Display omitted
•The use of arylsulfonium salts as versatile arylation reagents is summarized.•This digest describes the transition metal-catalyzed or -free arylation.•The metastable arylsulfonium ...intermediates for arylation are also discussed.
Arylsulfonium salts are versatile arylation reagents for the synthesis of functional molecules. This digest focuses on the recent advances on the transition metal-mediated or -free arylation using the stable arylsulfonium salts or the metastable arylsulfonium intermediates as arylation agents.
In this paper, we consider the security problem of dynamic state estimations in cyber–physical systems (CPSs) when the sensors are compromised by false data injection (FDI) attacks with complete ...stealthiness. The FDI attacks with complete stealthiness can completely remove its influences on monitored residuals, which have better stealthy performance against residual-based detectors than existing FDI attacks. Based on self-generated FDI attacks that are independent of real-time data of CPSs, we propose the necessary and sufficient condition of attack parameters such that FDI attacks can achieve complete stealthiness. Furthermore, we introduce the energy stealthiness of FDI attacks, which is a special case of complete stealthiness and makes the accumulated attack energy on residuals is bounded. Then, the existence and design conditions of FDI attacks with energy stealthiness are given. Finally, the superiority of the FDI attacks with complete stealthiness is demonstrated by the IEEE 6 bus power system.
A simple and efficient method for transition‐metal‐free N‐arylation of various amines by triarylsulfonium triflates is described. Both aliphatic and aromatic amines were smoothly converted at 80 °C ...in the presence of tBuOK or KOH to give the corresponding mono N‐arylated products in good to high yields. The molar ratios of the reactants and the choice of bases had a big effect on the reaction. When a large excess of Ph3SOTf and tBuOK were employed for primary amines under the standard conditions, the bis(N‐phenyl) products were predominantly formed. This method was also applicable to the synthesis of bioactive N‐phenyl amino acid derivatives. The control experiments, the deuterium labelling study, and the presence of regioisomers of N‐arylated products when using 4‐substituted triarylsulfonium triflates suggested that the reaction might proceed through an aryne intermediate. The present protocol demonstrated that triarylsulfonium salts are versatile arylation reagents in the construction of CAr−N bonds.
Transition‐metal‐free N‐arylation of aliphatic and aromatic amines by Ar3SOTf in the presence of tBuOK or KOH gave the mono N‐arylated products in good to high yields. The reaction might proceed via an aryne intermediate. The molar ratios of the reactants and the choice of bases had a big influence on the reaction. When a large excess of Ph3SOTf and tBuOK were employed for primary amines, the corresponding bis(N‐phenyl) compounds were obtained as the major products.
Burgers-type equations are used to describe certain phenomena in gas dynamics, traffic flow, plasma astrophysics and ocean dynamics. In this paper, a (2
+
1)-dimensional generalized Burgers system ...with the variable coefficients in a fluid is investigated. We obtain the Painlevé-integrable constraints of the system with respect to the variable coefficients. Based on the truncated Painlevé expansions, an auto-Bäcklund transformation is constructed, along with some soliton solutions. Via a truncated Painlevé expansions, certain multiple kink solutions are derived. Via a complex-conjugate transformation, some breather solutions, half-periodic kink solutions and hybrid solutions composed of the breathers and kink waves are seen.
Spin waves, usually used in radar and communication system, are the collective excitation of spin system in ferromagnetic metals, and considered as potential data carriers for computing devices ...because they have nanometre wavelengths. In this paper, in a Heisenberg ferromagnetic spin chain, we study a matrix Lakshmanan-Porsezian-Daniel equation. With regard to the slowly-varying envelope of the wave, we work out the N-fold Darboux transformation, and then we construct the N-fold generalized Darboux transformation, where N is a positive integer. Furthmore, the first-, second- and third-order vector breathers are derived according to the generalized Darboux transformation method. We show the propagation for three kinds of the first- and second-order vector breathers, and also analyze the influence of the strength of the higher-order linear and nonlinear effects on the first- and second-order vector breathers. All our results rely on the strength of the higher-order linear and nonlinear effects in that equation. Our results may provide some help for people to study the nonlinear characteristics of magnetic materials.
