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Described in this dissertation is the designed synthesis and characterization of a new class of materials – woven crystalline covalent organic frameworks (COFs). Molecular building units are stitched together through strong bonds in a process termed reticular synthesis. In conjunction with metal-templated synthesis woven frameworks are obtained. The products of this reticulation are extended covalently linked one-dimensional (1D) organic molecules that mutually interweave at regular intervals to construct crystalline two- and three-dimensional (2D and 3D) architectures. The mechanical entanglement between the constituents (i.e. 1D chains) allows for large spatial deviations to take place without the breaking of covalent bonds, leading to unusual mechanical properties and ultimately to materials with exceptional resilience and dynamics. In Chapter I, a general introduction of covalent organic frameworks (COFs) and their designed synthesis based on the fundamental concepts of reticular synthesis is given. Since the discovery of COFs in 2005, a plethora of COF structures with various structure types have been synthesized by reticulating judiciously selected building blocks of desirable connectivity and geometry. The structural tunability and crystallinity of COFs make them the ideal candidates for the synthetic realization of woven extended structures. The metal templation strategy, widely explored in the field of supramolecular chemistry, employs metal ions as templates to pre-organize organic linkers into desirable orientations, which can then be reticulated into woven extended frameworks. These metal ions also serve as the crossing points (points of registry) of the resultant woven threads, and upon demetaltion, the threads have high degrees of freedom to move about these points of registry without undoing the weaving. Chapter II describes the implementation of the design strategy of COFs toward the successful synthesis of the first woven material, COF-505. A copper(I)-bisphenanthroline core, a well-established template in the field of supramolecular chemistry, was functionalized with aldehyde groups and used as a building block for COF synthesis. Specifically, the tetratopic and tetrahedrally-shaped complex was reacted with a linear ditopic benzidine (BZ) linker through reversible imine condensation to form a 3D crystalline framework, COF-505, of dia topology. The structure was determined with atomic precision, by a combined 3D electron diffraction tomography (3D-EDT) and powder X-ray diffraction (PXRD) approach. On a fundamental level, COF-505 is constructed from organic helices that are covalently linked within the thread, while neighboring helices are held woven with copper(I) ions serving as the points of registry. Upon removal of these copper(I) templates, the threads are endowed with large degrees of freedom to move about the crossing points, which results in a ten-fold increase of elasticity, as observed by nanoindentation using atomic force microscopy (AFM). Owing to the entanglement of the threads, the underlying topology of the structure remains intact upon demetalation. Copper(I) ions can be added back to the demetalated material to recover the structure of the as-synthesized COF; the demelation and remetalation process can be performed in a reversible manner. In Chapter III, the design principle of woven COFs expanded to structures with large guest accessible internal void space within the structure. It was speculated that this parameter determines the magnitude of the thread movement upon demetalation. The original COF-505 was found to have a two-fold interpenetrated and consequently dense structure. Since it was believed that this might restrict the dynamics of the threads, two strategies were devised to prevent the formation of interpenetration in derivative woven structures: (i) A shorter ditopic linker, p-phenylenediamine (PDA), was employed instead of BZ to yield COF-504. The decreased pore size of the structure has limited internal space thus preventing framework interpenetration. (ii) Alternatively a non-interpenetrated framework can be formed using BZ as the linker when a bulky