Electrocatalytic nitrite reduction is of great significance for wastewater treatment and value-added chemicals synthesis. This review highlights the latest progress in electrochemical nitrite reduction to produce two types of products,...

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A comprehensive framework f o r probabil i s t i c steady-state and dynamic s e c u r i t y assessment i s presented. measure of system s e c u r i t y . bution of the time t o insecurity i s obtained from the solution of a l i n e a r vector d i f f e r e n t i a l equation whose c o e f f i c i e n t s a r e expressed i n terms of steady-state and dynamic s e c u r i t y regions. An i l l u s t r a t i v e example of a simple system is given.The time t o i n s e c u r i t y i s used a s the The probability d i s t r i - I . INTRODUCTIONSecurity of a power system i s considered t o be an instantaneous, time-varying condition t h a t i s a funct i o n of the robustness of the system r e l a t i v e t o i m i n e n t disturbances. Dy Liacco [l-41 has established a framework f o r deterministic s t e a d y -s t a t e s e c u r i t y assessment. In Dy Liacco's framework the robustness of the system i s t e s t e d , using a power flow, with respect t o a s e t of selected contingencies. two aspects of system f a i l u r e events t h a t should be considered i n s e c u r i t y assessment, namely, load curtailment and system collapse [5]. s e c u r i t y assessment addresses primarily t o the question of the adequacy of generating and transmission capacity t o meet load demand. of the avoidance of uncontrolled cascading t r i p o u t s t h a t lead t o system collapse, dynamic response of the system following a disturbance should be considered. Furthermore, because of uncertainty inherent i n the prediction of "imminent disturbances," a p r o b a b i l i s t i c framework f o r s e c u r i t y assessment i s more appropriate. Thus t h e r e i s a need t o extend the deterministic steady-state s e c u r i t y assessment t o p r o b a b i l i s t i c dynamic s e c u r i t y assessment. Transient s t a b i l i t y i s the principal component in dynamic s e c u r i t y assessment. Traditionally a s e t of s t a b i l i t y l i m i t s f o r l i n e flows i s derived by performing a l a r g e number of o f f -l i n e t r a n s i e n t s t a b i l i t y simulation f o r d i f f e r e n t operating conditions and possible contingencies. This set of operating cons t r a i n t s i s then included in a steady-state s e c u r i t y assessment program [6]. These c o n s t r a i n t s may be too conservative o r sometimes o p t i m i s t i c f o r the actual operating condition. Recent research i n the development of new t o o l s f o r on-line dynamic s e c u r i t y assessment i s focused on the following t h r e e d i r e c t i o n s , ( i ) f a s t simulation [7], ( i i ) pattern recognition [8,9], and ( i i i ) d i r e c t methods [9,10,11]. The d i r e c t method using the concept of Transient There a r e The steady-state To address the question ' On leave from Tianjin University, People's Republic o f China.8 3 WM 065-0 A paper recommended and approved by the IEEE Power System Engineering Committee of the IEEE Power Engineering Society for presentation at the IEEE/PES 1 Energy Function seems t o be q u i t e promising. stu...

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Reversible switching of OER performance is designed for the first time in COF materials through convenient phase transformation via ion exchange. This also facilitates to enhance atom utilization efficiency.