In this paper, from the perspectives of defenders, we consider the detection problems of false data-injection attacks in cyber-physical systems (CPSs) with white noise. The false data-injection ...attacks usually modify the sensor data to make CPSs unstable and keep stealth for the <inline-formula> <tex-math notation="LaTeX">\chi ^{2} </tex-math></inline-formula> detector. To guarantee system security, a novel detector, that is, the summation (SUM) detector, is proposed to detect the false data-injection attacks. Different from the <inline-formula> <tex-math notation="LaTeX">\chi ^{2} </tex-math></inline-formula> detector, the SUM detector not only utilizes the current compromise information but also collects all historical information to reveal the threat. Its evaluation value also satisfies <inline-formula> <tex-math notation="LaTeX">\chi ^{2} </tex-math></inline-formula> distribution when no attacks compromise the systems, and the false alarm rate can be restricted to less than any given value by choosing the proper threshold value. Furthermore, an improved false data-injection attack with a time-variable increment coefficient is introduced based on the existing approaches. The effects of the SUM detector are also verified for the traditional and the improved false data-injection attacks, respectively. Finally, some simulation results are given to demonstrate the effectiveness and superiority of the SUM detector.
The creation of a welcoming hospital atmosphere is necessary to improve patient wellbeing and encourage healing. The goal of this study was to examine the variables affecting hospitalised patients' ...comfort. The study procedure included a thorough search of the Web of Science and Scopus databases, as well as the use of software analytic tools to graphically map enormous literature data, providing a deeper understanding of the linkages within the literature and its changing patterns. Insights from a range of disciplines, including engineering, psychology, immunology, microbiology, and environmental science, were included into our study using content analysis and clustering approaches. The physical environment and the social environment are two crucial factors that are related to patient comfort. The study stress the need of giving patient comfort a top priority as they heal, especially by tackling indoor air pollution. Our research also emphasises how important hospital care and food guidelines are for improving patient comfort. Prioritising patients who need specialised care and attention, especially those who have suffered trauma, should be the focus of future study. Future research in important fields including trauma, communication, hospital architecture, and nursing will be built on the findings of this study. To enhance research in these crucial areas, worldwide collaboration between experts from other nations is also advised. Although many studies stress the significance of patient comfort, few have drawn conclusions from a variety of disciplines, including medicine, engineering, immunology, microbiology, and environmental science, the most crucial issue of thoroughly researching the improvement of patient comfort has not been addressed. Healthcare workers, engineers, and other professions will benefit greatly from this study's investigation of the connection between hospital indoor environments and patient comfort.
•A stochastic coding scheme is proposed to generate covariance difference of the compromised data under replay attack, which removes the performance degradations in existing works.•A residual-based ...detector is designed to detect the covariance changes caused by the coding scheme subject to the false alarm rate (FAR) and attack detection rate (ADR) limitations. Then, an output-based detector is proposed, which effectively reduce the design complexity of the residual-based detector.•Different from traditional detector, the above detectors apply a novel form to remove the non-convex constrain conditions in design optimal problems.
In this paper, the security problems in cyber-physical systems (CPSs) against replay attack are considered. With replay attacks, attacker records and covers the transmitted data between the senders and receivers of the sensors. In order to achieve the detection objective for malicious replay attacks, the stochastic coding scheme is proposed to make the CPSs generate covariance differences between the normal and compromised data. Different from the existing results, this method detects the replay attack without sacrificing any system performances in normal systems. Based on the coding scheme, two types of detectors are further designed to detect the covariance changes in residual and output, respectively. Moreover, the output-based detector has more low-computing solution process than the residual-based one. Finally, a practical example is proposed to demonstrate the superiority of the stochastic coding scheme.
This article focuses on how false-data injection (FDI) attacks compromise state omniscience, which needs each node in a jointly detectable sensor network to estimate the entire plant state through ...distributed observers. To reveal the global vulnerability of state omniscience, we investigate decentralized FDI (DFDI) attacks that destabilize the estimation error dynamics but eliminate their influences on the residual in each sensor node. First, the sufficiency and necessity for the existence of such attacks are studied from system eigenvalues and attackable sensors. Second, the self-generated DFDI attack sequences independent of system real-time data are designed to achieve the attack objective with elaborate parameters. Especially, the DFDI attack sequences are improved to maintain real values even if the system matrix only has unstable imaginary eigenvalues. Finally, we analyze the secure range for observer interaction weights and the sensor protection scheme to guarantee the security of state omniscience under DFDI attacks. The theoretical results for DFDI attacks are demonstrated with the linearized discrete-time model of an aircraft system.
In this paper, a (3+1)-dimensional Korteweg-de Vries-Calogero-Bogoyavlenskii-Schif equation in a fluid is investigated. By the virtue of the truncated Painlevé expansion, a set of the auto-Bäcklund ...transformations of that equation is worked out. Based on the auto-Bäcklund transformations with certain non-trivial seed solutions, one-, two-, three- and
N
-soliton solutions on the nonzero background of that equation are derived with
N
as a positive integer. According to those two-soliton solutions,
X
- and inelastic-type soliton solutions are obtained. Via the asymptotic analysis, influence of the coefficients for the above equation is discussed and the interactions between the solitons are also studied. Then, those solitons and interactions are shown graphically.