anion (diphenylphosphinate) was employed during COF synthesis. Post-synthetic anion exchange with smaller BF4- counterions yielded COF-506, a non-interpenetrated analogue of COF-505. The porosity of the two frameworks was investigated by vapor and dye adsorption, which confirmed the guest accessibility of their interior. In COF-506, the member of the series with the largest guest accessible void space, demetalation was found to affect structural dynamics within the structure. Spatial dislocations of the threads within the demetalated COF-506 structure allow for uptake of dye molecules that exceed the pore size of its metalated counterpart. As the crystallinity of COFs heavily relies on the full reversibility of bond formation during the solvothermal synthesis, COF formation conditions can be highly specific for one type of linkage, or even one particular framework. The development of solid-state anthracene photodimerization as a new linkage for COF synthesis is detailed in Chapter IV. The key feature of this strategy is to pre-organize photoreactive anthracene monomers in a face-to-face manner in the solid state. This arrangement allows for exclusively lateral [4 + 4] cycloaddition reactions in the solid state upon UV exposure to target single-crystal-to-single-crystal transformation through C-C bond formation. To employ this approach to the synthesis of woven COFs the copper(I)-bisphenanthroline core was functionalized with anthracene moieties that serve as points of extension. Various packing modes resulted from different crystallization conditions, however only the undesirable face-to-edge anthracene stacking was observed. Fluorine atoms were subsequently installed on the 1, 2, 3, and 4 positions of the anthracene units which effectively enhanced the cofacial interaction of neighboring anthracenes, but no reactivity towards dimerization was observed upon UV treatment. Further studies of the molecular analogue, 1,2,3,4-tetralfuoro-9-phenylanthracene, revealed that the dimerization was only observed in solution, but not in the solid state, which could be attributed to the large energy cost of phenyl rotation and movement upon formation of the C9-C10 bond. Future work should thus focus on the functionalization of the 2 position of anthracene which is remote from the reaction site for dimerization. Chapter V focuses on the discovery of higher modes of entanglement beyond woven structures. By reacting the tetrahedral aldehyde-functionalized copper(I) bisphenanthroline complex with square planar 4',4''',4''''',4'''''''-(ethene-1,1,2,2-tetrayl)tetrakis(([1,1'-biphenyl]-4-amine)) linkers (TBPA), the first interlocking COF-500 was synthesized. COF-500 is comprised of entangled 1D corner-sharing ladders and crystallized in a pts topology. Interlocking structures are fundamentally different from woven structures as their entanglement is based on closed rings which ensures that the entities remain entangled. Upon demetalation, the structure became less open, indicated by the decreased nitrogen sorption capacity. Elucidation of structural change accompanying this process is provided by solid-state photoluminescence measurement. Fluorescence of the material was turned on after demelataion and this can be attributed to restricted rotation of the phenyl rings of TBPA when the interlocked ladders move towards each other within the rigid ring systems. THF vapor adsorption studies highlight the dynamic behavior of these interlocked ladders as the demetalated material has a similar THF uptake with COF-500, in a manner that is analogues to swelling of polymers. A significant decrease of fluorescence response further confirms opening-up of demetalated structure in the presence of THF. Finally, in Chapter VI, a library of woven topologies were identified. By translating the geometries into linear line segments (sticks) joined at corners in their optimal embeddings, 2D and 3D woven and polycatenated structures can be viewed as an extended family of molecular knots and links. Based on mathematical calculations, the most plausible topologies that can be woven were systematically enumerated. Ripe synthetic targets of 2D and 3D weavings and polycatenanes were also provided.

