Search

Lacking an effective strategy to simultaneously address the challenges of quantum efficiency, luminescence intensity and thermal stability has become the key bottleneck for further development and large-scale application of solid-state lighting technology. Herein, inspired by the defect-engineering used in photoelectrocatalytic and photovoltaic materials, we acted in a diametrically opposite way and unprecedentedly proposed an anti-defect engineering strategy to develop high-efficiency phosphors. By constructing a rigid structure and introducing alkali metals to remove cation vacancy defects, similar to building blocks and jigsaw puzzle, we developed three groups of whitlockite phosphors, namely Ca3-xSrx(PO4)2:Ce3+, Ca3(PO4)2:Ce3+,M and (Ca0.5Sr0.5)3(PO4)2:Ce3+,Na+,Mn2+, and synchronously realized the significant of photoluminescence intensity (2.46 times), thermal stability (87.92% at 150 ��C), cathodoluminescence intensity (3.34 times), quantum yield (from 38.90% to 99.07%). We characterized the defect concentration by positron annihilation lifetime spectrum, and calculated Debye temperature and simulated the occupation of M according to DFT theory to reveal the improvement mechanism. Some advanced applications were also explored in this work, including warm-white LEDs, plant growth lighting and information security. The anti-defect engineering proposed in this work may contribute to the further development of high-efficiency phosphors for the next-generation smart solid-state lighting technologies.

Lacking an effective strategy to simultaneously address the challenges of quantum efficiency, luminescence intensity and thermal stability has become the key bottleneck for further development and large-scale application of solid-state lighting technology. Herein, inspired by the defect-engineering used in photoelectrocatalytic and photovoltaic materials, we acted in a diametrically opposite way and unprecedentedly proposed an anti-defect engineering strategy to develop high-efficiency phosphors. By constructing a rigid structure and introducing alkali metals to remove cation vacancy defects, similar to building blocks and jigsaw puzzle, we developed three groups of whitlockite phosphors, namely Ca3-xSrx(PO4)2:Ce3+, Ca3(PO4)2:Ce3+,M and (Ca0.5Sr0.5)3(PO4)2:Ce3+,Na+,Mn2+, and synchronously realized the significant of photoluminescence intensity (2.46 times), thermal stability (87.92% at 150 ��C), cathodoluminescence intensity (3.34 times), quantum yield (from 38.90% to 99.07%). We characterized the defect concentration by positron annihilation lifetime spectrum, and calculated Debye temperature and simulated the occupation of M according to DFT theory to reveal the improvement mechanism. Some advanced applications were also explored in this work, including warm-white LEDs, plant growth lighting and information security. The anti-defect engineering proposed in this work may contribute to the further development of high-efficiency phosphors for the next-generation smart solid-state lighting technologies.

Partial expansion was observed in stratified subsidence during foundation pit dewatering. However, the phenomenon was suspected to be an error because the compression of layers is known to occur when subsidence occurs. A slice of the subsidence cone induced by drawdown was selected as the prototype. Model tests were performed to investigate the phenomenon. The underlying confined aquifer was generated as a movable rigid plate with a hinge at one end. The overlying layers were simulated with remolded materials collected from a construction site. Model tests performed under the conceptual model indicated that partial expansion occurred in stratified settlements under coordination deformation and consolidation conditions. During foundation pit dewatering, rapid drawdown resulted in rapid subsidence in the dewatered confined aquifer. The rapidly subsiding confined aquifer top was the bottom deformation boundary of the overlying layers. Non-coordination deformation was observed at the top and bottom of the subsiding overlying layers. The subsidence of overlying layers was larger at the bottom than at the top. The layers expanded and became thicker. The phenomenon was verified using numerical simulation method based on finite difference method. Compared with numerical simulation results, the boundary effect of the physical tests was obvious in the observation point close to the movable endpoint. The tensile stress of the overlying soil layers induced by the underlying settlement of dewatered confined aquifer contributed to the expansion phenomenon. The partial expansion of overlying soil layers was defined as inversed rebound. The inversed rebound was induced by inversed coordination deformation. Compression was induced by the consolidation in the overlying soil layers because of drainage. Partial expansion occurred when the expansion exceeded the compression. Considering the inversed rebound, traditional layer-wise summation method for calculating subsidence should be revised and improved.

