Drop failure modes of Sn-3.0Ag-0.5Cu solder joints in wafer level chip scale package

To reveal the drop failure modes of the wafer level chip scale packages （WLCSPs） with Sn-3.0Ag-0.5Cu solder joints, board level drop tests were performed according to the JEDEC standard. Six failure modes were identified, i.e., short FR-4 cracks and complete FR-4 cracks at the printing circuit board （PCB） side, split between redistribution layer （RDL） and Cu under bump metallization （UBM）, RDL fracture, bulk cracks and partial bulk and intermetallic compound （IMC） cracks at the chip side. For the outmost solder joints, complete FR-4 cracks tended to occur, due to large deformation of PCB and low strength of FR-4 dielectric layer. The formation of complete FR-4 cracks largely absorbed the impact energy, resulting in the absence of other failure modes. For the inner solder joints, the absorption of impact energy by the short FR-4 cracks was limited, resulting in other failure modes at the chip side.

Crisis of existence in The catcher in the rye

Through carefully reading and studying the emotional crisis of Holden in The catcher in the rye, the main character＇s anxiety, isolation, bewilderment in the crisis of existence and his efforts to identify himself in the dilemma are interpreted. His experience exemplifies the plight experienced by the postwar generation and provides a good text from which one can study the American society and culture in 1950s.

Gradient based restoration of coal mine images obtained by underground wireless transmissions

Curvature-driven diffusion (CDD) principles were used to develop a novel gradient based image restora- tion algorithm. The algorithm fills in blocks of missing data in a wireless image after transmission through the network. When images are transmitted over fading channels, especially in the severe circum- stances of a coal mine, blocks of the image may be destroyed by the effects of noise. Instead of using com- mon retransmission query protocols the lost data is reconstructed by using the adaptive curvature-driven diffusion (ACDD) image restoration algorithm in the gradient domain of the destroyed image. Missing blocks are restored by the method in two steps: In step one, the missing blocks are filled in the gradient domain by the ACDD algorithm; in step two, and the image is reconstructed from the reformed gradients by solving a Poisson equation. The proposed method eliminates the staircase effect and accelerates the convergence rate. This is demonstrated by experimental results.

Abscisic acid negatively regulates post-penetration resistance of Arabidopsis to the biotrophic powdery mildew fungus

Pytohormone abscisic acid （ABA） plays important roles in defense responses. Nonetheless, how ABA regulates plant resistance to biotrophic fungi remains largely unknown. Arabidopsis ABA-deficient mutants, aba2-1 and aba3-1, displayed enhanced resistance to the biotrophic powdery mildew fungus Golovinomyces cichoracearum. Moreover, exogenously administered ABA increased the susceptibility of Arabidopsis to G. cichoracearum. Arabidopsis ABA perception components mutants, abil-1 and abi2-1, also displayed similar phenotypes to ABA-deficient mutants in resistance to G. cichoracearum. However, the resistance to G. cichoracearum is not changed in downstream ABA signaling transduction mutants, abi3-1, abi4-1, and abi5-1. Microscopic examination revealed that hyphal growth and conidiophore production of G. cichoracearum were compromised in the ABA deficient mutants, even though pre-penetration and penetration growth of the fimgus were not affected. In addition, salicylic acid （SA） and MPK3 are found to be involved in ABA-regulated resistance to G. cichoracearurn. Our work demonstrates that ABA negatively regulates post-penetration resistance of Arabidopsis to powdery mildew fungus G. cichoracearum, probably through antagonizing the function of SA.

Correction of leaf nutrient resorption efficiency on the mass basis

Nutrient resorption is a crucial mechanism for plant nutrient conservation,but most previous studies did not consider the leaf-mass loss during senescence due to lack of measured data.This would lead to an underestimation of nutrient resorption efficiency(NuRE),or calculating NuRE of various species based on the average mass loss at plant-functional-group level in the literature,thus affecting its accuracy.Here we measured the leaf-mass loss to correct NuRE with the species-specific mass loss correction factor(MLCF),so as to foster a more accurate calculation of the nutrient fluxes within and between plants and the soil.Green leaves and senesced leaves were collected from 35 dominant woody plants in northern China.Mass of green and senesced leaves were measured to calculate the MLCF at species level.The MLCF was reported for each of the 35 dominant woody plants in northern China.These species averagely lost 17%of the green-leaf mass during leaf senescence,but varied greatly from 1.3%to 36.8%mass loss across the 35 species,or 11.7%to 19.6%loss across the functional types.Accordingly,the MLCF varied from 0.632 to 0.987 across the 35 species with an average value 0.832.The NuRE corrected with MLCF was remarkably increased on the whole(e.g.both the average nitrogen and phosphorus NuRE became about 9%higher,or more accurate),compared with the uncorrected ones,especially in the case of low resorption efficiencies.Our field data provide reliable references for the MLCF of plants in related regions at both species and functional-type levels,and are expected to promote more accurate calculations of NuRE.