[en] Herein we report an isostructural solid solution of Mg₂(Ti_1-xSn_x)O₄:0.002Mn (0 ≤ x ≤ 1) in which cation substitution leads to the presence of two different Mn luminescence centers. When Mn sources of different valance states (MnCO₃/MnO₂/Mn₃O₄) were introduced into Mg₂TiO₄, the self-redox reaction of MnCO₃ occurred in air that can be proved by experimental results, from Mn²⁺→ Mn⁴⁺→ Mn³⁺ and eventually Mn₃O₄ can be obtained. Low valance state Mn^2+/3+ ions in Mn₃O₄ can be further oxidized to Mn⁴⁺ ions by O₂ in Mg₂TiO₄:Mn. Mn⁴⁺ red emission can be observed along with oxygen defects-induced blue emission in Mg₂(Ti_1-xSn_x)O_4:Mn (0 ≤ x<1). Eventually, the spectral emission of Mn⁴⁺ was converted to that of Mn²⁺, green emission, in Mg₂SnO₄:Mn though electrons transfer from oxygen vacancies ($V_o^{•}$) to Mn³⁺. This is the first time that compositional-tunability that induces Mn ions of different valance states luminescent behaviors and further interprets its spectral transition mechanism.

[en] This paper studies the dual-side event-triggered output feedback H_∞ control for networked control system with network-induced delays. Unlike continuous-time event-triggered mechanism (ETM) or state-dependent ETM, the discrete dual-side ETMs are firstly proposed by using plant output and controller output, respectively, which effectively reduce transmission rate of sampled data in both sensor-to-controller and controller-to-actuator channels. Then, the closed-loop system is modelled as a time-delay system, which characterizes effects of the dual-side ETMs and networked-induced delays in a unified framework. Based on the system model, asymptotic stability criterion satisfying H_∞ performance is derived, and conservatism is reduced by the delay decomposition method and reciprocally convex approach. Moreover, a co-design scheme is presented to design the dual-side ETMs and controller simultaneously, which is more convenient than two-step design method requiring controllers to be given a priori. Finally, examples confirm effectiveness of the proposed method.

[en] Highlight• Two-stage pretreatment of alkaline sulphonation and steam treatment was performed. • Alkaline sulphonation improved the degree of lignin removal/modification. • The following steam treatment further enhanced cellulose accessibility. • The two-stage pretreatment maximized sugar yield from raw biomass. • Fermentable sugars were efficiently converted to ethanol. This work proposed a two-stage pretreatment with alkaline sulphonation and steam treatment, and investigated its efficiency for converting Eucalyptus woody biomass to fermentable sugars and bioethanol. Comparing with steam pretreatment and subsequent sulphonation, this alkaline sulphonation-steam pretreatment improved carbohydrate recovery by maintaining a more neutral pH throughout the pretreatment process, while promoting the enzymatic digestibility of biomass through lignin removal and modification. Results showed that the alkaline sulphonation-steam pretreatment caused lignin removal of 69.37% and 120.28 mmol/kg acid groups incorporation into substrate, both of which could lead to significantly improved cellulose accessibility. About 80% of the sugars present in the original carbohydrate (cellulose and hemicellulose) were released, which could be recovered after pretreatment and enzymatic hydrolysis. The sugars released from enzymatic hydrolysis of substrate pretreated by alkaline sulphonation-steam pretreatment could be efficiently converted to ethanol, indicating that alkaline sulphonation-steam two-stage pretreatment is a promising pretreatment approach of lignocellulosic biomass for the production of biofuels.