电解还原制备U(Ⅳ)过程中的阳极材料腐蚀研究

用间歇电解还原法研究了在有机玻璃电解槽中阳极镀铂钛网在ＵＯ２（ＮＯ３）２－ＨＮＯ３－Ｎ２Ｈ５ＮＯ３－Ｈ２Ｏ体系中的耐腐蚀情况。研究结果表明：在无隔膜电解还原时，镀铂钛网上的Ｐｔ的腐蚀速率极低（＜２．５×１０－２μｍ／ａ），而在以阳离子交换膜作隔膜的电解还原中，镀铂钛网上的Ｐｔ有明显的腐蚀，其腐蚀速率为５．７μｍ／ａ。对这两种情况下Ｐｔ的腐蚀速率明显差别的原因进行了分析讨论。     

放射性核素~（137）Cs在石湖峪和阳坊花岗岩上的吸附与迁移特性的研究

用间歇法测定了１３７Ｃｓ在石湖峪和阳坊花岗岩上的吸附比和吸附平衡时间，研究了岩石颗粒度、固液比、水相ｐＨ值和核素载体浓度对吸附比的影响，测定了吸附等温线．用柱实验法研究了１３７Ｃｓ在石湖峪和阳坊碎石柱上的迁移行为，测定了阻滞因数和柱分配系数．结果表明：北京石湖峪和阳坊花岗岩对１３７Ｃｓ的吸附能力较差．     

Bug Attacks

In this paper we present a new kind of cryptanalytic attack which utilizes bugs in the hardware implementation of computer instructions. The best-known example of such a bug is the Intel division bug, which resulted in slightly inaccurate results for extremely rare inputs. Whereas in most applications such bugs can be viewed as a minor nuisance, we show that in the case of RSA (even when protected by OAEP), Pohlig–Hellman and ElGamal encryption such bugs can be a security disaster: decrypting ciphertexts on any computer which multiplies even one pair of numbers incorrectly can lead to full leakage of the secret key, sometimes with a single well-chosen ciphertext. As shown by recent revelation of top secret NSA documents by Edward Snowden, intentional hardware modifications is a method that was used by the USA to weaken the security of commercial equipment sent to targeted organizations.     

Slow-Release of Curcumin Induced by Core–Shell Mesoporous Silica Nanoparticles (MSNs) Modified MIL-100(Fe) Composite

As a biocompatible porous material, bio-MOF is a very promising material as a carrier for hydrophobic drugs, including curcumin. However, the stability of bio-MOF against water and humidity still needs to be improved; therefore, surface modifications are required. This study aims to modify the MIL-100(Fe)-based bio-MOF through core–shell architecture by employing mesoporous silica nanoparticles (MSNs or SiO₂) for improving the stability and performance of MIL-100(Fe) to provide a slow-release feature of curcumin. The composites were synthesized via sonochemistry-assisted or mechanochemistry-assisted green protocol to form core–shell structure of MIL-100(Fe)@SiO₂ (Composite-1) or SiO₂@MIL-100(Fe) (Composite-2). Structural, textural, and morphological analyses, including XRD, FTIR, SEM, TEM, and N₂ adsorption–desorption, are discussed in this study to evaluate the composite formation. BET surface area of the MIL-100(Fe) decreased from 1197.45 m²/g to 565.63 and 823.70 m²/g after forming composite-1 and composite-2 with SiO₂. The loading capacity, however, just increased slightly up to 97.89% after the modification. The presence of SiO₂ as shell (composite-1) protects the MIL-100(Fe) from degradation under the acidic condition at pH 5.8 and can maintain the slow-release of curcumin. In contrast, the presence of SiO₂ as core (composite-2) induces the sustained release due to faster degradation of MIL-100(Fe) in acidic condition. Both composites serve as a model for either sustained release or delayed release drug delivery systems.

     

Numerical investigation of the de-agglomeration mechanisms of fine powders on mechanical impaction

This paper numerically investigated the mechanisms of powder de-agglomeration on mechanical impaction, aiming to explain the experimental observations in our previous study (Adi et al., 2010). A numerical model based on a coupled computational fluid dynamics (CFD) and discrete element method (DEM) approach was developed to simulate the dispersion of drug mannitol agglomerates in the customised impaction throats containing one or two angles with different flow rates. Information in terms of particle-throat and particle-fluid interactions, number of fragments, fine particle fraction (FPF) and powder deposition was monitored over the whole process and quantitatively analysed. The results indicated that the breakage of the agglomerate was mainly attributed to the mechanical impaction and less affected by the shear effect from the flow-particle interaction. While the first impaction caused the major damage to the agglomerate, the second impaction in fact generated more fine particles with size less than 5 μm, resulting much improved dispersion performance for the throats with two angles. Powder deposition, which is dependent on impaction velocity and angle and fragment size, was another important factor affecting the dispersion. The analysis of dispersion mechanisms indicated that de-agglomeration at different conditions can be characterised by the ratio of the particle-wall impaction energy and agglomerate strength.     

The convergence of functions to fixedpoints of recursive definitions

The classical method for constructing the least fixedpoint of a recursive definition is to generate a sequence of functions whose initial element is the totally undefined function and which converges to the desired least fixedpoint. This method, due to Kleene, cannot be generalized to allow the construction of other fixedpoints. In this paper we present an alternate definition of convergence and a new fixedpoint access method of generating sequences of functions for a given recursive definition. The initial function of the sequence can be an arbitrary function, and the sequence will always converge to a fixedpoint that is “close” to the initial function. This defines a monotonic mapping from the set of partial functions onto the set of all fixedpoints of the given recursive definition.     

Mitigation of carbon dioxide from Indonesia's energy system

In Indonesia, energy consumption (excluding non-commercial energy) increased from 328 MBOE in 1990 to 478 MBOE in 1995. As a consequence, energy sector CO₂ emissions increased from 150 million tons to over 200 million tons during the same period. The present rapid economic growth Indonesia is experiencing (7–8%) will continue in the future. Based on a BAU scenario, primary energy supply for the year 2020 will be 18,551 PJ, an increase of 5.9% annually from 1990 CO₂ from the energy system will increase from 150 Teragrams in 1990 to 1264 Teragram in 2020. The mitigation scenario would reduce total CO₂ emissions from the BAU scenario by 10% for the year 2000 and 20% by 2020. Some demand side management and energy conservation programs are already included in the BAU scenario. In the mitigation scenario, these programs are expanded, leading to lower final energy demand in the industrial and residential sectors.

Indonesia's total primary energy supply in 2020 is approximately 5% lower for the mitigation scenario than for the BAU scenario. In the BAU scenario, coal and oil have the same contribution (25%). In the mitigation scenario, natural gas and nonfossil fuels such as hydropower, geothermal, and nuclear have higher contributions.