Novel heterobimetallic ruthenium(III)-cobalt(II) compounds constructed from trans-[Ru(III)(Q)2(CN)2](-) (Q = 8-quinolinolato): synthesis, structures and magnetic properties

Reaction of [Ru(II)(PPh(3))(3)Cl(2)] with HQ and KCN produces a new dicyanoruthenium(III) building block, [Ru(III)(Q)(2)(CN)(2)](-). It reacts with hydrated CoCl(2) in MeOH or DMF to produce a trinuclear compound 2 or a 1-D zigzag chain 3.     

Nanoimprint Lithography‐Directed Self‐Assembly of Bimetallic Iron–M (M=Palladium,Platinum) Complexes for Magnetic Patterning

Self‐assembly of d⁸ metal polypyridine systems is a well‐established approach for the creation of 1D organometallic assemblies but there are still challenges for the large‐scale construction of nanostructured patterns from these building blocks. We describe herein the use of high‐throughput nanoimprint lithography (NIL) to direct the self‐assembly of the bimetallic complexes [4′‐ferrocenyl‐(2,2′:6′,2′′‐terpyridine)M(OAc)]⁺(OAc)^? (M=Pd or Pt; OAc=acetate). Uniform nanorods are fabricated from the molecular self‐organization and evidenced by morphological characterization. More importantly, when top‐down NIL is coupled with the bottom‐up self‐assembly of the organometallic building blocks, regular arrays of nanorods can be accessed and the patterns can be controlled by changing the lithographic stamp, where the mold imposes a confinement effect on the nanorod growth. In addition, patterns consisting of the products formed after pyrolysis are studied. The resulting arrays of ferromagnetic FeM alloy nanorods suggest promising potential for the scalable production of ordered magnetic arrays and fabrication of magnetic bit‐patterned media.     

Checking key integrity efficiently for high-speed quantum key distribution using combinatorial group testing

With the increasing key generation rate in practical quantum key distribution, checking key integrity efficiently becomes an important problem. Since the original method that utilizes one hash value for a key string has to discard all the key bits even if just one error bit exists, it may eventually limit the practical rate of key generation. In this paper, we propose a new scheme based on combinatorial group testing to identify the rare error bits so as to avoid dropping all the key bits. Experimental results show that the scheme can precisely locate the error bits if the number of error bits is within the maximum guaranteed number set by the scheme while the overhead is insignificant (for a 10⁶-bit key, additional bits: 0.1% of the key; hashing time: 16 ms; checking time: 22 ms) and it can still keep the majority of the correct bits (95%) even if the number of error bits is 10 times of the maximum. The results also indicate that the minimum key size for the CGT-based scheme to gain an advantage over the original method is about 2 × 10⁴ bits.     

A Hybrid Descent Method for Global Optimization

In this paper, a hybrid descent method, consisting of a simulated annealing algorithm and a gradient-based method, is proposed. The simulated annealing algorithm is used to locate descent points for previously converged local minima. The combined method has the descent property and the convergence is monotonic. To demonstrate the effectiveness of the proposed hybrid descent method, several multi-dimensional non-convex optimization problems are solved. Numerical examples show that global minimum can be sought via this hybrid descent method.     

半无限空心截锥的特征值与端部效应

本文通过Birkhoff-Morgan关于单参数连续群不变性理论建立了空心半无限截锥的特征值方程,由此可以得到不同锥角下空心锥体的特征值,利用最小二乘法,本文得到了应力展开式中的各特征值系数,并由此得到问题的解。     

Synthesis,Discovery, and Quantitation of Dihomo‐Isofurans: Biomarkers for In Vivo Adrenic Acid Peroxidation

The growing importance of lipidomics, and the interest of non‐enzymatic metabolites of polyunsaturated fatty acids (PUFAs) prompted us to initiate the synthesis of novel dihomo‐IsoF compounds. Such metabolites of adrenic acid, the main PUFA in white matter, were synthesized using a divergent approach based on an orthoester cyclization. LC‐MS/MS investigation on pig brains showed the potential of this novel biomarker for the first time, as a powerful new tool for brain lipid peroxidation assessment.     

Synthesis and self‐assembly of polystyrene‐grafted multiwalled carbon nanotubes with a hairy‐rod nanostructure

Polystyrene‐grafted multiwalled carbon nanotubes (PS‐g‐MWNTs) with a hairy‐rod nanostructure were synthesized by the in situ free‐radical polymerization of styrene in the presence of multiwalled carbon nanotubes (MWNTs) terminated with vinyl groups. To quantitatively study the molecular weight and composition of polystyrene (PS) chains in PS‐g‐MWNTs, PS‐g‐MWNTs were fully defunctionalized by hydrolysis. The results showed that 1 of every 100 carbon atoms in MWNTs was functionalized at the tips and outer walls of the carbon nanotubes and grafted by PS with a weight‐average molecular weight of 9800 g/mol; therefore, a uniform thin layer (ca. 8–10 nm) of a PS shell was formed on the outer wall of MWNTs. PS‐g‐MWNTs were soluble in dimethylformamide and tetrahydrofuran. The thermal stability and glass‐transition temperature of PS in PS‐g‐MWNTs were obviously increased. Nanopins were formed on the glass substrates by the self‐assembly of PS‐g‐MWNTs, and the dewetting effect between the glass substrate and PS chains covered MWNTs during the evaporation of the solution. Both the length and diameter of the nanopins increased with the solution concentration. When PS‐g‐MWNTs were compression‐molded, MWNTs were dispersed uniformly in the PS matrix and formed good networks, such as circlelike and starlike structures, because of the entanglements of hairy PS chains on MWNTs. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3869–3881, 2006     

Impact and Prevention of Voice Problems in the Teaching Profession: Embracing the Consumers'' View

Teachers are vulnerable to developing voice problems due to their specific occupational demands during teaching. Information on how the teaching profession is impacted by voice problems and what the profession perceives to be useful information for preventing voice problems is important for health care service providers. A total of 122 subjects from the teaching profession (55 practicing teachers and 67 prospective teachers) were therefore surveyed to ascertain their perception of their voice condition and the impact of voice problems on their communication, social life, personal emotions, and occupation. The results showed that the practicing teachers perceived their voice to be significantly worse than the prospective teachers. In addition, the teachers also faced significantly more difficulties in their daily communication than the prospective teachers. These two groups of subjects believed that information on breathing exercises and specific vocal hygiene strategies would help them prevent voice problems.     

The Debye-Waller factor of graphite

The Debye-Waller factor of graphite is calculated, using the model proposed by Komatsu.