This article is aiming to summarise the main characteristics and implications of the Section 7 offense, Failure of commercial organisations to prevent bribery, and analyse the definition, legal significance and role of the ���adequate procedure��� defence introduced under Section 7(2) at a view to helping relevant commercial organisations in their compliance with the 2010 Bribery Act. This paper mainly takes the form of a literature review and commentary to undertake qualitative analysis on relevant law and legislation, as well as documents and reports of legislative, investigative and prosecuting bodies or international organisations. This article suggested that theoretically, the ���adequate procedure��� defence has a decisive role in the evidential stage of prosecution decisions and court convictions. However, the Act and the Ministry of Justice���s Guidance did not provide a specific definition or criteria of ���adequate procedure���, therefore, it is difficult and uncertain for commercial organisations to avoid liability by proving that they have ���adequate procedure��� in place in practice.

As the product of brain human mental activity, the basic real-time performance of brain cell activity is revealed when EEG is generated and changed. Thus, extracting mental activity information from EEG to reveal the brain mechanism of mental activity has always been an important direction of psychological research. By using computer superposition technology, the brain electrical signals generated by the mental activity of the brain can be extracted from the spontaneous power generation. The extracted waveform signals are evoked potentials, which are real real-time waveform of the EEG caused stimulus events including physical stimulation and psychological factors of which current time resolution can be accurate to microsecond level. The current ERP research on cognitive brain mechanisms is not limited to primary perceptual category, but has gone deep into the in-depth study of all aspects of human social behavior such as pre-behavior decision-making, behavior monitoring, behavioral consequences prediction and evaluation, behavioral correctness and error, and behavioral inhibition. With its unique advantages of high time resolution, ERP continues to play an irreplaceable role in the in-depth development of cognitive neuroscience, showing strong development prospects and broad application prospects.

Work fatigue refers to the laborer’s subjective symptoms such as tiredness after continuous work for a period of time, and the phenomenon of labor function decline. In general, the detection and evaluation of work fatigue mainly focus on mental fatigue. Current work fatigue measurement methods mainly include subjective scale method, objective experiment method, objective observation method, physiological index measurement method, and biochemical index measurement method. The physiological index measurement method is a method for detecting fatigue by relying on the human body’s response to various signals or stimuli. Commonly measured physiological indexes include ECG, EEG, EMG, etc. The physiological index measurement method can realize real-time fatigue monitoring during the operation process. At present, there are still many problems in the fatigue detection technology based on the physiological characteristics of the workers, and it is not possible to achieve a high accuracy rate in a short time and adapt to the individual differences of different workers. Future research should focus on the combination of the mining and extraction of fatigue physiological characteristics and the analysis of operational behavior changes. Through the fusion calculation of multiple information parameters in the operation process and full consideration of the impact of various operating environments on monitoring, the accuracy and efficiency of fatigue detection may be achieved.

Prediction of cognitive needs using voice signals is an important subject in information science, management science and sociology, and it is also a very potential research direction. The paper is about the regression prediction of cognitive needs by using speech signal modeling. Its purpose is to find a new cognitive needs assessment model that enables rapid, accurate and non-intrusive assessment of individuals, making up for the lack of timeliness and limited application scope. We obtained the voice data of 240 participants and their cognitive needs scale evaluation results. Then, we use principal component analysis to reduce the dimension of speech features, and use support vector machine, random forest and neural network models to predict cognitive needs. We find that the neural network model not only has the highest prediction accuracy, but also has the most uniform distribution of prediction errors. Through the research, we put forward our own suggestions and prospects for the future research direction of cognitive needs.

In power grid enterprises, a series of unsafe behaviors, such as violation of labor discipline, operating rules and methods, are easy to cause power safety accidents. Therefore, it is particularly important to predict the risks of unsafe behaviors of employees. Firstly, this paper uses the methods of literature review and questionnaire survey to explore the psychological factors related to the safety behavior of employees in specific positions in power grid enterprises, and obtains five indicators: personality quality, cognitive ability, work values, mental health and social environment. Then the method of fully connected neural network is adopted to finally obtain the safety psychological model. The average absolute value loss of this model is 0.049512, which can predict unsafe behaviors of employees well in specific positions.

This paper presents a method to identify individual coping styles based on gait information extracted by OpenPost. By recruiting 414 front-line employees of power distribution posts, psychological index evaluation and gait data acquisition experiments were completed. After preprocessing the gait data, the time domain and frequency domain features are extracted, and the support vector machine is used to train the classification model for identifying the types of coping styles. The correlation between the predictive score of regression model and the score of self-report scale reached a medium level: in the dimension of self-blame, the correlation coefficient between the predictive score of regression model and the score of self-report scale reached 0.52; in the three dimensions of “problem solving”, “help seeking” and “rationalization”, the correlation coefficient could reach 0. The correlation coefficients of avoidance and fantasy were 0.48. The accuracy of the classification model in predicting coping style types (“mature”, “immature” and “mixed”) reached 83%. The results show that by machine learning method, the type of coping style of employees in power grid enterprises can be identified based on gait data.