A 2,250 mm whirlpool foundation pit is located in Donghai Island, Zhanjiang City, Guangdong Province, China. The layers of the island are composed of multi-aquifers and multi-aquitards (MAMA). The aquifers are intersected by partial aquitard lenses. A large confined aquifer is frequently interbedded and separated into several sub-confined aquifers by partial aquitards. In the 2,250 mm foundation pit, the water level of two confined aquifers was reduced to satisfy excavation requirements and prevent water inrush. Construction of the 32.55 m deep foundation pit encountered MAMA and potential defects of the diaphragm wall. The pumping wells in the second confined aquifer were used to reduce the water level to ensure the safety of bottom excavation. The pumping wells in the first confined aquifer were used to reduce the water level under emergency conditions to prevent potential water inrush and piping from the defects of the diaphragm wall. Field pumping tests and numerical simulations were performed to determine the risk of leakage and verify the capability of the pumping wells to reduce the water level. Quicksand occurred during shallow excavation because of leakage although the confined aquifer had been cut off and pumped for a long time. Three pumping wells were installed to reduce the water level. When the foundation pit was excavated to a depth of 24 m, water inrush occurred at the middle of the pit bottom although the water level of the dewatered aquifer had been reduced to below the excavation face. A 90 m deep borehole was found where the underlying confined aquifer below the first aquifer induced the water inrush. Although the upper water level was reduced, the high water level in the deep part still induced water inrush. The pumping wells in the second aquifer were all opened, and the water level of the underlying confined aquifer was reduced. After the water level was reduced to below the pit bottom, the borehole was filled, and the water inrush stopped. However, water inrush occurred on the cracks of the diaphragm wall as predicted. The pre-installed pumping wells were opened to control the water inrush. The deepest foundation pit on the island was constructed successfully after dealing with the water inrush and leakages.

This report describes the isolation of a new azaphilone, designated hypocrellone A (2), together with five known compounds (1, 3–6) from a submerged culture of the entomopathogenic fungus Hypocrella sp. (isolate WYTY-21). The absolute stereostructures of the two compounds (1 and 2) were elucidated based on 1D and 2D NMR spectroscopic and mass spectrometric data combined with the data from various chemical transformations. Hypocrellone A (2) and three (3–6) of the five known compounds were cytotoxic to hepatoma cells (cell line BEL-7404); IC50 values ranged from 6.2 to 17.4 μM. At 200 μM, none of the six compounds was toxic to normal human liver cells (cell line HL-7702) or to normal human kidney epithelial cells (cell line HEK-293T).

Metarhizium anisopliae is a well-characterized entomopathogenic fungus that attacks a variety of insects. Its conidia are involved in its propagation and also in its infection of host insects. To investigate the protein expression profiles and to identify the proteins related to development and pathogenesis, we performed a comparative proteomic analysis of the conidia and mycelia of an M. anisopliae strain (Ma1291). The analysis used 2-dimensional gel electrophoresis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. We detected 898 ± 37 protein spots in conidia and 1072 ± 24 in mycelia of strain Ma1291. A comparison of the 2 protein-expression profiles indicated that only 28% of protein spots were common to both developmental stages. Finally, we identified 30 proteins (19 from conidia and 11 from mycelia). The identified proteins exclusive to conidia were those involved in protective processes, appressorium formation, and degradation of the host cuticle (protease PR1H). The identified proteins exclusive to mycelia included major proteins participating in biosynthetic and energy metabolism, such as UTP-glucose-1-phosphate uridylyltransferase and heat shock protein 70. This research provides the first proteomic analysis of different developmental stages of M. anisopliae, and the results should facilitate clarification of the molecular basis of these epigenetic variations.

