "Asian Pivot" or "Back to Asia" policy) has accomplished as well as what challenges and unmet opportunities remain. The administration has launched several successful multinational diplomatic initiatives in the region to supplement U.S. bilateral ties with key Asian partners; relations with ASEAN have clearly improved. The economic dimension of the Pivot has made progress as seen by the growth of support for the Trans-Pacific Partnership. U.S. efforts to promote democracy and human rights in Asia have proved far less successful, except perhaps for Myanmar, where the political transition remains a work in progress. The U.S. military has managed to establish a broader presence in the region, especially in Australia and Southeast Asia. U.S. officials have sought to impart new energy into the five existing formal U.S. bilateral defense alliances in Asia--with Australia, Japan, the Philippines, Thailand, and South Korea. But the main problem with the pivot has been the inability to overcome Chinese anxiety about U.S. rebalancing, which has complicated their cooperation over North Korea and other issues. Fortunately, relations between the United States and South Korea are also strong. The ROK is becoming an important U.S. partner in several dimensions of the Pivot, though ROK-U.S. differences over North Korea might emerge with the advent of a new government in Seoul. [ABSTRACT FROM AUTHOR]

This study assesses the role of LGBT advocates in repealing the military's Don't Ask, Don't Tell policy in the U.S. Congress. It draws on the author's direct involvement with that effort as well as personal interviews and media evidence to consider the contributions of the Obama Administration, members of Congress, the media, and individuals and pressure groups in the repeal process. It argues that repeal succeeded not because of the effective implementation of a White House plan but because the pressure of LGBT advocates ultimately shattered several key obstacles including inadequate messaging and dysfunction and inertia among both politicians and interest groups in Washington. The article offers insight into the role of public pressure in forwarding social change. [ABSTRACT FROM AUTHOR]

Abstract: One interesting pentanuclear zinc coordination polymer, [Zn5(OH)2(DTBA)4] n (1) (DTBA=2,2′-dithiobisbenzoic acid) has been synthesized by hydrothermal method, and characterized by X-ray single crystal diffraction, elemental analyses, IR and TGA. The pentanuclear zinc unit exhibits pentagon configuration, which acts as secondary building unit to construct a one-dimensional chain structure by DTBA ligands. As far as we know, this kind of pentagon zinc unit is unprecedented. In addition, upon the excitation at 390nm, the blue-fluorescence at 448nm of the compound 1 was observed. [Copyright &y& Elsevier]

Abstract: Using Razborovʼs flag algebras we show that a triangle-free graph on n vertices contains at most cycles of length five. It settles in the affirmative a conjecture of Erdős. [Copyright &y& Elsevier]

On 21 October 1967 Allen Ginsberg, Abbie Hoffman, and Ed Sanders of the band The Fugs, and others, organized an "exorcism" of the Pentagon in which several thousand demonstrators participated. Most historians have regarded this event as "a put on" or at best as "performance art." This article takes seriously the nominal status of the ritual as a "sacred" or "magical" event. It argues that the organizers were utilizing innovative strategies ofsocial action to alter the terms of debate regarding the Vietnam War. In as much as these strategies drew on "secret" insights into the nature of social reality, they were seen as "magical" and in continuity with pre-modern esoteric traditions. Finally, it is argued that the new left turned to such tactics out of a deepfrustration with traditional forms of democratic political engagement. [ABSTRACT FROM AUTHOR]