Lasing was observed from ZnO nanorods prepared by a simple method of chemical bath deposition (CBD) on ITOcoated glass substrates. The X-ray diffraction pattern showed a dominant peak for (002) plane typical for good crystalline quality of ZnO grown in the z-direction with a wurtzite structure. Continuous-wave photoluminescence (PL) spectra revealed a peak centered at 380 nm corresponding to the band gap of ZnO. Under pulsed optical pumping, lasing was observed above the nominal PL peak, initially for one mode at 384 nm. Two additional modes at 386 nm and 390 nm was observed when the pumping power is further increased. Threshold was achieved at 0.7 µJ which was 10 times smaller than that reported for powder-based random lasers. In addition, gain pinning was also observed for the dominant mode and the additional two modes appeared upon onset of this gain pining behavior.

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During the periods of strong winter monsoon, the occurrence of extensive floods in the low-lying areas mostly in the east coast part of the Peninsula Malaysia continually results in huge destruction to public and private utilities, damage to farmlands, and in addition, leads to loss of lives with outbreak of epidemic which prompted evacuations of hundreds of thousands from their homes and communities. This paper presents research results on the impacts of subsurface water on the east coast Peninsula Malaysian floods, therefore complementing the existing data on the flooding events in this area. In our finding, we present the vulnerability of the aquifer units in the flood-affected communities to floods during intense precipitations and then proffer suggestions to prevent near future occurrence. The partial coverage of the alteration zone that is completely nonexistent in this area should have provided the needed essential storage and transmissivity if present in the east coast Peninsula Malaysia environments. Most of the aquifer units in this part are unconfined and are opened to surface water. We applied electrical resistivity tomography methods of geophysical prospecting and borehole lithologic logs to study the subsurface structures prone to flooding in addition to the information on the rainfall data. However, the GOD vulnerability Index rating method was modified and improved upon with the additions of fluctuations of borehole water heights FBWH and the river bank heights RBH together with the topography parameters to produce the GOD-FBRT Index that better refine the method by considering the literal movement of fluids within the subsurface. The configuration of the Kelantan River basin land system as delineated by this study makes the entire east coast areas vulnerable to flooding with the degree of vulnerability as computed in the study area that ranged between 0.1 (very low) and 1.0 (very high).

This study reports several Late Paleozoic dropstone‐bearing formations in Peninsular Malaysia which were not previously investigated. Additionally, the source, formation mechanisms, and correlation to the global Late Paleozoic Ice Age (LPIA) of these dropstones are discussed. Dropstones occur as subrounded to rounded single clasts ranging in size from 0.5 to 20 cm, scattered in red mudstone, black shales, sandstones and shales, and are composed of granite, quartzite, and sandstone. Occurrence of dropstones as rounded, single clasts, and soft‐sediment deformation of the host rock with striations in the dropstones suggest a glaciomarine origin. Precambrian basement rocks and Cambrian–Ordovician quartzite and sandstones are the main sources of the dropstones. Dropstones hosted by shallow‐marine sediments are formed by dropping of clasts from icebergs, while, dropstones present in deep‐marine sediments are formed by dropping of clasts from an ice sheet. The oldest glaciomarine rocks of the Rebak and Chepor members (Singa Formation) can be correlated to the Early Carboniferous global glaciation of the LPIA episode of Gondwana. These sediments are considered as the first record of Lower Carboniferous (Mississippian) glaciomarine rocks in Southeast Asia. However, the glaciomarine deposits of the Kentut and Bukit Raja members (Singa and Kubang Pasu formations, respectively) are correlated with the global Middle Carboniferous glaciation. In addition, the glaciomarine deposits of the “undifferentiated” member (Kubang Pasu Formation), Ulang and Selang members (Singa Formation), as well as the Kenny Hill Formation, are correlative to the Late Carboniferous‐Early Permian glaciation episode known as the apex of the LPIA. These results confirm the paleomagnetic and paleontological data which suggest that the Sibumasu Terrane initially was attached to the Late Paleozoic Gondwana.