Non-linear conductance at the superconductor-insulator transition in titanium nitride

The mechanism for the superconductor-insulator transition in disordered films, the transition from a weak superconductor into a strong insulator at low temperature, is still an open question. One key issue is whether superconductivity is the driving force of this insulating behavior and to which extent charging effects play a role. In this work high resolution dc current-voltage characteristics are presented. Non-linear behavior is found at high and low bias. The high bias non-linearity can be mainly attributed to electron overheating. The insulating state is analyzed in the framework of charge dominated Josephson junction arrays. The low-bias non-linearity can be attributed to a charge Berezinskii-Kosterlitz-Thouless transition displaying the duality of the superconducting and the insulating state

Tahap Kesedaran Kakitangan Sokongan Universiti Pertanian Malaysia Yang Mendapat Kemalangan: Satu Kajian Kes

Tujuan utama kajian ialah untuk mengkaji tahap kesedaran terhadap keselamatan ditempat kerja di kalangan kakitangan sokongan Univesiti Pertanian Malaysia( UPM )yang pernah mengalami kemalangan. Kajian ini juga bertujuan untuk mengetahui:jenis kecederaan yang dialami oleh pekerja , sebab utama yang mengakibatkan kemalangan,program atau aktiviti yang dijalankan oleh Jabatan bagi menimbulkan kesedaran terhadap keselamatan,penerimaan pekerja terhadap kerja mereka dan program keselamatan yang diperlukan oleh pekerja bagi mengurangkan kejadian kemalangan. Seramai 41 orang pekerja sokongan UPM dalam kategori C dan D yang pernah mengalami kemalangan telah dipilih sebagai responden untuk kajian ini. Data yang dikumpul telah dianalisiskan dengan menggunakan "Statistical Package for Sosial Science" ( SPSS / PC+ ) . Frekuensi,peratus,dan min telah digunakan dalam analisis ini

Evidence for a Finite Temperature Insulator

In superconductors the zero-resistance current-flow is protected from dissipation at finite temperatures (T) by virtue of the short-circuit condition maintained by the electrons that remain in the condensed state. The recently suggested finite-T insulator and the "superinsulating" phase are different because any residual mechanism of conduction will eventually become dominant as the finite-T insulator sets-in. If the residual conduction is small it may be possible to observe the transition to these intriguing states. We show that the conductivity of the high magnetic-field insulator terminating superconductivity in amorphous indium-oxide exhibits an abrupt drop, and seem to approach a zero conductance at T<0.04 K. We discuss our results in the light of theories that lead to a finite-T insulator

Quantum spherical model with competing interactions

We analyze the phase diagram of a quantum mean spherical model in terms of the temperature $T$, a quantum parameter $g$, and the ratio $p=-J_{2}/J_{1}$, where $J_{1}>0$ refers to ferromagnetic interactions between first-neighbor sites along the $d$ directions of a hypercubic lattice, and $J_{2}<0$ is associated with competing antiferromagnetic interactions between second neighbors along $m\leq d$ directions. We regain a number of known results for the classical version of this model, including the topology of the critical line in the $g=0$ space, with a Lifshitz point at $p=1/4$, for $d>2$, and closed-form expressions for the decay of the pair correlations in one dimension. In the T=0 phase diagram, there is a critical border, $g_{c}=g_{c}(p)$ for $d\geq2$, with a singularity at the Lifshitz point if $d<(m+4)/2$. We also establish upper and lower critical dimensions, and analyze the quantum critical behavior in the neighborhood of $p=1/4$.Comment: 18 pages, 3 figures, refs added, minor modifications to match published versio

Industrial SO2 emission monitoring through a portable multichannel gas analyzer with an optimized retrieval algorithm

SO2 variability over a large concentration range and interferences from other gases have been major limitations in industrial SO2 emission monitoring. This study demonstrates accurate industrial SO2 emission monitoring through a portable multichannel gas analyzer with an optimized retrieval algorithm. The proposed analyzer features a large dynamic measurement range and correction of interferences from other coexisting infrared absorbers such as NO, CO, CO2, NO2, CH4, HC, N2O, and H2O. The multichannel gas analyzer measures 11 different wavelength channels simultaneously to correct several major problems of an infrared gas analyzer including system drift, conflict of sensitivity, interferences among different infrared absorbers, and limitation of measurement range. The optimized algorithm uses a third polynomial instead of a constant factor to quantify gas-to-gas interference. Measurement results show good performance in the linear and nonlinear ranges, thereby solving the problem that the conventional interference correction is restricted by the linearity of the intended and interfering channels. The results imply that the measurement range of the developed multichannel analyzer can be extended to the nonlinear absorption region. The measurement range and accuracy are evaluated through experimental laboratory calibration. Excellent agreement was achieved, with a Pearson correlation coefficient (r(2)) of 0.99977 with a measurement range from approximately 5 to 10 000 ppmv and a measurement error of less than 2 %. The instrument was also deployed for field measurement. Emissions from three different factories were measured. The emissions of these factories have been characterized by different coexisting infrared absorbers, covering a wide range of concentration levels. We compared our measurements with commercial SO2 analyzers. Overall, good agreement was achieved

Sickle cell disease in pregnancy – a rare condition with detrimental outcome: a case report

Sickle cell disease (SCD) in pregnancy is uncommon in Malaysia. We present a case of sickle cell disease in pregnancy with maternal and fetal complications. The patient presented with acute pain crisis and hemolysis in the third trimester. Despite thromboprophylaxis, she developed deep vein thrombosis. The pregnancy was further complicated by severe pre-eclampsia and intrauterine growth restriction which require preterm caesarean section. The baby was admitted to Neonatal Intensive Care Unit due to prematurity and low birth weight. Multidisciplinary approach in managing pregnant patient with SCD is essential in achieving good obstetrics outcome

Large-n expansion for m-axial Lifshitz points

The large-n expansion is developed for the study of critical behaviour of d-dimensional systems at m-axial Lifshitz points with an arbitrary number m of modulation axes. The leading non-trivial contributions of O(1/n) are derived for the two independent correlation exponents \eta_{L2} and \eta_{L4}, and the related anisotropy index \theta. The series coefficients of these 1/n corrections are given for general values of m and d with 0<m<d and 2+m/2<d<4+m/2 in the form of integrals. For special values of m and d such as (m,d)=(1,4), they can be computed analytically, but in general their evaluation requires numerical means. The 1/n corrections are shown to reduce in the appropriate limits to those of known large-n expansions for the case of d-dimensional isotropic Lifshitz points and critical points, respectively, and to be in conformity with available dimensionality expansions about the upper and lower critical dimensions. Numerical results for the 1/n coefficients of \eta_{L2}, \eta_{L4} and \theta are presented for the physically interesting case of a uniaxial Lifshitz point in three dimensions, as well as for some other choices of m and d. A universal coefficient associated with the energy-density pair correlation function is calculated to leading order in 1/n for general values of m and d.Comment: 28 pages, 3 figures. Submitted to: J. Phys. C: Solid State Phys., special issue dedicated to Lothar Schaefer on the occasion of his 60th birthday. V2: References added along with corresponding modifications in the text, corrected figure 3, corrected typo