Let (Ω,F,P) be a complete probability space, and E=(l,2,•••). σ(ω) is a random variable taking values in [0,∞). x(t,ω) is a function taking values in E and defined for all ω∈Ω,t∈[0, σ(ω))). For every t≥0, let $$ \tilde{x}\left( {t,\omega } \right) = \left\{ {\begin{array}{*{20}{c}} {x\left( {t,\omega } \right),} & {t < \sigma \left( \omega \right);} \\ {\Delta ,} & {t \leqslant \sigma \left( \omega \right).} \\ \end{array} } \right. $$

First we stipulate that all the Q-processes that occurred in §§13.1—13.3 possess the Property (D) introduced in §1.1, and their Q-matrices satisfy (9.1.1).

In the last chapter, we studied a method for calculating the minimal nonnegative solutions of systems of nonnegative linear equations. But most systems of nonnegative linear equations encountered are of a special type (called systems of 1-bounded equations). Their minimal nonnegative solutions possess special properties, and calculation of the solutions can be greatly simplified. This chapter is devoted to the study of the minimal nonnegative solutions of the systems of equations of this type.

Assume that X(ω) = {x{t, ω), t < σ(ω)} is a homogeneous denumerable Markov process defined on a complete probability space (Ω, F, P), with the denumerable set E = {1, 2, ⋯} as its minimal state space, (p ij (t), t ≥ 0, i,j∈E) as its standard transition probability matrix, and assume its Q matrix satisfies the relation: $$0 < \,{q_i}\, \equiv \, - \,{q_{ii}}\, < \, + \,\infty ,\,\,\,\sum\limits_{j \in E} {{q_{ij}}\,0\,\,\,(i\, \in \,E).} $$ (9.1.1)

Part I of this book, indicates that the minimal Q -process and Q -processes of order one are the bases for the study of general Q-processes. In the preceding chapter we studied the minimal Q-process, and in this chapter, we shall proceed to investigate Q-processes of order one.

Suppose X = {x(t,ω), t < σ (ω)} is a homogeneous denumerable Markov process defined on a complete probability space (Ω, F, P), with phase space E = {1, 2, ⋯}, and transition probabilities p ij (t), i, j∨E, t ≥ 0, which are real-valued functions satisfying the following conditions: $${p_{ij}}(t) \geqslant 0,$$ (12.1.1) $$\sum\limits_{j \in E} {{p_{ij}}(t) \leqslant }\,1,$$ (12.1.2) $$\sum\limits_{k \in E} {p{}_{ik}(t){p_{kj}}(s)}= {p_{ij}}(t + s),$$ (12.1.3) $$\mathop {\lim }\limits_{t \to 0} {p_{ij}}(t) = {p_{ij}}(0) = {\delta _{ij}},$$ (12.1.4) where \({\delta _{ii}} = 1,\,\,{\delta _{ij}} = 0\,\,(i \ne j)\).

For simplicity, we shall identify the Markov chain X(ω)= {xn(ω),n

Suppose(Ω,F,P)is a complete probability space, $${X^{(n)}}(\omega ) = \left\{ {{x^{(n)}}(t,\,\,\omega ),t\,\, < \,\,{\sigma ^{(n)}}(\omega )} \right\}$$ is a sequence of Q-processes of order one on it, and $${g_n}({X^{(n\,\, + \,\,1)}}(\omega )) = {X^{(n)}}(\omega )$$ .

The theory of the Martin exit boundary for a Markov chain was first established by Doob [12] and then generalized by Hunt. Many works appeared thereafter, but in all those works there are always some restrictions imposed on the Markov chain. For example, in [13] all the states of the Markov chain are assumed to be nonrecurrent, and in [14] it is assumed that there exists at least one state which can reach all the other states. So the Martin exit boundary theory for general Markov chains has not been established. Moreover, some subjects involved in the exit boundary theory have not been studied in detail. For example, only definitions of the atomic exit point and the nonatomic exit point are given, but no effective criteria. The aim of the present chapter is: (i) to establish the Martin exit boundary theory for general Markov chains; (ii) to present the criteria for the excessive functions, potential functions, minimal excessive functions, minimal potential functions, and minimal harmonic functions, atomic exit points and nonatomic exit points, and for the existence of atomic exit space and nonatomic exit space; (iii) to present the criteria for Blackwell decompositions of atomic almost closed sets, completely nonatomic almost closed sets and state spaces.

In this chapter, we shall investigate arbitrary Q-processes on the basis of the study of minimal Q-processes and Q-processes of order one.