China has become the fourth country that measuring of the Planck Constant independently, and achieved the breakthrough in core technologies of the quantum quality benchmark study of energy balance.

 Learned from the China Institute of Metrology, undertaking the topic of "Energy Balance Quality Quantum Benchmark Study" has passed the inspection of experts from AQSIQ on April 29th.The issues through a unique "energy balance" program, so that we get the ability of first measurement with the Planck constant and the absolute stability of kilogram baseline measurement, therefore, China becomes the fourth country that can independently measure the Planck Constant and step into the front ranks of international metrology research.

 Metrology basis is accurate or not, need the guarantee of seven base units of International System of Units.And the mass unit "kg" is the only physical quantity that rely on material standard save and recurrent.In order to settle this problem, many advanced national metrology institutes already began to do research, and they have proposed several solutions on this point.With the "Technology Support Program Key Projects ",China Metrology Science Study Institute carried out the above research.According to the introduction of Prof.Zhonghua Zhang who is the principal of the study, know of present research status, the study group proposed the scheme of "Energy Balance" originally which is different with the "Watt Balance" that widely used internationally.Through the measurement of Planck Constant, building the quality quantum benchmark.Now, the study group has firstly set the apparatus of measurement of Planck Constant that using Energy Balance,and passed the experimental confirmation.At the first stage, the related standard uncertainty of measurement of Planck Constant reaches 7.7x10-5, this is the one of the few measurement results.

 The study group gave plays to the Quantum Hall Resistance Standard world most advanced technology, overcame the core technology of energy balance scheme in mutual inductance precision measurement, solved three international problems: successfully developed a set of mutual inductance precision measurement system, traced mutual-inductance quantity to the Quantum Hall Resistance and Time Standard,mutual inductance testing system uncertainty of measurement achieved 1x10-7, superior to international minimum uncertainty: 3x10-6 ; developed a kind of sampling resistance with tiny load factor, proposed self-calibration method for load factor, this is the technology basis for the mutual-inductance trace to Quantum Hall Resistance and High Precision Steady Current Power Source; successfully developed a set of magnetic field constant current source with steady 3x10-7/30min and amplitude value 250mA.

 It's reported that this research has widely industrialization prospect and application, able to promote the accuracy of magnetic measurement instruments, electric measurement precision instruments substantially, enhance the usage value of rare earth, improve technology independent innovation level, so it has significant economic and social benefits.