Influence of Molecular Weight on the Performance of Organic Solar Cells Based on a Fluorene Derivative

The performance of organic photovoltaic (OPV) bulk‐heterojunction blends comprising a liquid‐crystalline fluorene derivative and a small‐molecular fullerene is found to increase asymptotically with the degree of polymerization of the former. Similar to various thermodynamic transition temperatures as well as the light absorbance of the fluorene moiety, the photocurrent extracted from OPV devices is found to strongly vary with increasing oligomer size up to a number average molecular weight, M_n ≈ 10 kg mol^?1, but is rendered less chain‐length dependent for higher M_n as the fluorene derivative gradually adopts polymeric behavior.     

Optimized test circuits for SER characterization of a manufacturingprocess

Novel test circuits for the accurate determination of soft error rate (SER) dependency on critical charges Q_CRIT have been developed. The minimum charge necessary for flipping the state of a sensor cell, denoted by Q_CRIT, is measured with 1%-2% accuracy before exposing the circuits to radiation. During the accelerated testing, circuits biased with multiple different supply voltages V_CC are simultaneously placed into a beam and any bit flips are logged. From the measured SER dependency on V_CC and previously measured Q_CRIT dependency on V_CC, the dependency of SER on Q_CRIT can be deduced by correlating V_CC's for the two measurements. Furthermore, the sensor cell utilizes a single dynamic node which can be programmed to detect strikes on either N- or P-type diffusions, but not both at the same time. The measured dependency SER(Q_CRIT), normalized by the diffusion area, can be used for predicting SER of any other circuit fabricated in the same process and aid designers in optimization for reduced SER. Predictions of a theoretical SER model, if one is available, can be compared directly with the measurements. Since the true Q_CRIT of the test circuits is known accurately, any discrepancy larger than given by the measurement uncertainty of SER(Q_CRIT) would be clearly due to limitations of the SER model. We implemented the test circuits in a 0.6-μm bulk CMOS process and verified accuracy of Q_CRIT(V_CC) calibration method     

On the Ring-Opening of Some 3-Lithiobithienyls and 3′-Lithio-α-terthienyls

3-Halobithienyls have been prepared through the Pd(PPh₃)₄-catalyzed coupling of thiopheneboronic acids with 2,4-dihalothiophenes. The ring-opening of the corresponding 3-lithiobithienyls obtained upon halogen-metal exchange with phenyllithium has been investigated. Compound 12 , 3′-iodo-2,2′,2″-terthienyl, was prepared in one step through the Pd(PPh₃)₄-catalyzed coupling of two equivalents of 2-thiopheneboronic acid with 2,3,5-triiodothiophene. Treatment of 12 with phenyllithium and methyl iodide gave a mixture of compounds 10 and 11 occurring in Berkheya and Cullumia species.     

A GC–MS-based metabonomic investigation of blood serum from irritable bowel syndrome patients undergoing intervention with acidified milk products

In the present study, the use of gas chromatography mass spectrometry (GC–MS)-based metabonomics to characterize blood serum in an intervention study of patients suffering from the common gastrointestinal disorder irritable bowel syndrome (IBS) was investigated. The patients included in the study consumed an acidified milk product with (n = 30) or without probiotics (n = 31) (Lactobacillus paracasei F19, Lactobacillus acidophilus LA-5 and Bifidobacterium lactis BB-12) for an 8-week period, and blood serum samples were collected before and after the intervention. Acidified milk is commonly used as a delivering vector for probiotics in commercial consumer settings. The serum samples were extracted and derivatized using N-Methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA), and GC–MS analysis was carried out. Multivariate data analysis including principal component analysis (PCA), orthogonal partial least squares-discriminant analysis (OPLS-DA), and S-plot was applied on the obtained GC–MS data, which revealed higher serum lactate, glutamine, proline creatinine/creatine, and aspartic acid levels and lower serum glucose levels after the intervention period for both treatment groups. Consequently, the present study indicated an effect of acidified milk consumption on the plasma metabolite profile, which was independent of a concomitant intake of probiotics. In addition, the present study demonstrates that GC–MS is a useful analytical technique for metabonomics studies of blood serum.     

Influence of nonlinearities on the frequency response of agrid-connected vector-controlled VSC

In this paper, the small-signal performance of different vector controllers for grid-connected voltage-source converters is investigated. Losses in the line filter, as well as nonlinearities due to blanking time and nonideal valves, are usually not modeled in the evaluation of the performance of control principles. A method to compensate for nonlinearities due to blanking time and nonideal valves is implemented. Furthermore, the influence of the compensation principle on the performance of traditional deadbeat controllers is shown in measured frequency responses. The compensation method reduces the cross-coupling gain and improves the direct-coupling gain. To show the influence of nonlinearities, measured frequency responses are compared with responses obtained from analytical models. At high frequencies, the frequency-dependent losses in the line filter should be taken into account to predict the dynamic performance correctly     

Application of automated video analysis for behavioural studies: concept and experience

Lund University, Sweden, is developing a video analysis system for making long-term behavioural studies, primarily in complex urban environments. Road users are detected using the KLT (Kanade-Lucas-Tomasi) interest point tracker. Trajectories are estimated using foreground-background segmentation, whereas speed is estimated using the shape analysis of interest points. The extracted trajectories are further used for behavioural analysis. The authors present the experience from an ongoing study in Stockholm city, where the task was to find out if allowing two-way bicycle traffic on one-way streets had negative effects on safety. The video analysis system was applied to detect biking in the -wrong- direction and analyse traffic conflicts between cyclists and other road users. The manual observations done in parallel allowed validating the accuracy of system performance.     

Optimum voltage swing on on-chip and off-chip interconnect

Reduced voltage swings are often used for saving power on interconnects. In this paper, we demonstrate the existence of an optimum voltage swing for minimum power consumption, for on-chip and off-chip interconnects. Actual values of optimum swings and corresponding power savings for high performance interconnects are estimated     

Substance P modulates sensory action potentials in the lamprey via a protein kinase C-mediated reduction of a 4-aminopyridine-sensitive potassium conductance

We have examined the effects of the tachykinin substance P on the action potential of lamprey mechanosensory dorsal cells. Substance P increased the spike duration and reduced the afterhyperpolarization. These effects were mimicked by stimulation of the dorsal root, which contains tachykinin-like immunoreactive fibres. The tachykinin antagonist spantide II blocked the effects of both substance P and dorsal root stimulation. The spike broadening was voltage-dependent, and was due to the reduction of a 4-aminopyridine-sensitive potassium conductance. The spike broadening was mimicked by G-protein activators and blocked by the G-protein inhibitor GDPbetaS. Pertussis toxin did not block the effects of substance P. The spike broadening was blocked by the protein kinase C and cAMP-dependent protein kinase inhibitor H7, and by the specific protein kinase C antagonist chelerythrine, but not by the cAMP and cGMP-dependent protein kinase inhibitor H8. The phorbol ester phorbol 12,13-dibutyrate mimicked and blocked the effects of substance P, supporting the role of protein kinase C in the spike modulation. The adenylate cyclase activator forskolin and the cAMP agonist SpcAMPs mimicked but did not block the effects of substance P on the spike duration, suggesting that protein kinase A also modulates the dorsal cell action potential, but that substance P acts independently of this pathway. Substance P also increased the excitability of the dorsal cells. This effect was blocked by 4-AP, PDBu and chelerythrine, but not by H8, suggesting that the increase in excitability shares the same intracellular and effector pathways as the spike broadening.